{"title":"Frequency Beamforming-Enhanced DBIM for Limited-Aperture Quantitative Imaging","authors":"Scott J. Ziegler;Matthew J. Burfeindt","doi":"10.1109/TAP.2025.3526904","DOIUrl":"https://doi.org/10.1109/TAP.2025.3526904","url":null,"abstract":"The distorted Born iterative method (DBIM) is a technique for reconstructing a dielectric profile from scattered electric fields. The potential for effective imaging with DBIM has been demonstrated for a variety of applications. However, it is more challenging to reliably produce high-fidelity imagery when the aperture formed by the sensors does not fully surround the region of interest and when data is collected over a narrow bandwidth. To address this challenge, we propose a beamforming enhancement to DBIM for limited-aperture scenarios. The beamforming enhancement pre-focuses the data prior to performing the DBIM optimization in order to achieve a better-conditioned inversion. The enhancement is an advance on previous beamforming work for DBIM in that it focuses simultaneously across not only space but also frequency, which allows for better leveraging of range information in the limited-aperture signal. Results for simulated and experimental data demonstrate that the frequency beamforming enhancement to DBIM results in less sensitivity to the choice of the regularization parameter and produces better reconstructions when spatial and frequency information is limited.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"73 2","pages":"1173-1184"},"PeriodicalIF":4.6,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143361480","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}
Jérôme Taillieu;Álvaro J. Pascual;Srđan Paković;Xavier Morvan;Walter Fuscaldo;Mauro Ettorre;David González-Ovejero
{"title":"High-Data-Rate and Resilient Wireless Links at the W-Band Enabled by All-Metal Spline Horns","authors":"Jérôme Taillieu;Álvaro J. Pascual;Srđan Paković;Xavier Morvan;Walter Fuscaldo;Mauro Ettorre;David González-Ovejero","doi":"10.1109/TAP.2024.3524724","DOIUrl":"https://doi.org/10.1109/TAP.2024.3524724","url":null,"abstract":"The self-healing property of Bessel beams (BBs) is used to create a robust wireless link at the W-band, maintaining high data rates despite metallic obstructions in their nondiffractive range (NDR). This is demonstrated experimentally using a broadband launcher, which comprises a photonic transmitter and a spline-profile horn, by placing a circular metallic obstacle in the beam’s path. Field measurements show that the BB profile remains intact after the obstacle over the 75–105-GHz band. Power transmission tests reveal a record broadband efficiency of up to 70% (−1.54 dB) at 99 GHz across distances of 10–30 wavelengths. Bit error rate and real-time communication tests confirm the link’s reliability, achieving error-free data transmission at 3 Gb/s using on-off keying (OOK) modulation.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"73 3","pages":"1834-1839"},"PeriodicalIF":4.6,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143553207","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}
Maximilian Nolte;Riccardo Torchio;Sebastian Schöps;Jürgen Dölz;Felix Wolf;Albert E. Ruehli
{"title":"A Low-Frequency-Stable Higher-Order Isogeometric Discretization of the Augmented Electric Field Integral Equation","authors":"Maximilian Nolte;Riccardo Torchio;Sebastian Schöps;Jürgen Dölz;Felix Wolf;Albert E. Ruehli","doi":"10.1109/TAP.2024.3524031","DOIUrl":"https://doi.org/10.1109/TAP.2024.3524031","url":null,"abstract":"This contribution investigates the connection between isogeometric analysis (IGA) and integral equation (IE) methods for full-wave electromagnetic problems up to the low-frequency limit. The proposed spline-based IE method allows for an exact representation of the model geometry described in terms of nonuniform rational B-splines (NURBS) without meshing. This is particularly useful when high accuracy is required or when meshing is cumbersome, for instance, during the optimization of electric components. The augmented electric field IE (EFIE) is adopted and the deflation method is applied, so the low-frequency breakdown is avoided. The extension to higher-order basis functions is analyzed and the convergence rate is discussed. Numerical experiments on academic and realistic test cases demonstrate the high accuracy of the proposed approach.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"73 3","pages":"1688-1697"},"PeriodicalIF":4.6,"publicationDate":"2025-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143553079","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}
Yanyang Wang;Hongxia Xu;Peng Zhao;Shichang Chen;Kanglong Zhang;Sen Yan;Jianxing Li;Gaofeng Wang
{"title":"Design of a Mode-Compressed Wideband Asymmetrical Dipole Antenna With Stable Omnidirectional Radiation Pattern","authors":"Yanyang Wang;Hongxia Xu;Peng Zhao;Shichang Chen;Kanglong Zhang;Sen Yan;Jianxing Li;Gaofeng Wang","doi":"10.1109/TAP.2024.3524412","DOIUrl":"https://doi.org/10.1109/TAP.2024.3524412","url":null,"abstract":"In this communication, an odd- and even-mode compression method is proposed to extend the bandwidth of conventional thin dipole antennas while maintaining a stable omnidirectional radiation pattern. Wide bandwidth is achieved by simultaneously exciting and compressing first-order (odd) and second-order (even) modes, enabling their combination. The offset-fed method is used to simultaneously excite the first- and second-order modes of the dipole. The second-order mode is compressed by widening one of the dipole arms, which shifts the second-order mode toward lower frequencies. The first-order mode can be compressed by shortening the length of the thin arm of the dipole that is not widened, which shifts the first-order mode toward higher frequencies. In addition, to convert the second-order mode splitting radiation pattern into an omnidirectional one, parasitic strips are loaded on both sides of the thin arm of the dipole. This loading also helps to further compress the first-order mode toward lower frequencies. The final antenna design features an asymmetric structure. To validate the concept, a prototype was constructed and tested, demonstrating reasonable agreement between the simulated and measured results. The measured impedance bandwidth is 55.6% (1.62–2.87 GHz), and a stable omnidirectional radiation pattern can be maintained across the entire operating frequency band.