Radio SciencePub Date : 2025-03-01DOI: 10.1029/2025RS008226
B. H. La Rosa;D. L. Hysell
{"title":"Modeling and analysis of artificial periodic inhomogeneities in the ionosphere","authors":"B. H. La Rosa;D. L. Hysell","doi":"10.1029/2025RS008226","DOIUrl":"https://doi.org/10.1029/2025RS008226","url":null,"abstract":"The artificial periodic inhomogeneity (API) technique is an ionospheric modification experiment that creates perturbations in the electron plasma density, studied through the scattering of probing radio waves. This work presents the first comprehensive observation of API irregularities at the HAARP facility including responses from the D, E, and F regions. The measurements were obtained by reprocessing backscatter echoes from an experimental campaign in 2014. To investigate the evolution of these structures, we extend a one-dimensional fluid model previously developed by Hysell and Rojas (2023, https://doi.org/10.1029/2023rs007710), that simulates the formation of API in the E region, incorporating mechanisms that dominate the API formation in other regions. The creation of these irregularities in the D region is accomplished by including a simplified chemical model that contains the reactions necessary for the production of negative ions. In the F region, we consider the inclusion of the ponderomotive force, which is proposed as the primary mechanism to generate these inhomogeneities. The updated model successfully produced API irregularities in the three distinct ionospheric regions according to their respective formation mechanisms. Information about the diffusion process of these structures is obtained by analyzing their decay times.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 5","pages":"1-15"},"PeriodicalIF":1.6,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144213610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Radio SciencePub Date : 2025-03-01DOI: 10.1029/2024RS007963
Xinhao Xu;Shuqi Lei;Dongxiao Yue;Feng Wang
{"title":"Land cover recognition from few samples of radar high-resolution range profile","authors":"Xinhao Xu;Shuqi Lei;Dongxiao Yue;Feng Wang","doi":"10.1029/2024RS007963","DOIUrl":"https://doi.org/10.1029/2024RS007963","url":null,"abstract":"Radar echo data, a refined representation of detected targets, is gaining attention in electronic warfare, marine environment monitoring, and agriculture intelligence for land cover recognition. In contrast to prevailing studies involving two-dimensional images such as synthetic aperture radar (SAR) or inverse SAR (ISAR) images, one-dimensional High-Resolution Range Profile (HRRP) data offers advantages of easy access and simple processing. Nonetheless, its potential application has yet to be explored, as current research on it remains insufficient. Meanwhile, deep learning methods that specialize in classification tasks but encounter challenges in modern electronic warfare, given their heavy reliance on the number of labeled samples. To tackle these issues, a feature fusion-based land cover recognition approach is proposed, which introduces Convolutional Embedding Sequence Encoder (CE-SE) to capture the complex clutter characteristics of HRRP, achieving land cover recognition with a small number of labeled HRRP samples and eliminating the reliance on two-dimensional image data. Experimental results validated on Mini-SAR data from unmanned aerial vehicles demonstrate effective land cover recognition using HRRP. This method significantly improves the recognition accuracy for five land cover types, exceeding 92%, even with only half the sample size compared to traditional deep learning methods. Additionally, the model's inference time for a single HRRP sample is just 1.3 milliseconds, demonstrating its capability for real-time land cover recognition.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 3","pages":"1-24"},"PeriodicalIF":1.6,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Radio SciencePub Date : 2025-03-01DOI: 10.1029/2024RS008092
I. A. Nosikov;M. V. Klimenko;A. M. Padokhin;V. V. Nosikova;P. F. Bessarab
{"title":"Generalized force method for point-to-point ray tracing in anisotropic ionosphere: Implementation and applications to NeQuick2 and IGRF13 models","authors":"I. A. Nosikov;M. V. Klimenko;A. M. Padokhin;V. V. Nosikova;P. F. Bessarab","doi":"10.1029/2024RS008092","DOIUrl":"https://doi.org/10.1029/2024RS008092","url":null,"abstract":"The generalized force method, previously developed for an isotropic inhomogeneous ionosphere, exploits the knowledge about the character of the extrema of the phase distance—where high ionospheric rays correspond to minima and low rays to saddle points—to systematically find all relevant rays between fixed points, thereby enabling efficient global point-to-point ray tracing. In this article, the generalized force approach is extended to magneto-active, anisotropic ionosphere by locating minima and saddle points of a more general phase distance functional where trial functions include both the candidate ray path geometry and the orientation of the wavefront. For both O and X modes, the rays are found using an optimization algorithm guided by the generalized force whose definition depends on the ray type. The generalized force method, implemented in the form of computer software, is applied to problems of oblique sounding in realistic ionosphere described by NeQuick2 and IGRF13 models. The results of the ionogram simulations demonstrate the method's ability to solve routine problems of ionospheric ray tracing and show its potential in solving various inverse problems, as well as in verifying and correcting models of the ionosphere.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 3","pages":"1-14"},"PeriodicalIF":1.6,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Radio SciencePub Date : 2025-03-01DOI: 10.1029/2024RS008072
