Additional Articles

Wideband 3-D Printed All-Metal Reflectarray With Notches for Low-Cost Millimeter-Wave Applications
17 January 2023Xiaowei Cao, Changjiang Deng, Yinan Hao and Youjia Yin present a 3-D printed all-metal reflectarray for millimeter-wave applications. The array has sub-wavelength element spacing, so that the elements are non-resonant. A two-stage notch is etched at the top of the element, which provides multiple degrees of freedom for phase tuning. The measured 1-dB gain bandwidth achieves 17.6%, ranging from 31 GHz to 37 GHz. In the whole 1-dB gain bandwidth, the measured aperture efficiency is higher than 47.7%, with a peak efficiency of 53.6% at 31 GHz.
Toward Pactive (Passive +Active) Sensing for Improved Identification of Material Properties
11 January 2023Arya Menon and Thomas M. Weller investigate a technique to noninvasively extract the complex permittivity and thickness of hidden dielectrics using a pactive sensor. A proof-of-concept demonstration of an optimization-based inversion technique is used to extract the properties of an unknown, hidden layer in a multi-layered dielectric structure. The technique uses active data to estimate dielectric constant and thickness, and passive data to estimate loss tangent. The experimental setup is selected to represent a simplified single-voxel security scenario consisting of multiple dielectric layers backed by a human phantom layer (heated water).
A Miniaturized MIMO Antenna With Dual-Band for 5G Smartphone Application
09 January 2023 Zhe Chen, Yi Liu, Tao Yuan and Hang Wong design a dual-band multiple-input and multiple-output (MIMO) antenna with ceramic substrate for the miniaturized application in 5G smartphone. It is a new method which not only associated with the path extending technique but also combined with the parasitic sub method so that a 68% size miniaturization is achieved. The antenna prototype is fabricated to demonstrate the proposed method.
Design of a 2-Bit Reconfigurable UWB Planar Antenna Array for Beam Scanning Application
06 January 2023 Zuqi Fang, Hanqing Yang, Yuan Gao, Feng Zhai, Jun Wei Wu, Qiang Cheng and Tie Jun Cui present a linearly polarized 2-bit ultra-wideband (UWB) antenna array in C-band. The antenna array consists of 16 Vivaldi elements, 16 wideband phase shifters and a feeding network. The structural symmetry is employed to provide a couple of opposite phase states in the broad bandwidth. The measured results show that the antenna array can operate well in a broad bandwidth from 4.0 to 5.5 GHz (the relative bandwidth ~31.5%) with reflection loss lower than −10 dB.
New Self-Isolated Wideband MIMO Antenna System for 5G mm-Wave Applications Using Slot Characteristics
05 January 2023 Oludayo Sokunbi, Hussein Attia, Abubakar Hamza, Atif Shamim, Yiyang Yu and Ahmed A. Kishk propose a simple novel technique for self-isolating a MIMO antenna for mm-wave applications. MIMO antenna elements with inter-element separation of 0.2 mm ( 0.023λ at 35 GHz) and measured high isolation (>50 dB) are presented. By observing the concentration of surface waves on the radiating patch, several rigorously optimized slots of different shapes, positions, and dimensions are etched on the patch to enhance the inter-element isolation and increase the bandwidth within 28-37.5 GHz.
Wideband MIMO Antennas for 5G Mobile Terminals
04 January 2023 Hanyang Wang and Pengfei Wu propose an approach of using the concept of CM (common mode) and DM (differential mode) to design two wideband antennas in a pair.The two antennas in the antenna pair have wide bandwidth and high isolation, though they share the same radiator and total electric length of the antenna pair is just a half wavelength. A rigorous analysis has been presented to explain and illustrate the operating principle of the wideband antenna pair.
Spectrum-Aware Compact Reconfigurable UHF Antenna for Interweave Cognitive Radio
30 December 2022F. A. Asadallah, H. Abdul Khalek, B. Abou Ali Modad, J. Aboul Hosn, J. Costantine, R. Kanj and Y. Tawk present a compact ultra-high frequency (UHF) folded antenna design that relies on a single radio frequency micro-electro-mechanical switch (RF-MEMS) to reconfigure its frequency of operation between 575 MHz and 760 MHz. The antenna is fabricated and tested where the measurements agree well with the simulation results. The antenna exhibits a radiation efficiency of 40% at 575 MHz and 62% at 760 MHz.
Wideband Substrate Integrated Cavity-Backed Dielectric Resonator Antenna at Sub-6-GHz Band
December 26 2022Reza Shamsaee Malfajani, Jean-Jacques Laurin and Mohammad S. Sharawi present the design and implementation of a wideband single-mode dielectric resonator antenna (DRA) with a substrate integrated cavity-backed structure. Two short-circuited striplines with differential feeding are placed inside the substrate integrated cavity (SIC) for pure mode excitation of the DRA, providing stable radiation characteristics, and low cross polarization levels.
Surface Electromagnetic Waves at Seawater-Air and Seawater-Seafloor Interfaces
December 26 2022Igor I. Smolyaninov, Quirino Balzano and Alexander B. Kozyrev present a detailed analytical and numerical consideration of TE and TM polarized surface electromagnetic wave properties. The resulting surface waves have propagation constants that permit communication ranges far longer than those of bulk propagation in the lossy media. They demonstrate theoretically and experimentally their ability to carry broadband radio signals over practical communication distances underwater.
An Innovative Method to Treat Very Small Apertures in Ray-Tracing Simulations
December 15 2022Andrea Sacchetti and Matthias Oscity address a specific type of configurations where typical ray-tracing simulations can fail to produce meaningful results, namely when the light intensity transmitted by a very small aperture needs to be determined. They lay down the mathematical formalism behind the method and present it also in the form of a simple, generalizable algorithm. An experimental test that confirms the validity of the proposal across a range of aperture sizes are also provided.
mmWave Yagi-Uda Element and Array on Liquid Crystal Polymer for 5G
December 13 2022Rajveer S. Brar and Rodney G. Vaughan present a Yagi-Uda structure on PCB with a bandwidth from 22 to 44 GHz to cover a set of standard mmWave bands for 5G. Their prototype uses the RFIC packaging material Liquid Crystal Polymer which is suitable for Antenna-in-Package technology. The associated improvements in the impedance bandwidth, scan range, gain and radiation efficiency are presented for edge- and corner-mounted arrays designed for a mobile terminal such as a cellphone.
Efficiency-Driven Design for Planar Antennas With Lossy Materials
December 9 2022Purna B. Samal, Shengjian J. Chen, Tran T. Tung, Dusan Losic and Christophe Fumeaux demonstrates a design strategy for improving the radiation efficiency of a planar antenna made of a layered conductor of MXene with modest conductivity on a lossy PDMS substrate. They also proposed new methods to reduce the conductor loss and the dielectric loss. The optimized antenna exhibits a high radiation efficiency of 71% and offers a wide impedance bandwidth of 56% covering operation for the 5 GHz WLAN band.
Low Profile GRIN Lenses With Integrated Matching Using 3-D Printed Ceramic
December 8 2022Yongduk Oh, Neal Kordsmeier, Hussain Askari and Jacob J. Adams investigate a shortened horn antenna with high gain that is enabled by a 3D-printed gradient index (GRIN) lens composed of high permittivity zirconia. The baseline H-plane sectoral horn antenna is designed with length that is 1/3 of the optimal horn antenna and exhibits a low gain due to the high flaring rate of the horn. Increased gain is achieved by adding a flat GRIN lens at the horn aperture.
Dual-Polarized 6–18-GHz Antenna Array With Low-Profile Inverted BoR Elements
December 8 2022Matti Kuosmanen, Sten E. Gunnarsson, Johan Malmström, Jari Holopainen, Juha Ala-Laurinaho and Ville Viikari investigates a dielectric-loaded Vivaldi-type antenna array that is formed inside a plastic block. It utilizes the inverted body-of-revolution (BoR) structure, where cone-shaped cavities are formed in a dielectric material and metalized from the inside.
Optimum Antenna Characteristics for Maximally Harvesting Ambient RF Energy
December 2 2022Constant M. A. Niamien investigates the best antenna characteristics to harvest ambient RF waves maximally. The proposed approach analyzes and compares key design aspects, including multi-polarization, multi-port, multi-band, omnidirectional, quasi-isotropic, and non-quasi-isotropic pattern options, over the same antenna size defined by the enclosing sphere radius.
An Ambient RF Powered Wireless Sensor System
November 28 2022Ming-Tai Chiu, Chi-Yuk Chiu, Charles Ng, Lap-On Wong, Shanpu Shen and Ross Murch develop an ambient radio frequency (RF) powered Internet of Things (IoT) wireless sensor system that integrates all major components including multiple antennas, rectifiers, a power management unit (PMU), a microcontroller unit (MCU) with RF transceiver module and sensing unit. A prototype demonstrates that it is possible to sense temperature, pressure and humidity and wirelessly transmit these signals to a central server with a duty cycle of approximately 15 minutes, when the background ambient RF signals are as low as −28.6 dBm at 950 MHz.
A Low-Cost Millimeter-Wave 5G V2X Multi-Beam Dual-Polarized Windshield Antenna
November 25 2022Abdelhamid M. H. Nasr and Kamal Sarabandi present a design procedure and experimental validation for a millimeter-wave (MMW) vehicular antenna with simultaneous multi-beam for 5G V2X application. The design overcomes the constraint for requiring both wide angular coverage and high gain through a compact multi-array design. It is a cost-effective technique compared to employing phase shifters and beam steering of a single array and avoids latency associated with beam steering.
Demonstration of Quantitative Microwave Imaging Using an Ideal Veselago Lens
November 16 2022Marzieh Eini Keleshteri, Vladimir I. Okhmatovski, Ian Jeffrey, Martina Teresa Bevacqua, Tommaso Isernia and Joe LoVetri demonstrate quantitative microwave imaging that employs an ideal Veselago lens using synthetic 2D experiments. Reconstructions of the complex-valued dielectric constant of an arbitrary object-of-interest are obtained from noiseless data using a non-iterative technique. A closed-form Veselago lens Green’s function is utilized in the formulation of the problem.
A Curved 3D-Printed S-Band Patch Antenna for Plastic CubeSat
November 16 2022Giacomo Muntoni, Giorgio Montisci, Andrea Melis, Martina Teresa Bevacqua, Matteo Bruno Lodi, Nicola Curreli, Marco Simone, Giacomo Tedeschi, Alessandro Fanti, Tonino Pisanu, Ilka Kriegel, Athanassia Athanassiou and Giuseppe Mazzarella propose a 3D printed ABS antenna easily embeddable in a plastic CubeSat for a suitable and cost-effective communication sub-systems. The 3D-printed material has been characterized in terms of dielectric, mechanical and thermal properties, and the compliance with space requirements has been assessed.
Compact and Planar End-Fire Antenna for PicoSat and CubeSat Platforms to Support Deployable Systems
November 8 2022Victoria Gómez-Guillamón Buendía, Symon K. Podilchak, Salvatore Liberto, Tom Walkinshaw, Constantin Constantinides, Dimitris E. Anagnostou, George Goussetis and Maarten Van Der Vorst propose a miniaturized planar Yagi-Uda antenna for integration with PicoSats or other SmallSat missions. Miniaturization techniques, such as meandering and 1-D artificial dielectric concepts to reduce the guided wavelength, are employed to overcome space constraints imposed by the SmallSat footprint while still maintaining good performance for the FR-4 antenna.
A Compact, Band-Notched Ultra-Wideband Fully-Recessed Antenna With Pattern Diversity for V2X Communications
November 9 2022 Ke Zhang, Zhi Hao Jiang, Wen Long Zhou, Peng Peng and Wei Hong propose and demonstrate a compact, band-notched ultra-wideband (UWB) fully-recessed antenna with pattern diversity for vehicle-to-X communications. The antenna is composed of a multi-port central radiator fully embedded inside a bowl-shaped ground structure with a flush top. The multi-port central radiator consists of a top circular plate, four split-quarter conical monopoles, four vertically- and horizontally-orientated strips, a central metallic cylinder, and a bottom cylinder.
Unmanned Aerial Vehicles Swarm-Based Distributed Phased Arrays for Grating Lobe Mitigation and Collision Avoidance
November 8 2022 Junming Diao proposes a novel 3-D aperiodic array design that adds an additional degree of freedom in the optimization of array configuration. The design largely reduces the sidelobe levels from the planar periodic arrays and decreases the collision risk for UAVs represented by the minimum separation distance between array elements. This work provides a feasible strategy for the design and optimization of the UAV swarm-based phased arrays for practical applications.
Full Lumped Element-Based Equivalent Circuit Model for Connected Slot Antenna Arrays
November 3 2022 Md Rasheduzzaman Al-Amin, Chao Li and Mohammad S. Sharawi propose a full lumped element-based equivalent circuit model for connected slot antenna arrays (CSAA). Three configurations, infinite, semi-infinite, and finite slots, of the CSAA being considered. A 2x2 CSAA prototype was fabricated at 3GHz to validate the proposed equivalent circuit model. It had a maximum of 4.55% and 5.27% average errors for the real and imaginary parts of the impedances, as compared with the full-wave simulator, while the computational time was reduced by more than two orders of magnitude.
High-Temperature Additively Manufactured C-Band Antennas Using Material Jetting of Zirconia and Micro-Dispending of Platinum Paste
November 2 2022 Carlos R. Mejias-Morillo, Jayaprakash B. Shivakumar, Seng Loong Yu, Blake Roberts, Pedro Cortes, Eric MacDonald, Anton V. Polotai and Eduardo A. Rojas-Nastrucci report the electromagnetic properties of 3D-printed Yttria-Stabilized Zirconia (YSZ) for 2–6 GHz and the DC and RF effective conductivity of sintered platinum ink, where the dissipative losses of the additively manufactured coplanar waveguides (CPWs) are less than 0.05 dB/mm when the frequency is below 4 GHz. A two-layer back-fed antenna based on 3D-printed YSZ and platinum ink is designed, manufactured, and tested. Results show a measured gain of 2.5 dBi and a front-back ratio of 9.6 dB at 4.1 GHz.
Influence of the Mesh Size on the Computation of the Close Near Fields of Dipole Antennas
October 26 2022 Alessandra Paffi, Eduardo Carrasco and Quirino Balzano develop an asymptotic expansion method for the near fields at the surface of dipole antennas and compare it to the computed fields. The results show that the software of the computed field should not use a uniform mesh. The mesh should be much tighter at the metal extremities than in the dipole body. The proposed technique can be used to check complex field computations, producing diverging values, with simple analytical equations.
A Lossy Transmission Line Model for the Scan Impedance of the Infinite Dipole Array
October 26 2022 Eric D. Robinson and Carey M. Rappaport present an analytical formulation of the infinite dipole array scan impedance. It introduces a lossy transmission line analogue which simultaneously models the Floquet modal impedances as well as the reactive properties of the dipole’s physical geometry. A scan dependent line inductance is implemented, resulting in accurate impedance predictions at extreme scan angles. Calculated impedances are compared to full-wave electromagnetic models, demonstrating high accuracy predictions from broadside to near 90° in each scan plane.
Implementation of Magnetoelectric Dipoles in Metasurfaces for 5G Applications
October 26 2022 Xuexuan Ruan, Kai Wang and Qinyu Zhang implement magnetoelectric dipole (ME-dipoles) in metasurfaces. The unit cell of an ME-dipole metasurface consists of a cross slot etched on the middle metal layer and an ME-dipole loaded on each side of the middle metal layer. The unit cell of an ME-dipole metasurface is designed based on the antenna theory, i.e., one ME-dipole works as a receiving antenna while the other ME-dipole works as a transmitting antenna. Three ME-dipole metasurfaces, including a frequency selective surface (FSS), a polarizer, and a transmitarray, are presented to show the potential of the proposed metasurface design method.
Impact of Amplitude and Phase Imbalance on Dual Differential Fed Patch Antenna With High Isolation
October 19 2022 Wenyu Zhou, Shakeeb Abdullah, Jorden Labossiere, Nima Javanbakht, Jafar Shaker, Gaozhi Xiao and Rony E. Amaya analyzed the impact of amplitude and phase imbalance on a proposed dual differential fed patch antenna in the context of system effective reflection coefficient and axial ratio (AR). A single square patch with four ports is used as a solo radiating element and provides absolute symmetry at radiating. An in-depth analysis will be presented to understand the impact of external RF chain components on the performance of the proposed antenna.
Broadband D-Band Patch Antenna Array in Wafer-Level Package Based on BCB Process
October 14 2022 Xiaocheng Wang, Gaobiao Xiao, Lixue Yang, Hao Li and Qihao Xu presented a broadband stacked patch antenna array in wafer-level package based on benzocyclobutene (BCB) process for D-band wireless communications. The BCB material is not only used as a substrate for the antenna, but also as an interconnection layer, enabling low-loss interconnection with RFICs through vias and transmission lines.
Phase-Encoded Linear Sampling Method Imaging of Conducting Surfaces From Full and Limited Synthetic Apertures
October 14 2022 Matthew J. Burfeindt and Hatim F. Alqadah presented a new LSM formulation for imaging conducting targets from a more limited sensor distribution. The technique mitigates the challenge of limited multistatic diversity by disciplining the solution via a propagation-based phase encoding. Simulated and experimental data were demonstrated and the proposed technique produces images of fundamentally greater fidelity compared to conventional LSM processing.
A Mechanically Rollable Reflectarray With Beam-Scanning Capabilities
October 12 2022 Antonio J. Rubio, Abdul-Sattar Kaddour and Stavros V. Georgakopoulos proposed a novel 1-D beam-steerable reflectarray antenna (RA) for the Ku -band. The RA aperture consists of 24×48 variable size square patch elements printed on a flexible plastic substrate. The aperture is wrapped around two cylinders to create a 12λ×12λ illumination window at the operating frequency of 14 GHz. Beam-steering is achieved by mechanically rolling the aperture. The design is able to steer its high gain beam without using complicated feed networks or complex mechanical systems and is relevant in SmallSat and space applications.
Packable and Readily Deployable Tightly Coupled Dipole Array (TCDA) With Integrated Planar Balun
October 12 2022 Md Rakibul Islam, Maxence Carvalho, Satheesh Bojja Venkatakrishnan and John L. Volakis presented a novel, foldable, dual-polarized Tightly Coupled Dipole Array (TCDA) to overcome the limited payload dedicated to onboard antennas for CubeSat/SmallSat applications. This array integrates a planar microstrip balun feed to enable foldability and attains 5.4:1 (0.6-3.20 GHz) impedance bandwidth with VSWR < 3 at broadside and scans down to 45° at all azimuth planes. This prototype achieves 80% one-dimensional size reduction, yielding 60% overall volume reduction.
Variable Inclination Continuous Transverse Stub Array-Based Beam Steering Antenna System for Vehicle-to-Satellite Communication
October 10 2022 S. Y. Liu, C. F. Zhou, J. Liu, J. H. Fu, Q. Wu and X. M. Ding designed a Ku-band variable inclination continuous transverse stub (VICTS) antenna system for vehicle-to-satellite communication with high gain and low sidelobe level (SLL). Taylor distribution is used to determine the radiation power for each slot by extracting the admittance of each slot to achieve a low SLL. The antenna system is prototyped and measured. Results show that within 13.75-14.5 GHz, the voltage standing wave ratio (VSWR) is below 1.4. A large beam scanning range of 7° ~ 64° or −7° − −64° in elevation and 360. in azimuth is achieved, with a maximum gain of 32.1 dBi.
Theory and Analysis of the Loop Antenna and Ω-Shaped Loop-Dipole Antenna
October 03 2022 Yulin Fang and Yue Ping Zhang examine and correct Storer’s theory of circular loop antennas, and then investigate theoretically the proposed Ω -shaped loop-dipole antenna. A theoretical model is proposed to analyze the radiation fields, directivity, and input impedance of the proposed Ω -shaped loop-dipole antenna based on the loop and dipole antennas’ theories.
Low-SAR Back Cover Mobile Antenna
September 26 2022 Harri Varheenmaa, Anu Lehtovuori, Pasi Ylä-Oijala and Ville Viikari introduce a novel antenna design with a low specific absorption rate (SAR) to be placed on the back cover of a mobile device at around 2 GHz. It provides relatively good efficiency, considering the extremely low profile, and the close proximity of lossy human tissue and the phone’s main body. The manufactured prototype exhibits almost 50% lower maximum SAR than a patch antenna used as a reference.
Electromagnetic Compatibility Analysis of Quadcopter UAVs Using the Equivalent Circuit Approach
September 15 2022 Mohamed Z. M. Hamdalla, Anthony N. Caruso and Ahmed M. Hassan study RF coupling to a quadcopter UAV in a computationally efficient manner using the Equivalent Circuit Approach (ECA) that is based on modeling the direct coupling to the wiring system with a Thevenin equivalent circuit terminated with the load under test. Different circuit representations for this Thevenin equivalent circuit are studied and the advantages of each representation are shown. The ECA provides physical insight that can facilitate the prediction of RF coupling to a UAV and other complex systems.
A Liquid-Metal-Based Crossed-Slot Antenna With Polarization and Continuous-Frequency Reconfiguration
September 15 2022 Yi Zhou, Ge Zhao, Xiao Yu Li and Mei Song Tong propose a novel reconfigurable antenna that can achieve four polarizations and continuously-tunable frequency to overcome the limitations of traditional reconfigurable antennas. The antenna is based on liquid metal and the pattern of the slots can be controlled by changing the amount of the liquid metal inserted into the 3-D printed channels. It can work under four polarization modes: left-hand circular polarization (LHCP), right-hand circular polarization (RHCP), and two orthogonal linear polarization (LP) modes.
