最新刊期
卷 ， 期 6 ， 1998
- 摘要：A multiple band cyclic least squares algorithm of estimation of direction of arrival in frequency domain for cyclostationary signals is presented which exploits efficiently spectral correlation of the entire frequency band of a system. Thus a more accurate estimate is achieved. Because of the great difference in spectral correlation across the system band, an algorithm keeping almost the same performance but reducing calculation costs is developed utilizing a simple and efficient selection of bands.关键词：Cyclostationarity;least squares;estimation of direction of arrival;Array processing4|52|2更新时间：2025-12-08
- 摘要：The envelope correlation algorithm is widely used in range alignment of ISAR motion compensation, however, this method often has error accumulation, and what is more, a jump error will occur when the reflection of target has strong scintillation. To reduce the error of range alignment, a minimum entropy criterion of range alignment in ISAR compensation is proposed. Using this method the range bin can be aligned correctly, which is verified by real radar data.关键词：逆合成孔径雷达;运动补偿;成像4|476|40更新时间：2025-12-08
- 摘要：A polystyrene foam-supported highly efficiency broadband microstrip antenna array is proposed. The analysis and design technique of this antenna array are presented. Theoretical and experimental results show that bandwidth up to 60 percent can be obtained.关键词：microstrip antenna;Printed antenna;Microstrip dipole;Primed dipole;Printed circuit radiator;Microstrip antenna array5|105|0更新时间：2025-12-08
- 摘要：A modified Vlasov equation which describes the evolution of the spatial and momentum distribution of axisymmetrical electron beams is developed based on the statistical dynamics theory. A semi-analytical solution of the equation is given in the paraxial approximation. The evolution and the beam envelope spreading for electron beams in drifting space are calculated using the above theory and methods; the calculation results agree very well with the numerical computation results.关键词：statistical distribution;electron beam;Statistical dynamics2|28|0更新时间：2025-12-08
- 摘要：The electron trajectory equation of electrostatic wide beam has been researched thoroughly. Equations of curvilinear paraxial trajectories with second order approximation have been derived, and converted into a suitable form for computing. The computational rationality and credibility of curvilinear trajectories are demonstrated by concentric spherical system. There is a difference about fifth order of magnitude between firstand second-order approximate values of curvilinear trajectories, and about fourth order of magnitude between these two aberrations. It can be neglected in general engineering applications, but cannot be neglected in some image tubes requiring high precision.关键词：electron optics;Wide electron beam focusing;Curvilinear coordinate system;Concentric spherical system;numerical computation;Aberration.2|27|0更新时间：2025-12-08
- 摘要：The optical experimentally excitation of a silicon cantilever resonator is studied both theoretically and experimentally. The amplitude-frequency response and the relationship between the output of resonators and the position of excitation are discussed.These results provide the theoretical basis for the optical-micromechanical resonators.关键词：Silicon cantilever resonator;Optical excitation2|45|1更新时间：2025-12-08
- 摘要：LiNbO3 tapped-delay-line（TDL）/p+ n diode array surface acoustic wave（SAW）memory correlator is introduced. The central frequency of the device is 30MHz, with the convolution efficiency and storage correlation efficiency of -54dBm and - 76dBm, respectively. The storage time is more than 70ms. The generation and cancellation of spurious signal are discussed, and the dependence of storage time on minority carrier lifetime is also discussed. The dependence of correlation output on reference signal and read signal are calculated. The results show that our device is "bilinear". Suggestions for the design and optimization of SAW memory correlator of this structure are given.关键词：Memory correlator;Diode array;Minority carrier lifetime;surface acoustic wave;Tapped-delay-line;electron irradiation2|24|1更新时间：2025-12-08
- 摘要：Two kinds of the new FDTD models have been proposed in this paper. According to the models,two algorithms are obtained. By comparison, the new algorithms have some advantages over the traditional Yee algorithm.关键词：FDTD;Difference algorithms;grid model2|89|3更新时间：2025-12-08
