Radio Science最新文献_第5页

Wideband LP to CP converter using a reflectarray based on modulated admittance surfaces capable of wide-range beam-scanning for Ku/K band applications 使用基于调制导纳面的反射阵列的宽带 LP 到 CP 转换器，能够为 Ku/K 波段应用提供宽范围波束扫描

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-08-01 DOI: 10.1029/2023RS007881

Hamid Tahermanesh;Mohammad Sadegh Abrishamian;Zahra Ghattan Kashani;Mahdi Salehi

{"title":"Wideband LP to CP converter using a reflectarray based on modulated admittance surfaces capable of wide-range beam-scanning for Ku/K band applications","authors":"Hamid Tahermanesh;Mohammad Sadegh Abrishamian;Zahra Ghattan Kashani;Mahdi Salehi","doi":"10.1029/2023RS007881","DOIUrl":"https://doi.org/10.1029/2023RS007881","url":null,"abstract":"This study provides the design and demonstration of a Ku/K band horn-fed linear polarization (LP) to circular polarization (CP) converter using a reflectarray antenna based on the holographic technique and the generalized law of total reflection without any iterative algorithms. The proposed hologram performs wide-range frequency beam scanning with minimum gain losses and cross-polarization levels. It comprises 2,500 diagonal slotted octagonal subwavelength metasurfaces with a periodicity of 0.266λ\u0000<inf>0</inf>\u0000 = 4 mm at 20 GHz as the center frequency. Two equations are defined to compute Y\u0000<inf>11</inf>\u0000 of the proposed unit cell regarding its dimensions for TE(0,0) and TM(0,0) Floquet modes. They significantly simplify the coding procedure and reduce the computational time for synthesizing the hologram. The antenna is simulated using the CST software from 14 to 25 GHz. As a confirmation, a prototype is manufactured and measured at 16, 18, 20, 22, and 24 GHz to verify its performance. The simulated and measured results are well-matched. The presented hologram achieves 40% 1.8-dB axial ratio (AR) bandwidth (16–25 GHz), 40% 3.3-dB gain bandwidth (16–24 GHz), and above 30% 2-dB gain bandwidth (16–22 GHz). Moreover, the antenna can perform beam scanning from 42° to 24° by changing the frequency from 16 to 24 GHz with peak gain values greater than 20.33 dBi. The LHCP pencil beams are at least 24° off-broadside, so the proposed hologram avoids the feed blockage. These achievements make the hologram one of the best candidates for satellite communications, radar applications, short-range communication, and point-to-point communication.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 8","pages":"1-13"},"PeriodicalIF":1.6,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142130259","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

Spatial structure of the radio-frequency noise field in a large city 大城市射频噪声场的空间结构

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-07-01 DOI: 10.1029/2023RS007909

Aaron C. Meyer;Daniel J. Breton;Matthew J. Kamrath;Sergey N. Vecherin

引用次数: 0

The robustness of an anti-noise BP neural network inversion algorithm for ground-based microwave radiometer 地基微波辐射计抗噪 BP 神经网络反演算法的鲁棒性

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-07-01 DOI: 10.1029/2023RS007941

Shijie Sun;Huaqiao Gui;Haihe Jiang;Tingqing Cheng

{"title":"The robustness of an anti-noise BP neural network inversion algorithm for ground-based microwave radiometer","authors":"Shijie Sun;Huaqiao Gui;Haihe Jiang;Tingqing Cheng","doi":"10.1029/2023RS007941","DOIUrl":"10.1029/2023RS007941","url":null,"abstract":"The ground-based microwave radiometer (MWR) retrieves atmospheric profiles with a high temporal resolution for temperature and relative humidity up to a height of 10 km. These profiles have been widely used in the field of meteorological observation. Due to the inherent fragility of neural networks, one of the important issues in this field is to improve the reliability and stability of MWR profiles based on neural network inversion. We propose a deep learning method that adds noise to the BP neural network inversion (NBPNN) process. Comparison of the radiosonde data and NBPNN results shows that if the error of MWR brightness temperature is in the range of − 2−2 K, the root-mean-square error (RMSE) of the temperature profile is 2.15 K, and the RMSE of the relative humidity profile is 19.46 % inverted by NBPNN. The results are much less than the errors of the temperature profile and relative humidity profile inverted by the traditional backpropagation neural network inverse method. From the comparison, we demonstrated that NBPNN significantly increases the inversion accuracy and robustness under the condition of errors in brightness temperature, which can reduce requirements for BT accuracy of MWR and achieve MWR long-term stability.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 7","pages":"1-14"},"PeriodicalIF":1.6,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141714228","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