Flexible Transparent Antennas: Advancements, Challenges, and Prospects
September 15 2022 Abu Sadat Md. Sayem, Ali Lalbakhsh, Karu P. Esselle, John L. Buckley, Brendan O’Flynn and Roy B. V. B. Simorangkir discuss the current advancements in the development of flexible transparent antennas, including potential applications, various enabling materials and manufacturing approaches, technical hurdles, as well as prospects. Challenges impeding the development of flexible-transparent electronics are also discussed, such as the contradictory relationship between the electrical conductivity and optical transparency of the transparent conductors, costly and complex processing of the transparent materials and unavailability of the appropriate materials.
Wide-Angle Beam-Steering and Adaptive Impedance Matching With Reconfigurable Nonlocal Leaky-Wave Antenna
September 07 2022 Gengyu Xu, George V. Eleftheriades and Sean Victor Hum present a simple reconfigurable leaky-wave antenna (LWA) capable of fixed-frequency continuous beam-scanning, along with an efficient optimization procedure with which its radiation pattern can be shaped. These features of the proposed LWA are confirmed through numerical simulations. Measurements of a fabricated prototype working at 10 GHz demonstrated a 130° continuous scan range, and a peak gain of 8.9 dBi.
A Compact 4×4 Filtering Microstrip Patch Antenna Array With Dolph-Chebyshev Power Distribution
September 06 2022 Wei Nie, Huai-Zhi Wen, Kai-Da Xu, Yu-Quan Luo, Xiao-Long Yang and Mu Zhou propose a compact 4×4 filtering microstrip patch antenna array with Dolph- Chebyshev distribution implemented by a multilayer structure. It features good filtering performance, but contains no extra filtering parts in the feeding or radiating element. The designed array is implemented, fabricated and measured. The maximum measured gain in the passband is 14.7 dBi, and the radiation suppression outside the passband is better than 25 dB.
A Monolayer Dually Polarized High-Order Space Harmonic Leaky-Wave SIW Antennas With Fixed and Scanning Beam Capability
September 06 2022 Mohammad Reza Rahimi, Mohammad S. Sharawi and Ke Wu investigate the concept of high-order space harmonics (HSHs) applied to a hybrid form of nonradiative dielectric (NRD) waveguide and substrate-integrated square waveguide (SIW) involving both TE10 and TE01 modes with the aim to develop multi-functional dually polarized leaky-wave antennas (DP-LWAs). Two DP-LWA prototypes are demonstrated as proofs of concept, and the obtained experimental results show a very good agreement with their simulation and analysis counterparts.
Mutual Decoupling for Massive MIMO Antenna Arrays by Using Triple-Layer Meta-Surface
August 31 2022 Shengyuan Luo, Yiming Zhang , Gert Frolund Pedersen and Shuai Zhang introduce a new decoupling method for massive MIMO arrays with an inner-element distance of around half a wavelength by using a triple-layer metasurface (TMS). An example of 4×4 dual-polarized wideband microstrip array with a TMS is proposed to verify the decoupling method. The simulation and measurement show that the TMS can help to reduce the coupling among the array elements to less than −24 dB in both the co-polarization and cross-polarization directions within 4.23-4.82 GHz.
Combined Single-Layer K-Band Transmitarray and Beamforming S-Band Antenna Array for Satcom
August 31 2022 Daniel Edelgaard Serup, Gert Frolund Pedersen and Shuai Zhang propose a shared aperture dual-band transmitarray and patch antenna for S- and K-band with beamforming capabilities. The obtained measurements show that the designed antenna achieves impedance bandwidths of 350 MHz and 3 GHz, and realized gains of 14.31 dBi and 22.64 dBi, at 4.5 GHz and 25. GHz, respectively. Additionally, the prototype antenna is shown to only have a 0.22 dB gain drop-off in a 60-degree beam scanning range. The design and unique features of the presented antenna make it interesting for many new and different use- cases and applications including satellite communication.
Bandwidth Enhancement of Millimeter-Wave Large-Scale Antenna Arrays Using X-type Full-Corporate Waveguide Feed Networks
August 31 2022 Fanqi Sun, Yujian Li, Junhong Wang, Lei Ge, Jianxin Chen and Wei Qin investigate a one-time-reflection equivalent model of the full-corporate waveguide feed networks to propose a novel approach to bandwidth enhancement of millimeter-wave large-scale antenna arrays. Excellent performance, including an improved bandwidth of about 40%, a gain of up to 27.8 dBi, and stable unidirectional radiation patterns with cross polarization of less than −32 dB, are confirmed experimentally by an 8×8 prototype.
A 5G Enabled Shared-Aperture, Dual-Band, in-Rim Antenna System for Wireless Handsets
August 29 2022 Reza Shamsaee Malfajani, Farhad Bin Ashraf and Mohammad S. Sharawi present a shared aperture (SA), dual-band in metal-rim antenna system targeting the sub-6GHz and millimeter-wave (mm-wave) bands of the 5G wireless standard. The proposed design provides more than 140 MHz of frequency bandwidth in the sub-6 GHz band, and more than 3.5 GHz of bandwidth in the 28 GHz band. Excellent efficiency, exceeding 75%, was achieved for all antennas within all bands.
Bidirectional Leaky-Wave Antenna Based on Dielectric Image Line for Remote Vital Sign Detection at mm-Wave Frequencies
August 25 2022 Solomon Mingle, Despoina Kampouridou and Alexandros Feresidis propose a bidirectional leaky wave antenna with beam scanning capabilities based on the dielectric image line for single-tone continuous-wave Doppler radar for remote vital sign monitoring in a dynamic environment. The measured and simulated results agree well, and the antennas are successfully used to detect respiration and heartbeat at radial distances between 0.5 and 1.5 metres and at angular positions between −43◦ and +27◦ to the subject’s body. The proposed design method could be particularly useful for producing low-cost, high-gain, longer-range antennas at even higher mm-wave frequencies.
A New Arraying Technique for Band-Switchable and Polarization-Reconfigurable Antenna Arrays with Wide Bandwidth
August 25 2022 Junyi Huang, Mahmoud Shirazi and Xun Gong propose a novel arraying technique for polarization-reconfigurable array applications. Each array element has one feeding port only. All three polarization states can be dynamically reconfigured by providing proper phases at each antenna port. This new arraying technique is demonstrated inside two reconfigurable wideband (4:1 frequency ratio) arrays since wide-band multifunctional antenna arrays are the future.
Indigenously Developed HD Video Transmission System for UAVs Employing a 3 × 3 MIMO Antenna System
August 16 2022 Zubair Akhter, Rana M. Bilal, Kuat Telegenov, Eric Feron and Atif Shamim propose a real-time HD video transmission system (VTS) with a multiple-input multiple-output (MIMO) antenna configuration and state-of-the-art coverage is proposed for security and inspection applications. The proposed VTS employs ultrathin, lightweight antennas that are suitable for seamless integration with a UAV’s body without any protrusion. The maximum and average data rates for various distances are reported. The proposed VTS is capable of transmitting real-time HD video up to a 3.56-km distance with a receiver sensitivity of −76 dBm. The maximum achieved data rates at a 500-m distance are ∼10 and ∼43 Mbps for operation in the 2.4- and 5.2-GHz frequency bands, respectively.
A Low Profile Planar Dual-Polarized Tightly Coupled Dipole Reflectarray With 5:1 Bandwidth
August 16, 2022 Muhammad Hamza, Constantinos L. Zekios and Stavros V. Georgakopoulos introduce a novel dual-polarized planar ultra-wideband (UWB) reflectarray with the highest ever reported frequency bandwidth of 5:1 (3 to 15 GHz). The novelty of this work is the introduction of a new design approach to implement true-time-delay lines, which enables dual-polarization in a planar reflectarray lattice. Following this implementation, the proposed reflectarray achieves an extremely low profile (0.4λhigh) in a modular unit-cell fashion, which does not require any electrical connection between the adjacent unit-cells in the horizontal plane. Due to its compact, low-cost and frequency scalable design, the proposed UWB reflectarray is an excellent candidate for sub-6GHz and sub-mmWave commercial applications.
Enabling High-Fidelity Ultra-Wideband Radio Channel Emulation: Band-Stitching and Digital Predistortion Concepts
August 11, 2022 Yilin Ji and Wei Fan revisit the conventional calibration method for the band-stitching for ultra-wideband channel emulation. To overcome its weakness at reshaping the intrinsic response of each sub-band to raised-cosine, they propose a digital pre-distortion method, which exploits the user-accessible fading channel filter in the channel emulator. The proposed method is numerically assessed with measured intrinsic responses of a commercial emulator, and the magnitude and phase variations of the stitched channel reduce by one order of magnitude in comparison to that of the conventional method.
Using an Equivalent-Circuit Model to Design Ultra-Wide Band-Stop Frequency-Selective Surface for 5G mm-Wave Applications
August 11, 2022 Deisy F. Mamedes and Jens Bornemann propose a system of two frequency-selective surfaces (FSSs) with an ultrawide band-stop response for 5G millimeter-wave applications. The analyses are based on the equivalent circuit method, which predicts the transmission characteristics for a plane wave with normal and oblique incidence, and the scattering matrix technique, which provides the result of the cascaded structure. Numerical and measured results show excellent agreement with a maximum error of 1.03%. All measured results closely follow those of simulated ones, thus validating the design approach and applications.
A Cost-Effective Tethered-UAV-Based Coherent Near-Field Antenna Measurement System
August 11, 2022 Raimund A. M. Mauermayer and Jonas Kornprobst propose a UAV-based near-field antenna measurement system for frequencies up to several GHz. The deployed components make the system very cost-effective. Still, verification measurements demonstrate its usability and the accuracy of the results for frequencies up to several GHz. from very cost-effective components. In all these aspects, the article demonstrates feasible ways of how to improve coherent tethered-UAV-based NF antenna measurements and hopefully inspires further research in this UAV application area.
A Compact Wideband Antenna With an Orthogonal Radiating Choke for Broadside Gain Enhancement
August 8, 2022 Lidong Chi, Yihong Qi, Francesco de Paulis, and Yueping Zhang propose a broadband compact antenna with an enhanced broadside gain performance in the +/− z directions. A design method of complementary gains is presented to overcome the gain reduction caused by the cancellation of reverse currents in the middle of the band of interest, where a design equation of the excited element of the antenna is given. This objective is achieved by accurately analyzing the resonant modes of the two parallel connected antennas of the excited element in order to achieve an overall wideband radiator. Both the simulated and measured results demonstrate that the proposed antenna exhibits desirable bandwidth and gain characteristics and is a promising candidate for broadband integrated wireless systems.
Wideband Corrugated Feedhorns, for Radar, Communications, Radiometry and Quasi-Optics
August 4, 2022 A wide variety of desirable antenna beam patterns can be synthesized by optimal excitation and phasing of the HE11 and HE12 modes in scalar corrugated feedhorns. However, the bandwidth of such two-mode horns is often limited by modal dispersion. Daniel J. Sung, Nina Thomsen, Stuart Macpherson, Robert I. Hunter, Samiur Rahman, Duncan A. Robertson, Richard J. Wylde, and Graham M. Smith introduce a class of low dispersion, two-mode feedhorns that can operate, in some cases, over operating bandwidths of 40-50%. They show methods to generate and phase multiple HE1n modes, to synthesize symmetric output beams at any desired frequency or gain.
Simulation and Measurement Validation of a Finite-Length Cylindrical 3D UTD Model
August 2, 2022 Ruwei Liu, Yi Gong, Sofie Pollin, and Yang Miao provide a modified 3D Uniform Theory of Diffraction (UTD) model for a finite-length cylinder, and validate the model by comparing to the simulation and the measured data. The presented finite-cylinder UTD model is adapted from the conventional infinite-cylinder model, while edge diffraction occurring at the edge of the cap of the finite cylinder is also added. This study proves the importance of the edge diffraction field for finite-cylinder UTD solutions specially when 1) the transmitter and receiver are at different heights relative to the cylinder, and 2) one is below and the other is above the height of the cylinder.
A Simple Auxiliary Model for Field Amplitude Shaping in Complex Environments, and Application to MRI Shimming
August 2, 2022 Sabrina Zumbo, Tommaso Isernia, and Martina Teresa Bevacqua address the canonical problem of designing the complex excitations feeding an array in a way to to ensure a desired field intensity distribution inside a given region of interest, while keeping it under control in some other region. They propose an auxiliary physics inspired model for the induced total field, whose off-line analysis allows a simplified approach to understand the convenient and non-convenient field interferences between canonical solutions for the induced total field, that are zero order Bessel functions. The problem at hand plays a key role in many different applications, including radio communications, wireless power transfer as well as hyperthermia treatment planning; the article focuses on radiofrequency shimming in magnetic resonance imaging.
Wideband Reflectarrays for 5G/6G: A Survey
August 02 2022Panagiotis Ioannis Theoharis, Raad Raad, Faisel Tubbal, Muhammad Usman Ali Khan and Abbas Jamalipour examine the state of the art of wideband reflectarrays for 5G/6G communication systems. Wideband reflectarrays are reviewed and categorized according to four wideband phase tuning mechanisms. The bandwidth is reviewed and compared both from a unit cell and reflectarray system perspective with emphasis on the gain-bandwidth performance. Different wideband unit cell geometries are covered and grouped by the wideband phase tuning approach. The phase tuning approaches are compared against each other, and guidelines are provided for designing reflectarrays with wide gain-bandwidth.
Limited-Information Signal De-embedding for a Grain Bin Electromagnetic Imaging System
July 29 2022De-embedding the network parameters from a Vector Network Analyzer (VNA) is essential for accurate measurements. For the specific case of electromagnetic imaging in grain bins, existing de-embedding techniques cannot be directly used. Seth Cathers, Kyle Nemez, Max Hughson, Hannah Fogel, Mohammad Asefi, Jitendra Paliwal, Joe LoVetri, Ian Jeffrey and Colin Gilmore propose an algorithm for estimating all the remaining parameters needed to perform de-embedding. Applying this technique reduces the error in the grain bin system without any additional hardware cost. As the field of electromagnetic imaging features a variety of applications, the proposed technique may find use in other imaging systems in the field, as well as contribute in reducing hardware cost so that full VNAs are not necessary.
Feasibility of Bone Fracture Detection using Microwave Imaging
July 27 2022Kesia C. Santos, Carlos A. Fernandes and Jorge R. Costa study the feasibility of Microwave Imaging (MWI) for detection of fractures in superficial bones like the tibia, using a simple and practical setup. First-responders could use it for fast preliminary diagnosis in emergency locations, where X-Rays are not available. It may prove valuable also for cases where X-ray are not recommended, e.g., length pregnant women or children. The method is based on the synthetic aperture radar technique, and is validated through a set of full-wave simulations and experiments on a multilayer phantom and on an ex-vivo animal bone. Results show that the system can detect and locate bone transverse fractures as small as 1 mm width and 13 mm deep, even when the bone is wrapped by 2 mm thick skin.
Experimental Assessment of Real-Time Brain Stroke Monitoring via a Microwave Imaging Scanner
July 21 2022 David O. Rodriguez-Duarte, Cristina Origlia, Jorge A. Tobón Vasquez, Rosa Scapaticci, Lorenzo Crocco and Francesca Vipiana present the experimental validation of a microwave imaging system for real-time monitoring of brain stroke in the post-acute stage. The system exploits a low-complexity sensing apparatus and a multi-frequency microwave imaging algorithm with a novel artifact removal feature. The results show the system’s capability to follow up the continuous progression of hemorrhage and ischemia zones with centimetric spatial resolution and to provide information on whether the stroke is growing or shrinking.
Dual-Ridge Gap Waveguide-Based Antenna With Diverse Beam Capabilities
July 12 2022Yan Shi and Hua Jie Wang propose a dual-ridge gap waveguide-based antenna to achieve multiple radiation capabilities. With the different signals fed into the two ports, the proposed antenna achieves the diverse radiation beams including beam scanning, sum-difference beam, and flat top beam. Measured and simulated results are given to demonstrate good performance including flexible radiation capabilities, stable gains, good front-to-back ratio and null depth, thus providing evidence regarding the application of the proposed antenna in the fields of wireless communications and radar targeting and ranging.
A Beam-Splitting Bianisotropic Metasurface Designed by Optimization and Machine Learning
July 12 2022 Stewart Pearson, Parinaz Naseri and Sean V. Hum present an end-to-end design methodology for Electromagnetic metasurfaces (EMMSs) which accepts far-field criteria such as beam level, side lobe level, and null location, and returns an EMMS ready to be fabricated. The required surface parameters are determined through an augmented Lagrangian-based optimization method using a homogenized model constructed with the method of moments. The unit cells are then synthesized using particle swarm optimization accelerated with surrogate models constructed with machine learning neural networks. The proposed approach is experimentally verified through the fabrication of a three-layer omega-type bianisotropic EMMS, and is expected to enable designers to systematically produce EMMSs for future applications, thus facilitating the proliferation of this powerful technology.
Design and Analysis of a Novel Wide-Angle Scanning Stub-Loaded Cavity Array Element
July 12 2022 Tobias Chaloun, Patrik Grüner and Wolfgang Menzel propose a novel design methodology to mitigate scan blindness in cavity antenna arrays without the need for any changes on the radiating structure itself. For a first proof-of-concept demonstration, a fully PCB-compliant dual-polarized cavity element is loaded by vertical stubs to manipulate the dispersion characteristics in the aperture plane. Employing the proposed design methodology, a low-cost dual-polarized 11×11 array prototype is also designed, realized, and experimentally verified.
Orientation Aware Intelligent 3D Cubic Antenna System with Automated Radiation Pattern Reconfigurability
July 12 2022Maria Bermudez Arboleda, Kirill Klionovski, Su Zhen and Atif Shamim demonstrate a novel 2.4 GHz 3D cubic antenna system, which comprises of a cube package with six microstrip patch antennas, one on each face. This antenna system is unique due to its three main characteristics: a highly shielded core for microelectronics, orientation aware automated reconfigurable radiation pattern, and quasi-isotropic radiation when specific phases are applied to each radiator. Design steps for switched beam and quasi-isotropic radiation are discussed. The design is fabricated and tested.
Forward and Inverse Scattering of Metallic Objects through Focused Bessel-shaped Fields
July 5 2022 Santi C. Pavone, Gino Sorbello and Loreto Di Donato address both forward and inverse electromagnetic scattering of metallic objects by focused Bessel-shaped incident field. After discussing the main features of this kind of field, it is shown that its focusing capabilities may offer new effective possibilities for the detection of metallic targets which are not so far extended with respect to the probing wavelength. Numerical examples are performed by means of full-wave simulations, and then inversion algorithms based on back-propagation and physical optics are exploited to show that more accurate reconstructions can be pursued using Bessel-shaped fields.
A Millimeter-Wave Planar Dual-Band Array Antenna Having Individually LHCP and RHCP Radiation Characteristics
July 5 2022Jian-Nan Wang, Zi-Jun Guo and Zhang-Cheng Hao demonstrate a planar dual-band array antenna for millimeter-wave applications, which has a left-hand circular polarization and a right-hand circular polarization for two operating bands, respectively. By using aperture-fed stacked-curls, the proposed antenna can attain broad axial ratio bandwidths in both K-and Ka-bands through a single port. Meanwhile, two stacked-curls are designed to rotate in different directions for achieving orthogonal circular polarizations in two bands, respectively. The proposed antenna can be used for developing compact satellite communication systems.
A Low-Profile Wideband Metasurface Antenna With Fan-Beam Radiation
June 29 2022 Xue Ren, Youpeng Bao, Zehai Wu, Quan-Wei Lin and Hang Wong present a design of a fan-beam metasurface antenna with a low profile and a wide operating bandwidth. They introduce a new meta unit of four-loop structure which produces high refractive index over the wide operating bandwidth. The proposed antenna shows an excellent fan-beam performance with a desirable gain of 15.5 dBi and is a promising candidate for applications in satellite communications and sensing networks.
2-D Beam Steering Performance of a Triple Mode Horn Antenna Integrated With Risley Prism and Phase Correcting Surface
June 29 2022Kaushik Debbarma, Nhat Truong, Satish Kumar Sharma and Jia-Chi Samuel Chieh present a passive 2-D beam steering solution comprising of a triple-mode circular waveguide horn antenna operating at Ka-band frequency of 30 GHz, a pair of identical dielectric lenses employing Risley prism and a parabolic phase correcting surface. The proposed antenna is suitable for application in tracking which includes steering of both sum and difference patterns. Measured scan angle coverage for the dominant mode and the higher order modes are found to be better than ±40° and ±30°, respectively.
Compact Dual Band Feed System for a Multifrequency Atmospheric Radar
June 29 2022 Srinivas Nagaraja, Paolo Focardi, Raquel Rodriguez Monje and Richard Cofield present the design, simulations and measurement results of a dual frequency feed horn operating at 35.75 GHz (Ka-band) and 94.05 GHz (W-band). The horn is designed to be used as a feed for a multifrequency atmospheric radar. The measured radiation patterns are symmetric in both azimuth and elevation and have side lobes and cross polarization levels below 20 dB from the peak. The measured results validate the design approach as a feasible solution for the design of compact multifrequency feed horns for upcoming multifrequency radar instruments.
