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Journal of Systems Engineering and Electronics 2024年第1期35卷 24-30页

作者： TIAN Jing ZHANG Wei School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of electromagnetic Space Security Chengdu 610036China

In engineering application,there is only one adaptive weights estimated by most of traditional early warning radars for adaptive interference suppression in a pulse reputation interval(PRI).Therefore,if the training samples used to calculate the weight vector does not contain the jamming,then the jamming cannot be removed by adaptive spatial *** the weight vector is constantly updated in the range dimension,the training data may contain target echo signals,resulting in signal cancellation *** cope with the situation that the training samples are contaminated by target signal,an iterative training sample selection method based on non-homogeneous detector(NHD)is proposed in this paper for updating the weight vector in entire range *** principle is presented,and the validity is proven by simulation results.

关键词： adaptive radar beamforming training sample selection non-homogeneous detector electronic jamming jamming suppression

Macroscopic model and statistical model to characterize electromagnetic information of a digital coding metasurface

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National Science Review 2024年第3期11卷 159-171页

作者： Rui Wen Shao Jun Wei Wu Zheng Xing Wang Hui Xu Han Qing Yang Qiang Cheng Tie Jun Cui institute of electromagnetic Space Southeast University State Key Laboratory of Millimeter Waves Southeast University Peng Cheng Laboratory Pazhou Laboratory(Huangpu)

A digital coding metasurface is a platform connecting the digital space and electromagnetic wave space, and has therefore gained much attention due to its intriguing value in reshaping wireless channels and realizing new communication architectures. Correspondingly, there is an urgent need for electromagnetic information theory that reveals the upper limit of communication capacity and supports the accurate design of metasurface-based communication systems. To this end, we propose a macroscopic model and a statistical model of the digital coding metasurface. The macroscopic model uniformly accommodates both digital and electromagnetic aspects of the meta-atoms and predicts all possible scattered fields of the digital coding metasurface based on a small number of simulations or measurements. Full-wave simulations and experimental results show that the macroscopic model is feasible and accurate. A statistical model is further proposed to correlate the mutual coupling between meta-atoms with covariance and to calculate the entropy of the equivalent currents of digital coding metasurface. These two models can help reconfigurable intelligent surfaces achieve more accurate beamforming and channel estimation, and thus improve signal power and coverage. Moreover, the models will encourage the creation of a precoding codebook in metasurface-based direct digital modulation systems, with the aim of approaching the upper limit of channel capacity. With these two models, the concepts of current space and current entropy, as well as the analysis of information loss from the coding space to wave space, is established for the first time, helping to bridge the gap between the digital world and the physical world, and advancing developments of electromagnetic information theory and new-architecture wireless systems.

关键词： electromagnetic information theory current entropy current space digital coding metasurface macroscopic model statistical model

An externally perceivable smart leaky-wave antenna based on spoof surface plasmon polaritons

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Opto-Electronic Advances 2024年第9期7卷 5-20页

作者： Weihan Li Jia Chen Shizhao Gao Lingyun Niu Jiaxuan Wei Ruosong Sun Yaqi Wei Wenxuan Tang Tie Jun Cui State Key Laboratory of Millimeter Waves Southeast UniversityNanjing 210096China institute of electromagnetic Space Southeast UniversityNanjing 210096China

Smart antennas have received great attention for their potentials to enable communication and perception functions at the same ***,realizing the function synthesis remains an open challenge,and most existing system solutions are limited to narrow operating bands and high complexity and ***,we propose an externally perceivable leakywave antenna(LWA)based on spoof surface plasmon polaritons(SSPPs),which can realize adaptive real-time switching between the“radiating”and“non-radiating”states and beam tracking at different *** the assistance of computer vision,the smart SSPP-LWA is able to detect the external target user or jammer,and intelligently track the target by self-adjusting the operating *** proposed scheme helps to reduce the power consumption through dynamically controlling the radiating state of the antenna,and improve spectrum utilization and avoid spectrum conflicts through intelligently deciding the radiating *** the other hand,it is also helpful for the physical layer communication security through switching the antenna working state according to the presence of the target and target beam tracking in real *** addition,the proposed smart antenna can be generalized to other metamaterial systems and could be a candidate for synaesthesia integration in future smart antenna systems.

关键词： smart antenna external perception spoof surface plasmon polaritons computer vision aids

A Novel Approach of electromagnetic Compatibility Conducted Susceptibility Analysis Based on Gaussian Even Pulse Signal

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Chinese Journal of Electronics 2024年第2期33卷 472-478页

作者： Youwei MENG Yanhua PENG Haoyang ZHANG Lilin LI Donglin SU The School of Electronic and Information Engineering Beihang University The institute of electromagnetic Compatibility Technology Beihang University The Research institute for Frontier Science Beihang University

The purpose of the electromagnetic compatibility conducted susceptibility test for interconnected cables in the system is to evaluate its ability to operate acceptably when subjected to interference. We propose a novel conducted susceptibility analysis approach: by injecting the Gaussian even pulse signal, we find that the susceptibility threshold of the system shows two different patterns with the change of signal parameters; then we locate the cause of the susceptibility of the device by analyzing the threshold level curves. The effectiveness of the proposed approach is verified by testing with devices containing digital modules such as navigation receivers. The proposed approach facilitates a deeper understanding of the susceptibility mechanism of systems and their appropriate electromagnetic compatibility design.

