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IEEE Transactions on Radar systems 2024年 2卷 661-676页

作者： Li, Nanjun Wang, Fulai Pang, Chen Li, Yongzhen National University of Defense Technology State Key Lab. of Complex Electromagnetic Environment Effects on Electronics and Information System Changsha410073 China

Aimed to enhance the robustness of simultaneously polarimetric radar (SPR) systems against interrupted-sampling repeater jamming (ISRJ) attacks by polarization and waveform diversity techniques, this article focuses on the joint design of unimodular sequences and receiving filters for jamming suppression. Specifically, we first develop a dynamic signal processing framework for target polarization scattering matrix (PSM) estimation based on their statistical properties and orthogonal conditions between receiving filters and ISRJ signals. Then, the weighted sum of integrated sidelobe levels (ISLs) of auto- and cross-ambiguity functions and signal-to-noise ratio losses (SNRLs) is minimized with unimodular and energy constraints to mitigate ISRJ in SPR systems considering both single pulse and multipulse. To handle the resulting NP-hard design problems, an iterative optimization method capitalizing on the alternating direction and majorization-minimization (MM) framework is proposed. The numerical results are provided to show the superiority of the proposed algorithm in comparison with a pair of linear frequency modulation (LFM) waveforms with opposite slopes with respect to the anti-ISRJ performance. © 2023 IEEE.

关键词： Iterative methods

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Polarization Control Method for the Main Lobe Based on Phase-only Beamforming

Polarization Control Method for the Main Lobe Based on Phase...

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2024 Photonics and Electromagnetics Research Symposium, PIERS 2024

作者： Lu, Dongwei Ma, Jiazhi National University of Defense Technology State Key Lab. of Complex Electromagnetic Environment Effects on Electronics and Information System China

ISBN: (纸本)9798350375909

The target detection ability of radar in environments with interference or clutter can be further improved by the adaptive beamforming method. However, most existing research results only address the receiving beam, and few research results concern transmitting beam control. Moreover, the typical phase-only methods only consider spatial beamforming, which means that the polarization state cannot be controlled. This paper proposes a novel phase-only beamforming method based on a polarimetric phased array that can control the polarization state of the main lobe to avoid receiving main lobe or sidelobe interference signals. © 2024 IEEE.

关键词： Beamforming

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Color liquid crystal grating based color holographic 3D display system with large viewing angle

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Light(Science & Applications) 2024年第1期13卷 103-112页

作者： Di Wang Yi-Long Li Fan Chu Nan-Nan Li Zhao-Song Li Sin-Doo Lee Zhong-Quan Nie Chao Liu Qiong-Hua Wang School of Instrumentation and Optoelectronic Engineering Beihang UniversityBeijing 100191China State Key Laboratory of Virtual Reality Technology and Systems Beihang UniversityBeijing 100191China Display Technology Research Center Seoul National UniversityGwanak-ro 1Gwanak-guSeoul 08826Republic of Korea Key Lab of Advanced Transducers and Intelligent Control System Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024China

Holographic 3D display is highly desirable for numerous applications ranging from medical treatments to military ***,it is challenging to simultaneously achieve large viewing angle and high-fidelity color reconstruction due to the intractable constraints of existing ***,we conceptually propose and experimentally demonstrate a simple and feasible pathway of using a well-designed color liquid crystal grating to overcome the inevitable chromatic aberration and enlarge the holographic viewing angle,thus enabling large-viewing-angle and color holographic 3D *** use of color liquid crystal grating allows performing secondary diffraction modulation on red,green and blue reproduced images simultaneously and extending the viewing angle in the holographic 3D display *** principle,a chromatic aberration-free hologram generation mechanism in combination with the color liquid crystal grating is proposed to pave the way for on such a superior holographic 3D *** proposed system shows a color viewing angle of~50.12°,which is about 7 times that of the traditional system with a single spatial light *** work presents a paradigm for achieving desirable holographic 3D display,and is expected to provide a new way for the wide application of holographic display.

关键词： holographic angle crystal

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Energy Storage Planning and Configuration of Active Distribution Network Based on Load Ordered Clustering

Energy Storage Planning and Configuration of Active Distribu...

