Spectral estimation for the transmission line matrix method

The transmission line matrix (TLM) method for microwave circuit analysis calculates the time-domain variation of the electromagnetic fields in response to an arbitrarily chosen excitation. Spectral estimation for the TLM method by use of the discrete fourier transform and fast Fourier transform is reviewed. Error bounds are given and checked by means of a numerical example. A spectral estimation method based on Prony's method for use with TLM is presented. A numerical example shows that the method allows an order of magnitude reduction in the number of iterations in the TLM method for equal accuracy     

The new method of time-domain analysis of a planar transmission line with discontinuity

In this paper, the new technique of time-domain analysis of discontinuities in a planar transmission line is presented. In the process of time-domain analysis, the analysis model of system and the concept of transfer function are employed and the frequency-domain method of lines and the technique of the fast Fourier transform are used. The results of time-domain data and frequency-domain characteristics for the shielded microstrip with step discontinuity are given and compared with the published results of other authors.     

Sensitivity analysis of a multiconductor transmission line

In this paper, the theory for the sensitivity analysis of a multiconductor line is described, and the sensitivities of the receivingend voltage and power with respect to the various line parameters have been evaluated.     

Microstrip transmission line analysis by the use of the least-squares collocation method

A simple method of analysis of microstrip transmission lines by the corner function method (eigenfunction approach) is presented. The inhomogeneous dielectric system of the microstrip is treated as a mixed boundary-value problem and is solved by the use of the least-squares collocation method. The results obtained by this method agree well with previous theoretical results and the method of analysis is much less laborious, simpler and faster.     

New method for analysis of electromagnetic coupling to an angled two-strip transmission line

The electromagnetic coupling to an angled two-strip transmission line is analysed to constructing an angled two-plate transmission line equivalent to the original geometry, and then solving the cylindrical transmission line equations of the original source analytically. The results agree with the numerical values of the circuit-concept approach.<>     

Boundary element analysis of a trapezoidal transmission line

A full-wave analysis is a transmission line with a trapezoidal cross-section is described. The boundary element method (BEM) is used, and by making a convenient choice for the dyadic Green's function, it is shown to be very efficient in comparison to alternative methods of analysis. It is shown that for electrically small dimensions, spurious solutions are suppressed by the selection of integral equations. The analysis is verified by comparisons to calculated results from a vector finite element computer program, and some dispersion data are presented     

Simple method for analysis of a class of switched-capacitor filters

A simple technique, applicable to most practical switched-capacitor filters (s.c.f.s) is used to model the s.c.f. by an analogue circuit containing only amplifiers, resistors and capacitors with real constant element values. Thus, the s.c.f. response and sensitivities can readily be found using available circuit analysis programs.     

基于矩阵束方法的传输线系统瞬态响应分析

带有频变负载的传输线系统的瞬态响应分析是电磁兼容领域的一个重要内容,特别是对于频变负载网络较为复杂或内部结构不清晰的情况,其瞬态响应的分析较为困难。本文首先在采样频率点处对频变负载端口导纳进行测量或计算得到相应的采样导纳,并采用有理函数逼近的方式对端口导纳进行等效;之后采用矩阵束(MPM)方法求解出有理逼近函数所需的极点和留数,并将其代入到分段线性递归卷积(PLRC)技术中,实现传输线和频变负载连接点处电压的分段线性递归卷积表达;最后,结合传输线方程实现带有频变负载的传输线系统的瞬态响应分析,并通过2个算例对所提方法的性能进行验证。结果表明,所提方法在计算精确度上具有明显的优势。     

一种“L-2L”传输线去嵌入方法的优化分析

介绍了一种基于硅基微波共面波导传输线的"L-2L"去嵌入技术的改进方法。该方法可更加精确地剥离在片器件S参数中探针焊盘寄生效应的影响。利用ADS软件对无焊盘的理想传输线结构进行了电磁仿真,确立了去嵌入结果精确度的判定标准。使用GSG微波探针提取了测试样品的S参数,推导了π型寄生参量等效电路模型中并联导纳Y不同位置(m=0,0.5,1)下左、右探针焊盘的ABCD矩阵,得到了去嵌入后在片器件的本征传输特性S参数,并结合电磁仿真对比。结果表明:m=1时,其S参数曲线与仿真结果最为接近(平均偏差量ΔS_(11)=18.431,ΔS_(21)=4.405,ΔS=11.418)。对于不同在片测试器件需要着重考虑m的取值。     

探究超高压输电线路继电保护的方法

智能电网迅猛发展带动了电力系统的高速发展。近年来,电力系统对超高压线路的需求量愈来愈大。超高压线路对电力环境、保护手段具有很高的要求。当前,我国超高压输电线路继电保护中存有很多不足之处,严重影响着电力系统的安全、稳定运行。如何加强超高压输电线路继电保护成为亟待解决的重要课题。文章结合相关文献资料,首先分析了超高压输电线路继电保护的特点及要求,而后在此基础上,从基于HHT的电力信号处理办法、电流差动保护、电流保护性能、基于人工神经网络的自适应电流保护四个方面对超高压输电线路继电保护的方法进行了探究,以期对确保我国电网正常运行有所帮助。     

Modal analysis of strip-loaded diffused optical waveguides by a variational method

The propagating modes supported by strip-loaded three-dimensional diffused optical waveguides are analyzed in detail theoretically by using a variational method. Some typical numerical examples of the propagation constants and the field distributions are illustrated. The dependence of propagation characteristics on the geometrical parameters of the loading dielectric strip is discussed.     

