Recent Articles
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A Review on Antenna Technology Developments for Sub-THz Wireless Communication: Applications, Challenges and Opportunities
25 February 2025 Jordi C.F. Zandboer, Gabriele Federico, Ulf Johannsen and A. Bart Smolders analyze state-of-the-art antenna concepts in the higher millimeter-wave frequency range (90-300 GHz), commonly referred to as the sub-THz frequency range. As the sub-THz range is still an emerging field of research, the aim of this review is to present and discuss different approaches and concepts reported in literature in the areas of antenna-in-package (AiP), antenna-on-chip (AoC) and other sub-THz antenna technology, focusing on the gain and occupied area parameters. Based on the analysis, it is concluded that AiP and AoC systems are very promising for highly integrated solutions requiring a small form factor, such as inter-device communication. At the same time, other concepts such as lens antennas provide a better solution for high-gain applications like fronthaul/backhaul scenarios.
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Reflective and Transmissive Linear Polarization Rotators: A Review
19 February 2025 Ahmed Abdelmottaleb Omar provides a comprehensive literature review of design principles and topologies for both reflective and transmissive polarization rotators. It begins with an overview of polarization rotators and their applications, setting the stage for an in-depth exploration of design methodologies. Reflective polarization rotator designs are first discussed, focusing on two primary approaches: tilted resonators and coupled current techniques. The article then examines various strategies for designing transmissive polarization rotators, including tilted resonators between grids, coupled currents, substrate-integrated waveguides, aperture coupling, meander lines, multilayer inclined wire gratings, and electromagnetic wave coupling techniques.
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Evaluating Vegetation Attenuation Characteristics at the 300-GHz Band
19 February 2025 Keisuke Matsui, Hiroaki Nakabayashi and Akihiko Hirata examine the seasonal variation in vegetation loss and the effects of moving foliage on signal propagation at the 300 GHz band. The variation in vegetation loss across seasons aligns well with the ITU-R model when parameters are adjusted for the month exhibiting maximum vegetation loss. During leafless seasons, slow fading is characterized by a frequency component below 0.2 Hz and occurs predominantly due to branch vibrations caused by wind. In environments where foliage consistently obstructs the line of sight between transmitter and receiver (quasi-line-of-sight, QLOS), rapid fading occurs due to foliage movement, with frequency components reaching up to 20 Hz.
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Fixed-Frequency 2-D Wide-Angle Scanning Leaky-Wave Array With Reconfigurable Probe-Fed Magneto-Electric Dipole
18 February 2025 Kai Qin, Bingjie Xiang and Kwai-Man Luk propose a new 2-D scanning leaky-wave antenna (LWA) design with a scanning range larger than competitors. It consists of a 1-bit reconfigurable magneto-electric (ME) dipole array and a pillbox beam-forming network (BFN). The probe-fed ME dipole is minimized to fit the holographic method and is introduced in LWA for the first time. A p-i-n diode is loaded in the L-shaped directly-fed probe to control whether it radiates. The dispersion characteristic of the linear LWA is examined to validate the effectiveness of the holographic method. A procedure is proposed to select the port and hologram for any-angle 2-D beam scanning.
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Metamaterial-Based Wide-Angle Scanning Circularly Polarized Phased Array With Stable Gain
12 February 2025 Xiangyu Yin, Wu Ren, Zhenghui Xue and Weiming Li propose a wide-angle scanning circularly polarized phased array with stable gain. The proposed antenna array is composed of truncated microstrip antennas, four rows of mushroom metamaterials, and two tensor holographic metasurfaces. The mushroom metamaterials generate TM10 mode on the same plane as the antenna elements, compensating for the imbalance between horizontal and vertical polarization when the beam pattern of the phased array is steered to a wide-angle point. Meanwhile, the tensor holographic metasurfaces convert surface waves into circularly polarized leaky waves, which superimpose on the radiation of the antenna array, thereby improving the axis ratio and increasing the realized gain.
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Dual-Mode, Dual-Polarization Fully-Woven Textile Antenna for Simultaneous Wireless Information and Power Transfer Applications in the 2.4 GHz Band
12 February 2025 Miguel Fernández, Carlos Vázquez and Samuel Ver Hoeye present a dual-mode, dual-polarization fully-woven textile antenna for simultaneous wireless information and power transfer in the 2.4 GHz band. It is based on a square patch with two independent ports. The first port is implemented with an offset T-match structure, to which a singlediode rectifier is connected. The selected feeding technique allows to obtain complex-conjugate impedance matching with the rectifier and right-hand circular polarization for the wireless power transfer mode. On the other hand, for the information transfer mode, a coaxial probe is used to excite the antenna with left-hand circular polarization, in order to minimize the coupling between both modes.
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Stability Analysis of the EFIE-IBC Formulation and Regularization via Spatial Filtering
04 February 2025Margaux Bruliard, Marcello Zucchi and Giuseppe Vecchi devise two “ground truth” test examples starting from a physical metasurface, then approximated via Impedance Boundary Condition (IBC). Comparison to ground truth results shows that the standard Electric-Field Integral-Equation with IBC (EFIE-IBC) may lead to significant errors, and that these may be challenging to detect. Conversely, the regularized system yields stable results that well match the ground truth of the physical structure of which the IBC is an approximation. Conversely, the regularized system yields stable results that well match the ground truth of the physical structure of which the IBC is an approximation.
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Dual-Fed DRA Subarrays Featuring Versatile Polarization Reconfigurability With High Port Isolation and Suppressed Cross-Polar Radiations
04 February 2025 Satyajit Chakrabarti and Debatosh Guha explore a near square Dielectric Resonator Antenna (DRA) geometry with dual-aperture feeding. This aims in achieving a number of attractive features from a standalone unit as well as a 4-element subarray. Unlike the earlier designs, it demonstrates four reconfigurable polarization states which are realized by conceiving a new near square shape of the DRA along with a novel feeding concept, proposed for the first time. They enable the subarray to significantly enhance the cross-polar discrimination (XPD). The design principles for dual-linear and dual-circular polarizations have been demonstrated and experimentally verified using a set of S-band prototypes. microcontroller through RC filter.
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A Sub-Aperture-Based Calibration Algorithm for MIMO Antenna Arrays
31 January 2025 Matthias Linder, Daniel Schmidt, Dominik Schwarz, Nico Riese and Christian Waldschmidt propose the deployment of sub-apertures to avoid near-field effects and to reduce the calibration effort, which is in this work related to the number of measuring points in the calibration measurement. An algorithm to create beneficial sub-apertures from a large array based on clustering is described. This allows the far-field distance to be reduced, as well as the effort required for state-of-the-art calibration methods, which depends on the aperture size. The trade-off between the benefits and error propagations as well as other limitations by the deployment of an increasing number of sub-apertures is demonstrated by simulations and measurements. Exemplary measurements show that even for large arrays in compact measuring chambers, far-field like conditions can be created.
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Point Cloud-Based Diffraction Path Extraction for Dynamic Human Body Shadowing Channel at 300 GHz
27 January 2025 Chechia Kang, Xin Du and Jun-Ichi Takada propose a method that estimates the diffraction paths from a complex human body as the ones from the cross-section of the human body. The extracted diffraction paths are used for the uniform theory of diffraction (UTD) simulation. The proposal was evaluated by an indoor measurement (3.3 m) of the human body shadowing channel and a simulation based on the modified edge representation and equivalent edge currents (MER-EECs) method. The proposal was found four times more accurate than the conventional point cloud (PC)-based vertical screen model and available for predicting the Doppler frequencies with complex human motions.