A Review of Magnetic Field Emissions from the Human Body: Sources, Sensors, and Uses
June 28 2022 Keren Zhu and Asimina Kiourti review the state-of-the-art technology in bio-magnetic field sensing, including both sensors and shielding techniques. Merits and limits of these approaches are presented in a critical manner. They also discuss the sources and clinical value of magnetomyography, magnetocardiography, magnetoencephalography, and magnetoneurography as well as provide example technologies used to capture these signals. This is the first paper that reviews bio-magnetic field sensing and related technologies. The paper aims at familiarizing readers with the state-of-the-art and inspire new technology development and clinical uses in this area.
A Pattern-Reversal Wideband Antenna Integrating Metal Rings, Diodes-Loaded Stubs and Defective Ground
June 22 2022Yu Liu, Li-An Bian, Kai-Da Xu, Kaicheng Huang, Yaokun Wang, Yanxiu Li and Shu Xie propose a pattern-reversal wideband microstrip antenna that is composed of a radiation patch with attached rectangular metal rings connected by a microstrip line on the upper layer and a four-defects ground plane connecting two PIN- diodes-loaded L-shaped stubs on the bottom layer. The designed antenna has much advantages, such as low cost, wider band, compact and simple structure along with explicit application scenarios.
A Generalized Flat-Topped Beam Synthesis Approach for Uniform Linear Array With Arbitrary Beam Directions
June 21 2022Xingyi He, Yan Zhang, Zhi Hao Jiang and Wei Hong propose a systematic approach to synthesize the flat-topped beam (FTB) with arbitrary beam directions for uniform linear arrays (ULAs). Based on the correspondence between the far-field pattern of ULAs and the response function of finite impulse response (FIR) filters, both the broadside and end-fire FTBs can be synthesized using window method, whereas the oblique FTB synthesis is failed due to the appearance of grating lobes. A linear phase method (LPM) is proposed to apply progressive excitation phases to each individual array element, which can eliminate the grating lobes by manipulating the two conjugate beams to overlap with each other. The proposed approach is promising for offering efficient beamforming functionalities for wireless communications, imaging, and radar applications.
A Compact Slot-Loaded Antipodal Vivaldi Antenna for a Microwave Imaging System to Monitor Liver Microwave Thermal Ablation
June 16 2022 Mengchu Wang, Lorenzo Crocco, Sandra Costanzo, Rosa Scapaticci and Marta Cavagnaro present the design and the experimental validation of a slot-loaded antipodal Vivaldi antenna. The intended use is in an array configuration for monitoring liver microwave thermal ablation by way of microwave imaging (MWI). To optimize electromagnetic power transfer to the human abdomen, the antenna was designed to operate in a coupling medium. The proposed antenna shows the most compact aperture dimension, as compared with other antennas designed for biomedical applications, working within the same bandwidth.
Toward the Optimal Antenna-Based Wireless Sensing Strategy: An Ice Sensing Case Study
June 14 2022 Mahmoud Wagih and Junjie Shi develop a systematic methodology for designing an antenna-based sensor, applicable to measurands inducing a dielectric change in the near-field of the antenna. The proposed methodology is applied to designing printable antennas as highly-sensitive sensors for detecting and measuring the thickness of ice, demonstrating best-in-class sensory response compared to more complex antenna designs. Antenna design is investigated systematically for wireless interrogation in the 2.4 GHz band, where it is found that a loop antenna outperforms a dipole owing to its more distributed capacitance. The developed loop antenna sensor exhibits resilience to interference and applicability to different real-world deployment environments, demonstrated through over 80% average ice thickness measurement accuracy and at least 5 dB real-time sensitivity to ice deposition.
Detection of Failures in Antenna Arrays Through a Lebesgue-Space Approach
June 8 2022 Valentina Schenone, Alessandro Fedeli, Claudio Estatico, Matteo Pastorino and Andrea Randazzo present a novel antenna array diagnostic approach. The failures in antenna arrays are detected by means of a non-Hilbertian Lebesgue-space Lp technique to solve the underlying inverse problem. The solution of this inverse problem enables to retrieve the distribution of faulty feed excitations of the antenna under test starting from far-field measurements. The developed approach has been numerically validated. Simulations concern planar arrays where different rates and distributions of failures have been tested. Results show good capabilities in detecting damaged regions in the analyzed scenarios.
Antenna Additively Manufactured Engineered Fingerprinting for Physical-Layer Security Enhancement for Wireless Communications
June 8 2022Physical layer security is increasingly being exploited as a technique to enhance the security of wireless communications. Well-known hardware security techniques leverage unintended manufacturing process variations or fixed unique hardware structures in the semiconductors for identification of different copies of an RF system. Noemí Miguélez-Gómez and Eduardo A. Rojas-Nastrucci present the fundamentally different concept of engineering a unique fingerprint for each antenna produced, by leveraging additive manufacturing. This is the first application of the concept of RF fingerprint engineering using additively manufactured antennas for hardware-based security mechanisms.
Directionally Resolved Measurement and Modeling of THz Band Propagation Channels
June 8 2022 Jorge Gomez-Ponce, Naveed A. Abbasi, Alan E. Willner, Charlie J. Zhang and Andreas F. Molisch present investigations of the channel characteristics in various scenarios at 145 GHz, which is the band currently envisioned for the first round of deployments. In particular, they review several extensive measurement campaigns performed by the University of Southern California in both outdoor and indoor environments. They present the measurement and evaluation methodology and sample results that illustrate the dominant propagation effects in different environments, and also summarize the parameters of the statistical channel models for path loss, delay dispersion, and angular dispersion.
Multi-Objective Fitness Functions with Non-Linear Switching for Antenna Optimizations
May 30 2022 Md Rayhan Khan, Constantinos L. Zekios, Shubhendu Bhardwaj and Stavros V. Georgakopoulos introduce a new class of multi-objective functions with non-linearity and switching behavior, and also provide a method for objective function engineering. Notably, the proposed objective functions introduce versatile forms of fitness growth during the optimization, and provide a systematic approach for integrating the expertise in antenna design with the optimization process. The proposed optimization processes are applied in antenna optimization to demonstrate their enhanced performance.
Spatial Domain Indirect Holography for a Full Phaseless Approach to Biomedical Microwave Imaging
May 19 2022 Sandra Costanzo, Giuseppe Lopez and Giuseppe Di Massa present a full phaseless two-step strategy for microwave imaging applications, where the phase of the incident field is retrieved by exploiting a spatial domain indirect holography technique, applied to the acquisition points only. The retrieved complex incident field can be used for the reconstruction of the incident field inside the domain of interest. Once performing the characterization of the incident field distribution, the proposed strategy is included in the framework of a phaseless inverse scattering problem, where intensity-only data of the total field are involved.
A Programmable Reconfigurable Two-Port Half-Loop Antenna Concept for mmWave Wireless Applications
May 12 2022 Bumhyun Kim, Junho Park, Dongkwon Choi, Dongseop Lee, Shao Yong Zheng, Sumin Yun, Jaehoon Jo, Hosaeng Kim and Wonbin Hong propose a reconfigurable phased array architecture utilizing a two-port half-loop antenna at mmWave spectrum. The polarization, pattern, and beam steering can be freely reconfigured without any changes in the hardware by adjusting the weighting vectors of each port through software control. This is the first work demonstrating a fully reconfigurable antenna which eliminates the need of any external and lumped components and is suitable for universal mmWave wireless applications.
Large Horizontal Near-field Scanner based on a Non-tethered Unmanned Aerial Vehicle
May 9 2022 Lorenzo Ciorba, Giuseppe Virone, Fabio Paonessa, Marco Righero, Eloy De Lera Acedo, Stefania Matteoli, Edgar Colin Beltran, Pietro Bolli, Giorgio Giordanengo, Giuseppe Vecchi, Alessio Magro, Riccardo Chiello, Oscar A. Peverini and Giuseppe Addamo present a large near-field horizontal scanner that provides both magnitude and phase. Such a scanner is implemented using a non-tethered UAV to maintain flight flexibility, agility and short setup time. An inverse source Near Field Far-Field (NF-FF) transformation is applied to UAV measurements of an array with digital beamforming. The two tangential components of the electric field used as input in the NF-FF transformation are sampled on two different sets of points. The calibration of the digital beamformed array is performed on the transformed embedded element patterns.
Adaptive Beamforming with Continuous/Discrete Phase Shifters via Convex Relaxation
May 9 2022 Yinman Lee proposes various phase-only beamforming strategies, that can successfully adapt to the random interference-limited environment. Essentially, thanks to the advances in convex-optimization techniques, all the formulated problems can be solved efficiently to achieve different levels of performance and hardware complexity. Experimental results give valuable guidelines for the design and development of these phase-only adaptive beamformers and demonstrate the benefit the usage of adaptive beamformers for real-world applications.
A Novel Cross-Band Decoupled Shared-Aperture Base Station Antenna Array Unit for 5G Mobile Communications
May 6 2022 Yejun He, Wei Huang, Zhou He, Long Zhang, Xiaobing Gao and Zhi Zeng propose a novel compact, dual-polarized, dual-broadband shared-aperture antenna array unit consisting of a lower band (LB) element and 4 upper band (UB) elements underneath for 5G mobile communications. The simulated and measured results show that the antenna array unit has good impedance matching, high polarization isolation and cross-band isolation, stable radiation pattern and cross-band coupling suppression in the lower bands of 0.69 to 0.96 GHz and the upper bands of 1.7-2.7 GHz, thus the presented antenna array unit can be used as a dual-band shared-aperture base station antenna array for 5G mobile communications.
3D Printed Linearly Polarized X-Band Conical Horn Antenna and Lens
May 6 2022 Ian Goode and Carlos E. Saavedra demonstrate a low-cost method to 3D print and metalize circular waveguide components using polylactic acid and aluminum adhesive backed tape. A gradient index (GRIN) lens, an externally metalized thin-walled conical horn, and a WR90 rectangular to linearly polarized circular waveguide transition are simulated, fabricated, and measured. The horn and lens are both monolithic prints that are externally metallized to simplify the metallization process. The walls of the thin-wall horn are printed at a thickness such that the dielectric layer does not impact the performance of the horn while being robust enough to support external metallization.
Optically Transparent Antenna Arrays for the Next Generation of Mobile Networks
April 29 2022 Ryan B. Green, Kai Ding, Vitaliy Avrutin, Umit Ozgur and Erdem Topsakal report the first ever antenna array with >90% transparency that is intended for 5G networks for smart cities. This level of transparency is achieved by using Gallium-doped Zinc Oxides. The array designed and tested is for sub-6GHz 5G and operates at 5.8GHz. This seamless design allows such arrays to be integrated into windows of buildings within the smart city to provide consistent network coverage. The phased array has good gain and scanning characteristics. A discussion is also included regarding gain and beam steering capabilities in comparison to similar arrays made of conventional copper and RF substrates.
A 2.45-and 5.8-GHz Dual-Band Stacked Differential Rectenna With High Conversion Efficiency in Low Power Density Environment
April 28 2022Kento Saito, Eisuke Nishiyama and Ichihiko Toyoda propose a novel stacked dual-band differential rectenna. The proposed rectenna consists of two rectifying diodes and a dual-band array antenna with four 5.8-GHz patch antennas arrayed on a three-element 2.45-GHz array. The rectenna can easily realize large-scale rectenna arrays by simply connecting the ground conductors on the back, and is practically attractive for wireless power transfer in many IoT applications, especially in the low-power density applications.
Investigations of Heat Sink Property of a Novel Dual Linear Polarized Low Cross-Polarization X-Band Phased Array Antenna Employing Silicon RFICs-Based Beamforming Network
April 27 2022Rudraishwarya Banerjee, Satish Kumar Sharma, Jia-Chi Samuel Chieh and Raif Farkouh present a 4x2 wideband dual linear polarized phased array antenna comprised of 3D metal printed radiators, serving also as heat sink, for X-band frequency. The beamforming network (BFN) is comprised of commercial silicon Radio Frequency Integrated Circuit chips which have been integrated with the antenna aperture. The temperature reduction of 60°C is achieved with the heat sink structure when the temperature distribution of BFN with and without heat sink are compared for the 4x2 array. Good radiation patterns with low cross-polarization are obtained, while the peak broadside gain is varying between 14-11 dBi.
Antenna Design using a GAN-based Synthetic Data Generation Approach
April 27 2022 Oameed Noakoasteen, Jayakrishnan Vijayamohanan, Arjun Gupta and Christos Christodoulou propose the use of GANs as learned, data-driven knowledge database that can be queried for rapid synthesis of suitable antenna designs given a desired response. As an example, they consider the problem of designing the Log-Periodic Folded Dipole Array antenna for two non-overlapping ranges of Q-factor values. Two alternative models are developed, i.e., a Conditional Wasserstein GAN and a label-switched library of vanilla Wasserstein GANs. It is demonstrated that in inference mode, such models can be relied upon for the fast generation of suitable designs.
Unique-Solution Single-Sample Complex Dielectric Characterization through Linear Phase Approximation
April 27 2022 Constant M. A. Niamien presents a transmission-only approach that solves the long-standing problem of transmission phase ambiguity. The approach considers a linear frequency-dependent phase approximation to derive the phase mode value analytically and uniquely based on three parameters: the first phase jump frequency, the start frequency, and the start phase value. Numerical and experimental validations confirm the proposed approach for weakly and highly dispersive microstrip samples, including low-and high-loss dielectrics.
Wide Band Raised Printed Monopole for Automotive 5G Wireless Communications
April 27 2022 Ahmad Yacoub, Mohamed Khalifa and Daniel N. Aloi introduce a compact MIMO antenna system for vehicular applications in sub-6GHz 5G systems, that operates in the middle and high frequency bands from 1.71GHz to 5GHz. The proposed design is an excellent candidate to be implement in a shark-fin housing due to its low-profile characteristics and good electrical performance. The antennas are simulated using HFSS software and then prototypes are made and measured on a one-meter rolled-edge ground plane in an anechoic chamber.
Mutual Coupling and Channel Imbalance Calibration of Colocated MIMO Radars
April 27 2022Measurement-based calibration techniques typically assume angle-independent system imperfections. This is in general a good approximation for a narrow field-of-view, however, for larger angles relative to the antenna boresight, the effects of antenna mutual coupling can degrade the calibration performance considerably. To resolve this problem, Ricard L. Grove, Jorgen Dall and Poul Leth-Espensen propose an angle-to-angle based calibration technique, which is found to obtain a performance for larger angles comparable to that of near-boresight angles. This is of special interest for MIMO radars, as a wide field-of-view is typically desired.
An Indirect Method for an Alternate Perspective to Dispersion Diagrams of Magnetoinductive Waveguides
April 27 2022The dispersion equation of magnetoinductive waveguides (MIWs) is traditionally solved directly for the propagation constant (𝛾) to obtain diagrams for the attenuation (𝛼) and phase (𝛽) constants vs. angular frequency (𝜔). Vigyanshu Mishra and Asimina Kiourti introduce an indirect method of solving the equation, in two steps. By doing so, additional information and insights are provided in the intermediate step, not available via the traditional direct method. The additional information obtained is fundamental in nature and can be utilized to aid in the understanding and design of MIWs. Additionally, the reported indirect method is generic and can be used for any type of MIW structure and any order of coupling.
Methodology for Measuring the Frequency Dependence of Multipath Channels Across the Millimeter-Wave Spectrum
April 19 2022 Damla Guven, Benjamin F. Jamroz, Jack Chuang, Camillo Gentile, Robert D. Horansky, Kate A. Remley, Dylan F. Williams, Jeanne T. Quimby, Alec J. Weiss and Rodney Leonhardt propose a methodology to measure mmWave frequency dependence, using the 26.5–40 GHz band as an example. The methodology emphasizes calibration of the equipment so that the measurement results represent the channel alone (and not the channel coupled with the channel sounder. Results confirm that free-space propagation is indeed frequency invariant – a well-understood phenomenon but reported nowhere else at mmWave to date. It is also found that specular paths – the strongest after the line-of-sight path and so pivotal to maintaining connectivity during blockage – are the least invariant compared to weaker diffracted and diffuse paths.
A Survey of Dense Multipath and Its Impact on Wireless Systems
April 19 2022 Suying Jiang, Wei Wang, Yang Miao, Wei Fan and Andreas F. Molisch provide a survey of studies of dense multipath component (DMC) in terms of different mathematical representations, channel modeling and channel parameters estimation methods. A comprehensive review of the channel characteristics and impacts of DMC on performance of communication, localization and sensing systems is presented. Some open research topics of DMC are also discussed.
Broadband Compact Substrate-Independent Textile Wearable Antenna for Simultaneous Near-and Far-Field Wireless Power Transmission
April 13 2022 Mahmoud Wagih, Abiodun Komolafe, Alex S. Weddell and Steve Beeby address the challenge of efficient wireless power transmission (WPT) to flexible e-textile devices, demonstrating for the first time, a near- and far-field wireless power receiver using flexible materials, and showing an unisolated/unshielded textile antenna powering a real-world load. The proposed antenna combines, for the first time, a broadband UHF radiator with a near-field HF resonant coil. Based on the proposed antenna, future e-textile wearable devices can be wirelessly powered in both the near- and far-field using a shared-aperture antenna, enabling different charging currents and ranges of operation for maximum versatility.
Dimension and sampling of the near-field and its intensity over curves
April 12 2022 Giovanni Leone, Raffaele Moretta and Rocco Pierri address the question of efficiently sampling the near field and its intensity over an arbitrary curved line. They aim at finding the minimum number of measurements and their position for discretizing the near field and its square amplitude without loss of information, and follow a common approach for both the radiation operator and the correspondent lifting operator. The proposed strategy enables the reduction of the acquisition time within the framework of the source current reconstrution and antenna testing from near field measurements, since it requires non-redundant number of data.
Design of microfluidic reflectarray elements for multi-reconfiguration using liquid metal
April 11 2022 Eduardo Carrasco, Juan Gomez-Cruz, Mario Serrano-Berrueco, Carlos E. Saavedra and Carlos Escobedo propose an optimized design of a new microfluidic-based chip, along with the use of a non-toxic liquid metal alloy, as an efficient mechanism for dynamically controlling the frequency or phase of reflectarray elements. A proof-of-concept of the required microfluidic technology is introduced from both mechanical and radiofrequency points of view, demonstrating promising results. The proposed method opens a new avenue for reconfigurable reflectarray elements that can be further reduced in scale, customized, and parallelized to satisfy the requirements of fast-evolving applied electromagnetics, particularly antennas and sensors.
Next-Generation Healthcare: Enabling Technologies for Emerging Bioelectromagnetics Applications
March 24 2022 Rapid advances in antennas, propagation, electromagnetics, and materials are opening new and unexplored opportunities in body area sensing and stimulation. Next-generation wearables and implants are seamlessly providing round-the-clock monitoring. In turn, numerous applications are brought forward with the potential to ultimately transform healthcare, sports, consumer electronics, and beyond. Asimina Kiourti et al. provide a comprehensive overview, discussing challenges and opportunities, and indicating future directions for: (a) enabling technologies needed to make body area sensing and stimulation a reality, and (b) emerging bioelectromagnetics applications that may readily benefit from such technologies.
Frequency Selective Computational Through Wall Imaging Using a Dynamically Reconfigurable Metasurface Aperture
March 22 2022 The Viet Hoang, Rupesh Kumar, Thomas Fromenteze, María García-Fernández, Guillermo Álvarez-Narciandi, Vincent Fusco, and Okan Yurduseven present a two-dimensional (2D) dynamically reconfigurable metasurface aperture able to perform frequency selective through wall imaging (TWI) with an unknown structure of the wall. A two-stage method is proposed that leverages the concept of a dynamically reconfigurable metasurface antenna (DMA) in a narrow frequency band in which the effects of the wall are minimum to perform TWI. A physical-layer compression scheme is adopted which significantly simplifies the data acquisition while the quasi-random sampling of the scene information eliminates the need for conventional raster-scan based modalities.
High-Gain Dual-Band Dual-Sense Circularly Polarized Spiral Series-Fed Patch Antenna
March 22 2022 Nghia Nguyen-Trong, Shengjian Jammy Chen, Christophe Fumeaux present a spiral series-fed patch array antenna that can meet the strict requirements of satellite communications on a single-layered substrate with a simple feeding network. A theoretical framework for a spiral 2D dual-band dual-sense series-fed patch array with proximity coupling is developed. Critical aspects of this type of antennas, including feeding, element placement, radiation efficiency and aperture efficiency are also thoroughly discussed.
Sensor Arrangement in Through-the Wall Radar Imaging
March 14 2022 Maria Antonia Maisto, Mehdi Masoodi, Rocco Pierri, and Raffaele Solimene present a strategy for addressing the problem of how to spatially collect the scattered field in microwave through-the wall imaging. The proposed approach allows reducing the number of measurements, by maintaining the achievable performance. This can decrease the data collection time and the required amount of data.
Dual-Band Circularly Polarized Antenna Array for 5G Millimeter-Wave Applications
March 9 2022 Samaneh Sadeghi-Marasht, Mohammad S. Sharawi and Anding Zhu present a dual-band miniaturized e-shaped antenna with circular polarization (CP) at 28 and 38 GHz for 5G millimeter-wave applications. The antenna consists of a main radiating patch surrounded by an L-shaped and hat-shaped metallic strips. Characteristic mode analysis is used in the design steps of the antenna. The developed array is suitable for a variety of 5G applications that require a compact CP array with high gain and efficiency, such as mm-wave mobile communication systems.
