Pub Date : 2026-04-01Epub Date: 2026-03-01DOI: 10.1029/2025RS008254
Valéria C. M. N. Leite;Alison Moraes
The rapid deployment of 5G and future 6G networks has raised concerns about interference with critical aeronautical systems, particularly radio altimeters and Wireless Avionics Intra-Communications (WAIC). This paper offers a comprehensive taxonomy of the 5G/6G signal interference mechanisms, operational impacts, and mitigation strategies in frequency bands close to aeronautical systems. The proposed taxonomy is based on an extensive review of the literature, technical publications, and international aviation safety research. The research analyzes the principal causes of interference, which are out-of-band emissions, intermodulation effects, and signal saturation. The research also considers potential mitigation techniques, such as spectrum management techniques, hardware design improvements, and sophisticated signal-processing algorithms. The findings provide input for aviation, telecommunication industries, and regulatory bodies to ensure coexistence among vital aeronautical systems and future mobile networks.
{"title":"Taxonomy of IMT interference on aeronautical systems","authors":"Valéria C. M. N. Leite;Alison Moraes","doi":"10.1029/2025RS008254","DOIUrl":"https://doi.org/10.1029/2025RS008254","url":null,"abstract":"The rapid deployment of 5G and future 6G networks has raised concerns about interference with critical aeronautical systems, particularly radio altimeters and Wireless Avionics Intra-Communications (WAIC). This paper offers a comprehensive taxonomy of the 5G/6G signal interference mechanisms, operational impacts, and mitigation strategies in frequency bands close to aeronautical systems. The proposed taxonomy is based on an extensive review of the literature, technical publications, and international aviation safety research. The research analyzes the principal causes of interference, which are out-of-band emissions, intermodulation effects, and signal saturation. The research also considers potential mitigation techniques, such as spectrum management techniques, hardware design improvements, and sophisticated signal-processing algorithms. The findings provide input for aviation, telecommunication industries, and regulatory bodies to ensure coexistence among vital aeronautical systems and future mobile networks.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 4","pages":"1-17"},"PeriodicalIF":1.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796206","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}
Pub Date : 2026-04-01Epub Date: 2026-03-01DOI: 10.1029/2025RS008514
Parshapa Padma;P. Ithaya Rani
Accurate brain tumor segmentation and classification are critical for effective clinical diagnosis and treatment planning. Nevertheless, the current deep learning solutions commonly face the problem of tumor heterogeneity, poor contextual modeling, and ineffective discriminating of features. In response to these issues, this paper will present a new multi-modal brain tumor detection model, which will combine noise-conscious pre-processing Difference of Gaussian Square Kernel Filtering (D-GSKF), fine-tuning tumor segmentation, UNet, Efficient Long-Range Attention Network (U-Net-ELAN), feature extraction using Point Transformer (PiT) and Siamese Neural Networks, which are optimized through the Walrus Optimization Algorithm (SNN-WaOA). This work is important because it introduces a novel synergistic combination of long-range attention-inspired segmentation, transformer-inspired spatial feature modeling, and bio-inspired optimization to similarity-based tumor classification. The effectiveness of the suggested framework is supported by the large number of experiments performed on four benchmark data sets, including Figshare, BraTS 2020, Harvard, and Brain MRI, with the highest accuracy rate of 99.9%, the highest recall of 99.8%, and the lowest error rate of 0.1%, surpassing the results of a number of state-of-the-art methods. These findings suggest that the suggested method can be a stable and clinically useful method of automated brain tumor detection in various MRI modalities.
