Recent Articles
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Multiband Distance Measuring Equipment, Traffic Collision Avoidance System and Radio Altimeter Antenna for Avionics Applications
15 December 2025 Omar M. Khan and Jean-Jacques Laurin present a multiband antenna for aircraft communication of traffic collision avoidance system (TCAS), distance measuring equipment (DME) and radio altimeter (RadAlt). This single antenna concept provides benefits of reducing the number of mounted antennas on the aircraft. Dual and single feed multilayered antennas are designed for omnidirectional and directional radiation characteristics. A circular metallic covered low profile L-band cavity is designed for omnidirectional radiations that comprises a novel power splitter for feeding the C-band RadAlt patch array placed on upper substrate of the circular cavity for achieving directional radiation pattern characteristics.
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On the Synthesis of Aperiodic Multi-Atom 1-Bit Reconfigurable Passive EMSs at 140 GHz
11 December 2025 Taeyoung Kim, Francesco Zardi, Sangmin Lee, Jinhyun Kim, Uichan Park, Jungsuek Oh, Sangjo Choi and Giacomo Oliveri propose an innovative reconfigurable passive electromagnetic skin (RP-EMS) architecture to support a single reflection beam while suppressing undesired beams, using 1-bit switching with minimal hardware complexity. The architecture is the first to simultaneously optimize the meta-atom arrangement and their 1-bit switching descriptors using the integer-coded evolutionary algorithm, supporting multiple reflection scenarios. The process yields one aperiodic meta-atom arrangement that effectively mitigates periodic phase quantization errors typical of 1-bit RP-EMS layouts, while changing reflection angles solely through 1-bit switching.
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Dual-Band SIW Filtering Antenna With High Selectivity and Individually Adjustable Bands
11 December 2025 Ke Gong, Jia Liu, Min Mao, Chunfeng Fan, Hang Qian, Qing Liu and Yan Zhang propose a high-selectivity stable-gain dual-band SIW filtering antenna with independently controllable frequency bands. The proposed antenna structure uses an orthogonal dual-mode rectangular SIW cavity as the common resonant cavity, with the feeding position located inside the cavity. The TE120 and TE210 modes in the common cavity are coupled to four radiation cavities through coupling windows. Mixed electromagnetic coupling occurs between the rectangular SIW cavity and a circular patch cavity by introducing a radiation null at the high-impedance side of the dual-band operation.
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Dual-Band Reflective Metasurface Integrated Circularly Polarized Antenna for Sub-6 GHz 5G N77 and Wi-Fi 7 Applications
11 December 2025 Varsha Kheradiya, Ganga Prasad Pandey and Arpan Desai address the critical need for polarization diversity in multi-band wireless systems. The proposed design achieves opposite-handedness CP operation—left-hand CP (LHCP) at one band and right-hand CP (RHCP) at the other, which helps in enhancing the interference mitigation and signal robustness. The system employs a compact, double-layer phase-change metasurface (DL-PCM) reflector integrated with a dual-band linearly polarized monopole antenna, enabling the independent control of the amplitude and phase of reflected waves at each frequency. The integrated antenna and DL-PCM configuration results in wide axial ratio bandwidths (27.3% and 25.3%) and high radiation efficiencies (90% and 87%), ensuring optimal performance across both bands.
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Advancing EMF Compliance for 5G Massive MIMO Antennas: From 2-D Time-Averaged Models to Realistic 3-D Spatial–Temporal Representations
09 December 2025 Simona Valbonesi, Riccardo Suman, Stefano D’Elia, Andrea Garzia and Paolo Grazioso present a novel extension to the effective maximum approach defined by IEC (International Electrotechnical Committee) by incorporating spatial dynamics derived from real-time base station measurements. These measurements are stored in counters that capture the three-dimensional (3D) power distribution of transmitted signals, enabling a more accurate representation of actual operating conditions. Two innovative methodologies are proposed (semi-vectorial and vectorial), both resulting in a more realistic estimation of RF-EMF exposure with respect to currently used methodologies. Each method uses different power reduction factors to reflect how signals change over time and space.