- 摘要：The space polarization structure of complex radar target is described in terms of its genus characteristic and stability in the optics region on the basis of polarimetric and high-resolution radar system. Furthermore, the recognition of four kinds of aircraft target is investigated and good results are achieved.关键词：polarization;Targer recognition;Null-polarization;Space polarization structure2|87|3更新时间：2025-12-08
- 摘要：The polarization property of electromagnetic signals is utilized to investigate the prolem of sigal enhancement in the presence of multiple scatterers by means of changing the polarization of receiving antenna. The receiving antenna’s global and local optimal polarizations with the constraint of polarization tracks are presented while adopting SINR （Signal-to-Interference-and-Noise-Ratio） and PDSI （Power-Difference-between-Signal-and-Interference） as the objective functions, respectively. The results are verified by a numerical example.关键词：极化;极化轨道;信号干扰噪声比;信号干扰功率差;最优接收极化2|145|10更新时间：2025-12-08
- 摘要：Partially andaptive processing in beam-space is an important method of reducing rank adaptive beamforming. The Characteristics of partially adaptive processing, the choice of auxiliary beams and reducing rank of interference signal subspace via per-beamforming are analyzed theoretically. An effective approach is proposed for the suppression of concentrated jammers, which is confirmed by numerical analysis.关键词：Partially adaptive proccessing;beam-space;interference suppression;adaptive beamforming2|130|1更新时间：2025-12-08
- 摘要：The efficient numerical solution of the potential excited by a single or multiple dipole sheets in complex inhomogeneous media has been made by use of the half analytical-half numerical hybrid method. The results are compared with the FEM results and the experimental data and the good agreecment is obtained. This method has been used for the modeling and solution of the spontaneous potential response.关键词：Inhomogeneous media;Dipole sheet;Analysis of the potential;Spontaneous potential response2|45|1更新时间：2025-12-08
- 摘要：A method to calculate the microwave attenuation coefficient of traveling-wave electrodes with complicated cross-sectious in Ti: LiNbO3 optical modulators is described in this paper. It is verified by comparing the calculating results from this method and from other method. Some electrode structures are analysed by using this method and the reasons of discrepancy between the calculating and experimental results are discussed. A modifying coefficient is given for designing broad-band optical modulators.关键词：Ti:LiNbO3;电光调制器;行波电极;微波损耗系数2|124|5更新时间：2025-12-08
- 摘要：The mixed-edge dement whie is developed in recent years is an effective method for eliminating the spurious solutions. In this paper, a systematic construction method of the triangular mixed-edge element is proposed. As examples, explicit formulations of the interpolation functions for one- and two-order triangular mixed edge dements are given. The calculations of the dispersion curves for several guiding structures verify that the proposed mixed-edge element not only eliminates the spurious solutions, but also has higher computing efficiency. The comparison between two mixed-edge elements shows that the accuracy and convergence of the low-order mixed-edge element are clearly improved by using the high-order one.关键词：Systematic construction method;Finite element space;Mixed-edge element2|20|1更新时间：2025-12-08
- 摘要：By using finite element method, the hybrid potentials and differential operators have been researched for remote field eddy current（RFEC） nondestructive test, and the formulations based on A, V-As-φ model and ▽×▽ operator are obtained. Numerical Simulation shows good agreement with experiment and furthermore, it can be used to explain some phenomena in RFEC test.关键词：电磁场;有限元;远场涡流;无损探伤2|51|1更新时间：2025-12-08
- 摘要：Mieroshield hne（MSL） is a new type of monolithic planar transmission line which will be widely used in millimeter circuit for its ultra-high frequency response and very low dispersion. The spectral domain impedance approach is extended to calculate this half-closed transmission line. The results of calculation agree well with the relevant experiments, which provides an effective method for calculating the MSL.关键词：Microshield line;Spectral domain impedance approach;dispersion3|56|1更新时间：2025-12-08
- 摘要：A point pattern relaxation matching method which is invariant to rotation and scale changes is proposed. Experimental results with large simulated images prove the effectiveness and feasibility of the method.关键词：matching;Relaxation;Point patterns;invariance2|206|8更新时间：2025-12-08