First results of Mars Express—ExoMars trace gas orbiter mutual radio occultation 火星快车-ExoMars 痕量气体轨道器相互射电掩星的首批结果

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-07-01 DOI: 10.1029/2023RS007873

Jacob Parrott;Håkan Svedhem;Olivier Witasse;Colin Wilson;Ingo Müller-Wodarg;Alejandro Cardesín-Moinelo;Peter Schmitz;James Godfrey;Olivier Reboud;Bernhard Geiger;Beatriz Sánchez-Cano;Bruno Nava;Yenca Migoya-Orué

引用次数: 0

Front matters 前方事项

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-07-01 DOI: 10.1002/rds.21243

引用次数: 0

A multi-objective optimization-based reflective metasurface for enhanced multi-point focusing with diffraction suppression 基于多目标优化的反射元面，用于增强多点聚焦并抑制衍射

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-07-01 DOI: 10.1029/2024RS007968

Dongping Xiao;Lanxin Xu;Dongping Su;Zhuxin Shi;Huaiqing Zhang

{"title":"A multi-objective optimization-based reflective metasurface for enhanced multi-point focusing with diffraction suppression","authors":"Dongping Xiao;Lanxin Xu;Dongping Su;Zhuxin Shi;Huaiqing Zhang","doi":"10.1029/2024RS007968","DOIUrl":"10.1029/2024RS007968","url":null,"abstract":"Metasurface arrays can achieve beam control at low cost and high quality by providing different phase compensations for each unit, effectively focusing microwave energy on target locations. With the development of short-range communication technology or microwave power transmission technology, the demand for focusing has also increased. Using metasurface arrays to achieve multi-target focusing has wide application value. However, as the number of focal points increases, the superposition of electromagnetic wave propagation paths leads to significant interference phenomena, which can impact potential applications. Existing solutions are unable to solve such complex problems involving a large number of targets with conflicts between them. Multi-objective algorithms, by iteratively obtaining a set of optimal solutions, provide decision support for designers in complex multi-objective problems. This paper alters the phase of cells in a reflective array, calculates the near-field electric field model using the Fresnel diffraction formula, and employs various solutions using the Non-dominated Sorting Genetic Algorithm III (NSGA-III) combined with different constraints. Finally, we select the balanced solution to establish the array. After simulation, three adjacent focal points with normalized central values of 1, 0.86, and 0.88 were obtained, with the maximum electric field value outside the focal points being only 0.58, demonstrating the feasibility of multi-objective algorithms in solving complex multi-focal problems.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 7","pages":"1-12"},"PeriodicalIF":1.6,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141847155","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

Multi-frequency SuperDARN interferometer calibration 多频超级雷达网干涉仪校准

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-07-01 DOI: 10.1029/2024RS007957

E. G. Thomas;S. G. Shepherd;G. Chisham

引用次数: 0

Widening multi-beam scan angle of conventional waveguide lens antennas by increasing focal points for multi-feed excitations 通过增加多馈源激励的焦点来拓宽传统波导透镜天线的多波束扫描角度

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-07-01 DOI: 10.1029/2024RS008018

