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Combining Local Electromagnetic Scattering and Global Structure Features for SAR Open Set Recognition

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 2025年 18卷 12572-12587页

作者： Lin, Qinjie Sun, Hao Xu, Yanjie Wang, Junyu Ji, Kefeng Kuang, Gangyao National University of Defense Technology State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System College of Electronic Science and Technology Changsha410073 China

Automatic target recognition (ATR) is crucial for synthetic aperture radar (SAR) image interpretation. However, existing SAR ATR primarily rely on algorithms from the field of computer vision, many methods have not adequately considered the imaging sensitivity of SAR images. Moreover, SAR ATR typically follows the closed set assumption, but in dynamic and open real-world environments, SAR systems may encounter target classes that have not been seen during training. To address these issues, this paper proposes a SAR open set recognition (OSR) method that combines local electromagnetic scattering and global structure features. The global structural features focus on the overall relationship between target and background, while the local electromagnetic scattering features can effectively capture the scattering characteristics of target. Hence, we construct a global and local feature guidance (GLGE) network, fuses these complementary features as prior knowledge to guide deep features. Then, a class-anchor-based loss function is constructed by Anchor loss and Tuple loss, which cluster the features of known classes targets around predefined class anchors. Finally, the distance ratio is calculated to identify known classes targets and reject unknown classes targets. The experimental results on the MSTAR and SAR-ACD datasets show that our method outperforms other OSR methods in recall, precision, F1, and accuracy, demonstrating a superior performance in OSR. © 2008-2012 IEEE.

关键词： Automatic target recognition

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InSb/Janus MoSSe van der Waals heterostructure: First-principles calculation study of electronic structure and optical properties

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Solid State Communications 2025年 401卷

作者： Qin, Xuebing Wang, Xuewen Zhao, Yingying Ye, Shengyun Hilal, Muhammad Guo, Jie Zhang, Weibin College of Physics and Electronics Information Yunnan Key Laboratory of Opto-Electronic Information Technology Key Laboratory of Advanced Technique & Preparation for Renewable Energy Materials-Ministry of Education Yunnan Normal University Kunming650500 China Department of Semiconductor System Engineering Sejong University Seoul05006 Korea Republic of

The Janus MoSSe and InSb monolayers exhibit direct bandgaps of 1.60 eV and 0.70 eV, respectively, positioning them as promising candidates for optoelectronic applications. The InSb/Janus MoSSe van der Waals heterojunction is characterized as a direct bandgap semiconductor with a bandgap of 0.56 eV, classifying it as a Type II heterojunction. Computational density of states analysis reveals that the valence band maximum is predominantly derived from the Sb 5s orbital. In contrast, the conduction band minimum is attributed to the hybridization of Mo 4d orbitals. As the interlayer spacing increases, the band gap gradually decreases and stabilizes at approximately 0.36 eV, whereas a reduction in spacing progressively narrows the band gap, ultimately inducing metallic characteristics. The work function of the Janus MoSSe monolayer is determined to be 5.57 eV, contrasting with the 4.79 eV work function of the InSb monolayer, yielding a composite work function of 5.15 eV for the heterojunction. Differential charge density analysis indicates electron transfer from the InSb monolayer to the Janus MoSSe layer, facilitating charge separation and transfer. Optical property investigations demonstrate that the InSb monolayer predominantly absorbs in the infrared and visible spectra. In contrast, the Janus MoSSe monolayer exhibits significant absorption in the visible and near-ultraviolet regions. Notably, the InSb/Janus MoSSe heterojunction synergistically integrates the optical advantages of its constituents, enabling broad-spectrum photon absorption spanning the infrared, visible, near-ultraviolet, and far-ultraviolet regions. These findings provide valuable theoretical insights, paving the way for advanced applications of the InSb/Janus MoSSe van der Waals heterojunction in next-generation optoelectronic devices. © 2025 Elsevier Ltd

关键词： Heterojunctions

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Random Coefficient-Moving Product Based Wireless key Generation