{"title":"Multi-modal brain tumor detection using pertained U-Net and Siamese neural networks with Walrus optimization algorithm","authors":"Parshapa Padma;P. Ithaya Rani","doi":"10.1029/2025RS008514","DOIUrl":"https://doi.org/10.1029/2025RS008514","url":null,"abstract":"Accurate brain tumor segmentation and classification are critical for effective clinical diagnosis and treatment planning. Nevertheless, the current deep learning solutions commonly face the problem of tumor heterogeneity, poor contextual modeling, and ineffective discriminating of features. In response to these issues, this paper will present a new multi-modal brain tumor detection model, which will combine noise-conscious pre-processing Difference of Gaussian Square Kernel Filtering (D-GSKF), fine-tuning tumor segmentation, UNet, Efficient Long-Range Attention Network (U-Net-ELAN), feature extraction using Point Transformer (PiT) and Siamese Neural Networks, which are optimized through the Walrus Optimization Algorithm (SNN-WaOA). This work is important because it introduces a novel synergistic combination of long-range attention-inspired segmentation, transformer-inspired spatial feature modeling, and bio-inspired optimization to similarity-based tumor classification. The effectiveness of the suggested framework is supported by the large number of experiments performed on four benchmark data sets, including Figshare, BraTS 2020, Harvard, and Brain MRI, with the highest accuracy rate of 99.9%, the highest recall of 99.8%, and the lowest error rate of 0.1%, surpassing the results of a number of state-of-the-art methods. These findings suggest that the suggested method can be a stable and clinically useful method of automated brain tumor detection in various MRI modalities.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 4","pages":"1-22"},"PeriodicalIF":1.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796279","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}
Pub Date : 2026-04-01Epub Date: 2026-03-01DOI: 10.1029/2025RS008509
Luyin Xiao;Yongjun Xie
Millimeter-wave radar and terahertz radar are increasingly applied in the near-field region. Nearfield scattering characteristics of targets need to be described in the spherical wave propagation model and nonuniform target illumination. A scattering characteristics prediction analytical method based on generalized radar range equation for near-field targets is proposed in this paper. The partial illumination effects of the targets and antenna near-field radiation characteristics are considered in this method. The scattered field of near-field targets is related to distance, target size and antenna radiation pattern. Near-field scattering characteristic of canonical targets (plate at 24 GHz and cylinder at 240 GHz) and a realistic vehicle model are calculated and validated by full-wave electromagnetic simulations using software Ansys HFSS and published literature, achieving deviations below 1 dB. The proposed approach provides both physical insight and fast evaluation compared with numerical surface-integration algorithms and full-wave simulation method. It can be applied into the high-resolution near-field imaging, short-range sensing and 6G terahertz systems.
{"title":"Near-field electromagnetic scattering accurate prediction for millimeter-wave and terahertz radar technology","authors":"Luyin Xiao;Yongjun Xie","doi":"10.1029/2025RS008509","DOIUrl":"https://doi.org/10.1029/2025RS008509","url":null,"abstract":"Millimeter-wave radar and terahertz radar are increasingly applied in the near-field region. Nearfield scattering characteristics of targets need to be described in the spherical wave propagation model and nonuniform target illumination. A scattering characteristics prediction analytical method based on generalized radar range equation for near-field targets is proposed in this paper. The partial illumination effects of the targets and antenna near-field radiation characteristics are considered in this method. The scattered field of near-field targets is related to distance, target size and antenna radiation pattern. Near-field scattering characteristic of canonical targets (plate at 24 GHz and cylinder at 240 GHz) and a realistic vehicle model are calculated and validated by full-wave electromagnetic simulations using software Ansys HFSS and published literature, achieving deviations below 1 dB. The proposed approach provides both physical insight and fast evaluation compared with numerical surface-integration algorithms and full-wave simulation method. It can be applied into the high-resolution near-field imaging, short-range sensing and 6G terahertz systems.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 4","pages":"1-8"},"PeriodicalIF":1.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796280","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}
Pub Date : 2026-04-01Epub Date: 2026-03-01DOI: 10.1029/2025RS008443
Yueyue Han;Lingji Xu;Fan Feng
In this study, we propose a novel three-dimensional (3D) interferometric synthetic aperture radar (InSAR) imaging method based on a uniform circular array to address azimuth coupling and energy defocusing in orbital angular momentum-based SAR imaging. The target's instantaneous azimuth angle is directly extracted through interferometric phase processing to effectively overcome the difficulties associated with decoupling terms in conventional methods. Based on this phenomenon, the proposed method integrates ωK imaging with spatial geometric constraints to achieve high-precision and computationally efficient 3D coordinate reconstruction. Furthermore, we reveal the mechanism behind energy dispersion in imaging and introduce Bessel function phase compensation to reconstruct the ideal signal model, remarkably improving image quality. Simulation results showed that the proposed method ensures imaging accuracy while reducing computational complexity, paving the way for its application in high-performance 3D radar imaging systems.
