最新刊期
卷 ， 期 3 ， 1995
- 摘要：Ion-Ripple Laser （IRL）, which is a new form of free-electron laser, is investigated using the kinetic theory. By considering the finite spread in beam longitudinal momentum and the effect of finite space-charge field of the electron beam,the dispersion relation of IRL instability is derived ,and the growth rate of IRL wave and the linear damping rate of the space-charge wave are also got. Detail discussion is carried out ,and some important results are obtained.关键词：Momentum spread;Ion ripple;Free-electron laser;Kinetic theory;Growth rate;Damping rate2|30|0更新时间：2025-12-08
- 摘要：A result is proved that the singular pointsηE and ηH of the boundary integral equations of the outer scattering fields Ez￣（s）and Hz￣（s） of a cylindrical conducting surface are equal. Then a method for solving the cutoff wave numbers of waveguide is suggested, in which the same one program may be used commonly for E mode and H mode. The only change needed is the adjustment of the sign of the main diagonal elements. The cutoff wave numbers of E mode are also the singular points for the outer scattering problem.关键词：Singular point;Boundary integral equations;Cutoff wave number2|33|0更新时间：2025-12-08
- 摘要：The transient response of multilayer multiconductor system is simulated by combining spectral domain approach with waveform iteration in frequency domain in this paper.The effect of dispersion and coupling has been taken into account.The reliability and application scope of this method has been proved by the results given.关键词：High speed interconnection;Spectral domain approach;Waveform iteration;Fast Fourier transformation2|51|1更新时间：2025-12-08
- 摘要：An improved simulated annealing method is presented.The method is based on adjusting and compressing the parameter bounds, following the tracks of optimal point and introducing the uniform experiment into Metropolis procedure.The method presented here has been successfully applied to the extraction of the parameters of equivalent circuits of microwave FETs.It is evident from optimization results that this approach is less time consuming and more efficient than the tree annealing and hybrid gradient descent and tree annealing approach.关键词：参数提取;模拟退火;边界压缩;最优解跟踪;均匀试验2|64|0更新时间：2025-12-08
- 摘要：Based on elliptical cylindrical harmonic expansion,this paper analyses the problem of electromagnetic scattering of obliquely incident wave by a multilayered elliptical dielectric cylinder.By using the addition theorem for Mathieu functions, the field on the outer surface of each layer is matched.The analytic equation of electromagnetic scattering of obliquely incident wave is obtained.关键词：Elliptical dielectric cylinder;electromagnetic scattering;Mathieu function;addition theorem2|157|5更新时间：2025-12-08
- 摘要：Kinetic theory of sideband instability for an electromagnetic pump free-electron laser （EM-FEL） without a guided magnetic field has been developed by applying Vlasov-Maxwell equations and integration along the unperturbed orbit.The properties of electron motions in the equilibrium distribution have been discussed and the general dispersion equation is derived. The maximum linear growth rates and the relavent frequencies of sideband for step distribution have been obtained. Numerical calculations for the dispersion equations are carried out.The properties of the EM-FEL sideband instability have been discussed in detail.关键词：Sideband instability;EM-FEL;Kinetic theory;Dispersion equation;Growth rate2|33|0更新时间：2025-12-08
- 摘要：From the physical optics assumption and Leontovich Impedance Boundary Condition （IBC） ,we build up the bistatic formulae of the electromagnetic field scattered from three dimensional conduct object coated with radar absorb materials（RAM） with an arbitrary smooth convex shape.This problem is formulated in terms of Fresnel reflect coefficients and IBC. The interrelation of twoincident fields between the coated surface and the conducting surface of the same configuration,as well as the coated surface electromagnetic current ratio coefficients are also derived. At last,the computational method of bistatic scattering matrix and bistatic cross section from electrically large coated bodies is given for non-edge structures.关键词：physical optics;Bistatic cross section;scattering matrix2|152|5更新时间：2025-12-08
- 摘要：A new method for determining the propagation constant from the phase information of standing waves is reported. The distinctive feature of this method is that the attenuation constant is the slope of a linear function of the displacement of a probe,providing a new approach for determining small attenuation constant on a transmission line. Experimental results are also given.关键词：Phaseshift of standing wave;Propagation constant;Slotted line2|92|0更新时间：2025-12-08