关键词： Analytical models Navigation Interference Receivers electromagnetic compatibility Physical layer Time-domain analysis

Growth,optical dispersion and magnetic behavior of Dy^(3+) doped yttrium iron garnet crystals

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Journal of Rare Earths 2024年第6期42卷 1110-1117,I0004页

作者： Yating Fang Hui Shen Yudie Ma Shijie Liao Shuang Xia Tian Tian Ding Zhou Yunfeng Ma Jiayue Xu institute of Crystal Growth School of Materials Science and EngineeringShanghai Institute of Technology National Engineering Center of electromagnetic Radiation Control Materials School of Electronic Science and EngineeringUniversity of Electronic Science and Technology of China

Y_(3)Fe_(5)O_(12)(YIG)crystals are highly desirable for the fabrication of mid-infrared isolators with the rapid growth of optical communications,although it is rather challenging to grow large size and high-quality single ***^(3+)doping is expected to improve the optical and magneto-optical prope ***,high quality Dy:YIG crystals and the adjustment of Dy^(3+)on the structure and optical behavior of YIG crystal remain unclear,impeding its practical ***,a series of Y_(3-x)Dy_(x)Fe_(5)O_(12)(x=0,0.5,1.0,1.5,3)solid solution crystals was grown by the flux-Bridgman method and single crystals up to 25 mm were *** the introduction of Dy^(3+),lattice parameters are gradually enlarged from 1.2379 nm(YIG)to 1.2420 nm(DyIG).Typical Dy^(3+)absorption peaks are observed around 1070,1265 and 1670 *** refractive index decreases from 2.37(500 nm)to 2.10(2500 nm)for YIG crystal,and it reduces from 2.47(500 nm)to 2.16(2500 nm)for DyIG *** optical bandgaps remain almost unchanged for Dy:YIG *** optical dispersion of the refractive indices was finely fitted by the Wemple and DiDomenico(WDD)and the Sellmeier models,*** the increase of Dy^(3+)content,the saturation magnetization(Ms)decreases significantly from 23.62 emu/g(YIG)to 5.33 emu/g(DyIG).Small coercive field is persisted for this system,endowing small external magnetic *** results provide valuable references for the manipulation of rare earths on the properties of magnetooptical crystals,which is beneficial to the design of high-performance garnet crystals for the application of optical switching and non-reciprocal related devices.

关键词： Magneto-optical crystal Yttrium iron garnet Dy^(3+)doping Crystal growth Optical dispersion Rare earths

Characteristic Mode Analysis for Pattern Diversity and Beamforming: A Survey

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Chinese Journal of Electronics 2024年第5期33卷 1117-1126页

作者： Qianyun ZHANG Biyi WU School of Cyber Science and Technology Beihang University Center for electromagnetic Simulation School of Integrated Circuits and Electronics Beijing Institute of Technology

With the rapid development of space-air-ground integrated communications, diverse requirements have been imposed on antenna radiation patterns. In addition, increasingly compact platforms brings significant challenges to the deployment of antenna arrays normally used for beamforming. This article comprehensively surveys characteristic mode analysis(CMA)-based pattern diversity realizations in past years. Specifically, exciting multiple characteristic modes independently achieves pattern reconfigurability and element-reduced multiple-input and multiple-output systems. We furthermore overview a series of works on modes superposition. Various methods have been explored for modal weights decision, and therefore specific patterns are synthesized. The weighted modal combination also fulfills single-element beamforming. A recent study on an antenna design for electrically small unmanned aerial vehicles(UAVs) is summarized, and the desired reconfigurable radiation patterns of the conformal radiator are realized based on CMA. Moreover, a formation-based beamforming technique, which takes advantages of the electromagnetic coupling among conformal radiators and the agility of UAVs, is introduced.

关键词： Characteristic mode analysis Beamforming Beamsteering Reconfigurable radiation pattern Characteristic mode analysis Beamforming Beamsteering Reconfigurable radiation pattern ANTENNA DESIGN MIMO FREQUENCY UWB

The nature of electron density enhancement over a wide altitude range during ionosphere heating experiments at EISCAT

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Earth and Planetary Physics 2024年第2期8卷 408-414页

作者： Jun Wu Jian Wu Jie Feng QingLiang Li ShuJi Hao ZhengWen Xu HaiSheng Zhao YaBin Zhang National Key Laboratory of electromagnetic Environment China Research Institute of Radio Wave PropagationBeijing 102206China School of Physics Xidian UniversityXi’an 710071China

During the course of ionospheric heating experiments, researchers at the European Incoherent Scatter Scientific Association (EISCAT) observed an apparent electron density enhancement. The enhancement extended over a wide range of altitudes, above the reflection altitude of the high-frequency pump wave. However, whether this enhancement actually corresponds to a true enhancement in electron density remains an open question. When the dispersion relation of ion acoustic waves is followed, the frequency ratio of the enhanced ion line to the background ion line suggests that the profile of the effective ion mass may have remained unchanged. Furthermore, the solar radio flux and ion drift velocity indicate no significant changes in the ion species and their densities. In conclusion, the electron density enhancement observed at EISCAT should not, in fact, be considered a true enhancement.