{"title":"Three-dimensional OAM-InSAR imaging algorithm based on the ωK method","authors":"Yueyue Han;Lingji Xu;Fan Feng","doi":"10.1029/2025RS008443","DOIUrl":"https://doi.org/10.1029/2025RS008443","url":null,"abstract":"In this study, we propose a novel three-dimensional (3D) interferometric synthetic aperture radar (InSAR) imaging method based on a uniform circular array to address azimuth coupling and energy defocusing in orbital angular momentum-based SAR imaging. The target's instantaneous azimuth angle is directly extracted through interferometric phase processing to effectively overcome the difficulties associated with decoupling terms in conventional methods. Based on this phenomenon, the proposed method integrates ωK imaging with spatial geometric constraints to achieve high-precision and computationally efficient 3D coordinate reconstruction. Furthermore, we reveal the mechanism behind energy dispersion in imaging and introduce Bessel function phase compensation to reconstruct the ideal signal model, remarkably improving image quality. Simulation results showed that the proposed method ensures imaging accuracy while reducing computational complexity, paving the way for its application in high-performance 3D radar imaging systems.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 4","pages":"1-13"},"PeriodicalIF":1.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796249","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}
Pub Date : 2026-04-01Epub Date: 2026-03-01DOI: 10.1029/2025RS008450
Shujaat Ali;Yanbo Che;Sathesh Ammaiappan;Mubashar Javed;Yazeed Mohammad Qasaymeh;Mohammad Alibakhshikenari
A novel switch-based Active-Neutral-Clamped (ANPC) inverter for low DC-link voltage is presented in this paper. The proposed ANPC topology minimizes switches and achieves 1.5 times better voltage gain than standard inverters. The main objective of this design is to reduce active switches in the inverter to increase system efficiency. A Flying Capacitor (FC) with self-voltage balancing makes this inverter unique. This flying capacitor enables the inverter to produce a 7-L output voltage. This study comprehensively analyses how it performs compared to existing technologies. The theoretical aspects of this proposed design have experienced thorough validation through a combination of experimental and simulation results, ensuring its efficacy and practical feasibility. The benchmark comparison further indicates reduced standing voltage requirement (TSV X Vin = 6.5) and a rated efficiency of 97.5%, supporting improved cost, control simplicity, and loss performance. Simulation and experimental results demonstrate the feasibility and effectiveness of the topology in terms of voltage balance, load adaptability, and modulation index adjustment. Simulation tests reveal stable voltage levels and current waveforms under different load conditions, with the peak output voltage reaching 1.5 times the initial input voltage. Experiments on a laboratory prototype validate the topology's dynamic response and self-balancing capability, showcasing its practical viability. The proposed 7L-ANPC topology offers a promising solution for enhancing power conversion efficiency and reliability in diverse applications.
提出了一种基于开关的低直流电压有源-中性箝位（ANPC）逆变器。提出的ANPC拓扑使开关最小化，并实现比标准逆变器更好的1.5倍电压增益。本设计的主要目的是减少逆变器中的有源开关，以提高系统效率。具有自电压平衡的飞行电容器（FC）使该逆变器独一无二。这个飞行电容使逆变器产生一个7升输出电压。本研究全面分析了它与现有技术相比的性能。本设计的理论方面通过实验和仿真结果的结合进行了充分的验证，保证了其有效性和实际可行性。基准比较进一步表明，降低了驻电压要求（TSV X Vin = 6.5），额定效率为97.5%，支持改善成本，控制简单性和损耗性能。仿真和实验结果验证了该拓扑在电压平衡、负载自适应和调制指标调整等方面的可行性和有效性。仿真试验显示了不同负载条件下稳定的电压电平和电流波形，输出电压峰值达到初始输入电压的1.5倍。在实验室样机上的实验验证了该拓扑的动态响应和自平衡能力，证明了其实际可行性。提出的7L-ANPC拓扑为提高各种应用中的功率转换效率和可靠性提供了一种有前途的解决方案。
{"title":"Design analysis of a seven-level active neutral point clamped (ANPC) inverter based on switched technique","authors":"Shujaat Ali;Yanbo Che;Sathesh Ammaiappan;Mubashar Javed;Yazeed Mohammad Qasaymeh;Mohammad Alibakhshikenari","doi":"10.1029/2025RS008450","DOIUrl":"https://doi.org/10.1029/2025RS008450","url":null,"abstract":"A novel switch-based Active-Neutral-Clamped (ANPC) inverter for low DC-link voltage is presented in this paper. The proposed ANPC topology minimizes switches and achieves 1.5 times better voltage gain than standard inverters. The main objective of this design is to reduce active switches in the inverter to increase system efficiency. A Flying Capacitor (FC) with self-voltage balancing makes this inverter unique. This flying capacitor enables the inverter to produce a 7-L output voltage. This study comprehensively analyses how it performs compared to existing technologies. The theoretical aspects of this proposed design have experienced thorough validation through a combination of experimental and simulation results, ensuring its efficacy and practical feasibility. The benchmark comparison further indicates reduced standing voltage requirement (TSV X Vin = 6.5) and a rated efficiency of 97.5%, supporting improved cost, control simplicity, and loss performance. Simulation and experimental results demonstrate the feasibility and effectiveness of the topology in terms of voltage balance, load adaptability, and modulation index adjustment. Simulation tests reveal stable voltage levels and current waveforms under different load conditions, with the peak output voltage reaching 1.5 times the initial input voltage. Experiments on a laboratory prototype validate the topology's dynamic response and self-balancing capability, showcasing its practical viability. The proposed 7L-ANPC topology offers a promising solution for enhancing power conversion efficiency and reliability in diverse applications.