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"73 3","pages":"1882-1887"},"PeriodicalIF":4.6,"publicationDate":"2025-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143553497","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":"Degrees of Freedom for Radiating Systems","authors":"Mats Gustafsson","doi":"10.1109/TAP.2024.3524437","DOIUrl":"https://doi.org/10.1109/TAP.2024.3524437","url":null,"abstract":"Electromagnetic degrees of freedom are instrumental in antenna design, wireless communications, imaging, and scattering. A large number of degrees of freedom enhance control in antenna design, influencing radiation patterns and directivity, while in communication systems, it links to spatial channels for increased data rates, reliability, and resolution in imaging. The correlation between computed degrees of freedom and physical quantities is not fully understood, prompting a comparison between classical estimates, Weyl’s law, modal expansions, and optimization techniques. In this article, it is shown that the number of degrees of freedom for arbitrarily shaped radiating structures approaches the shadow area measured in squared wavelengths asymptotically as the wavelength decreases.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"73 2","pages":"1028-1038"},"PeriodicalIF":4.6,"publicationDate":"2025-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143361247","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":"3-D Coupled Annular Aperture Antenna Array With Dual Circularly Polarized Isoflux Beam for CubeSat Earth Coverage Applications","authors":"Siyu Li;Benito Sanz-Izquierdo;Shaowei Liao;Quan Xue;Steven Gao","doi":"10.1109/TAP.2024.3523683","DOIUrl":"https://doi.org/10.1109/TAP.2024.3523683","url":null,"abstract":"This communication introduces the concept of coupled annular aperture antenna array (CAAAA) that enhances Cube Satellite (CubeSat) Earth coverage with dual-CP isoflux beams. Unlike the formerly reported annular aperture antenna array (AAAA), which relies on complex feeding networks with numerous excitation ports for amplitude and phase adjustment, the CAAAA simplifies design and reduces radiation losses by optimizing the 3-D spatial arrangement, thus tailoring excitation parameters of passive coupled annular aperture elements (coupled AAE) encircling a central excitation annular aperture element (excitation AAE). The inherent axisymmetric structure of the CAAAA yields a consistent axisymmetric radiation pattern. A C-band (5 GHz) prototype demonstrates ±30° isoflux coverage, 4.5-dBi peak gain, and an axial ratio (AR) beamwidth exceeding 180°, indicating robust dual-CP performance. Notable for its low profile (<inline-formula> <tex-math>$0.11lambda _{0}$ </tex-math></inline-formula>), lightweight design, ease of fabrication, and high radiation efficiency, the CAAAA offers a viable, efficient solution for CubeSat applications requiring extensive Earth coverage.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"73 3","pages":"1876-1881"},"PeriodicalIF":4.6,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143553392","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":"Real-Time Pattern Synthesis for Large-Scale Phased Arrays Based on Autoencoder Network and Knowledge Distillation","authors":"Jiapeng Zhang;Chang Qu;Xingliang Zhang;Hui Li","doi":"10.1109/TAP.2024.3513563","DOIUrl":"https://doi.org/10.1109/TAP.2024.3513563","url":null,"abstract":"In this article, a deep learning (DL) method based on autoencoder network is proposed to achieve the inverse design of phase retrieval for large-scale antenna arrays. The inverse problem between the beam pattern and antenna phases is established first in the context of planar phased array. Inception-Resnet-V2 with prior knowledge (IR-PK) is proposed as an efficient model, which involves the prior knowledge of array factor to guide neural network (NN) learning for stronger fitting ability. To obtain the real-time phase retrieval in small terminals, a MobileNet-distilled IR-PK (MD-IR-PK) model combining lightweight architecture and knowledge distillation (KD) is then designed under the condition of limited resources. The method is validated for array beamforming and hologram. Compared with popular solutions, IR-PK shows the advantages of good accuracy, fast convergence, and computational efficiency. Experiments have been carried out for metasurface-based holography, with the measured results agreeing well with the simulated ones. The proposed method is competitive for complex electromagnetic (EM) inverse problems involving high nonlinearity.