IEEE Transactions on Antennas and Propagation最新文献

{"title":"Line-of-Sight Probability in Urban Environments Representing Deterministic Grids","authors":"Kyung-Won Kim;Hyeyeon Kwon;Seungkeun Park","doi":"10.1109/TAP.2024.3513540","DOIUrl":"https://doi.org/10.1109/TAP.2024.3513540","url":null,"abstract":"This article proposes a line-of-sight (LoS) probability model based on geometric analysis of deterministic urban grids, assuming uniformly distributed antenna positions. The model can be adjusted with geometric parameters such as street width, building width, and building height, enabling its application in various environments. Antenna height is applicable from ground level to sky level, and Monte Carlo simulation results closely align with the proposed model. Comparisons between the proposed model and simulations using actual 3-D geographic information system (GIS) data of urban environments are also presented, indicating that even in realistic environments, adjusting environmental parameters related to building density and height yields similar results. It includes separate models for specific directions and a random direction, allowing for applications in both site-specific and site-general scenarios. These features facilitate simultaneous simulations for various wireless service deployment scenarios across multiple services in urban environments.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"73 3","pages":"1792-1804"},"PeriodicalIF":4.6,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143553487","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 Effective Method for Attributed Scattering Center Extraction Based on an Improved ESPRIT Algorithm","authors":"Xiaofeng Shen;Zhihong Zhuang;Hongbo Wang;Feng Shu","doi":"10.1109/TAP.2024.3502907","DOIUrl":"https://doi.org/10.1109/TAP.2024.3502907","url":null,"abstract":"According to the theories of physical optics and geometrical diffraction, the backscattered field of a radar target in a high-frequency domain can be obtained by coherently summing the responses of a series of independent scattering centers. The attributed scattering center (ASC) model has seven parameters: scattering intensity, 2-D coordinates, frequency-dependent factor, length, orientation angle, and aspect-dependent factor. While these parameters describe the geometric structure and electromagnetic scattering characteristics of a target concisely and accurately, they can also serve as features in synthetic aperture radar (SAR) automatic target recognition (ATR) tasks. Therefore, the ASC model finds widespread use in ATR. The extraction of ASC model parameters represents a high-dimensional, nonlinear, and nonconvex optimization problem. In this study, an innovative method for the ASC model parameter extraction is proposed. Initially, the proposed method simplifies the ASC model by eliminating the nonlinear term sinc, resulting in the simplified ASC (SASC) model with four parameters: scattering intensity, 2-D coordinates, and frequency-dependent factor. Subsequently, an improved estimating signal parameter via the rotational invariance technique (ESPRIT) algorithm is proposed and used to estimate the SASC model’s parameters. A binary graph is then constructed using the 2-D coordinates of the SASC model. Furthermore, both localized ASC (L-ASC) and distributed ASC (D-ASC) are distinguished from the binary graph, and their parameters, including 2-D coordinates, length, and orientation angle, are calculated. Finally, the frequency-dependent factor and scattering intensity are determined by search and least-squares methods, respectively. The proposed method accurately estimates the ASC model parameters in the frequency domain without the need for image segmentation or an iteration procedure, thereby enhancing computational efficiency. Simulations and experiments validate the effectiveness of the proposed method.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"73 3","pages":"1618-1629"},"PeriodicalIF":4.6,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143553081","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":"Sparse Regularization With Learnable Partition Weights for Super-Resolution Imaging of Ultrawideband Radar","authors":"Rui Li;Xueqian Wang;Gang Li;Xiao-Ping Zhang","doi":"10.1109/TAP.2024.3513647","DOIUrl":"https://doi.org/10.1109/TAP.2024.3513647","url":null,"abstract":"In this article, we propose a novel method based on sparse regularization with learnable partition weights (LPWs) for bandwidth extrapolation (BWE) 2-D imaging of ultrawideband radar. Our method aims to improve the quality of super-resolution image reconstruction with limited observation bandwidth, by the strategies of weighting and