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 4","pages":"1-18"},"PeriodicalIF":1.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796278","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}
Pub Date : 2026-04-01Epub Date: 2026-03-01DOI: 10.1029/2025RS008472
Muhammad Saleem;William O. F. Carvalho;Muhammad Irfan
Wireless sensor networks are increasingly deployed in Internet of Things (IoT) applications, demanding self-powered solutions to overcome the limitations of conventional batteries. Radio frequency energy harvesting (RFEH) offers a practical means to scavenge ambient RF power from ubiquitous sources such as mobile base stations, enabling sustainable operation of remote or inaccessible devices. This work presents a complete RFEH system integrating a 2 × 2 microstrip patch antenna array, impedance matching network, and rectifier circuit, optimized for the 2.1 GHz 3G downlink band. Full-wave simulations predict a resonance at 2.1 GHz, realized gain of 5.1 dBi, 60 MHz bandwidth, and half-power beamwidth of 34°. Circuit-level simulations indicate a rectifier DC output of 3.575 V under nominal excitation. Experimental measurements in an anechoic chamber confirm the predicted antenna performance and demonstrate a 706 mVRMS output under ambient 3G exposure, sufficient to illuminate an LED load. The discrepancy between simulation and measurement is attributed to lower ambient power levels, propagation losses, and rectifier nonlinearity. In contrast to prior RFEH studies centered on single-element rectennas, multi-band harvesting circuits, or controlled-source demonstrations, the present work emphasizes a complete 2.1 GHz UMTS harvesting prototype based on a compact 2 × 2 patch array. The measured antenna performance and the ambient 3G experiment, which produced 706 mVRMS and illuminated an LED, confirm the feasibility of system-level RFEH for low-power IoT nodes without a dedicated RF power transmitter.
{"title":"High gain array antenna for radio frequency energy harvesting in Internet-of-Things applications","authors":"Muhammad Saleem;William O. F. Carvalho;Muhammad Irfan","doi":"10.1029/2025RS008472","DOIUrl":"https://doi.org/10.1029/2025RS008472","url":null,"abstract":"Wireless sensor networks are increasingly deployed in Internet of Things (IoT) applications, demanding self-powered solutions to overcome the limitations of conventional batteries. Radio frequency energy harvesting (RFEH) offers a practical means to scavenge ambient RF power from ubiquitous sources such as mobile base stations, enabling sustainable operation of remote or inaccessible devices. This work presents a complete RFEH system integrating a 2 × 2 microstrip patch antenna array, impedance matching network, and rectifier circuit, optimized for the 2.1 GHz 3G downlink band. Full-wave simulations predict a resonance at 2.1 GHz, realized gain of 5.1 dBi, 60 MHz bandwidth, and half-power beamwidth of 34°. Circuit-level simulations indicate a rectifier DC output of 3.575 V under nominal excitation. Experimental measurements in an anechoic chamber confirm the predicted antenna performance and demonstrate a 706 mV<inf>RMS</inf> output under ambient 3G exposure, sufficient to illuminate an LED load. The discrepancy between simulation and measurement is attributed to lower ambient power levels, propagation losses, and rectifier nonlinearity. In contrast to prior RFEH studies centered on single-element rectennas, multi-band harvesting circuits, or controlled-source demonstrations, the present work emphasizes a complete 2.1 GHz UMTS harvesting prototype based on a compact 2 × 2 patch array. The measured antenna performance and the ambient 3G experiment, which produced 706 mV<inf>RMS</inf> and illuminated an LED, confirm the feasibility of system-level RFEH for low-power IoT nodes without a dedicated RF power transmitter.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 4","pages":"1-12"},"PeriodicalIF":1.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796247","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}
Pub Date : 2026-04-01Epub Date: 2026-03-01DOI: 10.1029/2025RS008411
Anupama Sindgi;Asha Mahadeva;Raghavendra Yellakur Manjunath;Vanitha G. Naik