Electromagnetic propagation along a multiconductor transmission line in a tunnel--approximate analysis

A general approximate formalism is presented which enables one to calculate in a simple manner the electromagnetic propagation characteristics of a multiconductor transmission line in an underground tunnel. This approach circumvents the tedious task of locating the complex roots of the exact mode equation. The formalism is based on an approximate treatment of the single-wire case due to Wait.Lambda, Omega, andZ_{s}in Wait's single wire formula for the propagation constant are replaced with corresponding quadratic forms in the eigenmodal wire currents to generalize the formula to an arbitrary number of wires. The foundations of this approximate approach in standard perturbation theory are indicated, lending physical meaning to the approximations. A simple example involving a two-wire line is presented to establish the order of accuracy to be expected in using this formalism.     

三维输电线路构建方法的研究与应用

随着二维GIS系统在电力行业应用的不断深入,其在对空间位置及周边地形的描述上遇到了一定的局限性。电力系统对输电线路三维展示的需求变得急迫,而为了在三维场景中快速生成符合实际线路台账的输电线路,形成三维电网结构,在此提出一种半自动的三维输电线路构建算法。该算法包括了三维建模规则、坐标转换、线路生成等步骤,可以为当前三维场景中输电线路的架设提供技术参考,此算法模型可复用、开放性、自由度高,具有广泛的应用前景。     

高压输电线路架线施工安全管理方法研究

输电线路工程施工中,安全管理是重点工作内容,也是施工安全的基本保障.本文针对高压输电线路架线施工安全管理方法展开研究.     

Effective index method for generalised waveguide dispersion characteristics analysis of optical channel waveguides

An approximate analysis of the generalised waveguide dispersion characteristics (GWDC) of optical channel waveguides based on the effective index (EI) method is presented. As an illustration of its practical applications, the possibility of achieving temperature-independence in glass rib waveguides is studied and predicted for the first time which may have important applications for integrated-optic devices requiring temperature-stabilised operations.<>     

A density-independent method for high moisture content measurement using a microstrip transmission line.

This paper describes a method to measure high moisture content in materials from 190% to 350% on a dry weight basis. The method uses a microstrip transmission line, on which the material under test is overlaid. A parameter calculated from the attenuation and phase shift of the microwave signal is proposed to measure the moisture content. The experiments were performed on samples of sawdust, and the results show that the method is able to determine high moisture content independent of density. The standard error of calibration for the moisture content determination was 12.4% in the moisture content range from 190% to 350%.     

针对输电线路周边工程机械的防撞在线预警方法

输电线路传输距离长、通道环境复杂,大型施工机械造成的撞击事故时有发生。现有的输电线路防撞监测方案主要依靠人工实现,既耗费大量人力资源,也难以保证监测覆盖面。因此,针对性地提出了针对输电线路周边工程机械的防撞在线预警方法,该方法创新地利用智能传感器及压缩感知算法,可实现输电线路通道内的工程机械类威胁异物自动在线预警。利用摄像模块、微波测距模块采集目标的像素分布特征、形状特征以及距离特征,并传输到后台。后台服务器利用建立的离线特征目标数据库,通过压缩感知算法实现针对该目标的研判结果,对具有威胁的目标及时发出预警。结果表明,所提算法的识别精度可达96.34%,能够为输电运检部门提供可靠的预警结果。     

A new method for the analysis of integrated transmission lines

A flexible and efficient technique for the analysis of transmission lines is described. The transmission line is considered as the union of « elementary waveguides », where the medium is uniformly stratified. The modes are determined by matching the field at the interfaces using a procedure that leads to a linear eigenvalue problem involving a limited number of variables.     

Coupled transmission line analysis for harmonic generation in travelling-wave MESFETs

A coupled transmission line analysis for non-linear MESFETs is presented. It includes the important non-linearities of MESFETs such as input capacitance (C_gs), transconductance (g_m) and output drain conductance (G_gs). The non-linear differential equation for the drain and gate modes can be solved for a relatively weak coupling approximation using the weierstrassian elliptical function.     

Perfectly matched layer for transmission line modelling (TLM)method

The authors present a development of Berenger's perfectly matched layer (PML) for direct application to the transmission line modelling (TLM) method of electromagnetic simulation