IEEE Transactions on Antennas and Propagation最新文献

{"title":"Exploring the Nature of Quasi-Bound States in the Continuum Using Metasurface Models","authors":"Peyman Abdipour;George V. Eleftheriades","doi":"10.1109/TAP.2026.3655488","DOIUrl":"https://doi.org/10.1109/TAP.2026.3655488","url":null,"abstract":"Bound states in the continuum (BICs) are nonradiating modes supported by wave-based systems, although their spectra are compatible with radiation. The most well-known feature of BICs is the formation of resonant behaviors with exceedingly high quality factors (<inline-formula> <tex-math>$Q$ </tex-math></inline-formula>-factors). In practice, due to the imperfect nature of the considered systems, the <inline-formula> <tex-math>$Q$ </tex-math></inline-formula>-factors are finitely large, and the modes are referred to as quasi-BICs (Q-BICs). As these modes are of particular interest in numerous applications, many physical systems supporting Q-BICs and various techniques for their realization have been reported in recent studies. In this work, metasurface models are proposed to investigate the nature of Q-BICs. It is shown that by utilizing metasurface models for BIC-supporting electromagnetic metastructures, which do not necessarily possess deeply subwavelength thickness, one can capture and analyze the salient features of BICs (or Q-BICs) in a far-field manner. This is achieved even though their formation is inherently related to internal information within the considered structures, which is not accessible in a far-field model. Multiple illustrative examples and numerical results are presented to corroborate the proposed approach. The proposed modeling technique provides an elegant method to predict, optimize, and analyze BIC-based phenomena across a wide range of wave-physics branches.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"74 10","pages":"9200-9211"},"PeriodicalIF":5.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149131501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Theory of Helicoidal Plane-Wave Modes in Coaxial Lines of Arbitrary Polygonal Cross Section With Metamaterial Deflectors","authors":"Piergiorgio L. E. Uslenghi","doi":"10.1109/TAP.2025.3630900","DOIUrl":"https://doi.org/10.1109/TAP.2025.3630900","url":null,"abstract":"A coaxial line of arbitrarily shaped polygonal cross section is considered. The insertion of deflecting prisms made of anti-isorefractive double-negative (DNG) metamaterial at all wedges of the metallic conductors enables the propagation of plane waves that wrap around the line in a helicoidal fashion. A formula for the angle of propagation and the number of such waves is provided. Some particular cases of coaxial lines of rectangular, triangular, regular polygonal, and concave polygonal cross section are discussed in detail. The results obtained represent a novel analytical solution to a boundary-value problem in guided propagation.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"74 10","pages":"9280-9287"},"PeriodicalIF":5.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149131505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Multilevel Hybrid Inhomogeneous/Propagating Plane-Wave Algorithm for Radiation Integral Evaluations Above Planar Multilayered Media","authors":"Thomas F. Eibert","doi":"10.1109/TAP.2026.3711134","DOIUrl":"https://doi.org/10.1109/TAP.2026.3711134","url":null,"abstract":"Electromagnetic radiation integral evaluations for planar multilayered media depend commonly on spectral integral representations in terms of mixed inhomogeneous/propagating plane waves, while purely propagating plane-wave representations are only feasible for homogeneous media. Both representations can be used to diagonalize the radiation integral for distributed source and observation configurations, where the purely propagating plane-wave representation has led to the multilevel fast multipole methods (MLFMMs) for the fast evaluation of radiation integrals. The fast inhomogeneous plane-wave algorithms (FIPWAs) map the inhomogeneous plane-wave translation operators back to propagating plane waves and they can, thus, also handle planar multilayered media. As an alternative, a hybrid algorithm for radiation integral evaluations above planar multilayered media is presented, which fully retains the MLFMM for the direct homogeneous medium radiation part, with all its flexibility, e.g., in the use of directive translation operators, and works directly with the mixed inhomogeneous plane-wave representation for the multilayered media contributions, with all its flexibility, e.g., no need of buffer boxes. The mixed inhomogeneous plane-wave radiation patterns of the sources and the observers are extrapolated from their propagating plane-wave counterparts only on the finest level of the underlying multilevel octree via spherical harmonics and a methodology is worked out for efficient numerical quadrature as well as local interpolations and anterpolations along the chosen mixed inhomogeneous plane-wave integration path. The algorithm is demonstrated and evaluated within the framework of an inverse source solver, where field evaluations from given sources as well as inverse source solutions from given observations are considered.