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Accurate Analyses of the On-Axis Fields of a Circular Disk by Transient and Harmonic Excitation

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Chinese Physics Letters 1997年第3期14卷 173-175页

作者： ZHU Xian-yang LI Jing REN Lang WANG Wen-bing institute of electromagnetic theory and microwave technology Southwest Jiaotong UniversityChengdu 610031 institute of Electronics and Information Xi'an Jiaotong UniversityXi'an 710049

The computation of near zone fields is very important in many practical *** analyses of the on-axis fields of a circular disk by transient and harmonic excitation show that there is an energy uprising zone on the axis rather than a non-decaying one,provided that the disk is excited by a rectangular pulse,the duration of which is less than the ratio of the radius to the light *** results corresponding to the time-harmonic excitation are also given,which are quite different from the conclusions derived by Silver.

关键词： excitation harmonic radius

Improved LMS adaptive algorithm with varying stepsize

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Chinese Science Bulletin 1996年第18期41卷 1568-1571页

作者：朱贤阳李敬任朗汪文秉 institute of electromagnetic theory & microwave technology Southwest Jiaotong UniversityChengdu 610031 China Department of Information & Control Engineering Xi'an Jiaotong University Xi'an 710049 China

In the field of system identification, the coefficients of a digital filter, which are used to illustrate the transfer function of a system, are often fixed by known input and output signal sequences. The least mean square (LMS) adaptive algorithm is often used for its small computational requirement and convergence ***, the input or the output signal sequence often contains directive current (DC) components. What is the effect of the DC component upon the adaptive algorithm? This is just the main objective of this note. Here we propose an improved LMS adaptive algorithm with varying stepsize, which is based on the DC components analyzing.

关键词： LMS adaptive algorithm system identification directive currents.

Compact Dual-Band Zeroth-Order Resonance Antenna

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Chinese Physics Letters 2012年第1期29卷 105-108页

作者： XU He-Xiu WANG Guang-Ming GONG Jian-Qiang electromagnetic Field and microwave Technique Missile Institute of Air Force Engineering UniversitySanyuan 713800 National Key Laboratory of Antennas and microwave technology Xidian UniversityXi’an 710051

A novel microstrip zeroth-order resonator (ZOR) antenna and its equivalent circuit model are exploited with two zeroth-order *** is constructed based on a resonant-type composite right/left handed transmission line (CRLH TL) using a Wunderlich-shaped extended complementary single split ring resonator pair (W-ECSSRRP) and a series capacitive *** gap either can be utilized for double negative (DNG) ZOR antenna or be removed to engineer a simplified elision-negative ZOR (ENG) *** verification,a DNG ZOR antenna sample is fabricated and *** and experimental results agree well with each other,indicating that the omnidirectional radiations occur at two frequency bands which are accounted for by two shunt branches in the circuit *** size of the antenna is 49% more compact than its previous *** superiority of WECSSRRP over CSSRRP lies in the lower fundamental resonance of the antenna by 38.2% and the introduction of a higher zeroth-order resonance.

关键词： antenna resonator Dual

Integration of Electrical Properties and Polarization Loss Modulation on Atomic Fe–N‑RGO for Boosting electromagnetic Wave Absorption

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Nano-Micro Letters 2025年第2期17卷 517-532页

作者： Kaili Zhang Yuefeng Yan Zhen Wang Guansheng Ma Dechang Jia Xiaoxiao Huang Yu Zhou State Key Laboratory of Precision Welding&Joining of Materials and Structures Harbin Institute of TechnologyHarbin 150001People’s Republic of China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001People’s Republic of China MIIT Key Laboratory of Advanced Structural‑Functional Integration Materials&Green Manufacturing technology Harbin Institute of TechnologyHarbin 150001People’s Republic of China