- 摘要：The electromagnetic characteristics associated with the creeping waves supported by a dielectric coated cylinder are investigated and a simple convenient and effective method-Perturbation-Iteration Method of calculating the propagation constants and the model impedance of creeping waves is presented. Finally ,formulae are given and some numerical examples presented.关键词：Propagation constant;Model impedance;perturbation-iteration method2|53|1更新时间：2025-12-08
- 摘要：In this paper,we base our analysis on the theory of the method of lines and use the Ohm’s Law in the Maxwell Eqations. We calculate the dispersion and the attenuation characteristics of the superconducting coplanar waveguide as the function of frequency and temperature. Comparison with the published data verifies the reliability of this paper.关键词：coplanar waveguide;The method of lines;Superconducting2|121|0更新时间：2025-12-08
- 摘要：The finite-difference time-domain（FDTD） method is used to analyze the tapered slot antennas in this paper ,here both special methods of modeling the thin dielectric sheets and of calculating the fields on narrow slot or near slot edge of the antennas are employed. By means of transformation from near zone to far zone the transient radiation fields are calculated. And a set of computed radiation patterns and transient pulse wave forms of the tapered slot antennas are presented ,they are in good agreement with the experimental results reported else-where. Transient pictures of both propagation on the antenna and radiation from the antenna are presented. And the effect of substrate thickness, geometry and dielectric constant on radiation properties and bandwidth of exponentially tapered slot antennas is studied also in this paper.关键词：Ultra-short pulse;Tapered slot antenna;finite-difference time-domain;transient electromagnetic field2|135|7更新时间：2025-12-08
- 摘要：A modified NILT method for time response analysis of transmission lines is presented by usage of the extended definition and initial value theorem about Laplace transform. The stepping algorithm and resetting of initial time in this method make it be more accurate and efficient than the traditional one.关键词：Transmission lines;Laplace transform;truncation error2|121|23更新时间：2025-12-08
- 摘要：The Volterra functional method is used for the electromagnetic inverse problems. A generally analytical procedure and symbolic code implemenation are succesfully constructed, which provides a new way for the inverse problems. The conductivity profiles,as an example ,is reconstructed by the method.The results show that only three terms of expansion have given an obvious improvement compared with the former approximations.关键词：Inverse problems;Volterra functional method2|20|0更新时间：2025-12-08
- 摘要：In this paper,a new method of solving frequency-domain harmonic balance equations about Newton iteration method is presented.关键词：nonlinear microwave circuit;Harmonic balance analysis2|264|7更新时间：2025-12-08
- 摘要：The electromagnetic scattering characteristics of a plane wave incident on an impedance cylinder embedded in a nonconcentric chiroferrite cylinder are investigated by using classical separation of variables technique and the addition theorem for cylindrical functions. Both TE and TM polarized wave incident normally on the cylinder are considered. Numerical results for various values of the parameters are discussed.关键词：electromagnetic scattering;Chiroferrite media;Radar cross-section2|34|4更新时间：2025-12-08
- 摘要：The paper studies the fundamental principle of the method of measuring equation of invariance（MEI）,and a variational explanation of MEI method is given. We also discuss various applications of MEI method with emphasis on the waveguide discontinuity problems.关键词：Measuring equation;Metron;waveguide discontinuity2|138|5更新时间：2025-12-08
- 摘要：In this paper,a multi-layer and a conventional high Tc superconducting transmission lines are firstly analyzed using the method of lines and two fluid model.The attenuation ,dispersion and characteristic impedance are calculated respectively.The results show better characteristics of superconductor compared with normal metal.The comparison with published data verifies the reliability of this method.关键词：The method of lines;High Tc superconductor;Two fluid model2|70|1更新时间：2025-12-08
- 摘要：A few promising composite transmission lines （microstrip + CPW,shielded microstrip +CPW and microstrip+asymmetric CPW）are proposed for the microwave packaging of the high speed optoelectronic devices in the paper. Using boundary element method, the characteristic impedance are calculated for the lines. Several sets of theoretical curves are given for the engineering design.The experimental results are discussed.关键词：Microwave packaging;transmission line;characteristic impedance;boundary element method2|182|2更新时间：2025-12-08