The convergence of Wireless Network-on-Chip (WiNoC) and quantum computing represents a significant frontier for advancing next-generation many-core systems. WiNoC enables efficient on-chip communication through single-hop wireless links, thereby reducing latency and power consumption compared to conventional wired Network-on-Chip. Despite these advantages, challenges such as congestion, security vulnerabilities, and energy inefficiencies persist. This review provides a comprehensive analysis of how quantum principles such as superposition, entanglement, and Quantum Key Distribution can enhance WiNoC scalability, security, and performance. Recent developments in WiNoC design, quantum communication techniques, channel modeling, optimization algorithms, and cryptographic frameworks are examined in detail. The discussion further explores emerging trends in quantum-assisted architectures that may leverage quantum computing to improve data throughput and secure transmission. Key research gaps are identified, including the limited scalability of quantum algorithms, the difficulty of managing dynamic traffic patterns, and the constraints of integrating quantum components within chip environments. Finally, the review outlines future research directions focusing on hybrid classical-quantum architectures, Artificial Intelligence-driven traffic prediction mechanisms, and the establishment of standardized protocols for quantum-classical communication. Collectively, these advancements are expected to drive the evolution of secure, energy-efficient, and scalable computing platforms.
{"title":"Integrating quantum technology with wireless NoC: A review of architectures, protocols, and future directions","authors":"Anupama Sindgi;Asha Mahadeva;Raghavendra Yellakur Manjunath;Vanitha G. Naik","doi":"10.1029/2025RS008411","DOIUrl":"https://doi.org/10.1029/2025RS008411","url":null,"abstract":"The convergence of Wireless Network-on-Chip (WiNoC) and quantum computing represents a significant frontier for advancing next-generation many-core systems. WiNoC enables efficient on-chip communication through single-hop wireless links, thereby reducing latency and power consumption compared to conventional wired Network-on-Chip. Despite these advantages, challenges such as congestion, security vulnerabilities, and energy inefficiencies persist. This review provides a comprehensive analysis of how quantum principles such as superposition, entanglement, and Quantum Key Distribution can enhance WiNoC scalability, security, and performance. Recent developments in WiNoC design, quantum communication techniques, channel modeling, optimization algorithms, and cryptographic frameworks are examined in detail. The discussion further explores emerging trends in quantum-assisted architectures that may leverage quantum computing to improve data throughput and secure transmission. Key research gaps are identified, including the limited scalability of quantum algorithms, the difficulty of managing dynamic traffic patterns, and the constraints of integrating quantum components within chip environments. Finally, the review outlines future research directions focusing on hybrid classical-quantum architectures, Artificial Intelligence-driven traffic prediction mechanisms, and the establishment of standardized protocols for quantum-classical communication. Collectively, these advancements are expected to drive the evolution of secure, energy-efficient, and scalable computing platforms.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 4","pages":"1-23"},"PeriodicalIF":1.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796250","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}
Pub Date : 2026-04-01Epub Date: 2026-03-01DOI: 10.1029/2025RS008295
Yinhe Cheng;Xindi Sun;Jiaxuan Yang;Zhiwei You;Wenli Qiao;Guozhen Zha;Shuwen Wang;Kunde Yang
The refractive environment of the South China Sea (SCS) is currently a prominent research focus due to its significant impact on electromagnetic wave (EMW) propagation, particularly for ship-borne radar and communication systems. Based on the Global Positioning System sounding data collected during the summer monsoon period in 1998, the surface refractive conditions of the SCS were analyzed, and the relationship between these conditions and various meteorological factors was further explored. The analysis reveals a pronounced daily cycle in the surface refractive environment, closely linked to fluctuations in temperature and humidity. The modified refractivity exhibits a one-day periodicity, with the southern SCS showing a higher consistency in surface duct occurrence (96.1% probability) compared to the northern region (49.7% probability). Wind direction, particularly westerly winds, plays a significant role in enhancing surface duct strength. Numerical simulations using the Parabolic Equation method demonstrate that surface ducts significantly extend the detection range of EMW, with path loss remaining below 150 dB at 150 km under ducting conditions. These findings emphasize the operational significance of surface ducts in the SCS, particularly for over-the-horizon radar detection of low-altitude targets. Understanding the refractive environment in this region is essential for optimizing radar and communication system performance in maritime operations.
