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IF 1.6 4区地球科学

Radio Science Pub Date : 2025-01-01 DOI: 10.1002/rds.21325

引用次数: 0

Angle and polarization insensitive RCS reduction metasurface based on hybrid mechanism of polarization conversion and absorption

IF 1.6 4区地球科学

Radio Science Pub Date : 2025-01-01 DOI: 10.1029/2024RS008052

H. J. Zhao;X. Y. Dai;H. Chu;X. H. Zhu;Y. X. Guo

{"title":"Angle and polarization insensitive RCS reduction metasurface based on hybrid mechanism of polarization conversion and absorption","authors":"H. J. Zhao;X. Y. Dai;H. Chu;X. H. Zhu;Y. X. Guo","doi":"10.1029/2024RS008052","DOIUrl":"https://doi.org/10.1029/2024RS008052","url":null,"abstract":"This article introduces the concept, theory, and design of an angle and polarization insensitive radar cross section (RCS) reduction metasurface, using a hybrid mechanism of polarization conversion and absorption. By introducing ladder- and rectangle-shaped metallic patches in the vertical dimension of a 3-D structure, polarization conversion rate (PCR) deterioration, brought by the increase of equivalent substrate thickness at oblique incidences, can be suppressed. Furthermore, lumped resistors are loaded at proper places in each polarization conversion cell, to achieve the power absorption while maintain the angular insensitivity of the PCR. With the above hybrid mechanism, a stable 10-dB RCS reduction can be achieved regardless of the angle of incidence in a wide range and polarization directions. An equivalent circuit model is established for explaining the physical mechanism of the proposed metasurface. For validation, a prototype is fabricated and tested. Measurement results indicate that, for both monostatic RCS at the normal incidence and specular RCS of off-normal incidences from 0° to 45°, a 10-dB TE- and TM-mode RCS reduction can be achieved in the entire X-band (8–12 GHz) and Ku-band (12–18 GHz).","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 1","pages":"1-11"},"PeriodicalIF":1.6,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143106324","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

A novel flexible ultra wide band wearable slot antenna with defected ground for WBAN applications

IF 1.6 4区地球科学

Radio Science Pub Date : 2025-01-01 DOI: 10.1029/2024RS008085

Nageswara Rao Regulagadda;U. V. Ratna Kumari

引用次数: 0

Agile detection of DRM signal via GLRT

IF 1.6 4区地球科学

Radio Science Pub Date : 2025-01-01 DOI: 10.1029/2024RS008164

Yangpeng Dan;Luyao Wang;Chaofan Duan;Fan Yang

{"title":"Agile detection of DRM signal via GLRT","authors":"Yangpeng Dan;Luyao Wang;Chaofan Duan;Fan Yang","doi":"10.1029/2024RS008164","DOIUrl":"https://doi.org/10.1029/2024RS008164","url":null,"abstract":"Digital Radio Mondiale (DRM) is a digital Orthogonal Frequency Division Multiplexing (OFDM) broadcasting standard that has been employed all over the world. The operating carrier frequency and time of DRM station change with the scheduling period. The user terminal commonly uses channel decoding and audio decoding to detect the DRM radio. This conventional signal detection method always fail when the station is not working, or the signal-to-noise ratio (SNR) is weak, or the designated frequency band is illegally occupied. Besides, the conventional method needs at least one DRM transmission super frame with a duration of 1.2 s, which causes delay and brings additional computations. To solve the challenges faced by conventional method, this paper has proposed an agile and efficient signal detection method based on the Generalized Likelihood Ratio Test. The proposed method coherently integrates the frequency pilots of successive OFDM symbols via discrete Fourier transform, then propose a sufficient statistic to detect the DRM radio. The required number of OFDM symbols, which is much smaller than that of one transmission super frame, is adaptively chosen from the given probabilities of false alarm and correct detection. The computations and SNR requirement of the proposed method are both smaller than the conventional method, which help the user terminal quickly detect the DRM signal over the given frequency band. The proposed method also provides a new perspective for electromagnetic spectrum management.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 1","pages":"1-15"},"PeriodicalIF":1.6,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143106327","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