S. Panigrahi;S. Kawdungta;D. Torrungrueng;H. T. Chou

{"title":"Widening multi-beam scan angle of conventional waveguide lens antennas by increasing focal points for multi-feed excitations","authors":"S. Panigrahi;S. Kawdungta;D. Torrungrueng;H. T. Chou","doi":"10.1029/2024RS008018","DOIUrl":"10.1029/2024RS008018","url":null,"abstract":"This paper presents an alternative approach to improve the achievable beam scan angle of a traditional multi-beam waveguide lens antenna. Due to the focusing mechanism by manipulating the geometrical curvatures of the waveguide lens, the angular scan range is limited in the conventional waveguide lens design using dual-focal points of excitations because the geometrical curvatures of the waveguide lens only provide two design freedoms. To overcome this limitation, a solution of treating the waveguide lens as a transmit array consisting of non-identical elements is proposed so that each element of the antenna array can be well calibrated to improve the maximum scan angular range, where a third focus point of excitation can be created by adding another design freedom from the differentiation between non-identical elements. Each element of this new transmitting array can be well calibrated with the help of a mathematical expression to improve the maximum angular scan range. Numerical simulations show that the proposed antenna architecture exhibits better radiation characteristics than the traditional waveguide lens antenna. Radiation characteristics are studied and compared for both types of lens antennas to validate the design concept. The proposed triple-focal point provides a higher gain than the traditional lens antenna with fewer antenna elements. The gains of the beams at ±10°, ±20°, ±30°, and ±40° are found to be 27.78, 26.94, 26.19, and 24.04 dBi, respectively. From the comparison, it is seen that the variation in gain by the proposed triple-focal array design is more stable than the conventional dual-focal point design.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 7","pages":"1-11"},"PeriodicalIF":1.6,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141847358","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 numerical consideration on the correlation between magnitude of earthquakes and current intensity causing ULF electromagnetic wave emission 地震震级与导致超低频电磁波发射的电流强度之间相关性的数值考量

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-07-01 DOI: 10.1029/2023RS007923

Ryota Kimura;Yoshiaki Ando;Leo Kukiyama;Tomoya Masuzawa;Katsumi Hattori;Masashi Hayakawa

引用次数: 0

Analysis of ionospheric delay correction model performance during geomagnetic storms 地磁暴期间电离层延迟校正模型性能分析

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-07-01 DOI: 10.1029/2023RS007803

Jialong Liu;Shuli Song;Na Cheng;Yongxing Zhu;Xulei Jin;Chao Huang;Jun Jiang;Hongzhan Zhao

{"title":"Analysis of ionospheric delay correction model performance during geomagnetic storms","authors":"Jialong Liu;Shuli Song;Na Cheng;Yongxing Zhu;Xulei Jin;Chao Huang;Jun Jiang;Hongzhan Zhao","doi":"10.1029/2023RS007803","DOIUrl":"10.1029/2023RS007803","url":null,"abstract":"Ionospheric delay, as one of the largest error sources in radio propagation, can only be corrected for this error using the ionospheric delay correction model for Global Navigation Satellite System (GNSS) single-frequency users. In this paper, the 2021 geomagnetic storm event is selected, and based on the measured ionospheric data from the GNSS observatory, the perturbation of the ionosphere by the geomagnetic storm event is analyzed, and it is found that the response of the ionosphere to the geomagnetic storm has obvious differences in the response characteristics and response time in different latitude regions. The performance of the global ionospheric map (GIM), the empirical model, and the broadcast ionospheric model during the geomagnetic storm-induced ionospheric perturbation is analyzed and the change in the accuracy of each ionospheric model during the geomagnetic storm-induced ionospheric perturbation is investigated, using the measured electron content of the GNSS as a benchmark. The results show that there is good agreement between the GIM products and the measured electron content during the period of ionospheric calm and the period of ionospheric perturbation. It is worth noting that geomagnetic storms do not necessarily lead to a decrease in the accuracy of ionospheric delay-correction models, and in some cases, the models that were originally under-accurate show a tendency to improve their accuracy during the period of perturbation instead. Neither the broadcast ionospheric model nor the electron content of the empirical model output responds to geomagnetic storm-induced ionospheric perturbations.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 7","pages":"1-12"},"PeriodicalIF":1.6,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141711879","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