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"74 10","pages":"9777-9789"},"PeriodicalIF":5.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149131702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extended Multibranch Basis Functions for the Method of Moments Analysis of Nonconformal Problems","authors":"Manuel Parejo;Víctor F. Martín;José M. Taboada;Luis Landesa","doi":"10.1109/TAP.2026.3705800","DOIUrl":"https://doi.org/10.1109/TAP.2026.3705800","url":null,"abstract":"To simplify the treatment of real-life electromagnetic analysis problems that use integral equations, an alternative to the well-known integral equation discontinuous Galerkin (IEDG) method is proposed. This approach enables the creation of computer-aided design and mesh models for separate subdomains, which can later be connected and used to analyze the problem as a whole without caring about mesh conformity. The proposed extended multibranch (EMB) basis functions allow for the analysis of nonconformal mesh problems, similar to IEDG, but with the advantage of avoiding the computation of the stabilization parameter beta (IEDG’s main drawback) while ensuring current continuity across tear lines. Several numerical experiments have been done to compare the results obtained from both methods (IEDG and EMB) with those from the equivalent conformal mesh model using RWG basis functions analyzed with the method of moments.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"74 10","pages":"9718-9730"},"PeriodicalIF":5.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11581391","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149131742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"AI-Assisted Antenna State Selection for Throughput Optimization in Higher Order MIMO Mobile Terminals Under Arbitrary User Scenarios","authors":"Bumhyun Kim;Donggeun An;Byunggwan Lee;Yong Nam Whang;Yongwon Song;Wonbin Hong","doi":"10.1109/TAP.2026.3717332","DOIUrl":"https://doi.org/10.1109/TAP.2026.3717332","url":null,"abstract":"This article presents an artificial intelligence (AI)-based optimization method for enhancing throughput in higher order multiple-input–multiple-output (MIMO) antenna systems for next-generation mobile devices. As MIMO increases channel capacity by employing multiple transmit and receive antennas, limited device space forces antennas into proximity, raising mutual coupling and degrading performance. Conventional lookup table (LUT)-based approaches become impractical due to the exponential increase in switch combinations and the dynamic variability of real-world user scenarios. To address these challenges, the proposed method employs a variational autoencoder (VAE), K-means clustering, and a hybrid search algorithm to enable real-time active <inline-formula> <tex-math>$Gamma $ </tex-math></inline-formula> optimization across diverse scenarios. Two kinds of MIMO antenna prototypes featuring different antenna configuration strategies are exemplified under 4, 6, and 8 Rx configurations to demonstrate the generalization of the proposed method with a large-scale active <inline-formula> <tex-math>$Gamma $ </tex-math></inline-formula> dataset. It is collected by reflecting the realistic scenarios of hand grips and human-body proximity. The overall algorithm detects the current device state within the latent space based on active <inline-formula> <tex-math>$Gamma $ </tex-math></inline-formula> data and can dynamically apply the optimal value in real time according to the given scenario. The measured throughput results demonstrate that maintaining the active <inline-formula> <tex-math>$Gamma $ </tex-math></inline-formula> as low as possible leads to enhanced throughput performance, thereby verifying the practical feasibility of the proposed optimization algorithm. This innovative framework not only enhances wireless performance in higher order MIMO systems but also establishes a scalable and adaptive approach for future on-device AI antenna optimization.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"74 10","pages":"10010-10024"},"PeriodicalIF":5.