Developing effective strategies to regulate graphene’s conduction loss and polarization has become a key to expanding its application in the electromagnetic wave absorption(EMWA)*** on the unique energy band structure of graphene,regulating its bandgap and electrical properties by introducing heteroatoms is considered a feasible ***,metal-nitrogen doping reduced graphene oxide(M–N-RGO)was prepared by embedding a series of single metal atoms M–N_(4) sites(M=Mn,Fe,Co,Ni,Cu,Zn,Nb,Cd,and Sn)in RGO using an N-coordination atom-assisted *** composites had adjustable conductivity and polarization to optimize dielectric loss and impedance matching for efficient EMWA *** results showed that the minimum reflection loss(RL_(min))of Fe–N-RGO reaches−74.05 dB(2.0 mm)and the maximum effective absorption bandwidth(EAB_(max))is 7.05 GHz(1.89 mm)even with a low filler loading of only 1 wt%.Combined with X-ray absorption spectra(XAFS),atomic force microscopy,and density functional theory calculation analysis,the Fe–N_(4) can be used as the polarization center to increase dipole polarization,interface polarization and defect-induced polarization due to d-p orbital hybridization and structural ***,electron migration within the Fe further leads to conduction loss,thereby synergistically promoting energy *** study demonstrates the effectiveness of metal-nitrogen doping in regulating the graphene′s dielectric properties,which provides an important basis for further investigation of the loss mechanism.

关键词： electromagnetic wave absorption Fe-N-RGO Dipole polarization Conduction loss Impedance matching

Theoretical Analysis of a Vertical Channel Dropping Tunnelling Process in a Photonic Crystal for Wavelength Division Demultiplexing

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Chinese Physics Letters 2001年第12期18卷 1613-1616页

作者： FU Jian HE Sai-Ling XIAO San-Shui QIU Min HE Jian-Jun Centre for Optical and electromagnetic Research State Key Laboratory for Modern Optical InstrumentationZhejiang UniversityHangzhou 310027 Department of electromagnetic theory Royal Institute of TechnologyS-10044 StockholmSweden

A theoretical analysis is presented for a channel drop tunnelling structure composed of a horizontal input channel, a vertical output channel and a multi-mode cavity in a photonic crystal. Criteria for a complete transfer are derived for applications of wavelength division demultiplexing. The analytical results are verified with a numerical simulation using a finite difference time domain method. The vertical channel dropping tunnelling system makes the demultiplexing device much more compact, as compared to the conventional parallel channel dropping system.

关键词： channel multiplexing Crystal

Satellite-based RAR performance simulation for measuring directional ocean wave spectrum based on SAR inversion spectrum

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Acta Oceanologica Sinica 2010年第4期29卷 13-20页

作者： REN Lin MAO Zhihua HUANG Haiqing GONG Fang Department of electromagnetic Fields and microwave theory Nanjing University of Science and Technology Nanjing 210094 China State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of Oceanography State Oceanic Administration Hangzhou 310012 China

Some missions have been carried out to measure wave directional spectrum by synthetic aperture radar （SAR） and airborne real aperture radar （RAR） at a low *** them have their own advantages and *** hope that SAR and satellite-based RAR can complement each other for the research on wave properties in the *** this study,the authors aim to simulate the satellite-based RAR system to validate performance for measuring the directional wave *** principal measurements are introduced and the simulation methods based on the one developed by Hauser are adopted and slightly *** enhance the authenticity of input spectrum and the wave spectrum measuring consistency for SAR and satellite-based RAR,the wave height spectrum inversed from Envisat ASAR data by cross spectrum technology is used as the input spectrum of the simulation *** the process of simulation,the sea surface,backscattering signal,modulation spectrum and the estimated wave height spectrum are simulated in each look *** wave spectrum are measured based on the simulated observations from 0 ？ to 360 ？ .From the estimated wave spectrum,it has an 180 ？ ambiguity like SAR,but it has no special high wave number cut off in all the ***,the estimated spectrum is compared with the input one in terms of the dominant wave wavelength,direction and SWH and the results are *** simulation shows that satellite-based RAR should be capable of measuring the directional wave ***,it indicates satellite-based RAR basically can measure waves that SAR can measure.