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China Communications 2025年第2期22卷 199-212页

作者： Lu Xinjin Lei Jing Li Wei College of Electronic Science and Technology National University of Defense TechnologyChangsha 410073China State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System Luoyang 471003China China South Industries Group Corporation Zhi Yuan Institute310012China

The physical layer key generation technique provides an efficient method,which utilizes the natural dynamics of wireless ***,there are some extremely challenging security scenarios such as static or quasi-static environment,which lead to the low randomness of generated ***,the coefficients of the static channel may be dropped into the guard space and discarded by the quantization approach,which causes low key generation *** tackle these issues,we propose a random coefficient-moving product based wireless key generation scheme(RCMP-WKG),where new random resources with remarkable fluctuations can be obtained by applying random coefficient and by moving product on the legitimate ***,appropriate quantization approaches are used to increase the key generation ***,the security of our proposed scheme is evaluated by analyzing different attacks and the eavesdropper’s mean square error(MSE).The simulation results reveal that the proposed scheme can achieve better performances in key capacity,key inconsistency rate(KIR)and key generation rate(KGR)compared with the prior works in static ***,the proposed scheme can deteriorate the MSE performance of the eavesdropper and improve the key generation performance of legitimate nodes by controlling the length of the moving product.

关键词： moving product random coefficient static environment wireless key generation

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A Passive ISAR Jamming Method Based on Time-Modulated Corner Reflectors Under Asynchronous Control

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IEEE Transactions on Aerospace and Electronic systems 2025年

作者： Gan, Lin Wu, Zehao Li, Jianbing National University of Defense Technology State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System Changsha410073 China

The time-modulated corner reflector (TMCR) is an improvement of the traditional corner reflector utilizing time-modulated metasurfaces, which demonstrates superior capability in dynamically modulating characteristics of electromagnetic waves in real-time. Despite its potential, the application of TMCRs in radar imaging remains underexplored. This paper presents a passive ISAR modulation method through the asynchronous control of TMCRs, which can directly disrupt the ISAR imaging mechanism. Through the joint inter-pulse and intra-pulse periodic modulation, multiple TMCRs are alternately switched between strong and weak reflection states asynchronously, which can interfere with the alignment process of range profiles and further causing errors in initial phase compensation. The intra-pulse modulation model is constructed firstly, and the influence of TMCR and modulation parameters on the envelope correlation is investigated quantitatively. On this basis, the optimization model of inter-pulse modulation is developed, which is calculated through Genetic Algorithm (GA). Then the effectiveness of the method is systematically analyzed under varying application parameters, with corresponding applicable boundaries subsequently determined. Finally, experiments are conducted based on the electromagnetic simulation data and measured data of the UAV, which verifies that the proposed method can effectively interfere with the envelop alignment and phase compensation processes, thereby making the ISAR image blurred. © 1965-2011 IEEE.

关键词： Inverse synthetic aperture radar

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Phase-Only Beamforming for Dual-Polarization Array Radar Based on Manifold Optimization

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IEEE Antennas and Wireless Propagation Letters 2025年

作者： Dongwei, Lu Jiazhi, Ma Zhanling, Wang Longfei, Shi National University of Defense Technology State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System Changsha410073 China

The phase-only beamforming (POB) technique manipulates the weighted phases of array antenna elements to create a desired radiation pattern, thereby reducing the hardware and power costs associated with large phased arrays. However, two significant challenges currently hinder the practical implementation of POB. First, the beam gain generated by POB can be severely distorted when a main lobe interference is present. Second, the POB method struggles to suppress interferences whose positions change within the spatial domain. To address these challenges, this letter proposes a novel POB method for dual-polarization array radar. This method incorporates polarization constraints on a Riemannian manifold under the condition of null broadening. By doing so, it generates robust nulls that can effectively suppress moving interferences in the main lobe and side lobes while preserving the beam gain. Numerical simulations demonstrate that this method exhibits excellent anti-interference performance. © 2025 IEEE.

