IEEE Transactions on Antennas and Propagation最新文献

{"title":"Dynamic Off-Body Propagation Channel Characterization for Underground Mining Wireless Systems","authors":"Isam Eddine Lamri;Mourad Nedil;Mohamed Nasr Eddine Temmar;Nahi Kandil","doi":"10.1109/TAP.2026.3717726","DOIUrl":"https://doi.org/10.1109/TAP.2026.3717726","url":null,"abstract":"This article presents an experimental characterization of dynamic off-body propagation at 2.4 GHz in an underground mine gallery. A single-input multiple-output (SIMO) measurement campaign was conducted using a body-worn receiver placed at chest level, on the hand, and on the helmet under line-of-sight (LoS), LoS-to-non-LoS (LoS–NLoS) transition, and NLoS conditions. The results show that tunnel geometry, miner movement, and antenna placement jointly influence large-scale attenuation, shadow fading, temporal dispersion, and channel capacity. Under LoS conditions, low-path-loss exponents are observed for chest-level and hand-mounted placements, indicating waveguide-like propagation behavior inside the mine gallery, whereas helmet placement provides a more stable early arrival structure by reducing body-induced shadowing. In LoS–NLoS and NLoS conditions, segmented two- and three-slope models improve fitting accuracy by capturing abrupt propagation-regime transitions. The rms delay spread is typically concentrated between 100 and 160 ns, with occasional excursions approaching 300 ns due to late-arriving reflected and diffracted components. Statistical fitting based on the minimum Akaike information criterion (AIC) shows that delay-spread distributions are scenario dependent; however, low goodness-of-fit p-values in some obstructed cases indicate that the selected distributions should be interpreted as empirical approximations rather than universal statistical models. SIMO maximal-ratio combining provides relative spectral-efficiency gains ranging from approximately 0.70–1.00 bit/s/Hz compared with SISO operation. The results indicate that the antenna placement should be selected according to the target metric: helmet placement provides stable LoS behavior, chest-level placement performs well in transition regions, and hand placement should not be used as the sole antenna position for safety-critical underground communications because of its strong sensitivity to body motion and orientation.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"74 10","pages":"9939-9954"},"PeriodicalIF":5.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11640345","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149131498","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":"Low-Profile Broadband Circularly Polarized Stacked Magnetoelectric Dipole Antenna and Its Array for Ka-Band Satellite Communications","authors":"Jianxing Li;Shan Gao;Yaxin Wen;Xiaoyan Yu;Sen Yan;Xiaoming Chen;Le Chang","doi":"10.1109/TAP.2026.3720300","DOIUrl":"https://doi.org/10.1109/TAP.2026.3720300","url":null,"abstract":"The Ka-band is widely used for satellite communications; however, most existing millimeter-wave (mmWave) circularly polarized (CP) antennas, including dielectric resonator antennas, spiral antennas, and magnetoelectric dipole (ME-dipole) antennas, fail to meet ultrawide bandwidths with profiles less than <inline-formula> <tex-math>$0.12lambda _{0}$ </tex-math></inline-formula>, which limits their suitability. To address this issue, this communication proposes a wideband CP ME-dipole antenna array covering the full Ka-band with a profile of <inline-formula> <tex-math>$0.096lambda _{0}$ </tex-math></inline-formula>. The antenna element integrates two sets of ME-dipoles, consisting of a curved patch pair and a rectangular patch pair, together with parasitic patches. By employing a coupling slot and stacked patches, the element achieves an impedance bandwidth of 62.35% and an axial-ratio (AR) bandwidth of 30.97%. A <inline-formula> <tex-math>$2times 2$ </tex-math></inline-formula> wideband CP antenna array employing a sequential-rotation feeding network is further investigated, fabricated, and measured. The measured overlapped (impedance, AR, and gain) bandwidth covers the entire Ka-band from 24.5 to 40.5 GHz. To the best of the authors’ knowledge, this is the first ME-dipole design that achieves full Ka-band coverage with the lowest profile, demonstrating strong potential for mmWave and satellite communication applications.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"74 10","pages":"10037-10042"},"PeriodicalIF":5.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149131503","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 Modal Analysis of Radiating Structures Based on a Frequency-Independent Eigenvalue Approach","authors":"Hannes Schreiber;Marco Leone","doi":"10.1109/TAP.2026.3711669","DOIUrl":"https://doi.org/10.1109/TAP.2026.3711669","url":null,"abstract":"A newly developed method for a broadband modal system analysis for radiating structures based on a frequency-independent eigenvalue problem is presented. The interpretation of the full-wave system behavior by an equivalent modal network enables the transfer into a state-space representation. The frequency-independent eigenvalue problem of the state matrix provides the system poles and associated modal current distributions. As an alternative to characteristic mode analysis (CMA), which requires multiple solutions of frequency-dependent eigenvalue problems and mode tracking, the presented method is numerically more efficient and directly provides the frequency-independent system poles (resonance frequencies) and corresponding modal current distributions.