- 摘要：Starting from the integral form’s Kirohhoff law of field theory, the most general equation of node electrical potential in both hnear and non-hnear network could be deduced strictly and simply, meanwhile the general relation of complex self-inductance and mutual-inductance with complex electrical conductance, including the sign rule, was also given.关键词：non-linear network;Node electrical potential method;general equation;deduction by field theory2|62|4更新时间：2025-12-08
- 摘要：The high Tc superconducting microstrip line and coplanar waveguide are analyzed by using the FDTD method. The two-fluid model which is expressed in frequency domain is converted into time domain by Fourier transform. For the line to be causal, the two-fluid model is processed by even conjugate continuation. Then the Maxwell’s equations are expressed in the time domain and discretized in time and all three space direstious. The attenuation constant and phase constant are obtained rigorously.关键词：Superconducting;finite difference time domain;microstrip line;coplanar waveguide4|47|2更新时间：2025-12-08
- 摘要：The quasi optical feed system and low noise cooled receiver technology for milimeter wave radio telescope are presented in this paper.The quasi optical feed system has many advantages:low loss and wide bandwidth （<0.5dB at 85-115GHz） and noise temperature of receiver TR （DSB）min=130K at 80-115GHz. The molectder spectrum lines O3, C12O（J=1-O）, C13O（J=1-0）are observed.关键词：Milimeter wave radio telescope;Quasi-optical feed system;Schottky diode chip mixer;Molecular spectrum lines2|79|3更新时间：2025-12-08
- 摘要：The 3-dimensional modeling of planar microwave networks with the imperfect conductor is discussed, and its Y-parameters are obtained by the functional approach, then a numerical example is given. The results show that the effect of the finite conductivity can not be neglected, especially for the resonant networks.关键词：Planar microwave networks with imperfect conduct;Y-parameters;Functional approach2|67|0更新时间：2025-12-08
- 摘要：The classical ISAR imaging method based on FFT cannot statisfy the imaging requirements in the case of large rotating angle and nonuniformly rotating targt. The variation rule of the Doppler frequency of a target scatterers is analyzied under the two situations mentioned above. We have proposed a method for compensating this variation based on the criteria of minimum entropy for estimating the chirp rate. The experimental resuits show great improvement in ISAR imaging.关键词：ISAR imaging;motion compensation;Minimum entropy2|78|1更新时间：2025-12-08
- 摘要：With fixed windows or kernels, Time-frequency representation（TFR）performs well only for limited signals, however representation with signal depended kernels can overcome this limitation. The TFR developed here is based on signal depended tilted Gaussian kernel. In order to find the optimal tilted Gaussian kernel we introduce expectation maximization（EM）algorithm. We can easily get the optimal Gaussian kernel from the estimated parameters of the auto-component by simply transplanting.关键词：Time-frequency representation（TFR）;Expectation maximization（EM） algorithm;Ambiguity function（AF）;Tilted Gaussian kernel2|43|0更新时间：2025-12-08
- 摘要：The dual polarization radar high-resolution range profiles are processed as follows: different receive/send state noncoherent integration,near azimuth data compression and noise level inhibition. After the processing, we obtain less and high signal-noise rateo target feature profiles. Using the above methods, we set up target feature data library of five ground targets. High classification performance can be obtained using the feature library to classify the five ground targets.关键词：high-resolution range profile;Target classification;feature extraction3|95|1更新时间：2025-12-08
- 摘要：This paper derives the general formulas of radiation patterns normalized to HE11 mode with reference to arbitrary modes, and of conical horns normalized to TE11 mode, And the general formulas of reflectional coefficients to arbitrary modes in corrugated horns are derived.关键词：Corrugated horns;Normalized patterns;Reflectional coefficients2|102|6更新时间：2025-12-08
- 摘要：We suggest a the corner based Fourier Descriptors of the object, which are taken as the features of 2-D objects and form the input of BP neural network. A multilayered perceptron architecture is used for the recognition of airplane. The scheme is invariant to rotation、translation and scale changes to object. The simulation results show that the pesented scheme gives very high recoginition accuracy and good associability.关键词：Corner based fourier descriptors;BP neural network2|119|4更新时间：2025-12-08