关键词： Antenna lobes

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Valley-Hall slow-light waveguide states with dual-band in all-dielectric valley photonic crystals

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Results in Physics 2025年 68卷

作者： He, Liu Yao, Jianquan Key Laboratory of Opto-Electronics Information Technology (Tianjin University) Ministry of Education School of Precision Instruments and Opto-Electronics Engineering Tianjin University Tianjin 300072 China

The slow-light waveguide states protected by topology could be used in strengthening interaction between light and matter, so they can be used for realizing a lot of unique physical optics phenomena and interesting applications. In this work, we consider a kind of all-dielectric valley photonic crystals (VPCs) with honeycomb lattice, realize dual-band photonic valley-Hall kink states at the stacking interface composed of two VPCs with mirror symmetry through breaking the parity-reversal symmetry of photonic system, such as low-frequency and high-frequency valley-Hall kink states. The valley-Hall kink states can be classified two categories: guided states and slow-light states, which depends on the magnitude of group index n_g. By full-wave simulations, we directly observe that the dual-band valley-Hall slow-light states are in a way of standing-wave-liked modes to transport along the interface, and the more group index n_g is, the half-wavelength λ_L/2 of standing-wave-liked is longer. Based on numerical calculation, the largest group indexes of low-frequency and high-frequency valley-Hall slow-light waveguide states are 1000, 1378, respectively. Hence in theory we can use half-wavelength λ_L/2 of standing-wave-liked modes to characterize slow-light states instead of judging respond time or fitting dispersion curve, which provides an alternative method or road to directly observe and demonstrate slow-light waveguide states in experiment. © 2024 The Author(s)

关键词： Dual-band valley-Hall kink states Slow-light waveguide states Standing-wave-liked modes Valley photonic crystals (VPCs)

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Timing jitter reduction of the sub-nanosecond Nd:YAG/Cr:YAG microchip laser via external optical triggering

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Infrared Physics and technology 2025年 148卷

作者： Chi, Jing Zhong, Kai Li, Fangjie Qiao, Hongzhan Wu, Tong Sun, Yue Zheng, Yizhe Liu, Yuxin Chen, Kai Li, Jining Xu, Degang Yao, Jianquan School of Precision Instrument and Opto-electronics Engineering Tianjin University Tianjin300072 China Key Laboratory of Optoelectronics Information Technology Ministry of Education Tianjin300072 China

A scheme to improve the temporal pulse stability of the passively Q-switched (PQS) sub-nanosecond Nd:YAG/Cr:YAG microchip laser was designed. By injection nanosecond laser pulses into the saturable absorber (SA) of the composite crystal, the SA is bleached compulsively to trigger the PQS laser and realize "optical synchronization". As a result, the PQS sub-nanosecond laser pulses are locked to the injected pulses temporally and the timing jitter is greatly suppressed. In this work, the timing jitter of the PQS sub-nanosecond laser pulses was reduced from 561.2 ns to 344 ps using the nanosecond laser pulse as the reference signal, improved by over 1600 times, while the required pulse energy was merely at the level of 100 μJ. Based on the rate equations, a timing jitter model of the PQS laser was established by introducing random disturbance and injected photon number density, which could depict the temporal behavior and contributing factors. The dynamic process of locking the sub-nanosecond laser pulses was discussed by varying the injecting pulse energy, triggering time and peak pump power, with consistent theoretical and experimental results. It was also found that the pulse waveform, output power stability and beam quality benefit from optical triggering. This simple and efficient scheme of timing-jitter reduction lays the foundation for high-performance sub-nanosecond lasers, which is of great importance in high-precision ranging and lidar systems. © 2025 Elsevier B.V.

关键词： Timing jitter

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Design and analysis of GPS satellite-based augmentation system based on low earth orbit constellations 3

Design and analysis of GPS satellite-based augmentation syst...