Graphene Based Tunable Terahertz Holographic Antennas
March 9 2022 Pengfei Ren, Lijun Jiang, and Ping Li leverage the property of graphene’s conductivity to be dynamically tuned by external DC biasing, and propose several representative terahertz holographic artificial impedance surface antennas. It is shown that the graphene is very suitable for tunable antenna design, as well as conformal antennas. Its reconfigurable feature makes it a good candidate in future terahertz wireless applications based on graphene. Moreover, the overall high performance of the array structure is very promising for design and integration of terahertz communication transceivers, sensors, and other devices.
A Finite Element Based Characteristic Mode Analysis
February 10 2022 Konstantinos D. Paschaloudis, Constantinos L. Zekios, Stavros V. Georgakopoulos, and George A. Kyriacou propose a novel robust and spurious-free characteristic modes (CM) formulation based on the finite element method (FEM). Using linear algebra operations the system is effectively expressed only in terms of the desired tangential field over the radiating apertures, retaining the equivalent currents. The obtained matrix as in the classical CM analysis is split into its real and imaginary part, defining the well-known CM eigenvalue problem. Key advantage of the proposed formulation is that it does not require the evaluation of Green’s function, thereby the study of any arbitrarily shaped, multilayered geometry loaded with anisotropic and inhomogeneous materials is feasible.
Experimental Validation of the DBIM-TwIST Algorithm for Brain Stroke Detection and Differentiation Using a Multi-Layered Anatomically Complex Head Phantom
February 9 2022 Olympia Karadima, Pan Lu, Ioannis Sotiriou, and Panagiotis Kosmas present an experimental validation of the distorted Born iterative method with the two-step iterative shrinkage thresholding (DBIM-TwIST) algorithm for the problem of brain stroke detection and differentiation, using an anatomically accurate, multi-layer head phantom. Simulation and experimental results demonstrate the potential and challenges for successful detection and differentiation of the stroke targets.
Broadband Circularly Polarized Microstrip Patch Antenna with Diamond-shaped Artificial Ground Structure
February 9 2022Uuganbayar Purevdorj, Ryuji Kuse, and Takeshi Fukusako present a broadband circularly polarized patch antenna with an artificial ground structure (AGS), which has rotated rectangular unit cells with respect to the sides of the rectangular ground plane, as a polarizer. A two- element (2×1) array configuration of the antenna is also presented. The rectangular unit cells are rotated by 45° with respect to the sides of a square dielectric substrate, named a diamond-shaped AGS (DAGS). The results show that the proposed structures are good candidates for broadband circular polarization applications.
Dual-Function Triple-Band Heatsink Antenna for Ambient RF and Thermal Energy Harvesting
February 7 2022The Internet of Things infrastructure requires billions of devices that must ideally be self-powered. Harvesting ambient RF and thermal energy has great potential since both sources are available continuously throughout the day. Azamat Bakytbekov, Thang Q. Nguyen, Ge Zhang, Michael S. Strano, Khaled N. Salama, and Atif Shamim present a transient type Thermal Energy Harvester (TEH) that generates energy from diurnal cycle temperature fluctuations. Smart integration is achieved by designing a heatsink antenna that enables boosting of the performance of both the RF and energy harvester. A complete trade-off analysis between antenna radiation and heat transfer performance is provided.
A Ray Tracing Tool for Propagation Modelling in Layered Media: a Case Study at the Chip Scale
February 3 2022Investigations on propagation in layered media can be of interest for many wireless applications, ranging from natural scenarios to artificial structures like meta-materials, photonics devices, or systems-on-chip. F. Fuschini, M. Barbiroli, G. Bellanca, G. Calò, J. Nanni, and V. Petruzzelli propose a ray tracing-based algorithm specifically conceived for electromagnetic propagation modelling in layered scenarios. The proposed model can complement traditional approaches (like the Dyadic Green Function method) for the description of propagation in layered media. Some speed up techniques are also discussed to further reduce the computational burden.
Statistics of the Effective Massive MIMO Channel in Correlated Rician Fading
January 28 2022 Correlated massive MIMO channels in Rician fading environments have been only described by their first and second order moments to quantify the spectral efficiency and capacity. Jens Abraham, Pablo Ramírez-Espinosay and Torbjörn Ekman provide distribution functions for the maximum ratio combining effective channel, a quadratic form of a random complex normal channel vector. Closed-form approximations of the distribution functions are presented to allow the fast evaluation of many real-world scenarios.
Two-dimensional Materials for Future Terahertz Wireless Communications
January 20 2022 Abdoalbaset Abohmra, Zia Ullah Khan, Hasan T Abbas, Nosherwan Shoaib, Muhammad A Imran and Qammer H Abbasi review several important electrical features of two dimensional materials such as graphene, MOs2, and perovskite enabled THz devices through which extraordinary electromagnetic phenomena can be exploited towards the development of efficient systems for future wireless communication systems.
Dual-Polarized 2–6 GHz Antenna Array with Inverted BoR Elements and Integrated PCB Feed
January 20 2022 Matti Kuosmanen, Sten E. Gunnarsson, Johan Malmström, Henri Kähkönen, Jari Holopainen, Juha Ala-Laurinaho and Ville Viikari present a wideband, dual-polarized antenna array with inverted body-of-revolution (BoR) elements. The antenna structure is based on the conventional BoR element, but it is inverted, i.e., instead of metallic cones, the elements are metalized cavities inside a dielectric block. This structure allows a more lightweight and low-cost design since all-metal parts are not needed. In addition, the paper proposes a feeding system that is fully integrated into a 5-mm-thick standard printed circuit board.
Multi layered Coating Metasurfaces Enabling Frequency Reconfigurability in Wire Antenna
January 14 2022 Stefano Vellucci, Davide De Sibi, Alessio Monti, Mirko Barbuto, Marco Salucci, Giacomo Oliveri, Andrea Massa, Alessandro Toscano and Filiberto Bilotti introduce a conceptually new approach for designing frequency reconfigurable wire antennas based on the use of multi-layered wrapping metasurfaces. The advantages and limitations of this approach are presented and, as a relevant example, the design of a reconfigurable half-wavelength dipole is discussed. It is shown that the operative frequency band of the antenna can be dynamically and continuously shifted within a broad range of frequencies, while preserving the current distribution of the fundamental mode and the omnidirectional shape of its radiation pattern on the horizontal plane. This makes the proposed solution particularly suitable for cognitive radio systems.
A Compact Wideband Dual-polarized Base Station Antenna Using Asymmetric Dipole
December 30 2021 Hai Lin, Wen Yu, Fangshun Deng, Baihui Liao and Rongxin Tang propose a compact wideband base station antenna, which aims to achieve broad impedance bandwidth in LB with low complexity as well as improved port-to-port isolation. Two methods are used to enhance bandwidth and improve the port-to-port isolation. Firstly, by integrating the parasitic elements to traditional dipoles, new resonant modes are introduced to realize broadband function, which can be controlled flexibly. Subsequently, part of the parasitic elements is removed to form asymmetric dipoles. The good performance of the proposed antenna makes it a promising candidate for 4G/5G base station applications.
Intelligence Enabled by 2D Metastructures in Antennas and Wireless Propagation Systems
December 27 2021 Mirko Barbuto, Zahra Hamzavi-Zarghani, Michela Longhi, Angelica Viola Marini, Alessio Monti, Davide Ramaccia, Stefano Velluci, Alessandro Toscano and Filiberto Bilotti show how the combination of 2D metastructures with conventional antennas and reflectors enables an unprecedented electromagnetic behavior, which is at the basis of new properties, capabilities, and applications. In particular, they propose an emerging design approach based on the shifting of the reconfigurability, adaptivity, sensing, and power management of a wireless system at the physical level, thanks to the use of properly designed 2D metastructures to be coupled with standard antennas and reflectors.
Mixtures of Multipoles – Should They Be in Your EM Toolbox?
December 23 2021 Richard W. Ziolkowski provides an overview of the recent surge in interest in multipole sources and their fields to achieve useful radiated and scattered fields with, for example, high directivities in preferred directions. The many concepts associated with this topic as characterized by the physics, optics and applied electromagnetics communities are reviewed. A number of examples are presented to illustrate how one can realize higher directivity with multipoles. Topics include Huygens sources, dielectric-based Mie-tronics, edge-singularity multipoles, and exotic metamaterial-inspired superdirective lenses and radiators.
Unified Reciprocal Space Processing for Short-Range Active and Passive Imaging Systems
December 21 2021 Aaron V. Diebold, Thomas Fromenteze, Ettien Kpré, Cyril Decroze, Mohammadreza F. Imani and David R. Smith propose the adaptation of a Fourier-based imaging technique, optimized for short-range active MIMO systems, to passive technologies, interrogating the emissivity of a spatially distributed target. They transfer reciprocal/k-space methods from the field of MIMO radar to short-range passive imaging, and illustrate how the proposed approach enables powerful predictive modelling as well as image reconstruction in both active and passive imaging configurations. The presented systematic method provides a novel framework for characterizing and optimizing short range coherent or incoherent systems used in threat detection and non-destructive testing applications.
Broadband Low-Loss On-Body UHF to Millimeter-Wave Surface Wave Links Using Flexible Textile Single Wire Transmission Lines
December 20 2021 On-body transmission represents a challenge due to human body shadowing. Mahmoud Wagih proposes a Sommerfeld-Goubau single-wire transmission line (SWTL), implemented using electronic textiles for low-loss on-body links up to millimeter-wave frequencies, overcoming the spherical spreading loss and on-body absorption. At 50 GHz, the realized textile SWTL exhibits the lowest attenuation compared to conventional microstrip lines and aligned horn antennas. With a very stable phase and magnitude response, single-wire transmission lines offer a low-complexity alternative to on-body wireless transmission.
Wide-Scan Focal Plane Arrays for mmWave Point-to-Multipoint Communications
December 20 2021 Roel X. F. Budé, Amr Elsakka, Ulf Johannsen and A. Bart Smolders propose an antenna system concept that allows for an increase of capacity of fronthaul and backhaul systems by allowing for point-to-multipoint operation with a single reflector. Furthermore, a solution for alleviating twist and sway of the antenna mast is presented. The proposed system is shown to be a good candidate for robust and adaptive fronthaul or backhaul for 5G and 6G wireless networks.
A Gain-Enhanced Patch Antenna with a Periodic Microstrip Rampart Line
December 14 2021 Xiaoning Chen, Yuming Wei, Yuanxin Li, Zhixi Liang, Shao Yong Zheng and Yunliang Long propose a gain-enhanced patch antenna with a periodic microstrip rampart line. The proposed antenna achieves gain improvement by embedding a periodic structure under the traditional antenna. After the periodic structure is embedded under the antenna, the phase constant of the periodic structure can be used to control the change of the equivalent dielectric constant. By controlling the equivalent dielectric constant of the dielectric substrate, the radiation aperture of the antenna can be increased, and the antenna gain can be improved.
The Use of Metasurfaces to Enhance Microwave Imaging: Experimental Validation for Tomographic and Radar-based Algorithms
December 14 2021 Navid Ghavami, Eleonora Razzicchia, Olympia Karadima, Pan Lu, Wei Guo, Ioannis Sotiriou, Efthymios Kallos, George Palikaras and Panagiotis Kosmas investigate the feasibility of combining metamaterial design concepts and imaging techniques to create innovative microwave imaging systems. An experimental study is presented with the aim of enhancing microwave imaging for haemorrhagic stroke detection using a new metasurface design. Simulation and measurement results indicate that the proposed metasurface design improves target localization and decreases image artefacts for the tomographic algorithm, while enabling target’s detection through the presented radar technique, paving the way for a hybrid microwave imaging prototype with metasurface enhanced antennas.
Quad-Furcated Profiled Horn: The Next Generation Highly Efficient GEO Antenna in Additive Manufacturing
December 13 2021 Charalampos Stoumpos, Jean-Philippe Fraysse, George Goussetis, Ronan Sauleau and Hervé Legay propose a novel technique and a design framework for the conception of compact and highly efficient dual-polarized full-corporate square aperture horns. The total antenna feed also includes the feeding network. The proposed radiating element is the first square aperture, dual-polarized, purely-metallic, full-corporate (OMT included) horn antenna that can achieve aperture efficiency values close to the theoretical maximum over a frequency bandwidth larger than 15% and for aperture sizes above 2λ0, while it maintains an axial profile lower than 6.5λ0.
Fundamental Limits on Substructure Dielectric Resonator Antennas
December 8 2021 Binbin Yang, Jaewoo Kim and Jacob J. Adams address the physical limits of substructure dielectric resonator antennas (DRAs) using the characteristic mode theory and a mathematical eigenvalue interlacing relation. Specifically, they first show that the characteristic modes of DRAs are inherently capacitive at the low frequency limit. Then, by combining the capacitive nature of DRAs and the mathematical eigenvalue interlacing relation, they demonstrate that substructure DRAs are bound to resonate at a higher frequency than the complete DRA structure, and similar bounds also exist for quality factors. Such bounding relations are established not only for the fundamental mode, but also higher order modes. This work is expected to further improve understanding of the characteristic modes of dielectric antennas, and the performance limits of DRAs.
Group Sparsity Penalized Contrast Source Solution Method for 2-D Non-Linear Inverse Scattering
December 7 2021 Yarui Zhang, Marc Lambert, Aurelia Fraysse and Dominique Lesselier propose a group sparsity penalized contrast source method in the transformed domain for single-frequency 2-D data. Emphasis is placed on combining the structure information (wavelet quad tree structure) of the contrast with the contrast source inversion method (CSI) via a mixed norm regularization term, as well as employing the dual-tree complex wavelet transform, which is an important enhancement to the traditional discrete wavelet transform. The approach is shown to overcome the standard CSI method in demanding situations.
Drone-Base-Station for Next-Generation Internet-of-Things: A Comparison of Swarm Intelligence Approaches
December 7 2021 Dimitrios Pliatsios, Sotirios K. Goudos, Thomas Lagkas, Vasileios Argyriou, Alexandros Apostolos A. Boulogeorgos and Panagiotis Sarigiannidis present an overview of five swarm intelligence approaches, namely the Cuckoo Search, the Grew Wolf Optimization, the Monarch Butterfly Optimization, the Elephant Herd Optimization, the Salp Swarm Algorithm, and the Particle Swarm Optimization. These approaches are compared in terms of performance in finding the optimal position of a drone-mounted base station, based on three evaluation scenarios. According to the Friedman ranking test and the Wilcoxon significance test, Grey Wolf Optimization is the best performing approach in finding the optimal drone-base station position.
Photonics-Based Near-Field Measurement and Far-Field Characterization for 300-GHz Band Antenna Testing
December 7 2021 Yusuke Tanaka, Cybelle Belem-Goncalves, Frederic Gianesello, Cyril Luxey, Issei Watanabe, Akihiko Hirata, Norihiko Sekine, Akifumi Kasamatsu and Shintaro Hisatake present the photonics-based near-field measurement and far-field characterization in a 300-GHz band, using an electrooptic (EO) sensor with planar scanning. The far-field pattern of a horn antenna is calculated from the measured near-field distribution with EO probe correction. The far-field pattern is comparable in terms of accuracy to the far-field pattern measured by the direct far-field measurement systems, using a set of sources/direct-detection and the vector network analyzer technique.
Imaging and Calibration of Electromagnetic Inversion Data with a Single Data Set
December 2 2021 Eungjoo Kim, Cena T. Mohammadi, Mohammad Asefi, Joe Lo Vetri, Ian Jeffrey, and Colin Gilmore introduce a new calibration method for Electromagnetic Inversion (EMI) systems, using a single S-parameter measurement of the unknown target only. In contrast to the conventional calibration and imaging process, which usually requires two datasets, this work proposes a novel calibration and imaging technique based on a single dataset. This new method is shown to work on experimental data from a small-scale grain bin imaging system.
A Wideband L-probe Fed Conformal Antenna Array Using Metasurface
November 29 2021 S. Huang, C. F. Zhou, J. X. Sun, S. S. Yuan, H. Li, X. M. Ding, Q. Wu, and X. B. Tang propose a broadband conformal metasurface (MTS) antenna array with high gain, fed by L-probes, for curving platform applications. The proposed antenna array is composed of a simple feeding network and 4×8 antenna elements. It exibits the merits of low profile, wideband design and high gain, and is a good candidate of aircrafts, UAVs, and automotive applications.
A Study on the Radiation Characteristics of Microelectronic Probes
November 29 2021 Ziyang Zheng and Yue Ping Zhang study a typical ACP40-GSG-100 probe through simulation and measurement. It is confirmed that the probe radiation is caused by current on its tips, and that its intensity depends on the current strength. The probe shows a symmetrical radiation pattern for it presents symmetrical current distributions on the GSG tips. The metal probe shell has strong effect on the radiated power distribution. A simple mathematical model is also provided to explain why lower-gain probes are preferred in antenna radiation tests.
Cylindrical MIMO-SAR Imaging and Associated 3-D Fourier Processings
November 29 2021 Fabien Berland, Thomas Fromenteze, Cyril Decroze, Ettien Kpre, Damien Boudesocque, Vincent Pateloup, Philippe Di Bin, and Christelle Aupetit-Berthelemot propose a new cylindrical MIMO-SAR architecture for applications focused on buried threat detection. In contrast to the systems existing in the literature, the antennas composing the MIMO array are positioned on an arc around the stage and a vertical displacement system is used to synthesize a 2D radiating aperture. Along this novel architecture, an adapted fast reconstruction algorithm based on Fourier transforms is also developed.
Ultra-Wideband Patch Antenna Array with an Inclined Proximity Coupled Feed for Small Unmanned Aircraft RADAR Applications
November 15 2021 Abhishek K. Awasthi, Christopher D. Simpson, Shriniwas Kolpuke, Tuan D. Luong, Jie-Bang Yan, Drew Taylor and S. Prasad Gogineni present the design of a lightweight and compact patch antenna array with an inclined proximity coupled feed. The antenna array is designed for operation on a small unmanned aircraft system with an ultra-wideband (UWB) radar for remote sensing of soil moisture and snow. To achieve UWB impedance matching, the design utilizes an inclined wide feed and inter-element coupling. A prototype 2 × 4 element array is fabricated and tested.
A Foldable Reflectarray on a Hexagonal Twist Origami Structure
November 13 2021 Antonio J. Rubio, Abdul-Sattar Kaddour, Collin Ynchausti, Spencer Magleby, Larry L. Howell, and Stavros V. Georgakopoulos introduce a novel deployable flat panel reflectarray antenna (RA) based on an origami folding pattern for Small Satellite applications. The design process of rigid-foldable structures with thickness accommodation is discussed and the hexagonal twist folding pattern is modified to develop two novel deployable RA apertures. The results of this work demonstrate that the proposed RAs are very well-suited for various SmallSat applications, such as, deep space and earth sciences.
Absorptive Microstrip-Fed Slot Antenna With Wide Reflectionless Band by Loading Band stop Filter
November 13 2021 Yanqun Liu, Peng Zhou, Shunli Li, Hongxin Zhao, and Xiaoxing Yin propose an absorptive microstrip-fed slot antenna with a wide reflectionless band and high radiation efficiency. The antenna design maintains the original structure and radiation characteristics of a conventional microstrip-fed slot antenna and can be easily extended to many kinds of antennas with similar feeding arrangements. The use of absorptive/reflectionless antennas can alleviate the problems caused by the reflected signal noise at the transmitter front-end, and has significant theoretical and application value.
2-D WFS Approach through Field Transformation -Application to Performance Prediction in Standard Antenna Simulators
November 13 2021 Constant M. A. Niamien presents a 2-D wavefield synthesis approach directly implementable in standard antenna simulation software. A vertically and horizontally polarized isotropic test zone of radius /10 is designed with just three dipoles located at a distance of 5 far from the phase center. Application to a test antenna (folded dipole) anticipates the received power and MEG directly inside the antenna simulator in receiving mode. This valuable design option, not handled by most antenna simulators, helps to optimize the antenna based on the propagation medium characteristics during the design stage.
A Broadband High-Efficiency Dipole Array Based on Frequency Selective Surface and Integrated Feeding Structure
November 12 2021 Hong Tang, Bowen Zheng, Sensong An, Hang Li, Mohammad Haerinia, Clayton Fowler, and Hualiang Zhang present a low-profile, ultra-wideband, and high-efficiency tightly couple antenna array based on a low-loss phase-modulated frequency selective surface and a microstrip-based feeding structure. The proposed design concept is verified through the measurements of an 8 × 8 array prototype and can be adopted to high-power RF/microwave systems such as high-resolution, long-range radar systems and imaging systems, as well as many other wireless systems.
Deployable Rigid-Flexible Tightly Coupled Dipole Array (RF-TCDA)
November 12 2021 Maxence Carvalho and John L. Volakis propose an origami-based Tightly Coupled Dipole Array (TCDA) for small satellite applications. The proposed TCDA is one of the first foldable, low-profile, and low-scanning ultra-wideband arrays in the literature. This new class of rigid-flexible TCDAs is successfully demonstrated via measurements and shown to deliver the designed 6:1 bandwidth with a radiation efficiency of 85%, on average. A study of the aperture’s performance under structural distortion is also given for practical considerations.
High Frequency Breast Imaging: Experimental Analysis of Tissue Phantoms
November 12 2021 Duy Hai Nguyen, Jonathan Stindl, Teresa Slanina, Jochen Moll, Viktor Krozer, and Gernot Zimmer present a high-frequency microwave breast imaging system operating from 16 to 20 GHz. They propose a new compact, ultra-wideband antenna structure based on common low dielectric property material as well as artificial breast tissue models based on agar-glycerol- oil and water mixture. A heterogeneous breast phantom with tumors is developed to evaluate the antenna’s performance. Preliminary results show the feasibility of achieving a high resolution with a compact microwave system for early-stage breast cancer detection.