关键词： incoherent scatter radar(ISR) ionospheric heating electron density ion acoustic wave

Conjugate Vectors Method Applied to Asymmetrical Fault Analysis of Power Electronized Power Systems

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CSEE Journal of Power and Energy Systems 2024年第4期10卷 1536-1549页

作者： Yingbiao Li Xing Liu Jiabing Hu Jianhang Zhu Jianbo Guo State Key Laboratory of Advanced electromagnetic Technology(Huazhong University of Science and Technology) Wuhan 430074China China Electric Power Research institute Beijing 100192China

With the wide application of power electronized resources(PERs),the amplitude and frequency of voltages show significant time-varying characteristics under asymmetrical *** a result,the traditional phasor model,impedance model,and symmetrical components method based on the constant amplitude and frequency of voltages are facing great ***,a novel asymmetrical fault analysis method based on conjugate vectors is proposed in this paper which can meet the modeling and analysis requirements of the network excited by voltages with time-varying amplitude/***,asymmetrical fault characteristics are *** an application,a faulted phase identification(FPI)strategy is proposed based on the fault *** correctness and superiority of the asymmetrical fault analysis method and FPI strategy are verified in time-domain simulations and a real-time digital simulator.

关键词： Asymmetrical fault characteristics conjugate vectors method dynamic asymmetrical fault analysis time-varying amplitude/frequency

Coordinated Capacitor Voltage Balancing Method for Cascaded H-bridge Inverter with Supercapacitor and DC-DC Stage

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CES Transactions on Electrical Machines and Systems 2024年第2期8卷 191-201页

作者： Ye Zhang Zixin Li Fanqiang Gao Cong Zhao Yaohua Li IEEE Key Laboratory of High Density electromagnetic Power and Systems(Chinese Academy of Sciences) Institute of Electrical EngineeringChinese Academy of SciencesHaidian District University of Chinese Academy of Sciences Shijingshan District

Cascaded H-bridge inverter(CHBI) with supercapacitors(SCs) and dc-dc stage shows significant promise for medium to high voltage energy storage applications. This paper investigates the voltage balance of capacitors within the CHBI, including both the dc-link capacitors and SCs. Balance control over the dc-link capacitor voltages is realized by the dcdc stage in each submodule(SM), while a hybrid modulation strategy(HMS) is implemented in the H-bridge to balance the SC voltages among the SMs. Meanwhile, the dc-link voltage fluctuations are analyzed under the HMS. A virtual voltage variable is introduced to coordinate the balancing of dc-link capacitor voltages and SC voltages. Compared to the balancing method that solely considers the SC voltages, the presented method reduces the dc-link voltage fluctuations without affecting the voltage balance of SCs. Finally, both simulation and experimental results verify the effectiveness of the presented method.

关键词： Cascaded H-bridge inverter(CHBI) Hybrid modulation strategy(HMS) Capacitor voltage balancing DClink voltage fluctuation Supercapacitor(SC)

The application of metal-organic frameworks and their derivatives for lithium-ion capacitors

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新型炭材料（中英文） 2024年第5期39卷 872-895页

作者： ZHAO Sha-sha ZHANG Xiong LI Chen AN Ya-bin HU Tao WANG Kai SUN Xian-zhong MA Yan-wei Key Laboratory of High Density electromagnetic Power and Systems(Chinese Academy of Sciences) Institute of Electrical EngineeringChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Shandong Key Laboratory of Advanced electromagnetic Conversion Technology Institute of Electrical Engineering and Advanced Electromagnetic Drive TechnologyQilu ZhongkeJinan 250013China

There is an urgent need for lithium-ion capacitors(LICs)that have both high energy and high power densities to meet the continuously growing energy storage *** effectively balance the high energy density of traditional rechargeable batteries with the superior power density and long life of supercapacitors(SCs).Nevertheless,the development of LICs is still hampered by limited kinetic processes and capacity mismatch between the cathode and ***-organic frameworks(MOFs)and their derivatives have received significant attention because of their extensive specific surface area,different pore structures and topologies,and customizable functional sites,making them compelling candidate materials for achieving high-performance ***-derived carbons,known for their exceptional electronic conductivity and large surface area,provide improved charge storage and rapid ion ***-derived transition metal oxides contribute to high specific capacities and improved electrochemical ***,MOF-derived metal compounds/carbons provide combined effects that increase both the capacitive and Faradaic reactions,leading to a superior overall *** review begins with an overview of the fundamental principles of LICs,followed by an exploration of synthesis strategies and ligand selection for MOF-based composite *** then analyzes the advantages of original MOFs and their derived materials,such as carbon materials and metal compounds,in enhancing LIC ***,the review discusses the major challenges faced by MOFs and their derivatives in LIC applications and offers future research directions and recommendations.

关键词： Lithium-ion capacitors MOFs Transition metal oxide Energy density Power density