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2023 IEEE International Conference on Advanced Power system Automation and Protection, APAP 2023

作者： Du, Xiangyang Cheng, Junjie Xiong, Xiaofu Xue, Meijia Ni, Yang Chongqing University State Key Lab. of Power Transmission and Distribution Equipment and System Safety and New Technology Chongqing China

ISBN: (纸本)9798350306668

In order to fully excavate scheduling, periodic characteristics of power load, raise the reliability and economy of the energy storage and distribution network planning, based on the year of the three typical load curves, on the basis of similarity analysis, through the orderly clustering analysis. distribution network planning, based on the year of the three typical load curves, on the basis of similarity analysis, through the orderly clustering method for all kinds of load curves according to the time series of annual finer clustering, and the time series of annual finer clustering. method for all kinds of load curves according to the time series of annual finer clustering, The minimum time unit of dynamic configuration of mobile The minimum time unit of dynamic configuration of mobile energy storage in distribution network is planned according to month, and a method of energy storage planning and configuration of active distribution network based on load ordered clustering. The minimum time unit of dynamic configuration of mobile energy storage in distribution network is planned according to month, and a method of energy storage planning and configuration of active distribution network based on load ordered clustering is proposed. Finally, IEEE33 node system is adopted to verify the proposed scheme. The calculation results show that the energy storage configuration scheme considering the actual time sequence characteristics of the load is more economical and can reflect the actual operation of the distribution network. The calculation results show that the energy storage configuration scheme considering the actual time sequence characteristics of the load is more economical and can reflect the actual operation of the distribution network. The scheme is an effective extension of the flexible use of energy storage equipment in the distribution network, and can better serve the variable operation of active distribution network load, so as to better play the role of

关键词： Electric power distribution

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The Effect of Coherent Frequency Diverse Array on Watson-Watt Direction-Finding system 4

The Effect of Coherent Frequency Diverse Array on Watson-Wat...

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4th International Conference on Neural Networks, Information and Communication Engineering, NNICE 2024

作者： Liu, Qiang Xiong, Kunlai Guo, Fucheng Xu, Tao National University of Defense Technology State Key Lab. of Complex Electromagnetic Environment Effects on Electronics and Information System College of Electronic Science and Technology Hunan Changsha410073 China

ISBN: (纸本)9798350394375

Frequency diverse array(FDA) offer potential applications for enhancing the RF safety performance of FDA systems. This is due to the time-varying angle-distance coupling characteristics of the transmit beam map, which are caused by small frequency shifts between subarray elements. In this paper, we investigate the impact of coherent FDA signals on amplitude-based direction-finding systems, taking the Watson-Watt direction-finding system as an example. Firstly, we establish receiving model for direction finding of FDA signals. Secondly, we evaluate the error of the direction-finding system when using coherent FDA signals and analyze it with the Cramér-Rao lower bound(CRLB). Finally, we conduct a simulation analysis to validate the proposed theory. Both the theoretical analysis and simulation results demonstrate that coherent FDA signals can improve the radio frequency(RF) stealth performance. Specifically, the analysis and simulation results reveal that coherent FDA signals exhibit superior low-intercept performance for the Watson-Watt direction-finding system. These findings can be applied to all amplitude direction-finding systems. © 2024 IEEE.

关键词： Radio direction finding systems

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A Novel Wideband Frequency Selective Rasorber With Ring Combination 3

A Novel Wideband Frequency Selective Rasorber With Ring Comb...

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3rd International Conference on Electronic Information Engineering and Computer Science, EIECS 2023

作者： Hu, Xueyi Wu, Weiwei Xu, Yixuan Yuan, Naichang National University of Defense Technology State Key Lab. of Complex Electromagnetic Environment Effects on Electronics and Information System Hunan Changsha China

ISBN: (纸本)9798350316674

In this letter, a novel wideband frequency selective rasorber is proposed. The structure consists two layers, a lossy layer and a bandpass layer, which are separated from each other by an air spacer. The resistive layer consists of rings and metal wires loaded with resistors. The bandpass layer is achieved by etching square grooves on the metal face. The simulation results shows reflection is smaller than -10 dB from 4.49 GHz to 14.63 GHz, and the fractional bandwidth of the reflection coefficient lower than -10 dB is up to 106%. The transmission coefficient is greater than -3dB is from 9.30 GHz to 9.96 GHz, which has a minimum insertion loss of 0.31 dB at 9.68 GHz. © 2023 IEEE.

关键词： absorption frequency selective surfaces insertion loss

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Scattering characteristics of a polyhedral Van Atta backtracking array

Scattering characteristics of a polyhedral Van Atta backtrac...

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2023 International Applied Computational Electromagnetics Society Symposium, ACES-China 2023

作者： Zehao, Wu Lin, Gan Jianbing, Li University of Defense Technology State Key Lab. of Complex Electromagnetic Environ. Effects of Electronic Information System National Changsha China

ISBN: (纸本)9781733509657

In order to achieve effective interference with multi-directional early warning radar and cover our combat targets in the process of implementing airborne high-value combat target surprise defense, a Van Atta retracing array based on 14-sided Archimedes polyhedral configuration is proposed, and a Van Atta array unit with positive hexagonal distribution is designed according to the polyhedral configuration. The research results show that this scattering polyhedron has a compact structure with the advantage of omnidirectional scattering, and has good potential for application in scenarios requiring strong omnidirectional retrieval capability. © 2023 Applied Computational Electromagnetics Society (ACES).