Analytic Sinusoidal Steady-State Electromagnetic Field Expressions for the Ideal Veselago Lens
October 21 2021 Marzieh Eini Keleshteri, Vladimir Okhmatovski, and Joe LoVetri derive analytic expressions for the sinusoidal steady-state electromagnetic field, associated with an ideal Veselago Lens (VL), based on power flow considerations and the imposition of appropriate boundary conditions. To this end, for the first time, closed-form time-harmonic 2D and 3D Green's functions, corresponding to the electromagnetic field of a point-source in front of a slab of double-negative material constituting the ideal VL, are obtained. The derived solutions satisfy Maxwell's equations in all domains as well as appropriate boundary conditions at all boundaries of the problem, and explicitly enforce conservation of power.
Origami Antennas
October 19 2021 Stavros V. Georgakopoulos, Constantinos L. Zekios, Abdul Sattar-Kaddour, Muhammad Hamza, Akash Biswas, Brooklyn Clark, Collin Ynchausti, Larry L. Howell, Spencer P. Magleby, and Robert J. Lang present emerging research on foldable and physically reconfigurable antennas. Such antennas morph their shape to adapt and reconfigure their EM performance. Origami antennas provide ultra-compact stowage, easy deployment, reduced weight, enhanced EM performance and multifunctional utility, and are expected to provide new capabilities to various systems, including small Unmanned Aircraft Systems, drones, airborne and spaceborne systems, small satellites, deployable reflectors, and expandable reconfigurable surfaces.
Microwave Imaging of the Neck by Means of Artificial Neural Networks for Tumor Detection
October 19 2021 Chiara Dachena, Alessandro Fedeli, Alessandro Fanti, Matteo B. Lodi, Giorgio Fumera, Andrea Randazzo, and Matteo Pastorino present a microwave imaging approach based on artificial neural networks for neck tumor detection. The aim of the proposed technique is to retrieve the geometric and dielectric properties of the neck towards identifying the possible presence of tumors, starting from scattered electric field data. The use of a fully-connected neural network in this application is explored for the first time in order to test the feasibility of the proposed approach.
Electromagnetic Integral Equations: Insights in Conditioning and Preconditioning
October 19 2021 Simon B. Adrian, Alexandre Dély, Davide Consoli, Adrien Merlini, and Francesco P. Andriulli review and discuss the main advancements in the field of integral equation preconditioning in electromagnetics, summarizing strengths and weaknesses of each technique. The article guides the reader through the choices of the right preconditioner for a given application scenario, and presents new analyses and discussions, providing a further and more intuitive understanding of the ill-conditioning of the electric field, magnetic field, and combined field integral equation, as well as of the associated remedies.
Wideband Via Loaded Cylindrical Open Ended SIW Cavity Antenna
September 29 2021Chun-Mei Liu, Shao-Qiu Xiao, Desong Wang, and Ke Wu propose a composite cavity-based antenna, based on the utilization of the via holes processing and multi-layer technique and the involvement of multiple modes towards achieving a wide bandwidth. The simple structure and the integration with other planar front-end circuits constitute benefits of the fabrication. Moreover, the transverse dimension is compact, which shows a great potential for the realization of future integrated systems.
Fixed-frequency Beam-steering Using Slotted Waveguide with Tunable Impedance Walls
September 24 2021 Amirmasoud Ohadi and George V. Eleftheriades describe the development of a new beam-steerable antenna array using a reconfigurable waveguide with tunable impedance side walls. The use of the proposed phase-shifting mechanism makes the antenna suitable for applications where the operating frequency is relatively close to the self-resonance frequency of the varactor. As the antenna has a simple feed network and bias circuitry with a relatively high efficiency, it can be used where simple antenna length extension is needed to achieve a larger gain and a narrower beamwidth.
A Dual mode, Thin and Wideband MIMO Antenna System for Seamless Integration on UAV
September 23 2021 Zubair Akhter, Rana M. Bilal and Atif Shamim present a dual band design that addresses all the key requirements for a UAV antenna. The thin and flexible nature of the antenna makes it attractive for a seamless integration with the UAVs surface. The proposed MIMO configuration can be used to achieve higher data rates for HD video transmission to larger distances as compared to conventional antennas. Furthermore, the full ground plane also reduces the body effect, making this design appealing for a generalized plug-and-play solution, irrespective or insensitive to UAV body materials.
Highly Efficient Angular Array Calibration Based on the Modal Wave Expansion Technique
September 9 2021 André Dürr, Matthias Linder, Dominik Schwarz, and Christian Waldschmidt propose a highly efficient angular array calibration procedure based on the modal wave expansion of the radiated electric field. The proposed method enables fast and high-quality calibration of large arrays with a high channel count and significantly reduces the calibration effort of commonly used arrays, enabling the compensation of misalignments during the calibration measurement. A comparison with conventional calibration techniques is also performed to demonstrate the advantages of the proposed approach.‬
Large Screen Enabled Tri-port MIMO Handset Antenna for Low LTE Bands
August 24 2021Hanieh Aliakbari, Li Ying Nie and Buon Kiong Lau apply characteristic mode analysis in order to design a tri-port MIMO handset antenna in low LTE bands, by the opportunistic use of the big metal-covered display screen to provide the dual resonances used to implement the third port. To the authors’ knowledge, it is the first time that the screen-assisted design concept is proposed and validated, and it is also the first time that a third port with considerable bandwidth and low correlation is achieved below 1 GHz. This added port can enhance the data rate (system performance) by 50%, relative to a two-port design.
Design Optimization of Origami-Tunable Frequency Selective Surfaces
August 24 2021Kazuko Fuchi, Deanna Sessions, Andrew Gillman, Venkatesh Meenakshisundaram, Alexander Cook, Gregory H. Huff and Philip R. Buskohl introduce topology optimization formulations that find origami fold-driven frequency selective surface (FSS) designs possessing electromagnetic filtering properties at target frequencies. Both gradient-based and genetic algorithm methods are used to find optimal origami crease patterns and folded configurations. The proposed methods, and qualitative characterization of the EM origami design landscape, are applicable for RF devices other than FSSs and can also be adapted and expanded to include additional multiphysics applications.
A Systematic Comparison of Near-Field Beamforming and Fourier-based Backward-Wave Holographic Imaging
August 24 2021Sebastian Paul, Fabian Schwartau, Markus Krueckemeier, Reinhard Caspary, Carsten Monka-Ewe, Joerg Schoebel and Wolfgang Kowalsky compare two commonly used algorithms for two-dimensional image reconstruction from coherently collected raw data, i.e., near-field beamforming and the backward-wave reconstruction algorithm. A detailed discussion of the constraints required for a digital implementation is presented. An exemplar scenario is simulated and processed, confirming the found equivalence between the two very different approaches of image reconstruction.
Dual-Polarized Wearable Antenna/Rectenna for Full-Duplex and MIMO Simultaneous Wireless Information and Power Transfer (SWIPT)
July 21 2021Mahmoud Wagih, Geoffrey S. Hilton, Alex S. Weddell and Steve Beeby present a dual-polarized four-port textile antenna/rectenna for wearable simultaneous wireless information and power transfer (SWIPT) applications. Based on the proposed antenna’s performance, SWIPT microstrip antennas can be adopted for both full-duplex and MIMO applications, significantly reducing the complexity of future battery-free networks for both wearable and non-wearable applications.
Dual-Resonant High-Gain Wideband Yagi-Uda Antenna using Full-Wavelength Sectorial Dipoles
July 21 2021Wen-Qi Jia, Fei-Yan Ji, Wen-Jun Lu, Chen-Xin Pan and Lei Zhu present a novel design approach to high-gain, wideband, dual-resonant, closely-spaced, three-element Yagi-Uda antennas. Unlike the conventional Yagi-Uda antennas based on half-wavelength dipoles, the director of the proposed antenna can be coupled in a close proximity to the principal dipole through a separation of 0.024- wavelength, which yields a high gain characteristic of over 10 dBi. The attractive characteristics of high gain, wide band, simple structure and easy fabrication make the presented antenna a promising candidate for future broadband wireless applications.
Multifunctional Leaky-Wave Antenna with Tailored Radiation and Filtering Characteristics Based on Flexible Mode-Control Principle
July 21 2021 Dongze Zheng and Ke Wu propose a class of single-layered multifunctional leaky-wave antennas (LWAs) with flexibly engineered radiation and filtering characteristics for microwave and millimeter-wave applications. The proposed LWAs are single-layer and low-cost, and are characterized by easy integration, thus constituting a good candidate for various system applications such as 5G communication and Internet of Vehicles.
FMCW Radar with Enhanced Resolution and Processing Time by Beam Switching
July 16 2021 Pascual D. Hilario Re, Davide Comite, Symon K. Podilchak, Cristian A. Alistarh, George Goussetis, Mathini Sellathurai, John Thompson and Jaesup Lee present the design of a novel K-band radar architecture for short-range target detection. Applications include direction finding systems and automotive radar. The proposed architecture is compact and low-cost and, by appropriate design, can be scaled to operate at other microwave and millimeter-wave frequencies, while also providing a computationally efficient multi-channel radar signal processing platform.
Scattering Suppression of Closely-Packed Cross-Band Patch Antennas Using Absorptive/Reflectionless Filtering Techniques
July 12 2021Shiyan Wang, Fei Fan, Roberto Gómez-García, Li Yang, Yin Li, and Gang Zhang present, for the first time, absorptive/reflectionless filtering techniques for cross-band decoupling or scattering suppression. ‪The proposed techniques are applied to a dual-antenna scenario. Equivalent-circuit, simulated, and measured results are provided to show the effectiveness of the presented engineered scattering-suppression method, which is believed to be promising for application in cross-band multi-antenna systems.‬
Performance-Enhancement of Platform-Based, HF Direction-Finding Systems Using Dynamic Mode Selection
July 6 2021Kai Ren, Ruyu Ma and Nader Behdad present a method to enhance the accuracy of platform-based, high-frequency (HF) direction-finding (DF) systems using dynamic mode selection. The efficacy of the proposed approach is demonstrated using computer simulations and scaled-model experiments. Simulation and measurement results show that dynamic mode selection can significantly enhance the DF accuracy of platform-based HF DF systems using a limited number of coherent receive channels.‬‬
Stochastic Channel Parameters for Train-to-Train Communications
July 5 2021The profound knowledge of radio wave propagation is essential for the design and test of wireless communication systems especiallyin demanding environments and for mobile transmitters and receivers. Paul Unterhuber, Michael Walter, Uwe-Carsten Fiebig and Thomas Kürner provide an accurate description of the relevant propagation parameters for train-to-train scenarios considering typical environments such as railway stations, open field and hilly terrain with cutting.‬‬
Quasi-optical Multi-beam Antenna Technologies for B5G and 6G mmWave and THz Networks: A Review
June 30 2021Y. Jay Guo, Maral Ansari, Richard W. Ziolkowski and Nelson J. G. Fonseca ‪provide a comprehensive review of various quasi-optical beamformers and multi-beam antennas suitable for beyond 5G (B5G) and more specifically 6G systems for the first time. ‬The operating principles and design techniques of different lens-based beamformers and multi-beam antennas for mmWave operations are presented. New research challenges and industry trends in the field, such as planar lenses based on transformation optics and metasurface-based transmitarrays, are discussed to foster further innovations in the microwave and antenna research community.‬‬
Co-designed 3+3 Port Dual-Band Broadside Tri-Modal Patch Antenna
June 21 2021Chi-Yuk Chiu, Buon Kiong Lau and Ross Murch propose a co-designed (3+3)-port antenna for dual-band operation that requires no feeding or decoupling network. The antenna consists of six ports which are divided into two groups resonating in two different frequency ranges. As all six ports are available for use all the time, no switching is needed. The antenna is compact, has a flexible usage of supporting dual-band operation, and is not only intended for use as massive MIMO element (unit cell) as in previous snowflake-shaped patch designs, but also opens up a new possibility of fully utilizing the antenna aperture for energy and information transmission.
A Millimeter-Wave Frequency Reconfigurable Circularly Polarized Antenna Array
June 21 2021M. Patriotis, F. N. Ayoub, Y. Tawk, J. Costantine and C. G. Christodoulou discuss the design of a high-gain right-hand circularly polarized millimeter-wave frequency reconfigurable antenna array. The proposed structure consists of a frequency reconfigurable modified ring resonator filter integrated within the feeding network of a 16-element antenna array. A comparison with related work and the 17.75 dB figure of merit index displays the superior performance of the proposed antenna array.
A Compact Double Ridged Horn Antenna for Ultra-Wide Band and Microwave Imaging
June 14 2021Stefania Diana, Danilo Brizi, Chiara Ciampalini, Guido Nenna and Agostino Monorchio introduce a novel and compact double-ridged horn (DRH) antenna for ultra-wide band microwave imaging. To the best of the authors’ knowledge, this is the most compact ultra-wide band DRH antenna ever presented; the reduced size, along with excellent radiating performance, make the antenna a good candidate to be employed in microwave imaging.
A Review of Design and Integration Technologies for D-Band Antennas
June 14 2021Martijn de Kok, Bart Smolders and Ulf Johannsen present an overview of published integrated antennas operating between 110 and 170 GHz. On-board, in-package, on-chip and waveguide-based antenna design techniques are summarized with examples from scientific literature. A novel comparison of the reported gain levels, bandwidths and sizes of on-board, in-package, on-chip and waveguide-based D-band antennas designs, is presented. Integrated Antenna-in-Package and Antenna-on-Chip designs can achieve competitive performance with short and low-loss interconnects.
Antenna Aperture Synthesis Using Mode-Converting Metasurfaces
June 14 2021Faris Alsolamy and Anthony Grbic utilise mode-converting metasurfaces to synthesize arbitrary, azimuthally-invariant TM apertures. The methods presented in this work can be used to design antennas that can meet specific near-field and far-field criteria unlike most metasurfaces which solely manipulate the far field. The proposed antennas consist of a coaxially-excited, radial cavity topped by the mode-converting metasurface, and present a height and weight advantage over Gaussian beam horn antennas.
Performance of Partially Deployed Spaceborne Ultra-Wideband Miura-Ori Apertures
June 7 2021Maxence Carvalho and John L. Volakis study the performance of partially deployed Miura-ori TCDAs. The presented antenna array analysis leads to a closed-form expression for the expected gain degradation caused by angular errors within the origami structure. This expression is verified with full-wave simulations for a novel TCDA architecture, where position errors inherent to origami designs are considered for the first time for phased arrays.
A Useful Sampling Representation for Mapping the Antenna Near-Field
June 2 2021Francesco D’Agostino, Flaminio Ferrara, Claudio Gennarelli, Rocco Guerriero, Massimo Migliozzi and Giovanni Riccio present a convenient sampling distribution and an optimal sampling interpolation algorithm for mapping the antenna near-field values on a planar surface. The mapping procedure is based on the theoretical background related to a non-redundant sampling representation of the electromagnetic field and uses an unconventional arrangement of the sampling points. ‬
Flat-Panel Mechanical Beam Steerable Array Antennas with In-Plane Rotations: Theory, Design and Low-Cost Implementation
May 28 2021 Qi Tang, Bart H. McGuyer, Eric Booen, Srishti Saraswat, Farbod Tabatabai, Hamid Bolandhemmat, Curt Von Badinski, and Wilhelmus H. Theunissen ‬propose a compact, flat-panel phased-array antenna design that beam steers using only mechanical in-plane rotations. ‪They present two prototype designs that use spiral or patch elements and focus on lowering cost through minimizing machining and integrating their coupling slots. Potential applications include low-cost and low-power flat-panel user terminals for the next generation of aerial and space communication systems.‬‬ ‬
4-Port MIMO Antenna using Common Radiator on a Flexible Substrate for Sub-1GHz, Sub-6GHz 5G NR and Wi-Fi 6 Applications
May 26 2021 Kumud R. Jha, Z. A. P. Jibran, Chitra Singh, and Satish K. Sharma present a four port common radiator MIMO antenna that covers additional emerging communication bands above 0.6 GHz in sub-1GHz, sub-6GHz 5G NR, and the Wi-Fi 6 communication bands. The antenna exhibits pattern diversity which is useful for MIMO applications. It can find a number of applications including Wi-Fi 6 routers, Access points, and LTE band user equipment.‬‬ ‬
VHF/UHF Ultrawideband Tightly Coupled Dipole Array for CubeSats
May 26 2021Recognizing the need to develop wideband antennas that can operate at VHF/UHF bands which are low-cost, light-weight, and packable, Vignesh Manohar, Shubhendu Bhardwaj, Satheesh Bojja Venkatakrishnan, and John L. Volakis propose a CubeSat deployable Tightly Coupled Dipole Array that achieves VSWR<3 from 80 MHz - 600 MHz, and VSWR<4 from65 MHz - 600 MHz. ‬The array design is presented in detail, the folding mechanism is demonstrated, and its performance is validated through measurements.‬
Dielectric Rod Antenna Array With Planar Folded Slot Antenna Excitation
May 19 2021Gabriel L. Saffold and Thomas M. Weller present a dielectric rod antenna (DRA) array fed by slot antenna radiators without the use of a metallic waveguide. While the normal approach to feeding DRAs involves some version of metallic waveguide, they show that the DRA may be integrated with a planar radiator feed and used effectively in an array configuration. The array is simple, cost-effective to fabricate, using standard PCB processes and 3D printed DRAs, and may be scaled into the mm-wave regime.
A High Gain and Pattern Reconfigurable Patch Antenna Under Operation of TM20 and TM21 Modes
May 13 2021Kai-Dong Hong, Xiao Zhang, Lei Zhu and Tao Yuan propose a high-gain square patch antenna with reconfigurable broadside and bidirectional beams under operation of TM20 and TM21 modes. The proposed antenna is characterized by higher gain and smaller gain difference between both states with respect to other pattern-reconfigurable antennas.
Reconfigurable Antennas Based on Pure Water
May 11 2021Changzhou Hua, Shiyan Wang, Zhenxin Hu, Zeqi Zhu, Zhen Ren, Wen Wu and Zhongxiang Shen focus on the design of reconfigurable antennas based on pure water. Three novel antennas are presented, along with simulated and measured results for their radiation performance. The main features of these pure-water antennas include high transparency, reconfigurability, low cost, and simple structure, which make them potentially very useful for future wireless communications.
A Multifunctional Compact Pattern Reconfigurable Antenna with Four Radiation Patterns for Sub-GHz IoT Applications
May 10 2021Saeed A. Haydhah, Fabien Ferrero, Leonardo Lizzi, Mohammad S. Sharawi and Azzedine Zerguine propose a compact pattern reconfigurable antenna with four radiation patterns for sub-GHz IoT applications. The antenna is characterized by a credit card size, and has two functional modes; one mode is suitable for Line-of-sight applications, while the second mode is suitable for multipath environments. The proposed antenna achieves two orthogonal radiation patterns (electrical and magnetic omnidirectional patterns), and two very directive radiation patterns.
15-40 GHz and 40-110 GHz Double-Ridge Open-Ended Waveguide Antennas for Ultra-Wideband Medical Imaging Applications
May 10 2021Milad Mirzaee, Amir Mirbeik-Sabzevari and Negar Tavassolian present the design, fabrication, and measurement of two ultra-wideband double-ridge open-ended waveguide antennas for emerging high-resolution mm-wave medical imaging applications. The proposed antennas can collectively provide a 95-GHz synthetic imaging bandwidth in the mm-wave regime. Extremely small aperture sizes, ultra-wide S11 performances, symmetric radiation patterns, and high gains turn the proposed antennas into great candidates for numerous mm-wave applications.
Bessel–Gauss Beam Launchers for Wireless Power Transfer
May 7 2021Srdan Pakovic, Siyi Zhou, David González-Ovejero, Santi Concetto Pavone, Anthony Grbic and Mauro Ettorre propose the use of Bessel–Gauss beam launchers for wireless power transfer (WPT) applications. Three approaches for characterizing power transfer efficiency between two aligned radiating apertures are presented. The power transfer efficiency between two radiating apertures is investigated in the radiative near field. The proposed approach aims to enhance the power transfer efficiency and operating range of current WPT systems.
Resource Optimization Framework for Physical Layer Security of Dual-hop Multi-carrier Decode and Forward Relay Networks
May 7 2021Marryam Nawaz, Wali Ullah Khan, Zain Ali, Asim Ihsan, Omer Waqar and Guftaar Ahmad Sardar Sidhu propose a joint resource optimization framework for the Physical Layer Security of dual-hop decode and forward relay network with and without cooperative jamming. Two models are provided to investigate the secrecy rate maximization problems under the constraints of subcarrier allocation and power control. Simulation results unveil that the proposed joint resource optimization framework performs significantly better than the benchmark frameworks.
Dual-Layer Radio-Transparent Dielectric Core Metasurface Antenna
April 26 2021 Diego Chachayma-Farfan, Younes Ra’di and Andrea Alù introduce a new approach for designing functional metasurface antennas that not only act as effective radiators over their intended bands, mimicking the behavior of standard dipoles, but also express negligible scattering over the radiation bands of the neighboring antennas. The proposed design is composed of two concentric cylindrical metasurfaces immersed in a dielectric host cylinder. The design addresses many of the issues of previously proposed designs for cloaked antennas, such as narrow bandwidth and polarization sensitivity. This performance improvement is achieved with a smaller aspect ratio making it an ideal candidate for closely packed arrays.