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149131698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Novel Highly Selectivity Full-Frequency Protection Ultrawideband Polarization, Frequency, and Energy Selectivity Integrated Surface","authors":"Shuangshuang Chen;Yanwen Zhao;Yongpin Chen;Sihao Liu;Zaiping Nie;Deqiang Yang","doi":"10.1109/TAP.2026.3719847","DOIUrl":"https://doi.org/10.1109/TAP.2026.3719847","url":null,"abstract":"This communication proposes a novel, highly selective UWB surface for full-band, high-power protection. This design represents the first reported surface to integrate polarization, frequency, and energy selectivity functions into a single structure (HS-PEFSS). Crucially, this design eliminates the need for the air gaps conventionally used to control interlayer coupling, enabling a low profile and miniaturization. By incorporating interlayer coupling into the overall design through an equivalent circuit transformation, the modified equivalent circuit model (ECM) suppresses unwanted out-of-band transmission poles caused by interlayer coupling. This achieves the desired UWB out-of-band rejection (OBR), thereby integrating high-selectivity energy selectivity (ES) and frequency selectivity (FS). Further enhancement of polarization selectivity (PS) performance across the entire frequency band is achieved through inductive and capacitive suppression within the unit. To validate the exceptional performance of the proposed unit, an HS-PEFSS prototype suitable for both waveguide and absorber-screen free-space measurements was fabricated and measured. Simulation and measurement results demonstrate that the proposed HS-PEFSS achieves an IL of less than 1 dB in low-power transmission mode and an SE greater than 15 dB in the high-power shielding mode across a UWB range of 2.73–3.48 GHz. The 1-dB transmission bandwidth exceeds 24%. It features high out-of-band selectivity, with BW-LFOBS being 14.0% and BW-HFOBS being 8.25%. Furthermore, the proposed HS-PEFSS achieves SE greater than 15 dB and an OBR greater than 10 dB in the 0.4–2.25 GHz and 3.91–40-GHz bands for both x-polarization (<italic>x-pol</i>) and y-polarization (<italic>y-pol</i>), respectively. This HS-PEFSS demonstrates outstanding performance in terms of FS, ES, and PS.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"74 10","pages":"10091-10096"},"PeriodicalIF":5.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149133897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Urban Macro/Microcellular Channel Characterization at 4.85 GHz With Literature-Referenced Upper FR1-to-FR3 Cross-Band Analysis","authors":"Inocent Calist;Minseok Kim","doi":"10.1109/TAP.2026.3717623","DOIUrl":"https://doi.org/10.1109/TAP.2026.3717623","url":null,"abstract":"The transition from 5G to 6G requires frequency-dependent, physically consistent radio channel models across the upper FR1/FR3 transition region, particularly in the underexplored 4–8-GHz region targeted in the current WRC-27 studies, where outdoor urban channel measurements and characterizations remain scarce. This article presents a 4.85-GHz measurement-anchored study of urban channels and a literature-referenced cross-band analysis. Double-directional measurements were conducted at 4.85 GHz in urban macrocell (UMa) and urban microcell (UMi) routes in Yokohama, Japan, from which path loss (PL), delay spread (DS), azimuth spread of arrival/departure (ASA/ASD), <inline-formula> <tex-math>$K$ </tex-math></inline-formula>-factor, and route-dependent spatial-consistency statistics were extracted. To align these results in a broader cross-band context, the measured 4.85-GHz large-scale parameter (LSP) means were combined with scenario-matched literature anchors to derive log–log trends for DS, ASA, and ASD over an approximately 4–28-GHz range around the 7.125-GHz upper FR1/FR3 cross-band boundary. The resulting trends were compared with 3GPP UMa/UMi reference parameterizations over the same interval, and the sensitivity of the UMi DS fit was examined via leave-one-out (LOO) analysis. Because the cross-band analysis still relies on a single in-house measurement band alongside heterogeneous anchors from different campaigns, it is presented as measurement-informed and indicative rather than as a definitive multiband model. This article therefore contributes both a detailed, parameterized 4.85-GHz urban measurement reference and a bounded literature-referenced view of channel behavior near the upper FR1/FR3 transition.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"74 10","pages":"9923-9938"},"PeriodicalIF":5.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149130882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An SIE-IBC and Adjoint Variable Method Approach for 3-D Planar and Conformal Composite Anisotropic Metasurface Design","authors":"Jordan Budhu;Shaofan Xu;Afshin Abbaszadeh","doi":"10.1109/TAP.2026.3686045","DOIUrl":"https://doi.org/10.1109/TAP.2026.3686045","url":null,"abstract":"A technique for the design of planar or conformal, reconfigurable or static, composite, anisotropic, metasurfaces is presented. The metasurfaces consist of arbitrarily shaped homogeneous dielectric bodies partially or wholly covered in conformal anisotropic impedance sheets and/or metallic surfaces. The forward solver is based on a surface integral equation (SIE) featuring the impedance boundary condition (IBC) (SIE-IBC). By evoking Love’s equivalence principle, meshing the volume of the dielectric is avoided and the free-space Green’s function enabled. The design occurs in three stages. In a first