关键词： Geometry

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A SAR Active Jamming Detection Method Based on Image Grayscale Features

A SAR Active Jamming Detection Method Based on Image Graysca...

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2023 International Applied Computational Electromagnetics Society Symposium, ACES-China 2023

作者： Zhang, Haoyu Xing, Shiqi Quan, Sinong National University of Defense Technology State Key Lab. of Complex Electromagnetic Environment Effects on Electronics and Information System Cemee ChangSha China

ISBN: (纸本)9781733509657

In response to the problem that the validation and evaluation of SAR active jamming effectiveness is more complicated and target detection of SAR image is seldom applied to active jamming, a method of SAR image active jamming detection based on image grayscale features is proposed in this paper. Herein, the principle and process of SAR image target detection algorithm processing, based on pulse coupled neural network are discussed. Through the simulation experiment, the active jamming region can be detected in the SAR jamming image. © 2023 Applied Computational Electromagnetics Society (ACES).

关键词： Image segmentation

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An Optimal Control Based Trajectory Planning Method for Cooperative Merging Maneuvers 3

An Optimal Control Based Trajectory Planning Method for Coop...

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3rd International Symposium on intelligent Robotics and systems, ISoIRS 2023

作者： Wang, Qi Ge, Hao Duan, Xuting Zhou, Jianshan School of Transportation Science and Engineering Beihang University State Key Lab of Intelligent Transportation System Beijing Key Laboratory for Cooperative Vehicle Infrastructure Systems and Safety Control State Key Laboratory of Air Traffic Management System and Technology Beijing China Nanjing Research Institute of Electronic Engineering State Key Laboratory of Air Traffic Management System and Technology Nanjing China School of Transportation Science and Engineering Beihang University State Key Lab of Intelligent Transportation System Beijing Key Laboratory for Cooperative Vehicle Infrastructure Systems and Safety Control Beijing China

ISBN: (纸本)9798350339963

Due to the prediction errors and diverse driving styles of surrounding vehicles, traffic congestion and even accidents can occur in the traffic bottleneck area where vehicles merge into the main road. To ensure that connected and automated vehicles (CAVs) can quickly and efficiently merge into the main road, this paper proposes a cooperative trajectory planning method based on optimal control for vehicle cut-in scenarios. A optimal control model is constructed, and a quintic polynomial is used to generate the initial solution of the optimal control problem to accelerate the solution process and improve the success rate. Finally, The obtained merging trajectory is then synchronized with the movement of vehicles on the main road to optimize their actions and ensure a safe merging process. Joint simulation with Robot Operating system (ROS) and RVIZ is utilized, and the results show that the proposed algorithm can quickly obtain cooperative results, the locally successful merging trajectory meets the requirements of smoothness and safety, and if the solution does not allow merging, the merging vehicle is instructed to terminate the execution. © 2023 IEEE.

关键词： Trajectories

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Research on 1050 nm high-power narrow linewidth fiber laser based on tapered ytterbium-doped fiber 7

Research on 1050 nm high-power narrow linewidth fiber laser ...

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7th Optics Young Scientist Summit, OYSS 2024

作者： Ye, Yun Wang, Xiaolin Wang, Yanbin Zhou, Xuanfeng Jiang, Chenglong Zhang, Defeng Xi, Xiaoming Xu, Xiaojun State Key Lab. of Complex Electromagnetic Environment Effects on Electronics and Information System Luoyang471003 China College of Advanced Interdisciplinary Studies National University of Defense Technology Changsha410073 China

ISBN: (数字)9781510688377

ISBN: (纸本)9781510688360

Compared to conventional uniform fibers, long tapered Yb-doped fibers (T-YDF) have outstanding potential to alleviate the detrimental nonlinear effects due to their unique mode field characteristics along the length direction. In this work, an T-YDF-based short-wavelength narrow linewidth monolithic fiber amplifier was constructed through one-stage MOPA configuration. The fiber amplifier emits at the central wavelength of ~1050 nm, and the output lasing performance is carefully studied for different pumping scheme. The experimental results indicated that compared with the co-pumping scheme, the counter-pump one holds a better properties involving spectral broadening suppression, SRS suppression and TMI threshold enhancement in the 1050 nm narrow-linewidth fiber lasers. As a result, an output power of 3.56 kW was achieved with a slope efficiency of ~83.6% by adopting bidirectional pumping scheme. At the maximum lasing power, the 3dB spectral linewidth was measured ~0.58 nm, and the SRS suppression ratio was greater than ~27.3dB. This work could offer a promising approach for extending the operating wavelength of high-power narrow linewidth fiber lasers. © 2025 SPIE.

关键词： Fiber lasers

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