The noise temperature analysis on a space-grade cryogenic low noise amplifier using two measurement methods

IF 1.6 4区地球科学

Radio Science Pub Date : 2025-01-01 DOI: 10.1029/2024RS008023

Junda Jin;Jie Liu;Dong Liu;Jiang-Qiao Ding;Xuan Zhang;Jing Li;Sheng-Cai Shi

引用次数: 0

A novel blind adaptive 3D beam steering algorithm for interference mitigation and performance enhancement in massive MIMO systems

IF 1.6 4区地球科学

Radio Science Pub Date : 2025-01-01 DOI: 10.1029/2024RS008075

Hosni Manai;Larbi Ben Hadj Slama;Ridha Bouallegue

{"title":"A novel blind adaptive 3D beam steering algorithm for interference mitigation and performance enhancement in massive MIMO systems","authors":"Hosni Manai;Larbi Ben Hadj Slama;Ridha Bouallegue","doi":"10.1029/2024RS008075","DOIUrl":"https://doi.org/10.1029/2024RS008075","url":null,"abstract":"This paper introduces an innovative blind adaptive 3D Beam steering algorithm designed to mitigate interference, ultimately improving the signal-to-interference and noise ratio (SINR) to enhance the overall performance of mMIMO (massive multiple-input multiple-output (MIMO)) networks. The proposed algorithm combines an optimized direction of arrival (DoA) estimation method with an inventive adaptive signal processing technique. To address the computational complexity associated with determining the 2D-DoA of incoming signals, an improved RD-MUSIC (Reduced Dimension — Multiple Signal Classification) estimator is proposed. This method streamlines the process into an efficient 1D search, significantly reducing computational overhead compared to conventional 2D-MUSIC and minimizing noise, maintaining superior accuracy over the conventional RD-MUSIC method. Leveraging the estimated 2D-DoAs, the proposed adaptive signal processing technique integrates the Dolph-Chebyshev weighting method with nulling constraints to calculate the optimal complex weig0hts necessary to accurately steer the main Beam toward the desired signal direction and create deep nulls in the directions of interfering signals, resulting in enhanced SINR. Compared to alternative algorithms, our approach demonstrates superior performance and offers an efficient solution without requiring a training signal or additional antenna elements. This is advantageous, particularly in environments with intense interference and high mobility, making it a promising candidate for future wireless systems.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 1","pages":"1-23"},"PeriodicalIF":1.6,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143106328","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

The geomagnetic storm time responses of the TEC, foF2, and hmF2 in different solar activity during solar cycle 24 and 25 第24和25太阳活动周TEC、foF2和hmF2在不同太阳活动条件下的地磁风暴时间响应

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-12-31 DOI: 10.1029/2024RS007961

Yekoye Asmare Tariku

{"title":"The geomagnetic storm time responses of the TEC, foF2, and hmF2 in different solar activity during solar cycle 24 and 25","authors":"Yekoye Asmare Tariku","doi":"10.1029/2024RS007961","DOIUrl":"https://doi.org/10.1029/2024RS007961","url":null,"abstract":"This paper mainly examines the response of variation of the TEC, foF2, and hmF2 obtained from observations (GPS and digisondes) and models (IRI 2016 and IRI-Plas 2017) across low-to-high latitudes during various geomagnetic storm time conditions in different solar activity years. The 19 February 2014, 17 March 2015, and 4 November 2021 geomagnetic storm cases caused positive storm effects (particularly at low latitudes), while the 8 September 2017, and 26 August 2018 geomagnetic storm cases resulted in negative storm effects, especially at mid and high latitudes. Furthermore, during the 19 February 2014 storm, the sharp increase (peak) diurnal digisondes TEC values are observed, on average, when the hmF2 values reach about 360, 282, and 312 km, in the low, mid and high latitudes, respectively. During the 26 August 2018 storm, the peak TEC values are observed, on average, when the hmF2 values reach about 313, 258, and 268 km in the low, mid and high latitudes, respectively. Hence, the digisonde-derived peak TEC in mid latitudes typically coincides with a decrease in hmF2, while in low latitudes, it is associated with an increase in hmF2. Additionally, during low solar activity periods, digisonde-derived peak TEC values were observed when hmF2 decreased, contrasting with patterns seen during high solar activity. Both the IRI 2016 and IRI-Plas 2017 models performed well, with the models peak TEC values being observed when the hmF2 variations attain similar values with the observations, reinforcing the models' reliability in capturing ionospheric responses during geomagnetic storms.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 12","pages":"1-18"},"PeriodicalIF":1.6,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142905768","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

