Radio Science最新文献

Effect of ground conductivity on VLF wave propagation 地面电导率对甚低频波传播的影响

IF 1.6 4区地球科学

Radio Science Pub Date : 2025-03-01 DOI: 10.1029/2024RS008150

P. Teysseyre;C. Briand;R. Marshall;M. Cohen

{"title":"Effect of ground conductivity on VLF wave propagation","authors":"P. Teysseyre;C. Briand;R. Marshall;M. Cohen","doi":"10.1029/2024RS008150","DOIUrl":"https://doi.org/10.1029/2024RS008150","url":null,"abstract":"Very Low Frequency (VLF, 3–30 kHz) waves propagate long distances in the waveguide formed by the Earth and the lower ionosphere. External sources such as solar flares and lightning discharges perturb the upper waveguide boundary and thereby modify the waves propagating within it. Therefore, studying the propagation of VLF waves within the waveguide enables us to probe the ionospheric response to external forcing. However, the wave propagation also depends on the lower waveguide boundary property, that is, the path conductivity. We tackle two main questions: how accurate should the path conductivity description be to obtain a given accuracy on the ionospheric electron density? Are the currently available ground-conductivity maps accurate enough? The impact of the ground conductivity values and their spatial extension on VLF wave propagation is studied through modeling with the Longwave Mode Propagator code. First, we show that knowledge of the path conductivity value should be more accurate as the ground conductivity decreases, in particular in regions where σ ≤ 10<sup>−3</sup> S/m. Second, we find that wave propagation is strongly sensitive to the spatial extension of ground conductivity path segments: segments of a few tens of km should be included in the path description to maintain below 50% the error on the derived electron density due to the path description. These results highlight the need for an update of the ground conductivity maps, to get better spatial resolution, more accurate values, and an estimate of the time-variability of each region.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 3","pages":"1-16"},"PeriodicalIF":1.6,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769445","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}

引用次数: 0

Fractional OAM vortex SAR imaging based on chirp scaling algorithm 基于啁啾缩放算法的分数阶OAM涡旋SAR成像

IF 1.6 4区地球科学

Radio Science Pub Date : 2025-03-01 DOI: 10.1029/2024RS008112

Liu Yu;Du Yongxing;Li Baoshan;Qin Ling;Li Chenlu

引用次数: 0

Land cover recognition from few samples of radar high-resolution range profile 基于少量雷达高分辨率距离像样本的土地覆盖识别

IF 1.6 4区地球科学

Radio Science Pub Date : 2025-03-01 DOI: 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}

引用次数: 0

Generalized force method for point-to-point ray tracing in anisotropic ionosphere: Implementation and applications to NeQuick2 and IGRF13 models 各向异性电离层点对点射线追踪的广义力法：在NeQuick2和IGRF13模型中的实现与应用

IF 1.6 4区地球科学

Radio Science Pub Date : 2025-03-01 DOI: 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}

引用次数: 0

Quad ports millimeter-wave MIMO antenna with parasitic element and defected ground structure for radar sensing application 四端口毫米波MIMO天线的寄生元件和缺陷的地面结构的雷达传感应用

IF 1.6 4区地球科学

Radio Science Pub Date : 2025-03-01 DOI: 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}

引用次数: 0

Front matters 前面问题

IF 1.6 4区地球科学

Radio Science Pub Date : 2025-03-01 DOI: 10.1002/rds.21327

引用次数: 0

Design procedure for interdigital waveguide bandpass filters based on flat metallic strips 基于平面金属条的数字间波导带通滤波器的设计程序

IF 1.6 4区地球科学

Radio Science Pub Date : 2025-03-01 DOI: 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}

引用次数: 0

Automatic scaling of vertical ionograms based on generative adversarial network 基于生成对抗网络的垂直电离图自动缩放

IF 1.6 4区地球科学

Radio Science Pub Date : 2025-03-01 DOI: 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}

引用次数: 0

Secrecy sum rate maximization of RIS assisted downlink NOMA system RIS辅助下行NOMA系统的保密和速率最大化

IF 1.6 4区地球科学

Radio Science Pub Date : 2025-02-01 DOI: 10.1029/2024RS008011

Zhitao Liu;Yongkang Peng;Youming Li;Yongfeng Du

引用次数: 0

Front matters 前面问题

IF 1.6 4区地球科学

Radio Science Pub Date : 2025-02-01 DOI: 10.1002/rds.21326

引用次数: 0