A Travelling-Wave-Fed Slot Spiral Antenna with Wide Axial-Ratio Bandwidth and Beamwidth for GNSS Applications
April 20 2021 Zeng-Pei Zhong and Xiao Zhang propose a travelling-wave-fed slot spiral antenna with wide axial-ratio (AR) bandwidth and beamwidth for GNSS applications. By improving the rotational symmetry of the antenna with proper number and shape of spiral slot radiators, a better AR roundness can be obtained in a more compact size. Simulated and measured results demonstrate that the proposed antenna achieves an AR bandwidth of 37.7% and AR beamwidth over 140°, and is a good candidate for GNSS applications.
18 Element Massive MIMO/Diversity 5G Smartphones Antenna Design for Sub-6 GHz LTE Bands 42/43 Applications
April 20 2021 Naveen Jaglan, Samir Dev Gupta and Mohammad S. Sharawi present an 18-element antenna system compatible with massive multiple input multiple output (MIMO)/Diversity fourth/fifth generation (4G/5G) smartphones. The antenna has a simple structure without any external decoupling mechanisms, that gives the added advantage of ease of fabrication. The proposed design shows excellent performance in terms of MIMO parameters. Impact of smartphone battery and user hand effect on performance of antenna is also discussed.
Electronically Pattern Reconfigurable Antenna for IoT Applications
April 14 2021 Luca Santamaria, Fabien Ferrero, Robert Staraj and Leonardo Lizzi present an electronically pattern reconfigurable antenna for Internet of Things (IoT) applications. The antenna structure is compact and printed on two cost-effective FR-4 printed circuit boards. Thanks to its high performance, small size, low cost, and low-power characteristics, the proposed structure is suitable for IoT applications.
A Numerical Exposure Assessment of Portable Self-Protection, High-Range and Broadband Electromagnetic Device
April 12 2021 Eliana Canicatti, Elisa Giampietri, Danilo Brizi, Nunzia Fontana and Agostino Monorchio perform a safety assessment of portable self -protection, high-range and broadband electromagnetic devices, with the aim of analyzing the effect on human body of high-power and broadband radiating systems, especially considering their near-field operating region. This study can be helpful to serve as a reference to accomplish a complete and accurate analysis on the electromagnetic safety of similar devices and, further, to undertake suitable containment measures to reduce exposition.
Screen-Printed Fabric Antennas for Wearable Applications
April 5 2021 Umar Hasni, McKenzie E. Piper, Jonathan Lundquist, and Erdem Topsakal present two antennas for wearable applications, including the development of new antennas on fabric substrates for communication with in-body and outside the body sensors. The design process for fabrication via screen printing on fabric substrates is outlined, using commercially available conductive inks. The antennas’ performance in terms of data transfer is investigated, showing a viable range of 20ft before any data loss during transmission. The antennas are also tested for wash sustainability and return loss.
Analysis of Interaction Scattering Cross Sections and their Physical Bounds for Multiple-Dipole Stimulation of a Three-Dimensional Layered Medium
March 31 2021 Excitation of a three-dimensional layered medium by N electric or magnetic dipoles constitutes a realistic model for applications spreading from low frequencies to the visible range. Andreas Kalogeropoulos and Nikolaos L. Tsitsas consider and analyze single layer excitation and mixed excitation, and introduce interaction scattering cross sections (ISCS), which quantify the energy flux rate due to interactions between the individual and q-excitation fields by dipoles lying in the same layer or in different layers. Extensive numerical investigations are performed for the variations of the ISCS and their physical bounds with respect to the geometrical and physical characteristics of the layered medium.
Miniaturization of a Filter-Antenna Device by Co-Design
March 31 2021 L. Huitema, M. Thevenot, S. Bila, A. Perigaud, and RC. Delaveaud present a novel miniaturization approach by co-designing together a filter and an antenna. Contrary to a classical filter-antenna design, which presents a 50Ω transition between the filter and the antenna, the proposed co-design methodology proves that both the antenna and the filter can be optimized on a complex impedance. Prototypes are fabricated and measurements confirm the benefits observed during the design phase.
Liquid Antennas: Past, Present and Future
March 29 2021 Yi Huang, Lei Xing, Chaoyun Song, Stephen Wang, and Fatma Elhouni present a comprehensive review on liquid antennas, covering both metallic and non-metallic liquid antennas. A detailed discussion on state-of-the-art designs and current technical challenges is performed, and the ways forward for the future are suggested. As a special feature, an in-depth review of materials for liquid antennas is also provided. The challenges of liquid antennas for real-world applications are identified and discussed.
Computational Polarimetric Imaging Using Two-Dimensional Dynamic Metasurface Apertures
March 29 2021 The Viet Hoang, Vincent Fusco, Thomas Fromenteze, and Okan Yurduseven present a two-dimensional dynamic metasurface aperture (2D-DMA) to perform computational polarimetric microwave imaging for the first time. Leveraging the developed 2D polarimetric DMA, the authors synthesize a computational imaging radar system consisting of two DMA apertures. Using a full-wave numerical analysis, the synthesized aperture is validated in terms of its computational polarimetric imaging capability.
Field Synthesis of High Directivity Beams for Conformal Sources
March 22 2021Giovanni Leone, Fortuna Munno and Raffaele Solimene examine the role of the source geometry in the radiation of focusing beams by conformal antennas, by focusing on the comparison of their directivity functions at different maximum directions. An inverse source problem approach is adopted, where solutions stable with respect to data uncertainties are to be found by relying on the analysis of the pertinent operator by the Singular Values Decomposition. The usefulness of the approach as a tool in antenna synthesis is shown by comparing different geometries for those applications where identical beams are required to be radiated for the coverage of a large angular domain.
Optimized Differential TCDA (D-TCDA) with Novel Differential Feed Structure
March 19 2021Alexander D. Johnson, Vignesh Manohar, Satheesh Bojja Venkatakrishnan and John L. Volakis propose an improved L-C band differentially-fed Tightly Coupled Dipole Array (D-TCDA). Emphasis is placed on achieving wide-angle resonance-free scanning for single and dual-linear polarized D-TCDA configurations. A key contribution of the paper is the novel Balanced Wideband Impedance Transformer feed that mitigates common-mode resonances when scanning to low angles across large bandwidths. Rigorous full-wave and circuit analysis is provided to show the benefits of the BWIT over standard twin-line balanced array feeds.
A Method for Tailoring the Gain Pattern of a Single Antenna Element
March 19 2021Riku Kormilainen, Anu Lehtovuori and Ville Viikari propose a novel method to tailor the radiation pattern of an antenna element, such as a single element of an array, by maximizing its partial radiation efficiency in the desired angular space. The tailored pattern of the single element is achieved by current distribution synthesis using multiple feed points in the antenna. A method to determine and realize the currents at the feeds is presented. The method is demonstrated by designing and manufacturing a four-element linear array consisting of tailored antenna elements and comparing its performance to the reference case.
Dual-Polarized High-Isolation Antenna Design and Beam Steering Array Enabling Full-Duplex Communications for Operation over a Wide Frequency Range
March 19 2021Maksim V. Kuznetcov, Symon K. Podilchak, Ariel McDermott and Mathini Sellathurai present a new In-Band Full-Duplex dual-polarized antenna element and 2×2 array for S-band applications. Two different single-element prototypes based on foam spacers and nylon screws are discussed and the presented designs offer improvements in terms of isolation and bandwidth when compared to similar structures previously reported. The operating bandwidths and isolation values offered by the proposed S-band antenna and array systems can support new datalink possibilities for beam steering and future low-cost IBFD wireless networks by simple antenna fabrication.
Superlens Enhanced 2-D Microwave Tomography with Contrast Source Inversion Method
March 17 2021Anton Menshov and Vladimir I. Okhmatovski present a modification of the Contrast Source Inversion (CSI) algorithm which conducts image reconstruction of an object from its scattered electromagnetic field in the presence of a focusing media. The improvements of the proposed modified CSI algorithm are demonstrated in the numerical image re-construction from the synthetic scattered field data, produced by inhomogeneous objects of complex shape.
The Method of Maximum Power Transmission Efficiency for the Design of Antenna Arrays
March 17 2021Wen Geyi reviews a technique, called the method of maximum power transmission efficiency (MMPTE), for the design of antenna arrays and wireless power transmission (WPT) systems. The paper summarizes the basic theory of MMPTE and demonstrates MMPTE through a number of near- and far-field applications, including focused antennas, smart antennas, shaped beam antennas, end-fire antennas, multi-beam antennas, polarization-reconfigurable antennas, and wireless power transmission systems.
A Circularly-Polarized-Reconfigurable Patch Antenna with Liquid Dielectric
March 9 2021Zhe Chen, Hao-Zhan Li, Hang Wong, Xiao Zhang and Tao Yuan propose a circularly-polarized (CP) reconfigurable patch antenna based on a fluidic control method. Compared with the state-of-the-art liquid CP antenna designs, the proposed design has a lower profile, higher total efficiency and more stable CP gain, and could be applied as a reader antenna in RFID applications.
Penta-Band Inverted-F Antenna Tuned by High-Voltage Switchable RF Capacitors
March 3 2021Valentyn Solomko, Oguzhan Oezdamar, Robert Weigel and Amelie Hagelauer present a penta-band inverted-F antenna tuned by two high-voltage aperture tuning networks. The authors provide a systematic design analysis of the antenna based on the transmission line model, and discuss the tuning approach for enabling carrier aggregation over two bands at a time. The hardware prototype demonstrates the ability to cover two frequency points at different bands simultaneously. The nonlinear performance fulfils the requirements of the 3GPP for maximum out of band spurious emission, making the proposed concept suitable for practical use.
Quantitative Non-Linear Inverse Scattering: a Wealth of Possibilities Through Smart Rewritings of the Basic Equations
March 2 2021Martina T. Bevacqua and Tommaso Isernia review and describe under a common rationale some approaches which have been introduced for counteracting non-linearity in inverse scattering. In particular, they focus on three rewritings of the Lippman Schwinger basic equation in order to reduce the ‘degree of non-linearity’ of the inverse scattering problem, which are compared and tested against different numerical examples.
Fluidic Stub-Loaded Patch Antenna for Frequency-Tunable Polarization Reconfiguration
March 2 2021Aditya Singh and Carlos E. Saavedra present a fluidic method for a frequency-tunable, polarization-reconfigurable microstrip patch antenna employing fluidically-tuned stubs. The authors propose for the first time an electrical circuit equivalent of the fluidically-tuned patch antenna using the first order parallel RLC circuit for the patch’s degenerate modes and a transmission line model for the fluidically-tuned stubs. The fully planar low profile antenna provides near continuous tuning range for LP, RHCP and LHCP modes with fluidic actuation.
A Stretchable Liquid Metal Coaxial Phase Shifter
March 2 2021 David M. Hensley, Christos G. Christodoulou, and Nathan Jackson present a stretchable liquid metal coaxial phase shifter constructed of a liquid metal center conductor, a liquid metal shield in the shape of a hollow cylinder, and a stretchable rubber-based polymer which encases and insulates the liquid metal. The paper builds on and enhances previous research; by modifying the design of the shield to consist of a hollow cylinder rather than woven strands, TEM breakdown at high frequencies is decreased, and the phase shifter improves its transmission and reflection coefficients at higher frequencies.
Antenna Array Calibration Using a Sparse Scene
February 24 2021Johanna Geiss, Erik Sippel, Markus Hehn and Martin Vossiek propose a low-effort near-field calibration method for radar systems, that overcomes the limitations of common calibration approaches. The method uses a synthetic aperture and sparsely distributed targets at unknown locations in the array’s near-field. It requires neither target position information and far-field conditions nor an anechoic chamber, because multipath propagation can be suppressed easily for targets located in the near-field.
A Novel Dual-Polarized Wideband and Miniaturized Low Profile Magneto-Electric Dipole Antenna Array for mmWave 5G Applications
February 24 2021Yin Chen Chang, Ching Cheng Hsu, M. Idrees Magray, Hsu Yung Chang and Jenn-Hwan Tarng propose a Ka-band dual-polarized low profile magneto-electric dipole antenna with wide operational bandwidth. The proposed antenna overcomes the challenges of low thickness and wide impedance bandwidth, and would be an attractive candidate for millimeter-wave 5G applications.
Low-rank Matrix Factorization Method for Multiscale Simulations: A Review
February 24 2021Mengmeng Li, Dazhi Ding, Alexander Heldring, Jun Hu, Rushan Chen and Giuseppe Vecchi present a review of the low-rank factorization method, emphasizing on its application to multiscale problems. Progress in solutions addressing challenges from realistic multiscale simulations is presented. Improved sampling technologies are introduced, leading to linear and quasi-liner computation complexities at low and high frequency. Large and realistic morphed aircrafts are tested to demonstrate the validity of the presented methods.
Scattering by perfectly conducting cylindrical targets hidden below a multilayered medium
February 18 2021Christina Ponti presents an approach to solve the scattered field by perfectly conducting cylinders with circular cross-section, placed below a multi-layered medium, under illumination by a line source. The developed theoretical formulation is a very compact one, as only two scattered-field contributions are used in each layer. The method can be applied to the modelling of several radar problems of targets in complex environments.
Profile Inversion and Closed Form Formulation of Compact GRIN Lenses
February 17 2021Francesca Maggiorelli, Anastasios Paraskevopoulos, John Vardaxoglou, Matteo Albani and Stefano Maci present new formulas for the design of cylindrical Graded-Index lens-antennas with integrated feeder. The possibility of integrating the feeder within the lens makes the system more compact, avoids complex mechanical design and alignment errors. The lens is characterized in analytical form by Geometrical Optics. The proposed formulation is successfully validated by using ray-tracing and a fullwave simulations.
A Non Iterative Crosswords Inspired Approach to the Recovery of 2D Discrete Signals from Phaseless Fourier Transform Data
February 16 2021Giada M. Battaglia, Roberta Palmeri, Andrea F. Morabito, Pasquale Giuseppe Nicolaci and Tommaso Isernia propose an innovative approach to the phase retrieval of 2-D discrete complex signals. The solution strategy profitably exploits some fundamental results available for the phase retrieval of one-dimensional discrete signals by following a simple yet effective philosophy resembling the solution of crossword puzzles. Numerical examples witnessing the interest of the proposed ideas are given for antenna applications.
DOA Estimation in Non-Uniform Noise Using Matrix Completion via Alternating Projection
February 16 2021Yingna Fei, Hui Cao, Yuntao Wu, Xitong Chen and Li Chen investigate direction-of-arrival (DOA) estimation in the presence of non-uniform noise. To achieve high estimation accuracy, the DOA estimation problem is solved with the use of a matrix completion approach based on the alternating projection algorithm. Simulation results verify the effectiveness and accuracy of the proposed method.
Design of a Cylindrical Crossed Dipole Phased Array Antenna for Weather Surveillance Radars
February 16 2021Mohammad-Hossein Golbon-Haghighi, Mirhamed Mirmozafari, Hadi Saeidi-Manesh and Guifu Zhang present a cylindrical dual-polarization phased array antenna for weather surveillance radars that features high isolation, matched copolar beams, low side lobe levels, and adaptive null steering. The proposed array can benefit national weather radar networks to provide accurate multiparameter measurements enabling reliable observation of severe weather phenomena.
RF-Powered Wearable Energy Harvesting and Storage Module based on E-Textile Coplanar Waveguide Rectenna and Supercapacitor
February 16 2021Mahmoud Wagih, Nicholas Hillier, Sheng Yong, Alex S. Weddell and Steve Beeby present an all-textile RF energy harvesting and storage unit that charges a textile supercapacitor with better efficiency than rigid systems. A textile energy storage can be charged more efficiently through omitting the power management circuitry, reducing cost and complexity while improving the efficiency. A compact flexible antenna can be concealed inside fabric maintaining its performance on and off the body.
Analytical Approach for MRI RF Array Coils Decoupling by Using Counter Coupled Passive Resonators
February 16 2021Danilo Brizi, Nunzia Fontana and Agostino Monorchio introduce an analytical approach to design decoupling filters for MRI radiofrequency array elements, adopting counter-coupled passive resonators as unit-cells. The developed analytical framework can be useful to model and control the mutual interactions between the various elements of an RF MRI system. In addition, the possibility to print the decoupling elements and the RF coils on the same dielectric substrate leads to a mechanically robust prototype.
Electromagnetic scattering by metallic targets above a biological medium with a spectral-domain approach
February 8 2021Cristina Ponti, Ludovica Tognolatti and Giuseppe Schettini study the scattering of a far-field source by perfectly conducting targets above a semi-infinite lossy medium. An analytical solution is applied to the electromagnetic scattering problem by utilising the Cylindrical Wave Approach, which allows modelling the interaction of an external source with a biological medium, in the presence of external metallic objects.
Wideband Printed Half Bow-Tie Antenna Array Based on a Quad-Mode Reconfigurable Feeding Network for UAV Communications
February 8 2021Ye-Yeong Jeong and Wang-Sang Lee present a wideband printed half bow-tie antenna array based on a quad-mode reconfigurable feeding network for unmanned aerial vehicle communications (UAV). The proposed array has a wide beam coverage and a wide bandwidth as well as a miniaturized size, a high gain, and a low-profile symmetrical structure for ease of installation and aerodynamic drag reduction in UAV.
Microwave Tomography with LSTM-Based Processing of the Scattered Field
February 4 2021Alessandro Fedeli enhances a multifrequency tomographic approach in nonconstant-exponent Lebesgue spaces by a preliminary step that processes the measured scattered field with a neural network based on long short-term memory cells. In the considered cases, this approach allows dealing with measurements in three-dimensional settings obtained with non-ideal antennas and measurement points, while retaining a canonical two-dimensional formulation of the inverse problem.
Wide-band and Wide-Angle Scanning Phased Array Antenna for Mobile Communication System
February 4 2021Guangwei Yang, Yiming Zhang and Shuai Zhang propose a wide-band phased array antenna that is a promising candidate for 5G mobile communications. A simple and efficient method is applied into the array antenna towards achieving wide angle scanning capability with high gain, corresponding to ±60° scanning in the wide operating bandwidth. Furthermore, the beam in the E-plane can scan over ±70° with a realized gain reduction under less than 3 dB.
A Metamaterial Position Sensor Based on Magnetoinductive Waves
February 4 2021Jiaruo Yan, Christopher J. Stevens and Ekaterina Shamonina present a new contactless localising sensor based on the propagation of slow waves in metamaterials. Using the properties of magnetoinductive waves in a one dimensional metamaterial, they are able to unambiguously locate a nearby object. Key performance metrics are investigated and the ultimate horizontal range of the sensor is demonstrated to be directly linked to the metamaterials quality.
Embedded Propagation Graph Model for Reflection and Scattering and Its Millimeter-Wave Measurement-Based Evaluation
January 13 2021Propagation graph (PG) is a stochastic channel simulation method for scattering propagation. Yuan Liu, Xuefeng Yin, Xiaokang Ye, Yongyu He and Juyul Lee propose a novel simulation-based channel modelling approach based on embedded-PG (EPG). The newly proposed method is capable of accordingly reproducing the channel characteristics attributed to reflecting components and scattering components.
UCA-Based OAM Non-Orthogonal Multi-Mode Multiplexing
January 13 2021Electromagnetic waves carrying orbital angular momentum (OAM) can improve the spectral efficiency of communication systems by multiplexing a number of OAM modes. Rui Chen, Runzhong Yao, Wen-Xuan Long, Marco Moretti and Jiandong Li propose a non orthogonal OAM multi-mode multiplexing scheme based on uniform circular arrays, which includes the generation, multiplexing transmission and reception of non-orthogonal OAM modes.
Eight-Port Feed Radial Line Slot Antenna for Wireless Power Transmission
January 13 2021Takashi Tomura, Jiro Hirokawa, Minoru Furukawa, Teruo Fujiwara and Naoki Shinohara propose a circular sector subarray to equalize input power to rectifiers and an eight-port radial line slot antenna (RLSA) with the circular sector subarray. The design methodology of the eight-port RLSA is detailed and it is fabricated by printed circuit board technology. The performance of the fabricated antenna showed good agreement with the simulated characteristics.
Multiband Patch Antenna Design Using Nature-Inspired Optimization Method
December 31 2020Achilles D. Boursianis, Maria S. Papadopoulou, Juliano Pierezan, Viviana C. Mariani, Leandro S. Coelho, Panagiotis Sarigiannidis, Stavros Koulouridis and Sotirios K. Goudos present a multiband microstrip patch antenna with three slits. The proposed antenna operates in the European LoRaWAN and the cellular (GSM-1800 and UMTS) communication frequency bands. The feasible solution of the multiband patch antenna is obtained by the utilization of the Coyote Optimization Algorithm, that is applied for the first time to address an electromagnetic problem. The proposed antenna demonstrates features of operation, which make it a promising candidate for RF energy harvesting applications.
Semi-Resistive Approach for Tightly Coupled Dipole Array Bandwidth Enhancement
December 25 2020Maxence Carvalho, Alexander D. Johnson, Elias A. Alwan and John L. Volakis present a new approach to enhance the bandwidth of Tightly Coupled Dipole Arrays (TCDA). The new design achieves the integration of a semi-resistive Frequency Selective Surface network (FSS) composed of a non-resistive low-pass FSS and two resistive band-stop FSS. The integration of this FSS network within a TCDA led to an increased impedance bandwidth of 28:1 from 0.20GHz to 5.6GHz.