关键词： satellite-based RAR directional wave spectrum SAR inversion performance simulation

Harmonic suppressed bandpass filter using composite right/left handed transmission line

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Journal of Zhejiang University-Science C(Computers and Electronics) 2012年第7期13卷 552-558页

作者： Jian-gang LIANG He-xiu XU electromagnetic Field and microwave Technique Missile InstituteAir Force Engineering UniversityShaanxi 713800China

A wideband composite right/left handed transmission line (CRLH TL) in conjunction with its corresponding equivalent circuit model is studied based on a cascaded complementary single split ring resonator (CCSSRR).The characterization is performed by theory analysis,circuit simulation,and full-wave electromagnetic (EM) *** negative refractive index (NRI) and backward wave propagation performance of the CRLH TL are *** application,a bandpass filter (BPF) with enhanced out-of-band selectivity and harmonic suppression operating at the wireless local area network (WLAN) band is designed,fabricated,and measured by combining the CRLH TL with a complementary electric inductive-capacitive resonator (CELC).Three CELC cells with wideband stopband performance in the conductor strip and ground plane,respectively,are utilized in terms of single negative *** design concept has been verified by the measurement data.

关键词： Composite right/left handed transmission line Cascaded complementary split single ring resonator Bandpass filter Complementary electric inductive-capacitive resonator (CELC) Negative permeability

An LMI-based decoupling control for electromagnetic formation flight

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Chinese Journal of Aeronautics 2015年第2期28卷 508-517页

作者： Huang Xianlin Zhang Chun Lu Hongqian Yin Hang Center for Control theory and Guidance technology Harbin Institute of Technology

electromagnetic formation flight （EMFF） leverages electromagnetic force to control the relative position of satellites. EMFF offers a promising alternative to traditional propellant-based spacecraft flight formation. This novel strategy is very attractive since it does not consume fuel. Due to the highly coupled nonlinearity of electromagnetic force, it is difficult to individually design a controller for one satellite without considering others, which poses challenges to communications. This paper is devoted to decoupling control of EMFF, including regulations, constraints and con- troller design. A learning-based adaptive sliding mode decoupling controller is analyzed to illustrate the problem of existing results, and input rate saturation is introduced to guarantee the validity of frequency division technique. Through transformation, the imposed input rate saturation is con- verted to state and input constraints. A linear matrix inequalities （LMI）-based robust optimal con- trol method can then be used and improved to solve the transformed problem. Simulation results are presented to demonstrate the effectiveness of the proposed decoupling control.

关键词： Decoupling control electromagnetic forces electromagnetic formationflight Linear matrix inequalities Satellite control

Compressed sensing application in interferometric synthetic aperture radar

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Science China(Information Sciences) 2017年第10期60卷 187-203页

作者： Liechen LI Daojing LI Zhouhao PAN Science and technology on microwave Imaging Laboratory institute of Electronics Chinese Academy of Sciences

A novel interferometric synthetic aperture radar(In SAR) signal processing method based on compressed sensing(CS) theory is investigated in this paper. In SAR image formation provides the scene reflectivity estimation along azimuth and range coordinates with the height information. While surveying the height information of the illuminated scene, the data volume enlarges. CS theory allows sparse sampling during the data acquisition, which can reduce the data volume and release the pressure on the record devices. In SAR system which configures two antennas to cancel the common backscatter random phase in each resolution element implies the sparse nature of the complex-valued In SAR image. The complex-valued image after conjugate multiplication that only a phase term proportional to the differential path delay is left becomes sparse in the transform domain. Sparse sampling such as M-sequence can be implemented during the data acquisition. CS theory can be introduced to the processing due to the sparsity and a link between raw data and interferometric complex-valued image can be built. By solving the CS inverse problem, the magnitude image and interferometric phase are generated at the same time. Results on both the simulated data and real data are presented. In comparison with the conventional SAR interferometry processing results, CS-based method shows the ability to keep the imaging quality with less data acquisition.

关键词： synthetic aperture radar(SAR) interferometric synthetic aperture radar(In SAR) compressed sensing(CS) sparse sampling sparsity in the transform domain