Recent Articles
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Improving the Performance of the Phaseless Sources Reconstruction Method for Antenna Diagnostics and Characterization
24 April 2024 Yuri Álvarez López, María García Fernández, Jaime Laviada Martínez and Fernando Las-Heras Andrés explore the possibility of improving the convergence of the iterative phase retrieval methods by reducing the number of unknowns involved in the minimization problem. They propose the use of meshless basis functions to characterize the Antenna Under Test (AUT). In particular, Fourier expansion and wavelets will be analyzed. An offset reflector antenna, measured at a spherical range in anechoic chamber as well as with a UAV-based antenna measurement system, were considered for validation purposes.
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A Novel Quad-Band Electrically Small Antenna With Low Q
25 March 2025 Hanguang Liao and Atif Shamim present a novel method to design a quad-band fully Electrically Small (ES) antenna. The proposed method is based on the even and odd modes of a split-ring antenna and uses radio frequency trap loading to achieve dual-band operation for each mode. The proposed antenna is ES for all bands. At each band, the radiating structure uses almost the whole available volume, so a good bandwidth is obtained for all four bands. The proposed antenna is fabricated, and the performance at each band is measured in a proper setup designed for multi-band ES antennas.
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An Anisotropic Metamaterial Cover Layer for Scan Range Enhancement of Patch-Antenna Phased Arrays in Both Principal Planes
24 March 2025 Mohammad Soltani and George V. Eleftheriades introduces a metamaterial cover layer designed to extend the scan range of patch-antenna phased arrays in both principal planes without compromising directivity. The key innovation lies in the anisotropic properties of the cover layer which suppress the excitation of the fundamental surface-wave (SW) mode, effectively mitigating scan blindness within the desired angular range. This suppression mechanism is simply not possible with a conventional dielectric-slab wide-angle impedance matching (WAIM) layer.
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Active Retrodirective Rotman Lens Antenna for Wide-Angle RCS Enhancement
24 March 2025 Hanieh Kiani Amiri and Michal Okoniewski present measurement results and analysis of an innovative active retrodirective Rotman lens antenna architecture, designed to enhance the radar cross-section (RCS) for backscattering applications. Unlike conventional passive retrodirective systems, our design integrates custom-designed reflection amplifiers to significantly boost backscattered signal gain while maintaining low DC power consumption. A novel biasing technique enables independent phase and gain control of the amplifiers, ensuring a uniform array response and reducing DC power consumption by approximately 30%. Experimental monostatic RCS measurements at 5.15 GHz with a linearly polarized incident wave demonstrate a uniform RCS response over a ±40° scan angle.
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A Triband Wearable Antenna for Location Tracking Using Cospas-Sarsat and GNSS
20 March 2025 Rais Ahmad Sheikh, Azremi Abdullah Al-Hadi, Thennarasan Sabapathy, Roy B. V. B. Simorangkir, Rizwan Khan, Prayoot Akkaraekthalin, Che Muhammad Nor Che Isa, Surentiran Padmanathan, Toufiq Md Hossain and Ping Jack Soh present the design of a tri-band antenna operating in the Cospas-Sarsat (C-S) and GPS/GNSS bands applicable for the Internet of Things (IoT). Implemented with flexible and robust materials, the antenna operates in three distinct frequencies: 406 MHz for C-S applications and 1227 MHz (L2) and 1575 MHz (L1) for GPS/GNSS applications. The measured 10-dB impedance bandwidth is from 1.517-1.587 MHz (in L1 band) and from 1.192-1.232 MHz (in L2 band). In C-S band, the measured 6-dB bandwidth is from 393 to 406.5 MHz. The 3 dB axial ratio (AR) bandwidth in the L1 and L2 bands are 17 MHz (1.08%) and 18 MHz (1.47%), respectively.
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Distributed Phased-Array Radars Exploiting Collaborative Beamforming and Diversity Techniques for Remote Sensing Applications
18 March 2025 Sandra Costanzo and Giovanni Buonanno illustrate the analysis of phased-arrays exploiting the paradigm of collaborative beamforming together with excitation and position diversity in this work. Excitation diversity is based on a thinned arrays framework, while position diversity is implemented in terms of binned arrays paradigm. The proposed approach can fall under collaborative beamforming related to wireless sensor networks. After introducing the description of the above arrays and the related mathematical model, stochastic analysis is carried out to highlight the main characteristics, by modeling the excitation coefficients and the element positions in terms of random variables.
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Low-Complexity Wideband Circularly Polarized Modular Scalable Phased Array for Vehicular Satellite Communication
14 March 2025Behzad Yektakhah, Abdelhamid M. H. Nasr, Abdel Halim Mohamed and Kamal Sarabandi present a low-complexity wideband circularly polarized (CP) array in X-band for vehicular satellite communication. The array comprises dual-polarized corner-fed patch elements for achieving wide bandwidth. The active elements are integrated in a modular manner using interposers that enables the scalability of the array and simplicity of routing RF signals, as well as dc bias and digital control lines on the array surface. The building block of the scalable array is a 2×2 subarray of dual-polarized patch elements and an interposer with an 8-channel beamformer integrated circuit mounted on it. The interposer circuit simplifies the routing of dc and digital lines on the surface of larger arrays, lowers the cost of fabrication, and makes the array debugging simple.
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Active Antennas Beyond the Standard Impedance Matching Technique: Concepts and Applications
11 March 2025 Constant M. A. Niamien presents a new design concept for improving active antennas’ performances beyond the standard impedance matching technique. The proposed approach expands the mismatch at the antenna-amplifier interface to create a voltage excess, transferred to the matched output receiver using a voltage-type amplifier instead of a power type. Compared with a standard dual-input-output matching, this leads to comparable bandwidth and DC consumption but significantly improves the peak gain, gain-bandwidth-product (GBWP), stability, and noise figure. Experiments with a conventional dipole antenna confirm an improvement factor near two on gain and GBWP.
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Design Guidelines of Stacked Dual-Band SIW Slot Array With Optimal Aperture Reuse Ratio and High Aperture Efficiency
10 March 2025 Yihong Su, Yulei Yang, Xian Qi Lin and Yong Fan propose the design guidelines of a stacked dual-band (28/35 GHz) substrate integrated waveguide (SIW) slot antenna array to achieve the optimal aperture reuse ratio and high aperture efficiency. The dual-band array consists of two-layer substrates, and each layer acts as an independent SIW slot antenna array. The upper substrate is composed of nonadjacent SIW slot sub-arrays for the high band operation, while the low band array is located in the lower substrate radiating through the gap between the high band sub-arrays. A dual-band antenna array with an 8×8 array in each band is designed and demonstrated as an example, where the center frequencies of the two bands are chosen to be 28 GHz and 35 GHz.
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Application of Relational Databases to the Acceleration of Ray Tracing in High Frequency Asymptotic Techniques
10 March 2025 David Cabornero, Lorena Lozano, Iván González, Álvaro Somolinos and Felipe Cátedra present a new ray-tracing acceleration technique for electromagnetic simulation problems using the Uniform Theory of Diffraction and meshes of planar facets. The innovation involves using relational databases to accurately store spatial information, enabling spatial indexing through space partitioning with R-trees. This technique effectively reduces the computational cost of several critical phases, including the shadowing test. Additionally, there are multiple advantages to utilizing this technology, such as automated memory and disk management along with a query planner that organizes the instructions automatically. Direct rays, multiple reflections, multiple transmissions, simple diffraction, and combinations of these effects have been implemented in PostgreSQL and its spatial library PostGIS.