supervised learning. First, in our new sparse regularization, we assign different LPWs to scattering centers based on their frequency dependence factors (FDFs). These LPWs can provide different regularization strengths regarding FDFs, which improve the accuracy of BWE. Then, we propose an unrolling algorithm named fast iterative shrinkage thresholding algorithm (FISTA)-LPW, to optimize these LPWs through supervised learning. We utilize the full band spectrums as training labels, to reduce extrapolation error in a data-driven manner. We analyze the advantage of our sparse regularization with LPWs and show that it can address the issue of degraded extrapolation accuracy in the cases of limited observation bandwidth. The experimental results on simulated and real radar data demonstrate that our method outperforms existing methods for BWE in terms of super-resolution image quality. Notably, our method achieves a radar image reconstruction accuracy of 90% while only utilizing 75% of the full bandwidth on real radar data.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"73 2","pages":"1149-1161"},"PeriodicalIF":4.6,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143361476","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 Direct Solver for Subwavelength Periodic Problems via the Multilevel Green’s Function Interpolation Method","authors":"Shidong Jiang;Haogang Wang","doi":"10.1109/TAP.2024.3513552","DOIUrl":"https://doi.org/10.1109/TAP.2024.3513552","url":null,"abstract":"In this article, a novel direct solver via multilevel Green’s function (GF) interpolation method (DSMLGFIM) is proposed for efficient analysis of 3-D composite dielectric and metallic structures with subwavelength double periodicity. In DSMLGFIM, the method of moments (MoM) matrix is quickly calculated via the newly devised multilevel interpolation scheme for both the far- and near-field interactions and then explicitly stored in order to apply the LU decomposition for fast solving the MoM matrix equations. Compared with the <inline-formula> <tex-math>$O(N^{2}$ </tex-math></inline-formula>) complexity for evaluations of the periodic GFs (PGFs) in the conventional MoM, the corresponding complexity of PGFs evaluations in DSMLGFIM is only <inline-formula> <tex-math>$O(N ,log ,N)$ </tex-math></inline-formula>, where N is the number of unknowns. In addition, the direct evaluation of the gradient of PGFs is avoided by performing the gradient operation on the interpolation formula of the PGFs. The numerical simulations on the reflection and transmission characteristics of three composite dielectric and metallic subwavelength structures are presented to demonstrate the efficiency and accuracy of the proposed method. Up to 82 times speedup is achieved in our simulated examples compared with the conventional MoM.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"73 2","pages":"1059-1070"},"PeriodicalIF":4.6,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143361539","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 Forecast Model of Ionospheric foF2 for HF Radio Wave Propagation Based on Echo State Network","authors":"Yafei Shi;Cheng Yang;Jian Wang","doi":"10.1109/TAP.2024.3513559","DOIUrl":"https://doi.org/10.1109/TAP.2024.3513559","url":null,"abstract":"The critical frequency of the ionospheric F2 layer (foF2), one of the essential channel parameters for high-frequency (HF) global communications via sky waves, shows significant variability in the equatorial region. This is mainly due to its nonlinear and nonstationary, which poses a considerable challenge for making efficient and accurate short-term forecasts of foF2 in low-latitude areas. Neural network algorithms have shown promising results in forecasting foF2 time series. This communication first introduces a neural network model based on the echo state network (ESN) to forecast HF propagation ionospheric parameters foF2 time series. By modeling and analyzing the foF2 data collected in 2014 and 2017 at the Sanya (18.34°N, 109.42°E) station in China, the ESN model effectively captures the characteristic trends of the foF2 time series. The results indicate that the forecast accuracy of the ESN model surpasses that of the international reference ionosphere (IRI), long short-term memory (LSTM), and bidirectional LSTM (Bi-LSTM) models, with significantly higher computational efficiency than other deep learning models. Moreover, it accurately tracks the foF2 trend during the geomagnetic storm in May 2017.