Double-Layer 45∘ Linearly Polarized Wideband and Highly Efficient Transmitarray Antenna
December 22 2020Mingbo Cai, Zehong Yan, Fang-Fang Fan, Shu-Yang Yang and Xi Li present a double-layer 45° linearly polarized wideband and highly efficient transmitarray antenna (TA). The proposed antenna has the advantages of simple structure, low profile, light weight and absence of assembly error. Thus, it is a good candidate for future wireless communication systems and mobile base stations, and using a double-layer structure has great potential to facilitate the design of high-performance TAs.
Decoupling Modes in Multi-Band Microstrip Patch Antennas
December 22 2020Nicholas E. Russo, Constantinos L. Zekios and Stavros V. Georgakopoulos present an elegant approach for designing multi-band multi-mode rectangular microstrip antennas with high isolation between the bands. Compared to other methods, the proposed one preserves the low profile of microstrip antennas and provides a simple way to design and fabricate multi-band and multi-mode antennas. Therefore, this method is very well-suited for designing antennas for next generation communication systems.
Surface-Mounted Ka-band Vivaldi Antenna Array
December 22 2020Henri Kähkönen, Juha Ala-Laurinaho and Ville Viikari propose the first electrically steerable dual-polarized Ka-band Vivaldi antenna array with connector-less, surface-mount interface. The antenna interface includes integrated coaxial feed lines within the antenna element structure and contact pads on the PCB. The 8×8 antenna array is manufactured with a feeding network for one polarization, and the operation of the interface and the electrical beam steering is demonstrated. Measurements are used to characterize the manufactured feed network, the gain of the antenna array and the steering range.
Array Optimization for Maximum Beam Collection Efficiency to An Arbitrary Receiving Plane in the Near Field
December 14 2020Seishiro Kojima, Tomohiko Mitani and Naoki Shinohara propose an array optimization method for maximizing beam collection efficiency (BCE) to an arbitrary receiving plane in the near field. The presented method boils down to the generalized eigenvalue problem, and the best solution can be obtained mathematically. Results are better than those obtained by the application of the optimum far-field pattern into the near field. Moreover, the optimization method can maximize BCE with consideration of the polarization direction of the receiving antenna.
Millimeter-Wave End-Fire Magneto-Electric Dipole Antenna and Arrays with Asymmetrical Substrate Integrated Coaxial Line Feed
December 14 2020Ao Li and Kwai-Man Luk propose a wideband vertically-polarized end-fire magneto-electric dipole antenna, fed by an asymmetrical substrate integrated coaxial line, for mm-wave applications. A fixed-beam array and a 1×4 linear array with multiple beams are designed, fabricated and measured to verify the design concept and its application in arrays. The obtained results make the proposed antenna and arrays attractive candidates for many mm-wave applications, including the 5G and beyond.
Wideband Dipole Array with Balanced Wideband Impedance Transformer (BWIT)
December 14 2020Alexander D. Johnson, Jingni Zhong, Matilda Livadaru, Satheesh Bojja Venkatakrishnan, Elias A. Alwan and John L. Volakis present a novel Balanced Wideband Impedance Transformer (BWIT) feed for dipole arrays, specifically targeting 2G to 5G communications bands. The proposed BWIT mitigates common-mode currents across the entire band while scanning to low angles. In reference to past common-mode mitigation techniques, the BWIT is unparalleled in achieving balanced feeding on low-cost PCB, with no added fabrication steps or losses.
5G NR FR2 Femtocell Coverage Map Using an Omnidirectional Twisted SWAA
December 14 2020H. R. D. Filgueiras, E. S. Lima, T. H. Brandão and S. Arismar Cerqueira implement a 5G NR indoor femtocell in mm-waves, using a previously-developed omnidirectional high-gain and a wideband twisted slotted-waveguide antenna array. The authors demonstrate the applicability of the femtocell implementation in a real scenario and its ability to achieve an omnidirectional coverage, under line-of-sight (LOS) and NLOS (non-LOS) propagation conditions.
A Study of Wearable Wireless Power Transfer Systems on the Human Body
December 9 2020Juan Barreto, Gianfranco Perez, Abdul-Sattar Kaddour and Stavros V. Georgakopoulos perform a study to evaluate the performance of wearable Wireless Power Transfer (WPT) systems on various parts of the human body. Specifically, the effects of the human body on the Power Transfer Efficiency of a Conformal Strongly Coupled Magnetic Resonance WPT system are systematically examined. Simulations and measurements of two configurations are performed for 26 different placement locations on the human body.
High Gain Periodic 2D Leaky-Wave Antenna with Backward Radiation for Millimeter-Wave Band
December 9 2020Abdullah Attar and Abdel Razik Sebak propose a two-dimensional periodic leaky-wave antenna that can be potentially used for millimeter-wave applications. Analytical equations are presented as an indicator for the antenna’s performance, and their validity is shown. A prototype is fabricated to validate the design. The simulated results and the measured results are in good agreement.
Large Minimum Redundancy Linear Arrays: Systematic Search of Perfect and Optimal Rulers Exploiting Parallel Processing
December 9 2020Minimum Redundancy Linear Arrays (MRLAs) have a mathematically identical counterpart called perfect ruler. Fabian Schwartau, Yannic Schröder, Lars Wolf and Joerg Schoebel revisit the problem of sparse ruler construction and use two exhaustive search algorithms to compute longer rulers than previously published. Further, they present an approach to accelerate the execution by distributing the recursive search algorithms over multiple computers.
Review on Ray Tracing Channel Simulation Accuracy in Sub-6 GHz Outdoor Deployment Scenarios
December 2 2020Allan Wainaina Mbugua, Yun Chen, Leszek Raschkowski, Lars Thiele, Stephan Jaeckel and Wei Fan present a review of the achieved accuracy in the literature for ray tracing-based channel modelling, with a focus on outdoor propagation scenarios in the sub-6 GHz frequency range. The impact of different interaction mechanisms on the prediction accuracy is outlined. Simulations are also presented to demonstrate the impact of material parameters’ setting on the path loss for urban macrocell and microcell scenarios.
3D Printed Wideband Multilayered Dual-Polarized Stacked Patch Antenna with Integrated MMIC Switch
December 2 2020Capability of 3D printing for developing wideband multilayered antenna systems packaged with active RF circuit components remains relatively unexplored. To address this gap, Merve Kacar, Thomas M. Weller and Gokhan Mumcu demonstrate a wideband patch antenna that is integrated with a polarization selection switch.
Meshed High-Impedance Matching Network-Free Rectenna Optimized for Additive Manufacturing
November 12 2020Mahmoud Wagih, Alex S. Weddell and Steve Beeby present a novel scalable high-impedance optically-transparent antenna fabricated using a low-cost off-the-shelf dispenser printer on a lossy substrate for energy harvesting applications. The antenna is designed with>1 mm features to accommodate all low-cost printing processes, can be tuned to match high-impedance capacitive rectifiers, and achieves a peak power conversion efficiency improvement of over 37% over state-of-the-art flexible rectennas for low power densities.
Dielectric Resonator Antenna Geometry-dependent Performance Tradeoffs
November 12 2020Eric B. Whiting, Sawyer D. Campbell, Galestan Mackertich-Sengerdy and Douglas H. Werner combine a flexible shape generation technique with multiobjective evolutionary optimization algorithms in order to synthesize geometrically-diverse dielectric resonator antennas and explore the impact geometry has on relevant performance metrics. The proposed approach is compatible with various feed designs, antenna performance parameters, and 3D printing techniques.
Sensor Arrangement in Monostatic Subsurface Radar Imaging
November 12 2020Maria Antonia Maisto, Rocco Pierri and Raffaele Solimene focus on microwave subsurface imaging achieved by inverting the linearized scattering operator, and introduce a strategy for spatial data sampling, which allows to reduce the spatial data measurements and at the same time to keep the same achievable performance in the reconstructions.
Radar Main-Lobe Jamming Suppression Based on Adaptive Opposite Fireworks Algorithm
November 10 2020In the presence of the main lobe jamming, the performance of the modern radar system would degrade significantly. Weilin Luo, Hongbin Jin, Hao Li and Keqing Duan combine independent component analysis and swarm intelligence, and propose a blind source separation method based on an Adaptive Opposite Fireworks Algorithm in order to address the problem of ineffective target echo detection when the radar is subjected to main lobe jamming.
Practical Diversity Design for PCB IoT Terminals
November 2 2020Maryam Razmhosseini, Abhijit Bhattacharya and Rodney Vaughan provide a comprehensive review of diversity evaluation metrics, clarifying their assumptions and formulations, and establish new diversity designs as well as benchmarks including the study of loss mechanisms. Independent standard measurement facilities are used to compare the results throughout the paper. The performance impact of polarized and 3D directional scenarios are discussed with von Mises-Fisher distribution.
Low-cost S-band Reconfigurable Monopole/Patch Antenna for CubeSats
October 27 2020The development of reconfigurable antennas compatible with a CubeSat form factor can aid several space missions. Alexander D. Johnson, Vignesh Manohar, Satheesh Bojja Venkatakrishnan and John L. Volakis present a unique reconfigurable antenna concept enabled by adhesive polyimide tapes. The antenna can switch from a conventional patch to a monopole-like antenna with minimal actuation complexity. The proposed technique significantly reduces weight, cost and power associated with conventional electronic techniques which use active elements or complex mechanical techniques.
Mitigating Quantization Lobes in mmWave Low-bit Reconfigurable Reflective Surfaces
October 27 2020Single-bit Reconfigurable Reflective Surfaces (RRSs) are planar beamforming structures, which under plane-wave illumination suffer from undesired side lobes or quantization lobes, caused by the periodicity of the errors due to the limited number of bits used in phase quantization. Bharath G. Kashyap, Panagiotis C. Theofanopoulos, Yiran Cui and Georgios C. Trichopoulos present a robust technique for mitigating quantization lobes in sub-mmWave single-layer 1-bit RRSs under plane wave illumination using random phase delays.
Error Analysis of Higher Order Bivariate Lagrange and Triangular Interpolations in Electromagnetics
October 12 2020 Wen Luo, Jinbo Liu, Zengrui Li, and Jiming Song measure the interpolation errors of the higher order bivariate Lagrange polynomial interpolation based on the rectangular, right and equilateral triangular interpolations by using the maximum and root-mean-square errors. The error distributions of above three kinds of interpolations are analysed to find the regions having the smallest interpolation error. Both analytical and numerical results show that the right triangular interpolation is the most efficient interpolation method.
Millimeter-wave Butler Matrix Beamforming Circuit using Finline in Double-layer Dielectric Substrate
October 8 2020 Nguyen Thanh Tuan, Kunio Sakakibara, Kojiro Iwasa, Takeshi Okunaga, Nobuyoshi Kikuma, and Yoshiki Sugimoto present a new kind of finline in double-layer dielectric substrate and its beamforming circuit of Butler matrix in the millimeter-wave band. The proposed finline design aims to provide a low-complexity and low-loss transmission line, which is applied to the Butler matrix design. The advantages of simple structure and low cost make the finline in double-layer substrate an attractive solution for millimeter-wave applications.
Millimeter-Wave Power Harvesting: A Review
October 1 2020Mahmoud Wagih, Alex S. Weddell and Steve Beeby present a review of recent advances in mmWave wireless power transmission at a component- and system-level. Low-cost antennas and components for mmWave power harvesting, such as high efficiency scalable rectifiers on polymers and high radiation efficiency antennas on textiles, are reviewed. The authors also provide an overview of future antenna design challenges and research directions for mmWave power harvesting.
An Accurate Equivalent Circuit Model of Metasurface-Based Wireless Power Transfer Systems
October 1 2020Danilo Brizi, Nunzia Fontana, Sami Barmada and Agostino Monorchio introduce a general analytical procedure to unambiguously characterize a metasurface through its lumped circuital equivalent in resonant inductive Wireless Power Transfer (WPT) applications. The proposed procedure is extremely accurate to achieve a reliable RLC equivalent circuit, and provides quantitative and manageable parameters to predict and improve the entire WPT system performance. The obtained results can pave the way to a simpler and more effective approach to metamaterials and metasurfaces in resonant inductive WPT.
Eddy Current Modeling in Multiply Connected Regions Via a Full-Wave Solver Based on the Quasi-Helmholtz Projectors
September 29 2020Tiffany L. Chhim, Adrien Merlini, Lyes Rahmouni, John Erick Ortiz Guzman and Francesco P. Andriulli present a novel boundary element method for the simulation of eddy current scenarios. The effectiveness of quasi-Helmholtz projectors is leveraged to obtain a versatile solver, which is computationally efficient and allows for a seamless transition between low and high frequencies. The stability and accuracy of the new method are demonstrated both theoretically and through numerical experiments on canonical and realistic structures.
Bandwidth Enhancement Technique for Broadside Tri-Modal Patch Antenna
September 18 2020Chi-Yuk Chiu, Buon Kiong Lau and Ross Murch describe a technique for enhancing the bandwidth of a broadside tri-modal patch antenna. The key idea is to incorporate a dual-resonance structure into the broadside tri-modal patch geometry. The proposed technique does not sacrifice the desirable properties of its base design, including compactness, multi-port, broadside radiation, low mutual coupling and rotational symmetry. Therefore, the presented wideband tri-port antenna is suitable for constructing practical massive MIMO arrays.
Microwave Detection of Brain Injuries by Means of a Hybrid Imaging Method
September 15 2020Alessandro Fedeli, Claudio Estatico, Matteo Pastorino, and Andrea Randazzo introduce an innovative hybrid microwave imaging method, which combines the benefits of a fast qualitative processing technique with an accurate tomographic reconstruction of the dielectric properties of the human head. The method is successfully applied to obtain microwave images from both synthetic data and laboratory measurements. Numerical simulations and experimental testing yield promising results, which may be considered a preliminary step towards the realization of a clinical imaging prototype.
Social Network Optimization based Procedure for Beam-Scanning Reflectarray Antenna Design
September 8 2020A. Niccolai, M. Beccaria, R.E. Zich, A. Massaccesi, and P. Pirinoli deploy the Social Network Optimization (SNO) algorithm for assessing an effective design procedure of a beam-scanning passive reflectarray (RA). The performance of SNO and the beam-scanning capabilities of the optimized RA are assessed through the comparison with other well established Evolutionary Algorithms. The designed optimization environment makes the system easily scalable to larger reflectors with more degrees of freedom.
A Water-Based Huygens Dielectric Resonator Antenna
September 4 2020Huygens antennas, composed of single element structures supporting a special combination of electric and magnetic modes, provide an alternative route for compact and directive antennas. Rasmus E. Jacobsen, Andrei V. Lavrinenko and Samel Arslanagić investigate a subwave length water-based Huygens dielectric resonator antenna with strongly excited electric and magnetic dipoles at around 350 MHz. The proposed antenna may serve as an easy–to–fabricate and cheap alternative for the VHF and low end of the UHF bands.
Fast Semi-Analytical Design for Single-FSS-Layer Circuit-Analog Absorbers
September 4 2020Xiaojing Lv , Shengjian Jammy Chen , Amir Galehdar , Withawat Withayachumnankul and Christophe Fumeaux present a design approach for analyzing and synthesizing circuit analog absorbers based on a single-layer frequency-selective surface (FSS). The proposed approach integrates analytical, empirical, and numerical techniques, and dramatically reduces the number of full-wave simulations required for global optimization, so that the potential of fundamental FSS geometries can be exhaustively exploited.
Terahertz Antenna Array based on a Hybrid Perovskite Structure
August 28 2020Abdoalbaset Abohmra, Hassan Abbas, Muath Al-Hasan, Ismail Ben Mabrouk, Akram Alomainy, Muhammad A. Imran and Qammer H. Abbasi propose a novel terahertz (THz) antenna array design comprising a layered structure of a perovskite material, which enhances the radiation characteristics of an antenna overlaid on a conventional metallic antenna element. The presented designs could help in realising future wireless communication systems that require miniaturisation, fast reconfigurability and wearability.
Microwave breast imaging with prior ultrasound information
August 27 2020Yingying Qin, Thomas Rodet, Marc Lambert and Dominique Lesselier investigate microwave breast imaging with prior information on tissue boundaries acquired from ultrasound reflection data. A regularization term is to incorporate the information that two neighboring pixels should exhibit similar dielectric properties when not on a boundary while a jump would be allowed otherwise. Imaging quality appears greatly improved with this regularization when tissue boundaries are indeed provided.
Integrated-EBG Ridge Waveguide and Its Application to an E-Band Waveguide 32×32 Slot Array Antenna
August 26 2020Zhongxia Simon He, Cheng Jin, Sining An, Lingwen Kong and Jinlin Liu propose a design methodology for an E-band waveguide 32×32 slot array antenna with high-efficiency and low-cost manufacturing characteristics. It is based on an integrated electronic bandgap (EBG) ridge waveguide, designed by integrating a cross rectangle-hollow EBG structures in the conventional ridge waveguide. The authors demonstrate that the proposed cross rectangle-hollow EBG structures constitute a promising candidate for high-performance millimeter-wave antennas.
Synthesis of Reflectors Characterized by the Spatial Dispersion of the Reflection Coefficient
August 13 2020Planar antenna reflectors are attractive for the design of both narrow-beam antenna arrays and frequency-scanning arrays. Kirill Klionovski, Sergey Bankov, and Atif Shamim develop a novel stable, accurate and fast numerical method based on triangular meshing and space transformations for electrodynamics problems with arbitrary boundaries. A modified finite difference time domain (FDTD) algorithm is presented and a novel averaging method is used to ensure the stability and accuracy of the proposed algorithm when dealing with anisotropic and inhomogeneous materials in the transformed space.
Efficient Analysis of Electromagnetic Scattering in Post-Wall Waveguides and Its Application to Optimization of Millimeter Wave Filters
August 12 2020 Arkadi Akopian, Guga Burduli, Vakhtang Jandieri, Hiroshi Maeda, Wonbin Hong, Ahmed Abdelmottaleb Omar, Kiyotoshi Yasumoto, Douglas H. Werner, and Daniel Erni analyse functional post-wall waveguides and waveguide based compact passive circuits that are formed by introducing additional metallic or dielectric posts inside the post-wall waveguide. The developed formulation is numerically very fast, and can be considered as one of the best-suited approaches for the analysis of multiple scattering in post-wall waveguides and for numerical structural optimization.
A Passive and Wireless Sensor Based on RFID Antenna for Detecting Mechanical Deformation
August 11 2020Sensors are key components in structural health monitoring (SHM). Yuan He, Meng Li, Guo Chun Wan, and Mei Song Tong propose a RFID patch antenna as a new absolutely passive and wireless sensor, which can measure the strain of structures by monitoring the antenna’s resonant frequency offset. The change of the targeted structure’s strain can be measured in real time and its health state can then be evaluated. The sensor provides a new perspective for the development of SHM systems and it possesses obvious advantages compared to traditional methods.
An Unbalanced Sinuous Antenna for Near-Surface Polarimetric Ground-Penetrating Radar
August 11 2020Sinuous antennas are capable of producing ultra-wideband radiation with polarization diversity. Dylan Crocker and Waymond Scott propose a novel approach to operating a sinuous antenna for near-surface polarimetric GPR applications. Each arm of a four-arm sinuous antenna is operated independently or “unbalanced”, thereby allowing the separation of transmitting and receiving channels while still providing dual-polarized radiation in a quasi-monostatic configuration, i.e., small bistatic angles.
Physics-Informed Deep Neural Networks for Transient Electromagnetic Analysis
August 04 2020Oameed Noakoasteen, Shu Wang, Zhen Peng, and Christos Christodoulou propose a deep neural network based model to predict the time evolution of field values in transient electrodynamics. The key component of the presented model is a recurrent neural network, which learns representations of long-term spatial-temporal dependencies in the sequence of its input data. The trained network can emulate a transient electrodynamics problem with more than 17 times speed-up in simulation time compared to traditional finite difference time domain solvers.
Novel Time-Domain Electromagnetic Simulation Using Triangular Meshes by Applying Space Curvature
July 27 2020M. R. Kazemzadeh, N. G. R. Broderick, and W. Xu develop a novel stable, accurate and fast numerical method based on triangular meshing and space transformations for electrodynamics problems with arbitrary boundaries. A modified finite difference time domain (FDTD) algorithm is presented and a novel averaging method is used to ensure the stability and accuracy of the proposed algorithm when dealing with anisotropic and inhomogeneous materials in the transformed space.
Low-Profile Two-Port MIMO Terminal Antenna for Low LTE Bands with Wideband Multimodal Excitation
July 21 2020Characteristic mode analysis (CMA) had been used to design efficient two-port MIMO terminal antennas for frequency bands under 1 GHz, but they are relatively narrowband. Hanieh Aliakbari and Buon Kiong Lau present for the first time a CMA-derived wideband solution that can cover LTE Low Band (698-960 MHz). The proposed wideband solution is developed using a step-by-step procedure enabled by CMA. In addition to wideband orthogonal MIMO operation, the proposed antenna is characterized by a low profile and high total efficiency of above 67% over the below 1 GHz operating band.
Mutual Coupling Suppression in Antenna Arrays using Meandered Open Stub Filtering Technique
July 17 2020Sandhiya Reddy Govindarajulu, Alexander Jenkel, Rimon Hokayem and Elias A. Alwan introduce a mutual coupling suppression technique using an open stub meandered (OSM) bandstop filter (BSF) design for MIMO applications. The OSM-BSF is optimized and implemented on the ground plane side of a two-element patch array. The proposed technique provides avenues for a new class of mutual coupling suppression techniques where high isolation plays a crucial factor in defining the system’s performance.