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"74 10","pages":"9731-9742"},"PeriodicalIF":5.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11611581","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149131743","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":"Global Multitrace, Single-Source Integral Equation for the Scattering by Composite Objects","authors":"Cedric Münger;Kristof Cools","doi":"10.1109/TAP.2026.3707684","DOIUrl":"https://doi.org/10.1109/TAP.2026.3707684","url":null,"abstract":"Global multitrace (MT) integral equations offer an appealing option for the integral equation-based description of the scattering of time-harmonic electromagnetic waves by composite objects. They lead to linear systems that are amenable to Calderón preconditioning. However, they also double the number of degrees of freedom at the shared interfaces of the composite object. This contribution introduces a global MT, single-source (SS) formulation for modeling the scattering of time-harmonic waves by composite objects. It is based on a multiplicative rather than an additive combination of the interior and exterior Calderón projectors and a conforming discretization scheme that relies on both primal and dual finite element spaces. Special treatment of perfectly conducting objects is discussed to avoid spurious resonances. This treatment is based on the combined source technique applied in the context of MT, SS integral equations. Numerical experiments demonstrate the method’s correctness by comparing numerical results with analytical solutions and an additive MT formulation. A numerically rigorous study of the convergence rate of the energy norm is conducted. Details are provided on how to generalize the algorithm to handle nonconforming meshes, allowing for greater freedom in device design.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"74 10","pages":"9743-9752"},"PeriodicalIF":5.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149131744","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":"Measurement-Based Statistical Modeling of Spatially Selective ELAA Channel in UMi Scenario","authors":"Guangzheng Jing;Yixiao Tong;Jingxiang Hong;José Rodríguez-Piñeiro;Xuefeng Yin","doi":"10.1109/TAP.2026.3707688","DOIUrl":"https://doi.org/10.1109/TAP.2026.3707688","url":null,"abstract":"In recent years, extremely large antenna arrays (ELAAs) have garnered significant attention in both academia and industry. However, channel modeling efforts for ELAA in outdoor scenarios with long-range propagation remain limited. As the array aperture increases, spatial selectivity becomes increasingly pronounced, making it difficult for conventional approaches that uniformly distribute power across multipath components (MPCs) within each cluster to accurately capture the true spatial variations in the channel. To analyze channel characteristics and establish an accurate channel model based on real measurement data, this article proposes a time-efficient frequency-domain channel sounder for ELAA, which combines switch-based and virtual array methods with radio-over-fiber (RoF) to enable long-range measurements. Extensive channel measurements were conducted in an urban microcell (UMi) scenario using a 32-element Tx linear antenna array and a <inline-formula> <tex-math>$32 times 32$ </tex-math></inline-formula>-element Rx planar antenna array at the carrier frequency of 10 GHz. Significant power variations across the antenna array are observed in the measurement data, and to accurately model the constructive and destructive addition of MPCs, a new parameter referred to as the intracluster K factor is introduced in this article. The optimized searching strategy-aided space-alternating generalized expectation-maximization (OSS-SAGE) algorithm, under the spherical-wave assumption, is proposed and utilized to extract the near-field characteristics. By exploiting the orthogonality among multiple parameter domains, the algorithm compresses the data dimensionality, thereby reducing computational complexity arising from the increased number of resolvable MPCs enabled by the high spatial resolution of ELAAs. The large-scale channel characteristics are presented, such as path-loss and composite parameter spreads. A clustering algorithm is exploited to group the extracted MPCs with similar parameters. Finally, a measurement-based statistical channel model for ELAA in the UMi scenario has been established. This work provides an accurate channel model considering near-field and spatial selectivity for ELAA in UMi scenario.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"74 10","pages":"9799-9814"},"PeriodicalIF":5.