- 摘要：The patterns of array placed on the aircraft in arbitrary direction for AEW phased array radar are derived. The models for random amplitude and phase errors as well as coupling errors existing in array elements and attitude errors of aircraft are presented. Some results of simulation and conclusions of research are given.关键词：机载雷达;相控阵;天线方向图;模型;误差;仿真2|274|1更新时间：2025-12-08
- 摘要：This paper deals with a distributed detection system in multistatic radars, which consists of a number of independent local radars and a fusion center. This system has the advandage of hgher reliability, survivabilty and immune to electronic attack than monostatic radars. The detection performances（detection probabilty and false alarm probabilty）for low RCS target in multistatic radars is related to following: target movement, fluctuating target and different position of the radars. It is very useful to design the system in multistatic radar.关键词：分布检测;雷达信号处理;分布处理;信号检测2|80|3更新时间：2025-12-08
- 摘要：Using the sub-domain method of lines to solve equipotential lines of several verieties of planar resonators which are parts of the microwave ferrite devices is convenient. Irregular hoxagonal, wye and double wye planar resonators with magnetic wall are computed and a graph of the cutoff numbers of the three lowest modes versus the dimensions of those resonators is illustrated in this paper.关键词：Method of lines;Planar resonator;Microwave ferrite2|19|0更新时间：2025-12-08
- 摘要：A novel iterative algorithm based on the measured equation of invariance （IA-MEI） is proposed for the scattering analysis of multi-cylinders with arbitrarily shaped cross-sections. By using the MEI’s, the truncated mesh boundary, can be much close to the surface of each cylinder, which resuhs in dramatical savings in memory needs and computing time. Based on the invariance to excitation of MEI, the MEI coefficients at truncated boundary nodes of the meshes around each cylinder may be used repeatedly in the iterative procedure, which also greatly reduce the computing time. The results of some circular cylinders are in good agreement with exact solutions. Besides, the scattering fields of some electrically large compound multi-cylinder structures are presented.关键词：iterative algorithm;Measured equation of invariance;Multi-conductor;Electromagnetic scattering2|25|0更新时间：2025-12-08
- 摘要：In this paper,a set of FDTD fomulation of magnetized plasma is derived,which involves electron motion equation of magnetized plasma under electromagnetic field. This has overcome the defects of rescursive convolution method which is not suitable for the incident pulse with D. C component and is small signal approximation. The accuracy of this method is demenstmted by numerical computations.关键词：Finite Difference Time Domain method;magnetized plasma;Anisotropic dispersive media;absorbing boundary condition2|86|2更新时间：2025-12-08
- 摘要：This paper deals with the interaction of the electromagnetic pulse（EMP） with human body by the Frequency-Dependent Finite-Differenee Time-Domain method（（FD）2TD method）. According to the original experimental dielectric constants of human tissue in the frequency band 10MHz-3GHz,this paper proposes a simplified dispersive model of the human body which is composed of two types of tissues （Fet/bone/cartilage, muscle）. Both this model and the 12 types of tissues dispersive model are used to analyse Specific Absorption（SA） and Induced Current in human body for exposure to raised-cosine EMP and nuclear EMP for different incident directions. The feasibility of the simplified model is verified by comparing the results. The calculated results show that the maximum SA（15mJ/kg） is three orders lower than the limited values（28.8 J/kg） given by the ANSI/IEEE C95.1-1992 guideline for the human body exposed to the typical nuclear pulse（the maximum E-field is 6SkV/m, and the pulse duration is shorter than 85ns）.关键词：(（FD）2)TD method;EMP;Human body;Dispersive model;Specific absorption2|70|1更新时间：2025-12-08
- 摘要：The mathematial model expression of the differential wide synchronizing band IL （DWSBIL） which is used to implement PIL is presented,and the formula for the synchronizing band of the DWSBIL is derived, where the maximum synchronization band of the same frequency IL is μ times as large as the famous Adler’s formula, μ>>1.关键词：IL;Synchronization band;Adler’s formula2|29|0更新时间：2025-12-08
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