Nila Bagheri;Jon M. Peha;Fernando J. Velez
{"title":"Fractal patch antenna based on photonic crystal for enhanced millimeter-wave communication in intelligent transportation systems","authors":"Nila Bagheri;Jon M. Peha;Fernando J. Velez","doi":"10.1029/2024RS008072","DOIUrl":"https://doi.org/10.1029/2024RS008072","url":null,"abstract":"This paper introduces a Fractal Patch Antenna (FPA) integrated with Photonic Crystals (PhC) designed for Intelligent Transportation Systems (ITS) in the Millimeter-wave bands (mmWaves) given the importance of the application of mmWaves in Vehicle-to-Everything (V2X) networks, we assumed, as examples, that the antenna is designed to resonate at three frequency bands: 31.42 GHz, 37.76 GHz, and 38.92 GHz. With a gain of 10.88 dBi, at 38.92 GHz, the antenna demonstrates promising signal reception and transmission capabilities, which are anticipated to be important for ITS operations. The antenna bandwidth covers multiple frequency bands, enabling versatile communication in mmWaves V2X applications. To evaluate the performance of the antenna, we conducted a detailed analysis of its configuration. This included a comparison of the antenna with and without the PhC integration, as well as an exploration of rectangular lattice structure. In addition, variations in hole sizes and spacing were examined to assess their impact on key parameters such as the gain and reflection coefficient. The integration of fractal geometry and PhC structures results in a compact, high-performance antenna suitable for mmWave communication. The integration of fractal geometry and PhC structure results in compactness and high performance in mmWaves communication applications. Through simulation and analysis, including radiation pattern, gain, and reflection coefficient plot assessment, the antenna performance is thoroughly evaluated. The study highlights the potential of the proposed FPA-PhC antenna configuration to enhance communication networks within the ITS, significantly advancing the ITS system with support from the mmWave bands.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 5","pages":"1-18"},"PeriodicalIF":1.6,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144213517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Radio SciencePub Date : 2025-03-01DOI: 10.1029/2024RS008174
Muhammad Irshad Khan;Muhammad Kabir Khan;Saeed Ur Rahman;Muhammad Anab;Abdul Basit
{"title":"Quad ports millimeter-wave MIMO antenna with parasitic element and defected ground structure for radar sensing application","authors":"Muhammad Irshad Khan;Muhammad Kabir Khan;Saeed Ur Rahman;Muhammad Anab;Abdul Basit","doi":"10.1029/2024RS008174","DOIUrl":"https://doi.org/10.1029/2024RS008174","url":null,"abstract":"This paper presents a quad-element MIMO antenna with a novel decoupling structure for mm-wave 5G radar sensing applications. The proposed MIMO antenna is fabricated on Rogers RT/5880, which is suitable for high frequency communication. Furthermore, effective techniques for novel parasitic elements and a defected ground structure (DGS) are introduced to minimize inter-element coupling in the required bandwidth. The parasitic element consists of a square ring and a four-line parasitic. The ring parasitic is rotated 45° anticlockwise and line parasitic elements are rotated 5° from the original position to obtain the proposed design. The line parasitic elements coupled from adjacent elements and square ring parasitic neutralize current. The DGS is introduced to enhance isolation further. The slot is inserted in the center of the ground plane. Two rectangular slots are also inserted to isolate adjacent elements. The edge-to-edge space between the radiation elements is 5.6 mm. The antenna exhibits S11 of <—10>9.99 dB and multiplexing efficiency is —0.5 dB within the given bandwidth. The multiplexing efficiency, radiation pattern, ECC, DG, and peak gain are also calculated and evaluated for practical authentication.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 3","pages":"1-12"},"PeriodicalIF":1.6,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Radio SciencePub Date : 2025-03-01DOI: 10.1029/2024RS008155
Jiajing Chen;Mingran Sun;Lu Bai;Xiang Cheng;Xuesong Cai