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"73 2","pages":"1275-1280"},"PeriodicalIF":4.6,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143184466","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 Improved Entropy Regularization Method for Defect Detection in Multilayer Composites","authors":"Kang An;Changyou Li;Guoqian Long;Jun Ding","doi":"10.1109/TAP.2024.3513548","DOIUrl":"https://doi.org/10.1109/TAP.2024.3513548","url":null,"abstract":"Microwave time reversal (MTR) as a microwave imaging method can provide autofocus and super-resolution with real-time, efficient, high-contrast, and low-cost properties. It is applied here for nondestructive testing (NDT) of small defects buried in multilayer composites backed by metal. It is critical to estimate the focusing time with localization methods in MTR. The traditional entropy regularization method (ERM) may give the wrong focusing time estimation for the strong reflection from background metal. This leads to a wrong localization of the defect. An improved ERM (IERM) is proposed here by properly combining ERM and target initial reflection method (TIRM) to ensure a correct localization. MTR based on IERM (IERM-MTR) is then applied to detect the defect in multilayer composites when the permittivities of each layer are known. Its stability, accuracy, and noise tolerance are proved by multiple numerical investigations. An iterative strategy based on the IERM-MTR and particle swarm optimization (PSO) method is also proposed here for detecting the defect in multilayer composites when the permittivities of each layer are unknown. Numerical investigations are carried out to prove its effectiveness. Small defects are easily detected in multilayer composites applied here.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"73 2","pages":"1071-1083"},"PeriodicalIF":4.6,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143361477","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 Efficient Scheme of Waveguide Port Modeling Based on Conformal and Nonuniform Mesh for Time-Domain Finite Integration Technique","authors":"Guanjie Lin;Tao Huang;Wenjin Cai;Dapeng Gong;Xiaolin Jin","doi":"10.1109/TAP.2024.3511919","DOIUrl":"https://doi.org/10.1109/TAP.2024.3511919","url":null,"abstract":"A general numerical scheme for waveguide port modeling based on the contour integrated theorem (CIT) is proposed to improve the accuracy and efficiency, which is fully compatible with the 3-D time-domain finite integration technique (TDFIT). In this scheme, a compact 2-D finite-difference frequency-domain (FDFD) method with conformal and nonuniform mesh is derived, along with a novel method for accurately applying the perfect magnetic conductor (PMC) boundaries in this method. An improved two-component form is also developed and used in a 2-D eigenmode solver. Then, the positive-negative (P-N) transparent source is improved to be compatible with the TDFIT method based on the CIT for source feeding, and a novel implementation scheme of waveguide port based on a virtual domain suitable for the P-N source is also proposed. Finally, a simplified S-parameter extraction scheme that requires only modal voltage is proposed. Numerical examples are given to validate the proposed numerical scheme, and the results show good accuracy, lower memory consumption, and higher computational efficiency.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"73 2","pages":"1047-1058"},"PeriodicalIF":4.6,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143361249","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":"Machine-Learning-Assisted Swarm Intelligence Algorithm for Antenna Optimization With Mixed Continuous and Binary Variables","authors":"Kai Fu;Kwok Wa Leung","doi":"10.1109/TAP.2024.3510114","DOIUrl":"https://doi.org/10.1109/TAP.2024.3510114","url":null,"abstract":"Many existing surrogate-assisted optimization algorithms are limited to designing antennas with continuous variables only. However, numerous challenges emerge when tackling antenna optimization problems that involve both continuous and binary design variables. This article proposes an efficient surrogate-assisted mixed continuous/binary particle swarm optimization (SAMPSO) algorithm to address these mixed-variable antenna optimization problems. The SAMPSO tightly integrates machine learning (ML) models with PSO in two key aspects: an ML-guided swarm updating method and an ML-assisted prescreening strategy. In addition, a novel local ML model training method is developed to reduce the algorithm time complexity. To verify its effectiveness, the SAMPSO is compared with two existing algorithms in solving benchmark functions and designing antennas. The results demonstrate that SAMPSO can achieve design objectives with a faster convergence speed.