引用

2024 3rd International Conference on Aerospace and Control Engineering, ICoACE 2024

作者： Yang, Jianlei Jin, Zhengzhen Zheng, Shuaiyong Huang, Shiyong Ma, Guoyu Ji, Shiran Key Laboratory of Satellite Navigation System and Equipment Technology Shijiazhuang050081 China The 54 Research Institute China Electronics Technology Group Shijiazhuang050081 China School of Integrated Circuit Science and Engineering Tianjin University of Technology Tianjin300384 China College of Software Tianjin Normal University Tianjin300387 China

Addressing the need for improved GPS accuracy, especially for low-dynamic users, this study introduces a GPS augmentation system employing Low Earth Orbit (LEO) satellites. We detail the principles of satellite navigation and augmentation and simulate the GPS-LEO constellation to analyse its performance in terms of satellite visibility and Position Dilution of Precision (PDOP). The results demonstrate substantial augmentation in navigation accuracy with the integrated system, as verified by UAV flight experiments. The integration of LEO satellites is anticipated to advance global navigation capabilities, with implications for intelligent transportation, logistics, and precision agriculture. © 2025 Institute of Physics Publishing. All rights reserved.

关键词： Global positioning system

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A review of ultrafast supercapacitors for AC-line filtering

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新型炭材料(中英文) 2025年第2期40卷 243-269页

作者： SUN Qian FAN Ya-feng XIE Li-jing WANG Zhen-bing HUANG Xian-hong SU Fang-yuan CHEN Cheng-meng Shanxi Key Laboratory of Carbon Materials Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China University of Chinese Academy of Sciences Beijing 100049China College of Materials Science and Opto-electronics Technology University of Chinese Academy of SciencesBeijing 100049China

Filter capacitors play an important role in altern-ating current(AC)-line filtering for stabilizing voltage,sup-pressing harmonics,and improving power ***,traditional aluminum electrolytic capacitors(AECs)suffer from a large size,short lifespan,low power density,and poor reliability,which limits their *** contrast,ultrafast supercapacitors(SCs)are ideal for replacing commercial AECs because of their extremely high power densities,fast charging and discharging,and excellent high-frequency *** review the design principles and key parameters for ultrafast supercapacitors and summarize research pro-gress in recent years from the aspects of electrode materials,electrolytes,and device *** preparation,structures,and frequency response performance of electrode materials mainly consisting of carbon materials such as graphene and carbon nanotubes,conductive polymers,and transition metal compounds,are focused ***,future research directions for ultrafast SCs are suggested.

关键词： Ultrafast supercapacitors AC-line filtering Electrode materials Electrolytes Cell configuration design

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Design of a wideband non-uniform microstrip line for complex impedance matching at automotive radar frequency

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Hongwai Yu Haomibo Xuebao/Journal of Infrared and Millimeter Waves 2025年第3期44卷 430-439页

作者： Zhang, Shuang-Gen Yu, Tao Wang, Yu-Lan Cheng, Zhi-Hua Yao, Jian-Quan Tianjin Key Laboratory of Film Electronic and Communication Devices School of Integrated Circuit Science and Engineering Tianjin University of Technology Tianjin300384 China The Institute of Laser & Opto-electronics Tianjin University Tianjin300191 China

Microstrip transmission lines connecting to the millimeter wave radar chip and antenna significantly im⁃ pact on the radiation efficiency and bandwidth of the antenna. Here，a wideband non-uniform wavy microstrip line for complex impedance in automotive radar frequency range is proposed. Different to the gradient transmis⁃ sion line，the wavy structure is composed of periodically semi-circular segments. By adjusting the radius of the semi-circular，the surface current is varied and concentrated on the semi-circular segments，allowing a wider tun⁃ ability range of the resonant frequency. The results reveal that the bandwidth of the loaded wavy transmission line antenna improves up to 9. 37 GHz，which is 5. 81 GHz wider than that of the loaded gradient line. The gain and the half power beam width of the loaded antenna are about 14. 69 dB and 9. 58º，respectively. The proposed nonuniform microstrip line scheme may open up a route for realizing wideband millimeter-wave automotive radar ap⁃ plications. © 2025 Chinese Optical Society. All rights reserved.

关键词： Millimeter waves

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