A Wideband Circularly Polarized Microstrip Antenna With Multiple Modes
July 16 2020Lei Wang and Yun-Fei En propose a new compact wideband circularly polarized (CP) antenna consisting of a CP square-loop with sequential phase (SP) characteristics, four strip-lines as driven elements, four L-shaped patches with I-slots and four I-shaped patches as parasitic elements. By combining these structures, multiple CP modes can be generated to realize wideband CP operation.
Techniques for Achieving High Isolation in RF Domain for Simultaneous Transmit and Receive
July 14 2020With the growth of wireless data traffic, innovative approaches are needed for efficient management of the available limited spectrum. Satheesh Bojja Venkatakrishnan, Alexander Hovsepian, Alexander Johnson, Toshifumi Nakatani, Elias Alwan and John Volakis present a review of novel approaches for achieving improved cancellation across wide bandwidths in RF and propagation domains. An average cancellation of 50 dB over 1 GHz BW is obtained by using two stages of RF signal cancellation.
Antenna Classification using Gaussian Mixture Models (GMM) and Machine Learning
July 9 2020Radio frequency fingerprinting (RFF) is the concept arising from classification of wireless emitters due to their unique radio frequency features. Yihan Ma and Yang Hao adopt a Gaussian Mixture Models (GMM) technique in order to extract RFF of antennas. The GMM approach demonstrates better performance on large datasets with respect to conventional feature extraction approaches, achieving classification accuracy above 88% when combined with a SVM classifier.
Time Domain Characteristic Mode Analysis for Transmission Problems
July 9 2020Characteristic mode analysis (CMA) is based on time-harmonic electromagnetics and applied mostly in frequency domain. Qi Wu and Zhongkui Wen extend CMA to time domain (TD) for transmission problems. The proposed method is based on full-wave solutions, which makes it applicable to different structures. TD-CMA depicts the whole picture instead of discrete resonances, providing useful information about the structure. TD-CMA can also reveal the propagation mechanisms and indicate possible optimization through mode control.
Modeling HF radio wave propagation in 3D non-uniform ionosphere with smooth perturbation method
July 8 2020Alexei V. Popov presents an analytical approach to the problem of long-range HF electromagnetic wave propagation, based on the asymptotic solution of the ray equations by smooth perturbation method (two-scale expansion in a small parameter characterizing horizontal gradients of the ionospheric plasma). The obtained approximate solution, combined with a standard ionosphere model, facilitates global ray tracing and calculation of radio signal physical parameters.
Characteristic-Mode-Based Design of Planar In-Band Full-Duplex Antennas
July 7 2020In-band full-duplex radios demand simultaneous-transmit-and-receive (STAR) antennas with high isolation, com-pact and ultra-low profiles, and simple feed networks. Current state-of-the-art designs rarely meet all of these requirements at the same time. Qianyi Li and Ting-Yen Shih present a characteristic-mode-based design approach to achieve high isolation using compact fully-planar STAR antennas with a simple feed structure.
Direct-Splitting-based CN-FDTD for Modeling 2D Material Nanostructure Problems
July 3 2020Naixing Feng, Yuxian Zhang, Qingsheng Zeng, Mei Song Tong, William T. Joines and Guo Ping Wang present a complex-frequency-shifted direct-splitting-based Crank-Nicolson finite-difference time-domain (CFS-CNDS-FDTD) for infrared two-dimensional layered material (2DLM) metasurface implementation on all-dielectric nanostructures. The proposed CFS-CNDS-FDTD can greatly improve the computational efficiency when solving infrared terahertz problems with few-atomic-layer thickness of 2DLMs due to possessing capabilities of implicit FDTD method and unsplit-field CFS-PML.
Patch Antenna and Antenna Array on Multilayer High-Frequency PCB for D-band
June 24 2020 Antti Lamminen, Jussi Säily, Juha Ala-Laurinaho, Jesus de Cos and Vladimir Ermolov present a patch antenna and a scalable array design on a low-cost multilayer Printed Circuit Board (PCB) technology for future wireless communications application at D-band (135-155 GHz). The low-loss and low-cost multilayer PCB technology enables the integration of complex MMICs and antennas into scalable phased antenna arrays.
Huygens metasurface lens for W-band switched beam antenna applications
June 19 2020 Switched beam antennas provide an efficient and cost effective alternative to complex phased array and digital beam forming techniques. Andreas Olk and David Powell present the design and characterization of an electrically thin Huygens metasurface lens operating at 83 GHz with high transmission efficiency, and demonstrate its applicability to switched beam antenna applications by exciting it with an omnidirectional waveguide antenna placed at different positions.
A method for optimising superdirectivity of coupled meta-atoms via planar directivity evaluation
June 11 2020 Jiaruo Yan, Anna Radkovskaya, Svetlana Kiriushechkina, Irina Khromova, Christopher Stevens, Laszlo Solymar and Ekaterina Shamonina propose a simple and rapid way of optimising directivity in metamaterial-inspired endfire antenna arrays with strong inter-element coupling. Their method can be extended to arrays comprising larger number of meta-atoms of various shape and would enable rapid prototyping of 3D-printed meta-atoms with desired radiation properties.
Dual Circularly Polarized Aperture Array Antenna in Gap Waveguide for High-Efficiency Ka-band Satellite Communications
June 9 2020 Miguel Ferrando-Rocher, Jose I. Herranz-Herruzo, Alejandro Valero-Nogueira and Bernardo Bernardo-Clemente present a novel fully metallic Ka-band dual circularly polarized antenna array, consisting of 64 circular apertures, and implemented in gap waveguide technology. The design, integration and assembly of a novel hybrid coupler with a dual linearly-polarized antenna provide a prototype with attractive features for SATCOM on-the-move applications, such as high efficiency and low profile.
Test-Driven Design of an Active Dual-Polarized Log-Periodic Antenna for the Square Kilometre Array
June 3 2020 Pietro Bolli, Lorenzo Mezzadrelli, Jader Monari, Federico Perini, Alberto Tibaldi, Giuseppe Virone, Mirko Bercigli, Lorenzo Ciorba, Paola Di Ninni, Maria Grazia Labate, Vittorio Giuseppe Loi, Andrea Mattana, Fabio Paonessa, Simone Rusticelli and Marco Schiaffino present an active dual-polarized log-periodic antenna that meets the requirements of the low-frequency (50 -350 MHz) radio telescope of the Square Kilometre Array (SKA). The antenna design has been intensively characterized through numerical simulations and experimental tests, showing very consistent results.
A Generalized Transition Matrix Model Combined with Discontinuous Galerkin Method for Open Cavities
June 3 2020 Yuyang Hu, Gaobiao Xiao and Shang Xiang apply the generalized transition matrix (GTM) model combined with the discontinuous Galerkin (DG) method to extract internal scattering information of open-ended cavities. The DG method makes the model feasible and accurate regardless of the normal continuity of the surface current at the transitional interface. The computational cost can be significantly decreased when the GTM model with the identical inner region is reused.
Conformal Strongly Coupled Magnetic Resonance Systems with Extended Range
June 2 2020 Juan Barreto, Abdul-Sattar Kaddour and Stavros V. Georgakopoulos present a significant range extension for Wireless Power Transfer (WPT) systems based on the Strongly Coupled Magnetic Resonance (SCMR) method by utilizing an easy to fabricate relay resonator known as the “U-loop.” This work could advance WPT charging pads that could be utilized with mobile devices and drones for significantly large coverage of area, while still providing excellent PTE.
A Simple Low-profile Coaxially-fed Magneto-electric Dipole Antenna without Slot-cavity
May 26 2020 Linyu Cai, Hang Wong and Kin-Fai Tong present a simple low-profile magneto-electric dipole antenna, which demonstrates comparable bandwidth and gain performances, without the vertical quarter-wavelength slot cavity. The antenna is characterized by a simple and effective structure, that makes it easy to be implemented, and reduced production cost. The prototype of the proposed antenna has been fabricated to verify the performances.
Isolation Improvement of Two Tightly Coupled Antennas Operating in Adjacent Frequency Bands Using Filtering Structures
May 26 2020 Jiayin Guo, Feng Liu, Luyu Zhao, Guan-Long Huang, Yingsong Li and Yingzeng Yin propose a mutual coupling reduction technique using filtering structures between two antennas resonating in adjacent frequency bands. The proposed method can be easily applied to either mobile terminal or 5G CPE (Customer Premise Equipment) devices where both 5G and Wi-Fi are installed as well as many other antennas with similar application scenarios.
A Polarization Reconfigurable Patch Antenna in the Millimeter-Waves Domain Using Optical Control of Phase Change Materials
May 26 2020 In recent years, the increase in data traffic and the rapid development of wireless communication technologies have increased the interest in designing more compact antenna systems with reconfigurability functions. Jehison Leon Valdes, Laure Huitema, Eric Arnaud, Damien Passerieux and Aurelian Crunteanu propose a simple and suitable way to realize antennas operating at millimeter-waves and having variable, on-demand, linear or circular polarization states.
Polarization Enhancement of Microstrip Antennas by Asymmetric and Symmetric Grid Defected Ground Structures
May 19 2020 Yujie Zhang, Zixiang Han, Shanpu Shen, Chi-Yuk Chiu and Ross Murch propose a new approach to controlling cross-polarization (XP), for either suppressing XP or exciting circular polarization (CP), in single-fed microstrip antennas, using novel grid defected ground structures. Results from two experimental prototypes demonstrate that XP can be suppressed by 15 dB and CP can be excited with 78 MHz (2.2%) 3-dB axial ratio bandwidth and 6.6 dBic gain, respectively on single-fed microstrip patch antennas.
Eight-Element Compact UWB-MIMO/Diversity Antenna with WLAN Band Rejection for 3G/4G/5G Communications
Apr 30 2020 Muhammad S. Khan, Adnan Iftikhar, Raed M. Shubair, Antonio-D. Capobianco, Benjamin D. Braaten and Dimitris E. Anagnostou present an eight element, compact UWB-MIMO antenna capable of providing high data rates for future 5G terminal equipment. The simplicity, compact size, and good performance of the proposed design make it a very strong candidate for small portable devices, vehicular network, vehicle to vehicle communication, and imaging radar.
Analysis and Design of Dual-Band Folded-Shorted Patch Antennas for Robust Wearable Applications
Apr 29 2020 Wearable antennas in recent years have advanced significantly and been researched for various applications. Rahil Joshi, Symon K. Podilchak, Dimitris E. Anagnostou, Constantin Constantinides, Muhammad N. Ramli, Herwansyah Lago and Ping J. Soh present a flexible folded-shorted patch antenna that is suitable for wearable applications such as military search and rescue operation and emergency services.
Learning Parameters of Stochastic Radio Channel Models from Summaries
Apr 23 2020 Ayush Bharti, Ramoni Adeogun and Troels Pedersen present two different machine learning methods, based on approximate Bayesian computation and deep learning, for fitting data to stochastic channel models. The proposed methods are validated on simulated and measured data, and demonstrate excellent performance when used to calibrate the polarimetric propagation graph model.
Offset Dual Reflector Shaping Based On The Pfaffian Integrability Condition
Apr 21 2020 The shaping problem of offset reflector antennas has attracted wide scientific interest and different formulations have been proposed in the literature to address it. Lynn Baker presents a rigorous theory for the synthesis of offset dual reflector antennas, which allows for a wide choice of the input to output mapping and, combined with a judicious choice of geometry, produces practical designs which outperform traditional conic section designs.
Development of Low-Profile Filtering Antennas with Dual-Mode Cavities
Apr 17 2020 Antennas and filters are the key RF/microwave components for the receiver and transmitter sub-systems. Their specifications substantially impact the performance of the radio systems. Zhan Wang and Yuandan Dong propose two novel filtering antennas, which are implemented on the dual-mode cavities and developed by utilising the single-layer substrate integrated waveguide technology.
Bio-Matched Antennas with Flare Extensions for Reduced Low Frequency Cutoff
Apr 17 2020 John Blauert and Asimina Kiourti have previously reported a new class of broadband and high gain antennas for into-body radiation, called Bio-Matched Antennas (BMAs). A major limitation of BMAs is that their volume increases significantly as the low cutoff frequency is reduced. In order to overcome this challenge, the authors propose a novel design that extends the BMA’s conducting flares along the tissue surface.
Differentially-Fed Aperture-Coupled Magneto-Electric Dipole Antenna With Continuously Variable Beamwidth
Apr 14 2020 Pattern reconfigurable antennas have been extensively used in wireless communication systems during the past few decades, for their high security, interference suppression, and large coverage area. Yuan Ji, Lei Ge, Jianpeng Wang, Quangang Chen and Wen Wu present a beamwidth reconfigurable linear array antenna utilizing three magneto-electric dipole antenna elements with no need for a complex feeding network.
Modeling the Electromagnetic Scattering Characteristics of Carbon Nanotube Composites Characterized by 3D Tomographic Transmission Electron Microscopy
Apr 14 2020 In all prior electromagnetic modeling studies of carbon nanotube (CNT) composites, the exact three-dimensional (3D) shape and spatial distribution of the CNTs in the composite were unknown. A. M. Hassan, M. K. Islam, S. On, B. Natarajan, I. Y. Stein, N. Lachman, E. Cohen, B. L. Wardle, R. Sharma, J. A. Liddle and E. J. Garboczi calculate the electromagnetic responses of experimentally mapped 3D structures of aligned-CNT polymer nanocomposites using both full-wave electromagnetic solvers and dilute-limit Effective Medium Approximations.
A Complex Domain Mapping of the SCN for an Effective PML Implementation in TLM
Apr 08 2020 Transmission Line Modelling (TLM) method is a powerful time-domain numerical technique with a demonstrated success for simulating complex electromagnetic problems. Jomiloju S. Odeyemi, Ana Vukovic, Trevor M. Benson and Phillip D. Sewell present an improved implementation of the perfectly matched layer (PML) for the TLM method based on a mapping of the symmetrical condensed node (SCN) to an analytically extended geometric space.
Machine Learning Classification of S-Band Microwave Scattering Measurements from the Forearm as a Novel Biometric Technique
Apr 08 2020 Microwave biometric scans have recently gained traction as a non-contact technique due to their robustness to environmental lighting and unobtrusiveness. Ala-Addin Nabulsi, Waleed Al-Shaikhli, Clayton Kettlewell, Kyle Hejtmanek, Ahmed M. Hassan, Reza Derakhshani present an 8-antenna (Wi-Fi) data collection setup to evaluate the microwave signature of the human forearm as a biometric modality.
Analysis of Electromagnetic Energy Absorption in the Human Body for Mobile Terminals
Mar 25 2020 The human body’s absorption of electromagnetic fields from communication enabled devices has consistently been a research topic for both researchers from universities and companies in the mobile communication industry. Hanyang Wang performs a comprehensive analysis of electromagnetic field absorption by the human body in order to explain and answer some of the key questions in this area.
Correction of Channel Sounding Clock Drift and Antenna Rotation Effects for mmWave Angular Profile Measurements
Mar 09 2020 Proper characterization of the millimeter-wave (mmWave) propagation channel requires measuring the power angular-delay profile of the channel which includes angle-of-departure and angle-of-arrival of the multipath components (MPCs). Fatih Erden, Ozgur Ozdemir, Wahab Khawaja, and Ismail Guvenc focus on a specific sounder class, based on the use of rotating directional antennas, and propose an algorithm that addresses two main problems in extracting the MPCs from the measurements: (1) the timing drift that is introduced due to the use of separate clocks (SECLs) for signal triggering; (2) the MPC delay errors appearing due to antenna rotation.
A New Corner-Reflector Antenna with Tunable Gain Based on Active Frequency Selective Surfaces
Mar 05 2020 Wireless local area networks (WLANs) and point-to-point (PTP) systems are widely used to connect two locations (stations), because of their low cost, simplicity, and flexibility. Reconfigurable corner reflector antennas have received much attention as a promising solution for PTP wireless communications due to the high level of directivity that hey can achieve. Ghada Elzwawi, Arun Kesavan, Rabeia Alwahishi, and Tayeb Denidni present a new corner-reflector antenna with a tunable gain based on active frequency selective surfaces (AFSSs), comprising a radiation source and three AFSS screens of different sizes.
Ku-Band Dual Linear-Polarized 1D Beam Steering Antenna using Parabolic-Cylindrical Reflector Fed by a Phased Array Antenna
Mar 05 2020 An ever-increasing demand for high data rate wireless communication has augmented the interest in the design of energy-efficient and cost-effective antenna systems. Antennas enabling high data rate wireless networks require wide impedance bandwidth, stable radiation pattern, high gain, and beam steering characteristics. Ghanshyam Mishra, Satish Sharma, Jia-Chi Chieh, and Randall Olsen propose a 1D beam steering high gain hybrid reflector-phased array antenna system for enhanced data rate wireless communication at Ku-band (12 - 14 GHz).
A Low-Profile Wideband Shared-Aperture Dual-Polarized Antenna Utilizing Dual-Function Slot
Mar 05 2020 Dual-polarized antennas are important for many applications including radar, wireless local area network (WLAN), and many others. Ahmed Abdelmottaleb Omar, Youngno Youn, and Wonbin Hong propose the design of a low-profile wideband shared-aperture dual-polarized antenna, consisting of a cavity-backed slot antenna to produce vertical polarization and a slot-backed monopole antenna for horizontal polarization.
Triple-Band Reconfigurable Low-Profile Monopolar Antenna with Independent Tunability
Mar 03 2020 For multi-band reconfigurable antennas, the inter-band independence of frequency sweeping is one desirable feature. Ken Paramayudha, Shengjian Jammy Chen, Thomas Kaufmann, Withawat Withayachumnankul, and Christophe Fumeaux present a reconfigurable low-profile monopolar antenna with triple-band independent tuning capability. The multi-band antenna is based on the concept of a center-fed patch with shorting vias to create independent magnetic current loops sharing the same thin circumferential aperture. The proposed antenna design is promising for advanced applications that require independent reconfigurability in multi-band operation, such as software-defined radio or carrier aggregation systems.
Analysis and Design of Checkerboard Leaky-Wave Antennas with Low Radar Cross Section
Feb 24 2020 Metasurface leaky-wave antennas (LWAs) are radiating structures with thin and light-weight geometries that are characterized by high gains and narrow beamwidths. LWAs has been an attractive topic ever since the high gain from sinusoidally-modulated impedance surfaces was interpreted using leaky waves. Subramanian Ramalingam, Constantine Balanis, Craig Birtcher, and Sivaseetharaman Pandi present the analysis and design of a new class of metasurface LWAs that inherently have low monostatic radar cross section (RCS) for normal incidence parallel polarization.
An Energy-Synchronous Direct Antenna Modulation Method for Phase Shift Keying
Feb 05 2020 Antennas face fundamental limits in their minimum radiation Q-factor (and hence, maximum bandwidth efficiency product) as their electrical size decreases. This makes transmitting wideband signals difficult using electrically small antennas because the signals are inherently bandlimited by the undesired bandpass nature of the antenna’s impedance match. Kurt Schab, Danyang Huang, and Jacob Adams present a novel scheme for transmitting broadband phase shift keyed signals from electrically small antennas using energy-synchronous direct antenna modulation.
Simplifying Through-Forest Propagation Modelling
Jan 20 2020 Propagation analysis and modelling is critical for radio systems design, but remains a challenge for most through-vegetation situations, including forests. Through-vegetation propagation models, including the standard radiative energy transfer (RET), are not very accurate, introducing uncertainties that rise up to tens of dB. Roshanak Zabihi and Rodney G. Vaughan propose a simpler propagation model, which strives to keep a reasonable association with the physics, while providing an accurate fit to the dual-slope profile of through-forest propagation.
The Periodic MLWA With Non-Uniform Aspect Ratios Based on Trapezoid DSPSL With Back-Firing to End-Firing Beam-Scanning Capacity
Jan 15 2020 As a classical planar antenna, the microstrip leaky wave antenna (MLWA) has attracted extensive research attention since being introduced in 1979. MLWA has played a significant role in microwave or millimeter-wave projects owing to its advantages of low-profile, simple structure and ease of matching. Yiming Du, Bin Xi, Yuanxin Li, Zhixi Liang, Shao Yong Zheng, and Yunliang Long present a periodic MLWA constructed of microstrip patch periods with non-uniform aspect ratios. Effective equations and simulations for the relevant antennas are used to obtain the propagation constants of the proposed antenna and design it.
Screen-Printed, Flexible, Parasitic Beam-Switching Millimeter-Wave Antenna Array for Wearable Applications
Dec 15 2019 Millimeter-wave antennas, designed for modern miniaturized devices and systems, must be low profile, flexible, and low cost. Some applications also require beam steering for detection purposes. Combining all these features into an antenna system and delivering decent antenna performance is challenging. Azat Meredov, Kirill Klionovski, and Atif Shamim combine a partially reflective surface with a parsitic patch array to create a simple beam-switching, low-profile, and flexible wearable detection system.
Dual-Polarized Multi-Resonance Antennas with Broad Bandwidths and Compact Sizes for Base Station Applications.
Dec 10 2019 Cellular base station antennas are critical components in wireless mobile communication systems. Hai-Han Sun, Can Ding, He Zhu and Y. Jay Guo present a novel design method for dual-polarized multi-resonance antennas. The method relies on attaching additional strips to cross-dipole arms to create multiple current paths and introduce additional resonant points.

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