- 摘要：In this paper,an insulated , watercooled microwave dipole applicator radiating in a biological tissue ,is analyzed with a theoretical electromagnetic mode. The specific absorption rate （SAR）distribution is calculation is calculated taking into account the effect of the water flowing inside the applicator, and compaed with the SAR distribution of no-water-cooled radiating dipole. The result suggests that ,the SAR distribution will be improved on the extension of the therapy depth due to the effect of water-cooled, and it comforms to the engineering experiments and clinical reality.关键词：Radiating dipole;Hyperthermia;Specific absorption rate（SAR）2|57|14更新时间：2025-12-08
- 摘要：Exact impedance boundary condition on general impedance face is presented first in this paper ,then it is put into use on the faces of an impedance wedge.With the help of Maxwell’s equations, and considering two cases of perpendicularly incident plane waves and obliquely incident plance waves,the expressions of exact impedance boundary condition are deduced in the form of first order partial differential equations.关键词：Exact impedance boundary condition;impedance wedge;scattering2|79|0更新时间：2025-12-08
- 摘要：The signal flow graph is generalized for directed matrix systems in this paper.A generalized signal flow graph is proposed with topological rules. Some examples are given to illustrate its application to complex network systems.关键词：Directed matrix;Topological rule;Complex network system;Generalized signal flow graph2|40|0更新时间：2025-12-08
- 摘要：The reconstruction of scattering potential of one-dimensional Schrodinger equation is studied. A variational formulation is constructed from the famous Gel’fand-Levitan （G-L） equation to reconstruct the scattering potential. Besides its variational property ,this formulation has the advantage with which the complete information of the approximation solution of the G-L equation has been fully used. Therefore ,it may be used to improve the results of some approximation methods to solve the G-L equation. Some examples are given to illustrate the improvement by applying the formulation to the results of iteration method.关键词：inverse scattering;Scattering potential;G-L equation;Variational method2|40|1更新时间：2025-12-08
- 摘要：An analytical study of a cylindrical cavity loaded by an eccentric dielectric rod is proposed in this paper.The method is rigorous for arbitrary modes, material properties, and the relative dimensions of the structure.Mode charts are constructed by careful numerical evaluation.The dependence of resonances on material properties and the dimensions of the cavity is discussed.关键词：resonant cavity;Resonant mode;Delectric loaded2|33|0更新时间：2025-12-08
- 摘要：The process of calculating generalized Sommerfeld integrals using Prony’s method is detailed in this paper.The near-zone radiation field due to horizontal electric dipoles near a ground surface is also described.It is proved that the results of Prony’s method agree well with those of numerical integration method if approach path and adjustable parameters have been chosen validly,so that the optimized method can be given up.关键词：antennas;Sommerfeld integrals;Prony’s method;Horizontal electric dipoles2|165|15更新时间：2025-12-08
- 摘要：In this paper,calculation formulae of the correction factors of low level measurement on a specturm analyzer are derived using the envelope probability density function of a sinusoidal signal plus Gaussian noise.Correction curves of numerical value are given.The experiment results are reported to verify the correctness of theory calculation.关键词：频谱仪;正弦信号加高斯噪声;低电平测量;修正因子4|78|6更新时间：2025-12-08
- 摘要：A matrix perturbation theory for the matrix equation[A][u]=[b] is presented,and its application to the computation of internal fields inside a three-dimensional lossy biological body has been investigated.关键词：Matrix perturbation;moment method;Lossy biological body;Internal fields;Disease2|67|1更新时间：2025-12-08
- 摘要：For the urgent need of engineering realization,a new adaptive MTI filtering algorithm called"Power Estimation Algorithm’’is presented in this paper. This new adaptive algorithm has a simple structure and it is easier to realize than other algorithms. Based on this algorithm ,an optimum adaptive MTI system model is constructed. Computer simulation results show that properties of this system are almost same as the ideal system and the correctness and practicality of this algorithmhave been proved.关键词：Power estimation algorithm;Improvement factor;maximum likelihood;Cancellation ratio2|76|2更新时间：2025-12-08
- 摘要：用ＤＳＰ实现图象的直接捕获与显示国澄明，李铁盘（天津大学电子工程系，天津３０００７２）（河南教育学院，郑州４５０００３）ＤｉｒｅｃｔＶｉｄｅｏＡｃｑｕｉｓｉｔｉｏｎａｎｄＤｉｓｐｌａｙｉｎｇｂｙＤＳＰ￥／／大多数视频捕获系统都要有专门的控制电路，用来...2|78|5更新时间：2025-12-08
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