The impact and sources of radio frequency interference on GNSS signals 无线电频率干扰对GNSS信号的影响及来源

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-12-31 DOI: 10.1029/2024RS008109

Endawoke Yizengaw

{"title":"The impact and sources of radio frequency interference on GNSS signals","authors":"Endawoke Yizengaw","doi":"10.1029/2024RS008109","DOIUrl":"https://doi.org/10.1029/2024RS008109","url":null,"abstract":"The utilization of the global navigation satellite systems (GNSS) services in both military and civilian applications as well as for scientific investigation has grown exponentially. However, the increasing reliance on GNSS applications has raised concerns about potential risks from intentional radio frequency interference (RFI) transmitters. RFI significantly affects GNSS's environmental monitoring capabilities by inflating the scintillation index and misleading the scientific community with scintillation indices not attributable to ionospheric dynamic events. Consequently, the existing climatological distribution of GNSS scintillations may require careful reevaluation, as it may not adequately filter out RFI induced scintillations. Thus, characterizing the global RFI occurrence regions and developing real-time detection capabilities to mitigate its effects is critically important. Leveraging GNSS measurements from ground stations and six COSMIC-2 satellite constellations, we have developed a technique to detect RFI events and identify RFI active regions. Additionally, for the first time, we have implemented techniques that differentiate RFI associated scintillations from scintillations caused by ionospheric turbulence.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 12","pages":"1-12"},"PeriodicalIF":1.6,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142905915","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

Optimization of variational mode decomposition using stationary wavelet transform and its application to transient electromagnetic signal noise reduction 平稳小波变换的变分模态分解优化及其在瞬变电磁信号降噪中的应用

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-12-31 DOI: 10.1029/2023RS007889

Xianxia Wang;Xiaoya Wei;Duxi Song;Linfei Wang;Haochen Wang;Zhicheng Zhang;Tingye Qi

{"title":"Optimization of variational mode decomposition using stationary wavelet transform and its application to transient electromagnetic signal noise reduction","authors":"Xianxia Wang;Xiaoya Wei;Duxi Song;Linfei Wang;Haochen Wang;Zhicheng Zhang;Tingye Qi","doi":"10.1029/2023RS007889","DOIUrl":"https://doi.org/10.1029/2023RS007889","url":null,"abstract":"To solve the problem of signal loss due to local reconstruction in the variational mode decomposition (VMD) method, this study proposes to use the stationary wavelet transform (SWT) to extract the effective signal in the mixed noise modes and reconstruct the noise-reduced signal. First the slime mold algorithm (SMA) takes to realize the adaptive difficulty of selecting the important parameters K (the number of eigenmode decompositions) and a (the quadratic penalty coefficient) in the VMD. Then, the VMD decomposed modes are divided into the basic signal and noise signal according to the definition of Euclidean distance, finally the noise signal is decomposed in a new step by using SWT, and the basic signal is reconstructed with the effective signal to get the final noise reduced signal. Through the establishment of simulation tests and transient electromagnetic field tests in the mined-out area, the results show that the VMD-SWT method exhibits a better denoising effect and higher inversion accuracy for the transient electromagnetic signals, proving the superiority and applicability.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 12","pages":"1-18"},"PeriodicalIF":1.6,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142905912","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

Finite element method modeling of the wire thickness of a monopole on a circular ground plane 圆形地平面上单极子导线厚度的有限元建模

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-12-31 DOI: 10.1029/2024RS008068

C. G. Hynes;R. G. Vaughan

引用次数: 0