Recent Articles
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Ka-Dual-Band Oblique-Incidence Multi-Layer Metasurface for Linear to Circular Polarization Conversion
25 December 2025 Habiba Hafdallah Ouslimani, Gerard Collignon and Vincent Mallepeyre present a dual-band linear-to-circular polarization converter for Ka-band mobile satellite communication antennas operating under variable incidence. The converter operates in transmission mode, providing left-hand circular polarization (LHCP) at 20 GHz for signal reception and right-hand circular polarization (RHCP) at 30 GHz for signal transmission (or vice versa with a mechanical rotation of 90°). The polarizer consists of three anisotropic metasurfaces separated by two identical dielectric layers, with low-loss impedance transformers on both sides to improve matching and maintain stable performance up to 60° incidence.
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3D-Printed mmWave Quasi-Holographic Antenna for 2-D Beamforming
24 December 2025 Amir Tag, Sabit Ekin, Hussein Alnuweiri, Albert E. Patterson, Manoj Prabhakar Mohan, Arokiaswamy Alphones, Herng Tun Seng Henry and Muhammad Faeyz Karim present the design and manufacturing of a novel 2D-scanning antenna that integrates a 3D-printed Rotman lens with a quasi-holographic leaky-wave antenna (HLWA). The proposed design achieved beam-scanning capabilities by leveraging the beamforming of the Rotman lens and the high-gain directive properties of the quasi-HLWA. The Rotman lens (RL) enables beam steering in the elevation plane by switching between input ports. The quasi-HLWA, designed using holographic principles, achieves frequency-controlled beam scanning in the azimuth plane.
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Multipath-Enhanced Directional Modulation for Secure mmWave On-Body Communication
22 December 2025 Wasi Ur Rehman Khan, Max. J. Ammann, Hossein Raghib Hokmabadi, William G. Scanlon and Adam Narbudowicz propose Directional Modulation (DM) for secure millimeter-wave (mmWave) on-body communication, where security is enhanced by leveraging multipath propagation. The double two-ray ground reflection model is employed to analyze a two-antenna Multi-Input Single-Output (MISO) system placed on human skin. The system operates at 24 GHz with polarization tangential to the skin. Key parameters such as antenna-separation, antenna-to-skin spacing and phase difference between transmitter antennas are varied to analyze the resulting path gain.
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Asymptotic Phase Synthesis by Transport Maps — Part II: Optimal Transport Problem
22 December 2025 Piero Angeletti, Giovanni Toso and Raffaele Vitolo address the general problem of synthesizing beams with shapes that cannot be obtained as a linear transformation of the aperture. According to a fundamental result of Brenier, the irrotational transport map satisfying the Monge–Ampère PDE can be obtained as a solution of Monge’s Optimal Transport Problem (OTP) with quadratic cost. The phase profile can then be obtained by direct integration. A numerical method based on Von Neumann’s alternating projections is adopted with an original discretization of the involved differential equations and boundary conditions.
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Asymptotic Phase Synthesis by Transport Maps—Part I: Theory and Irrotational Linear Maps
22 December 2025 Piero Angeletti, Giovanni Toso and Raffaele Vitolo address the problem of phase synthesis of apertures with assigned amplitude. Applying the method of stationary phase it will be shown that the asymptotic solution satisfies a Monge–Ampère partial differential equation (PDE) with appropriate boundary value conditions. In agreement with Chu’s energy mapping principle for reflector shaping, the Monge–Ampère PDE can be solved identifying an irrotational transport map from the source aperture to the target beam.
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Wireless Channel Parameter Estimation for Millimeter-Wave Hybrid Beamforming Systems
22 December 2025 Nigus Shimuye, Claude Oestges and François Quitin proposes a sub-antenna array beamsteering-domain channel estimation framework for millimeter-wave (mmWave) systems with hybrid beamforming. Unlike conventional array-domain methods that require access to per-antenna baseband, the proposed approach leverages joint transmitter (Tx) and receiver (Rx) beamsteering observations to enable high-resolution, digital-beamforming-like parameter estimation under practical hardware constraints. A generalized signal model is developed that incorporates measured beam patterns, including sidelobe and phase effects, ensuring a practical representation of hybrid transceivers.
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Compact Broadband Circularly Polarized Filtering Patch Antenna With Multi-Element Coupling Structure
19 December 2025 Xianjing Lin, Wenyong Liu, Zuhao Jiang and Weichao Kuang presents a compact broadband circularly polarized (CP) filtering patch antenna with multi-element coupling structure. The antenna consists of two substrate layers. The upper substrate layer incorporates a main radiating patch with an etched rectangular slot, a pair of unequal-sized L-shaped parasitic stubs placed along the + 45° diagonal of the main patch, and surrounding microstrip patches. The lower substrate features a ground plane etched with an asymmetric U-shaped slot on its top surface and a microstrip feedline on the bottom. The signal enters the port, propagates along the microstrip feedline, and couples to the main radiating patch through the asymmetric U-shaped slot, generating CP radiation.
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A Wideband Reconfigurable Surface Enabled by Schiffman Phase Shifter for 6G cmWave OAM Beam Scanning
19 December 2025 Mohamed Mamdouh M. Ali, Larbi Talbi and Khelifa Hettak introduce a compact wideband Reconfigurable Intelligent Surface (RIS) leveraging Schiffman phase shifters to overcome the traditional narrowband limitations of RIS technology. The proposed design achieves ±15° phase balance across a broad frequency range of 7.5–13 GHz, addressing a key challenge in RIS design. The proposed RIS features a compact unit cell, with dimensions of (0.25λ×0.25λ) at 10.25 GHz, integrating a single PIN diode and a tailored internal geometry to enable efficient phase control and scalable implementation.
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Gauge-Free Whittaker Potentials to Model Wave Propagation in Homogeneous Medium
28 November 2025 Thomas Reum deals with alternative scalar potential formulations where no side effect associated to gauging exists whose purpose is to enhance the variety of accessible methods for efficient calculations of electromagnetic (EM) wave fields. In previous investigations, it was shown that in the process of gauging ordinary electrodynamic potentials, an unintentionally changed phase velocity of certain potentials occurs in specific scenarios. Some workarounds for correction were provided there. This aspect in particular suggests as an overriding goal the desire to circumvent any kind of gauge fixing. To realize that, the unusual Whittaker potentials are utilized, which are closely related to the better known Hertz potentials.
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A Low-Complexity Path Loss Prediction Model for Multi-UAV Communication in Urban Environments
07 April 2025 Yangboyin Zheng, Wenqing Xing, Yongqin Yang, Ting Su, Fei Song, Xianpeng Wang and Changhua Yao propose a low-complexity deterministic path loss prediction model based on RT and backpropagation neural network (BPNN) for online decision-making systems of multiple UAVs in urban environments. The dataset is built by calculating the path loss (PL) between each pair of receivers and transmitters in a deterministic urban scenario via RT.