stage, a homogenized complex-valued impedance sheet necessary to support a desired field transformation is obtained via a direct solve of the SIE-IBC. In a second stage, the complex-valued impedance sheet is converted to a purely reactive sheet via adjoint variable optimization (AVO) of the reactances retained from stage 1 and resistances discarded. The optimization introduces power-balancing surface waves, which reshape the power density normal to the metasurface. As a result, the purely passive and lossless metasurface performs wavefront transformations that are normally associated with active surfaces. This allows, in a third stage, the metasurface to be realized using simple conformal printed circuits. Several examples designed using the three-stage approach are provided, including a varactor-studded reconfigurable metasurface, a sinusoidally shaped, pin-fed, leaky wave antenna (LWA), and a doubly curved conformal metasurface patterned using a Goldberg polyhedron discretization technique.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"74 10","pages":"9172-9187"},"PeriodicalIF":5.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149131298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exact Local-Field Renormalization for Deep-Subwavelength Particles in Rectangular Cavities","authors":"Koffi-Emmanuel Sadzi;Yakir Hadad","doi":"10.1109/TAP.2025.3648150","DOIUrl":"https://doi.org/10.1109/TAP.2025.3648150","url":null,"abstract":"We present a rigorous, semi-analytical framework for predicting the joint eigenfrequencies of a deep-subwavelength particle embedded in a perfectly conducting rectangular cavity. The formulation retains the <italic>full</i> cavity-mode spectrum and is therefore strictly causal, in contrast to Jaynes–Cummings-type models that truncate the spectrum and fail in strong coupling. A ladder-type Green-function renormalization is introduced: three successive subtractions—cavity minus rectangular waveguide, waveguide minus parallel- plate, and parallel-plate minus free space—remove the “<inline-formula> <tex-math>$infty -infty $ </tex-math></inline-formula>” singularity of the local field. The resulting local dyadic Green function is obtained with a rapidly convergent recursive algorithm whose cost scales linearly with the number of spectral terms. Once the local field is known, the cavity-renormalized polarizability <inline-formula> <tex-math>$ boldsymbol {alpha }_{mathrm {eff}}(omega)=[boldsymbol {alpha }^{-1}-mathbf {G}_{mathrm {loc}}(mathbf {r}')]^{-1}$ </tex-math></inline-formula> yields the coupled resonances from <inline-formula> <tex-math>$ det [boldsymbol {alpha }_{mathrm {eff}}^{-1}(omega)]=0$ </tex-math></inline-formula>. Benchmark cases involving isotropic, gyrotropic, and chiral spheres confirm exponential convergence and capture both weak- and strong-coupling regimes without adjustable parameters. The method is numerically robust, applies to arbitrary material tensors, and can be extended to structured waveguides whose transverse eigenfunctions are obtained numerically, providing a practical design tool for cavity–particle systems from microwave to terahertz frequencies.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"74 10","pages":"9222-9235"},"PeriodicalIF":5.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149131735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Broadband Characteristic Mode Tracking for Pixel Structures Using Adaptive Hybrid Scoring Method","authors":"Sheng-Yang Wang;Fan Jiang;Zhen Zhang;Liang Hua Ye;Jian-Feng Li","doi":"10.1109/TAP.2026.3712119","DOIUrl":"https://doi.org/10.1109/TAP.2026.3712119","url":null,"abstract":"Characteristic mode theory (CMT) provides an effective tool for analyzing the wideband radiation characteristics of pixelated antennas by revealing the inherent characteristic modes of various topological structures. However, tracking characteristic modes across wide frequency bands remains challenging, particularly when a large frequency sampling step is used or numerous and closely packed modes, where traditional eigenvector correlation-based methods tend to result in mode mismatching, mode swapping, and resultant discontinuous modal trajectories. To address these issues, this article proposes a mode tracking approach, which integrates an adaptive scoring and dynamic error correction technique. By comprehensively considering eigenvalue variations, eigenvector correlations, and modal significance (MS), this method dynamically adjusts the matching scores, thereby substantially enhancing the accuracy and robustness of mode tracking. This method effectively addresses the issues of mismatch and mode swapping in conventional tracking techniques, enabling stable and precise mode tracking across a wide frequency band.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"74 10","pages":"9790-9798"},"PeriodicalIF":5.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149131836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}