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"73 3","pages":"1662-1673"},"PeriodicalIF":4.6,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143553080","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":"Electronically Reconfigurable Reflectarray Antennas Using 2-bit Phase Shift Unit Cells Embedded With Reflecting Circuits","authors":"Jiahao Zhao;Shichen Qiao;Halil Topozlu;Jinkai Wu;Mohammad Mahdi Honari;John H. Booske;Nader Behdad","doi":"10.1109/TAP.2024.3511945","DOIUrl":"https://doi.org/10.1109/TAP.2024.3511945","url":null,"abstract":"We present an electronically reconfigurable reflectarray capable of performing 2-D beam-scanning. This reflectarray uses an electronically reconfigurable unit cell, consisting of an antenna and a reflecting circuit that provides a 2-bit reflection phase shift. A general method for designing this unit cell is presented that can be adapted for use with different antenna types and reflecting circuit designs according to the user’s requirements. The unit cell used to verify this approach consists of an E-shaped patch located above a ground plane and a reflecting circuit located underneath it. The reflecting circuit uses three p-i-n diodes to provide four phase shift states. Each unit cell uses three dc bias lines to switch the p-i-n diodes on and off. The p-i-n diodes are the only lumped element components used in each unit cell, which reduces the design and assembly complexity when constructing large-scale reflectarrays. Simulation results demonstrate that the unit cells can achieve less than 2.2-dB loss and a phase error under 35° in the frequency range of 5.6–6.2 GHz. This unit cell was used to design a 208-element reconfigurable reflectarray prototype with a circular aperture diameter of 40 cm (<inline-formula> <tex-math>$8lambda $ </tex-math></inline-formula> at 6.0 GHz). The reflectarray prototype along with its digital control circuit was designed, fabricated, integrated, and experimentally characterized. The system is capable of controlling the state of each individual p-i-n diode to perform electronic beam steering. Measurements of the reconfigurable reflectarray reveal its capability to perform 2-D beam scanning within a scan range of up to ±60° across the operational bandwidth of 5.6 to 6.2 GHz. The aperture efficiency was measured to be 34.2%.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"73 1","pages":"314-328"},"PeriodicalIF":4.6,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142993223","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":"Pre-Phased 1-bit Reflective Passive Metasurface With Optimum Number of Pre-Phasing for Low QLL and SLL at 140 GHz","authors":"Taeyoung Kim;Sangmin Lee;Seongwoog Oh;Jinhyun Kim;Jungsuek Oh;Sangjo Choi","doi":"10.1109/TAP.2024.3510861","DOIUrl":"https://doi.org/10.1109/TAP.2024.3510861","url":null,"abstract":"Recent advancements introduced a pre-phased reflective metasurface (MS) using 1-bit control to suppress the quantization lobe (QL) inherent in a typical 1-bit MS under plane wave incidence, particularly in millimeter and submillimeter wave bands. However, the optimal method for pre-phasing using random phases has yet to be fully explored. This study investigates the optimal number of pre-phasing, which denotes the minimum number of discrete random phases for effective suppression of QLs and side lobes while ensuring low design complexity. The results indicate that employing four discrete phases, equally spaced at 45° intervals, is the optimal solution for both normal and oblique incidences. The random phases with a 45° separation are implemented into four pairs of unit cells with passive<sc>on/off</small> switching using multilayer PCBs at 140 GHz. Each unit cell consisted of a metallic patch coupled to a transmission (Tx) line through a slot, with embedded static<sc>on/off</small> switching in the Tx line to enable 1-bit reflection phase control. Finally, three MSs with <inline-formula> <tex-math>$30times 30$ </tex-math></inline-formula> unit cells, each with fixed random pre-phases, are designed and fabricated to reflect normal incidence at reflection angles (<inline-formula> <tex-math>$theta _{r}$ </tex-math></inline-formula>) of 15°, 30°, and 45° at 140 GHz. The experiment results demonstrate peak reflected beams at 15°, 29°, and 45° with frequencies of 139.7, 139.1, and 135.9 GHz, respectively. In addition, significant reductions in QL to −20 dB were observed, along with a reflection efficiency of 26%, and a 3 dB gain bandwidth exceeding 10%, on average, across all reflection angles in the 140 GHz band.","PeriodicalId":13102,"journal":{"name":"IEEE Transactions on Antennas and Propagation","volume":"73 2","pages":"975-985"},"PeriodicalIF":4.6,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143361277","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}