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149133602","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":"Near-/Intermediate-Field Region WPT Framework via Plane-Wave Generation for Spatially Uniform Power Delivery","authors":"Hong Soo Park;Sooyoung Oh;Sun K. Hong","doi":"10.1109/TAP.2026.3719848","DOIUrl":"https://doi.org/10.1109/TAP.2026.3719848","url":null,"abstract":"This communication presents a near-field wireless power transfer (WPT) framework for achieving spatially uniform power delivery using a plane-wave generation (PWG) approach. Unlike conventional near-field focusing (NFF), which produces spherical wavefronts and localized power concentration, the proposed method synthesizes quasi-plane waves by optimizing the transmit-array excitation coefficients through a ridge regression formulation. Under a perfectly aligned reference configuration, PWG and NFF are compared in terms of RF-domain transfer efficiency and received-power variation across the receiver array. Fabricated Tx and Rx arrays are characterized through pairwise S-parameter measurements, and the measured channel matrix is used to reconstruct the RF received-power distributions. The reconstructed RF powers are further mapped through a separately measured 5.8-GHz rectifier response to estimate the rectified-voltage distribution. These results show that PWG improves RF-domain spatial uniformity and can stabilize the rectifier operating points across the receiving array. Owing to its optimization-based and array-compatible nature, PWG provides a practical and reconfigurable strategy for uniform near-/intermediate-field WPT.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"74 10","pages":"10085-10090"},"PeriodicalIF":5.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149133895","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 Low-Profile and High-Efficiency GRIN Lens Antenna for Wide-Angle Multibeam Radiation","authors":"Li-Zhao Song;Shan Huang;Shu-Lin Chen;Pei-Yuan Qin;Y. Jay Guo","doi":"10.1109/TAP.2026.3713192","DOIUrl":"https://doi.org/10.1109/TAP.2026.3713192","url":null,"abstract":"This article presents a new folded multibeam flat gradient-index (GRIN) lens antenna that achieves a wide angular coverage and high aperture efficiency within a compact physical profile. The proposed antenna integrates a transmissive primary lens for multibeam radiation, a secondary lens featuring anomalous reflections for profile reduction, and multiple feeds positioned between the two lenses. The secondary lens is innovatively synthesized to efficiently redirect waves from a designated feed toward the primary lens while compensating for spatial phase delays for optimal beam generations at 0° and ±45°. Several intermediate feed locations are optimized to produce additional beams across the ±45° angular range. For concept validation, a lens prototype incorporating seven compact feeds is designed, fabricated, and measured. Experimental results demonstrate stable multibeam performance between 8.5 and 11 GHz, producing seven independent beams covering around <inline-formula> <tex-math>$pm 45^{circ }$ </tex-math></inline-formula> with low scanning losses. A measured peak aperture efficiency of 46% is obtained with a 63% reduction of the lens profile compared to the conventional unfolded configuration.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"74 10","pages":"9547-9559"},"PeriodicalIF":5.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149130807","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 Pair-Centric Phased-Array Antenna Enabled by Reciprocity-Based Mode Separation for In-Band Radiation and Scattering","authors":"Yuqi Wang;Yinglu Wan;Zhi Ning Chen;Hanyang Wang;Quan Xue","doi":"10.1109/TAP.2026.3709592","DOIUrl":"https://doi.org/10.1109/TAP.2026.3709592","url":null,"abstract":"Low-observable phased-array antennas face a fundamental difficulty in jointly achieving in-band co-polarized scattering suppression, preserved radiation, and scalable array implementation. Element-level approaches often neglect coupling effects or rely on bulky loading structures, whereas full-array optimization is usually computationally intensive. This article presents a pair-centric design paradigm, in which a compact antenna pair (<inline-formula> <tex-math>$0.33lambda {,}times{,} 0.31lambda ~times{,} 0.02lambda $ </tex-math></inline-formula>) is used as the basic building block for integrated in-band radiation and scattering control. A reciprocity-based mode-separation framework is developed to guide the design by exploiting the asymmetric responses of odd and even mode spaces under offset port and normal-incident plane-wave excitations. This framework reveals that pattern restoration, port decoupling, and in-band scattering suppression can be achieved in a unified manner. Based on this concept, the optimized pair is extended to linear and planar arrays through pair-level beamforming under large-spacing array arrangements. Simulated and measured results demonstrate more than 20 dB in-band co-polarized RCS reduction under normal incidence, together with port isolation exceeding 20 dB and wide-angle scanning up to 86° for the experimentally validated 1-by-8 linear array; the scalability to the 8-by-8 planar array is further demonstrated by full-wave simulation. These results verify, in a proof-of-concept manner, the feasibility of integrating radiation and scattering control within pair-centric phased arrays.