{"title":"Simulation-based channel modeling at 28 GHz for different vehicular traffic densities in vehicle-to-vehicle scenarios","authors":"Jiajing Chen;Mingran Sun;Lu Bai;Xiang Cheng;Xuesong Cai","doi":"10.1029/2024RS008155","DOIUrl":"https://doi.org/10.1029/2024RS008155","url":null,"abstract":"Vehicle-to-Vehicle (V2V) communications have received a lot of attention as it can significantly improve efficiency and safety of road traffic. This paper introduces a novel data set, constructed at urban crossroads in different vehicular traffic densities (VTDs) for line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios, utilizing Ray-tracing techniques for its development. Channel modeling was performed for the path loss, shadowing, and multipath characteristics of the propagation channel, that is, the root-mean-square delay spread, azimuth of arrival (AoA) spread and elevation of arrival (EoA) spread, correlations of spreads, and coherent distances of spreads of interest. The simulation results indicate that scenarios with low and medium VTD exhibit lower path loss and delay spread values compared to scenarios with high VTD. The AoA spread is significantly larger in the LOS scenarios compared to the NLOS scenarios, and the EoA spread demonstrates greater variations with different VTDs in both the LOS and the NLOS conditions. These results are important for generating realistic channel realizations for the design and performance evaluation of V2V communication algorithms in the context of the sixth-generation (6G) wireless networks.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 5","pages":"1-10"},"PeriodicalIF":1.6,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144213611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Radio SciencePub Date : 2025-03-01DOI: 10.1029/2024RS008195
R. García;A. A. San-Blas;S. Bonte;A. Coves;M. A. Sánchez-Soriano;M. Guglielmi;V. E. Boria
{"title":"Design procedure for interdigital waveguide bandpass filters based on flat metallic strips","authors":"R. García;A. A. San-Blas;S. Bonte;A. Coves;M. A. Sánchez-Soriano;M. Guglielmi;V. E. Boria","doi":"10.1029/2024RS008195","DOIUrl":"https://doi.org/10.1029/2024RS008195","url":null,"abstract":"In this work, we describe a new topology for interdigital bandpass filters implemented in waveguide technology. Compared to classical coaxial resonators, which are typically based on cylindrical metallic posts, the resonators that we propose are based on rectangular boxed cavities loaded with flat metallic strips of a finite thickness. The main advantages of the proposed topology are low-cost practical realization and manufacture simplicity. The design process, which is based on the classical circuit-based approach combined with an efficient segmentation of the component, uses the well-known Aggressive Space Mapping technique, with the aim of reducing the overall computation effort. In order to validate the new topology and the design procedure, interdigital bandpass filters of orders 3 and 5 operating at the S-band have been designed. For validation purposes, the results obtained are successfully compared to simulations provided by two different full-wave electromagnetic tools (i.e., Ansys HFSS and CST Studio Suite). Furthermore, a multipactor study has also been performed, with the aim of exploring the power handling capability of the proposed filters in view of possible space applications. Finally, the design of classical interdigital filters based on cylindrical posts is also discussed, with the aim of comparing both topologies regarding compactness, as well as in terms of their electrical and high-power performance.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 3","pages":"1-13"},"PeriodicalIF":1.6,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Radio SciencePub Date : 2025-03-01DOI: 10.1029/2024RS008123
Wen Liu;Xinxin Huang;Na Wei;Zhongxin Deng
{"title":"Automatic scaling of vertical ionograms based on generative adversarial network","authors":"Wen Liu;Xinxin Huang;Na Wei;Zhongxin Deng","doi":"10.1029/2024RS008123","DOIUrl":"https://doi.org/10.1029/2024RS008123","url":null,"abstract":"Ionospheric vertical sounding is a well-established and widely used ground-based technique for ionospheric detection. Efficient and accurate automatic scaling of ionograms is crucial for real-time applications of vertical sounding. However, current scaling methods face challenges in achieving precise trace segmentation due to noise, interference, and various ionospheric disturbances. This paper proposes a deep learning model for ionogram automatic scaling based on generative adversarial network (GAN), which is named IASGAN. The model integrates a 50-layer residual network (ResNet50) and a feature pyramid network (FPN) as the generator, with a multi-layer convolutional neural network (CNN) as the discriminator. Given a vertical ionogram, the generator produces segmentation result that closely resemble the corresponding label, while the discriminator provides feedback loss to the generator for adversarial training, thereby enhancing the segmentation performance of the generator. Experimental results demonstrate that the IASGAN model can precisely and effectively autoscale E, FI, and F2 layer traces. Compared to existing scaling methods, the IASGAN model can produce finer trace extraction from ionograms, with a mean maximum critical frequency absolute deviation (D-MCF) of 0.0803 MHz and a mean minimum virtual height absolute deviation (D-MEH) of 5.8205 km. This capability can provide technical support for the extraction of characteristic parameters and ionospheric inversion, which is significant for real-time acquisition of ionospheric characteristics and structure information.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 3","pages":"1-11"},"PeriodicalIF":1.6,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}