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"73 3","pages":"1471-1481"},"PeriodicalIF":4.6,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143553490","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":"Modeling of Human Body Shadowing Loss at 300 GHz Based on Measurement of Path Loss and Direction of Arrival","authors":"Akihiko Hirata;Shunta Takagi","doi":"10.1109/TAP.2024.3520664","DOIUrl":"https://doi.org/10.1109/TAP.2024.3520664","url":null,"abstract":"The modeling of the shadowing loss due to the human body in the 300-GHz band is important for the practical application of 300-GHz band wireless local area networks (LANs) and body area networks. In this study, the shadowing loss characteristics due to the human body was investigated by measuring the propagation loss and direction of arrival (DOA) of diffraction waves when a human body phantom blocks the line-of-sight (LOS) propagation path. The DOAs and the shadowing losses were measured by a terahertz hemispheric scanner and vector network analyzer (VNA). For a human body phantom positioned upright with a gap between the arms and torso, the removal of the arms increased the shadowing loss by more than 10 dB. DOA measurements revealed a reduction in the shadowing loss upon attachment of the arms, attributed to the additional propagation path created by diffraction inside the arms. The shadowing loss for a human body with arms could be estimated using a model comprising a double-isolated-knife-edge diffraction (DIKED) model for the torso and a single-knife-edge diffraction (SKED) model for the arm when a gap exists between the torso and arms. By comparing with actual measurement values, we demonstrated that this method can estimate the diffraction at the head and torso. When the phantom without arms was dressed in a down coat, the shadowing loss decreased by approximately 9 dB because the scattering induced by the down coat broadened the DOA of the received radio wave diffracted at the side of the torso. When the phantom’s head was covered with a wig, the shadowing loss at the head reduced by approximately 2.8 dB due to scattering by the wig. These results indicate that arms, hair, and clothing have a significant impact on shadowing loss by the human body at 300 GHz. The human body shadowing (HBS) loss was successfully calculated using the DIKED model with the effects of arms, hair, and clothing added as correction terms.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"73 2","pages":"1162-1172"},"PeriodicalIF":4.6,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143361475","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 Architecture of Retro-Reflective Beamforming for Wireless Power Transmission With a 2-D Transmitting Antenna Array Controlled by 1-D Receiving Antenna Arrays","authors":"Xin Wang;Huaiqing Zhang;Mingyu Lu","doi":"10.1109/TAP.2024.3520352","DOIUrl":"https://doi.org/10.1109/TAP.2024.3520352","url":null,"abstract":"A novel architecture of retro-reflective beamforming is proposed for wireless power transmission applications. In contrast to a conventional retro-reflective beamformer with a 2-D transmitting antenna array controlled by a 2-D receiving antenna array, the novel retro-reflective beamformer includes a 2-D transmitting antenna array controlled by multiple 1-D receiving antenna arrays. Compared with the conventional architecture of retro-reflective beamforming, the architecture proposed in this communication has better flexibility and lower complexity. Numerical results indicate that the wireless power transmission efficiency of the novel architecture has little difference from that of the conventional architecture when the location of a wireless power receiver with a clear line-of-sight path is not far off the broadside direction of the retro-reflective beamformer. Some preliminary experiments are conducted in an anechoic chamber as well as an indoor environment to verify the numerical studies. The experimental data are in agreement with the numerical results.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"73 2","pages":"1233-1238"},"PeriodicalIF":4.6,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143184196","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}
Sravan Kumar Reddy Vuyyuru;Le Hao;Markus Rupp;Sergei A. Tretyakov;Risto Valkonen
{"title":"Modeling RIS From Electromagnetic Principles to Communication Systems—Part I: Synthesis and Characterization of a Scalable Anomalous Reflector","authors":"Sravan Kumar Reddy Vuyyuru;Le Hao;Markus Rupp;Sergei A. Tretyakov;Risto Valkonen","doi":"10.1109/TAP.2024.3520416","DOIUrl":"https://doi.org/10.1109/TAP.2024.3520416","url":null,"abstract":"This work aims to build connections between the electromagnetic (EM) and communication aspects of reconfigurable intelligent surfaces (RISs) by proposing a methodology to combine outputs from EM RIS design into an RIS-tailored system-level simulator and a ray tracer. In this first part of the contribution, a periodic anomalous reflector is designed using an algebraic array antenna scattering synthesis technique that enables electromagnetically accurate modeling of scattering surfaces with both static and reconfigurable scattering characteristics. The multimode periodic structure, capable of scattering into several anomalous angles through manipulation of reactive loads, is then cropped into finite-sized arrays, and the quantization effects of the load reactances on the array scattering are analyzed. An experimental anomalous reflector is demonstrated with a comparison between simulated and measured scattering performance. In the second part, the simulated receiving and transmitting scattering patterns of the anomalous reflector are utilized to build an electromagnetically consistent path loss model of an RIS into a system-level simulator. Large-scale fading is analyzed in simple scenarios of RIS-assisted wireless networks to verify the communication model, and an indoor scenario measurement using the manufactured anomalous reflector sample to support the simulation analysis. After verifying the connections between EM and communication aspects through simulations and measurements, the proposed communication model can be used for a broad range of RIS designs to perform large-scale system-level and ray-tracing simulations in realistic scenarios.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"73 3","pages":"1743-1755"},"PeriodicalIF":4.6,"publicationDate":"2024-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10816354","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143553203","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}