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"74 10","pages":"9560-9573"},"PeriodicalIF":5.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149130808","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 Compact Filtering Grid-Slotted Patch Antenna Array With Enhanced Sidelobe Suppression for 5G Millimeter-Wave Applications","authors":"Chao Chen;Jianlin Han;Jun Wang;Ruofeng Xu;Lei Zhao;Jixin Chen;Ying Liu","doi":"10.1109/TAP.2026.3706111","DOIUrl":"https://doi.org/10.1109/TAP.2026.3706111","url":null,"abstract":"In this article, a compact filtering grid-slotted patch antenna (GSPA) without additional parasitic structures is proposed for the 5G millimeter-wave (MMW) n257 band (26.5–29.5 GHz). To effectively suppress sidelobe level (SLL), a 20 dB Taylor amplitude taper is implemented in the design of the 1-to-16 corporate-feed network. The proposed filtering antenna is primarily composed of a stacked GSPA and a forked microstrip feeding structure. By introducing 16 blind holes into the radiating elements, a radiation null is induced near the upper passband edge, while the overall operating bandwidth is considerably enhanced. Additionally, to suppress unwanted radiation in the lower stopband, four E-shaped strips are positioned directly beneath the GSPA, resulting in the formation of another radiation null. Since the added parasitic structures do not occupy additional space, the proposed filtering GSPA unit features a compact configuration with dimensions of only <inline-formula> <tex-math>$0.39lambda _{0} times 0.39lambda _{0}$ </tex-math></inline-formula>. For demonstration, a <inline-formula> <tex-math>$4times 4$ </tex-math></inline-formula> filtering GSPA array is fabricated and measured. The measured results demonstrate reasonable agreement with the numerical simulations, achieving a 19.6% impedance bandwidth (25.6–31.1 GHz), an average gain of 16.2 dBi within the passband, and out-of-band suppression greater than 18 dB. Furthermore, the measured SLLs in the E-plane and H-plane are lower than −17.2 and −19 dB, respectively.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"74 10","pages":"9375-9385"},"PeriodicalIF":5.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149130880","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":"Artificial Dielectric Waveguide for Efficient Traveling-Wave MRI at 7T","authors":"Zicheng Wen;Georgiy A. Solomakha;Stanislav B. Glybovski;Xiaotong Zhang;Yang Gao","doi":"10.1109/TAP.2026.3654138","DOIUrl":"https://doi.org/10.1109/TAP.2026.3654138","url":null,"abstract":"Uniform nuclei-spin excitation via the circularly polarized transverse magnetic field (B<inline-formula> <tex-math>${}_{1}^{+}$ </tex-math></inline-formula>) is essential for high-quality clinical magnetic resonance imaging (MRI). At ultrahigh field (UHF, <inline-formula> <tex-math>$ge 7$ </tex-math></inline-formula>T), it becomes increasingly challenging due to the higher operational frequency (<inline-formula> <tex-math>$ge 297$ </tex-math></inline-formula> MHz) required for excitation, where conventional volume resonators fail to produce a homogeneous transmit field over the electrically large human body because of standing-wave (SW) effects. Traveling-wave (TW) excitation based on metallic circular waveguides offers a promising alternative, yet its clinical application has been hindered by low transmission efficiency and inhomogeneous field distribution caused by suboptimal waveguide modes, radiation losses, as well as phase-velocity mismatches. While high-permittivity dielectric waveguides (DWs) have been proposed to enhance the TW performance, their practical implementation is limited by the availability of suitable natural materials. Water-based DWs offer improved field confinement and transmission efficiency, but they introduce MRI signal artifacts and are susceptible to long-term degradation, thereby limiting their reliability and clinical applicability. In this study, we present an artificial dielectric waveguide (ADW) engineered to replicate the electromagnetic (EM) properties of a water-based DW while mitigating the high weight and undesired MRI signal of the latter. The proposed design achieves efficient hybrid-mode conversion—over 95% of the magnetic field energy in transverse components under unloaded conditions and about 80% under realistic loading—thereby improving power confinement and achieving 75% improvement in B<inline-formula> <tex-math>${}_{1}^{+}$ </tex-math></inline-formula> field efficiency compared with the classic TW method, as well as a 14% improvement in field homogeneity over a conventional single-channel system for human brain MRI at 7T.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"74 10","pages":"9288-9301"},"PeriodicalIF":5.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149131310","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}