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Design of Broadband Aperture-Stacked Patch Microstrip Antennas Based on Third Order Filtering Equivalent Circuits
05 December 2025 Ignacio M. Delgado-Lozano, Rafael R. Boix, Vicente Losada and Armando Fernández-Prieto describe the design of a broadband aperture-stacked patch (ASP) microstrip antenna based on a filtering equivalent circuit. The antenna consists of two stacked microstrip patches that are fed by a microstrip line through a resonant aperture. An equivalent circuit is proposed for the antenna consisting of three LC parallel resonators, out of which two resonators are inductively coupled and two resonators are capacitively coupled. The equivalent circuit is de-embedded from the antenna response by means of the least squares method, and the dimensions of the antenna are adjusted in such a way their equivalent circuit matches the response of a broadband third order filter.
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An Efficient Design Methodology for Finite-Size Anomalous Reflectors Based on Equivalent Circuit Model and Artificial Neural Networks
05 December 2025 Xin You and Panagiotis Kosmas propose an efficient design methodology for finite-size PARs based on the equivalent circuit model (ECM) and artificial neural network (ANN) techniques. An accurate ECM-based genetic algorithm (GA) of infinite-size PARs, derived from Floquet modal expansion is implemented first to provide an efficient initial guess which reduces the data size and improves the accuracy of the ANN implemented for the finite-size PARs. As a final step, ANN and GA are combined to find finite-size PARs yielding optimal BRCS results. The surface wave analysis method has been adopted to decrease the data collection time, and a modified poles-residues tracking technique has been proposed to broaden the bandwidth and the geometrical variable ranges and improve ANN’s predictive accuracy.
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Stacked Rotman Lenses for Dual Band Beamforming
04 December 2025 Muhammad Mubasshir Hossain, Stavros Koulouridis, Satheesh Bojja Venkatakrishnan and John L. Volakis presents a thin planar stacked antenna array for simultaneous dual-band beamforming. The uniqueness of the design is the use of passive beamformers in a compact module with sharp filters to enable beamforming when transmitting at closely spaced frequency bands. It uses two identical Rotman lenses to feed two separate series-fed patch arrays operating at 15.3 GHz and 17.2 GHz. The lenses and arrays are vertically stacked, with simplified stripline-to-microstrip transitions, enabling efficient energy transfer between layers to reduce losses. This vertical stacking reduces the required planar area as compared to conventional multi-layer designs with airgaps. To improve performance, elliptic filters are used to achieve sharper transitions from passband to stopband, effectively reducing mutual coupling between the two bands.
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Low-Profile Circularly Polarized Metasurface Antenna Based on Characteristic Angle Compensation
03 December 2025 Wen-Feng Zeng, Fu-Chang Chen, Yu-Zhong Liang and Zhi-Hong Tu propose a low-profile circularly polarized metasurface (MTS) antenna for 5G indoor applications. To balance the intricacy of the feeding network design and that of the characteristic mode (CM) control, a novel modal manipulation method is proposed to generate three axial ratio (AR) zeros. A simple feeding network, comprising three T-shaped power dividers and 90° microstrip phase delay lines, excites the coupling slots and provides the first AR zero. The width-to-length ratio of the metasurface patches is adjusted to regulate the degenerate broadside modes of the MTS. The second AR zero is achieved by lowering the first MTS mode and cooperating with the coupling slot mode. The third AR zero is generated by controlling the characteristic angle of two MTS modes.
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Frequency-Diverse Additive Processing for Active Incoherent Millimeter-Wave Imaging
28 November 2025 Jorge R. Colon-Berrios and Jeffrey A. Nanzer present an approach for improving spatial frequency sampling in active incoherent millimeter-wave (AIM) imaging systems using frequency diversity. AIM imaging relies on active transmission of spatio-temporally incoherent signals to illuminate a scene, from which interferometric Fourier domain imaging can be implemented using a sparse receiving antenna array. One of the benefits of Fourier domain imaging is the sparsity of the receiving array, which can form images with equivalent resolution to traditional filled beamsteering arrays, but with a small fraction of the elements.