{"title":"Periodic characteristics of surface electromagnetic wave propagation in the South China sea","authors":"Yinhe Cheng;Xindi Sun;Jiaxuan Yang;Zhiwei You;Wenli Qiao;Guozhen Zha;Shuwen Wang;Kunde Yang","doi":"10.1029/2025RS008295","DOIUrl":"https://doi.org/10.1029/2025RS008295","url":null,"abstract":"The refractive environment of the South China Sea (SCS) is currently a prominent research focus due to its significant impact on electromagnetic wave (EMW) propagation, particularly for ship-borne radar and communication systems. Based on the Global Positioning System sounding data collected during the summer monsoon period in 1998, the surface refractive conditions of the SCS were analyzed, and the relationship between these conditions and various meteorological factors was further explored. The analysis reveals a pronounced daily cycle in the surface refractive environment, closely linked to fluctuations in temperature and humidity. The modified refractivity exhibits a one-day periodicity, with the southern SCS showing a higher consistency in surface duct occurrence (96.1% probability) compared to the northern region (49.7% probability). Wind direction, particularly westerly winds, plays a significant role in enhancing surface duct strength. Numerical simulations using the Parabolic Equation method demonstrate that surface ducts significantly extend the detection range of EMW, with path loss remaining below 150 dB at 150 km under ducting conditions. These findings emphasize the operational significance of surface ducts in the SCS, particularly for over-the-horizon radar detection of low-altitude targets. Understanding the refractive environment in this region is essential for optimizing radar and communication system performance in maritime operations.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 4","pages":"1-18"},"PeriodicalIF":1.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796207","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}
Pub Date : 2026-04-01Epub Date: 2026-03-01DOI: 10.1029/2025RS008517
T. Aishwarya;Priyanka Das
In this study, a fractal antenna integrated with a cardboard stapled frequency selective surface (FSS) is designed for broadband operation. The dimensions of the stapler pins used in constructing the FSS control the electromagnetic response of the antenna. Two types of staple pin FSS have been investigated - one with higher dimensions and the other with lower dimensions. The big pin FSS shows strong resonance at 4.97 GHz, while operating from 2.4 to 8.6 GHz with a peak gain of 6.7 dBi at 5 GHz. The small pin FSS exhibits minimum return loss at 7.07 GHz, while operating from 3.4 to 11.5 GHz, with a peak gain of 7 dBi at 5 GHz. The proposed antenna with 1g average SAR lower than 0.1 W/Kg, presents a viable option for biomedical and wearable applications, especially in brain phantom settings in which controlled resonance and wideband operation are crucial. Prototypes of the wearable antenna and FSS have been fabricated and measured. Presence of tumor is predicted from the reconstructed image using confocal and MDAS (Multiply Delay and Sum) algorithm using gradient descent optimisation. The ground penetrating radar (GPR) algorithm has been implemented to detect the depth of the brain tumor.
{"title":"Stapler pin FSS embedded fractal antenna for brain tumor detection","authors":"T. Aishwarya;Priyanka Das","doi":"10.1029/2025RS008517","DOIUrl":"https://doi.org/10.1029/2025RS008517","url":null,"abstract":"In this study, a fractal antenna integrated with a cardboard stapled frequency selective surface (FSS) is designed for broadband operation. The dimensions of the stapler pins used in constructing the FSS control the electromagnetic response of the antenna. Two types of staple pin FSS have been investigated - one with higher dimensions and the other with lower dimensions. The big pin FSS shows strong resonance at 4.97 GHz, while operating from 2.4 to 8.6 GHz with a peak gain of 6.7 dBi at 5 GHz. The small pin FSS exhibits minimum return loss at 7.07 GHz, while operating from 3.4 to 11.5 GHz, with a peak gain of 7 dBi at 5 GHz. The proposed antenna with 1g average SAR lower than 0.1 W/Kg, presents a viable option for biomedical and wearable applications, especially in brain phantom settings in which controlled resonance and wideband operation are crucial. Prototypes of the wearable antenna and FSS have been fabricated and measured. Presence of tumor is predicted from the reconstructed image using confocal and MDAS (Multiply Delay and Sum) algorithm using gradient descent optimisation. The ground penetrating radar (GPR) algorithm has been implemented to detect the depth of the brain tumor.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 4","pages":"1-23"},"PeriodicalIF":1.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796248","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}
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