不等长非均匀有损耗传输线FDTD瞬态分析

以分析等长均匀无损耗多导体传输线的时域有限差分(FDTD)法为基础,在考虑传输线损耗的情况下,对不等长非均匀多导体传输线进行分析。首先,在考虑传输线损耗的情况下给出传输线上各点电压和电流的迭代计算公式;其次,利用该公式对不等长非均匀有损耗传输线模型进行数值计算和理论分析;最后,通过仿真实验,其结果表明所提计算方法是正确和有效的。该方法对不等长非均匀有损耗传输线的研究提供理论计算参考。     

基于FDTD的不等长有损耗传输线的瞬态分析

本文在考虑传输线损耗的情况下,对时域有限差分(FDTD)法应用于不等长有损耗传输线的情况进行了研究。首先,在考虑传输线损耗的情况下给出了传输线上各点电压和电流的迭代计算公式;其次,利用该公式对不等长有损耗传输线模型进行数值计算和理论分析;最后,通过仿真实验,其结果表明了所提计算方法是正确和有效的。该方法对不等长有损耗传输线的研究提供了理论计算参考。     

任意截面的非平行多导体传输线瞬态分析

以分析多导体传输线的时域有限差分(FDTD)法为基础,在考虑任意截面传输线分布参数无法直接计算的情况下,提出MOM-FDTD 混合方法对不平行多导体传输线进行瞬态分析。首先,利用FDTD建立多导体传输线时域差分模型,然后用MOM 法计算任意截面形状的非平行传输线的分布参数,并且与FDTD法混合进行瞬态分析计算。此算法相对于全波算法,在时间与存储空间消耗上具有很大的优势,并且满足精度要求。最后通过同轴传输线与矩形带状线的例子验证这个方法是正确有效的。     

多导体传输线高频分布参数分析

多导体传输线高频场线耦合研究是当前电磁兼容研究的重点和难点,而多导体传输线上的耦合响应与线上的高频分布参数紧密相关。由于经典传输线理论中采用准TEM波近似,使其不适用于求解高频分布参数。为此,从基于TLST理论的非均匀多导体传输线高频场耦合模型出发,对多导体传输线高频分布参数进行了研究和分析,计算出多导体传输线上的沿线单位长度高频分布参数,并将其与利用经典传输线理论计算得到的结果进行了比较,对二者的差异进行了分析,最后通过高频场线耦合算例说明了本文高频分布参数计算的正确性。     

用多极理论分析圆柱—正N边形内导体同轴传输线

本文提出用多极理论准解析计算方法分析圆柱－ 正Ｎ 形内导体同轴传输线,介绍了多极理论的准解析计算规则。实例计算结果表明：用多极理论准解析计算方法分析圆柱－ 正Ｎ 边形内导体同轴传输线,其计算精度是相当高的,多极理论准解析计算方法是一种较好的传输线分析方法,可以很方便地应用于传输线工程问题的设计与计算     

基于广义传输线方程的平行双导线电磁耦合分析

近地传输线系统的电磁耦合特性分析一直是通信电力系统电磁兼容分析中比较重要的一部分内容。主要对 双线传输线系统进行BLT 建模分析,在此模型中分析高度、半径参数对传输线上电流的影响,并且分析了传输线系 统在不同入射情况下的电流结果。计算结果物理意义明确,可供EMC 设计时参考。     

多导体传输线的邻近效应和分布参数研究

随着多导体传输线内各导体之间间距的减小, 导体之间的近邻效应对传输线的分布参数和传输特性的影响越来越大.为此, 我们针对三种典型的传输线结构, 分别建立了基于矢势有限元方法分析的多导体传输线的模型, 并分析了近邻效应对磁通密度和分布电感的影响.利用提出的方法计算了同轴传输线的单位长度分布电感, 并将它与采用解析方法得到的结果进行比较来证明该方法的正确性.计算双线传输线在不同间距时的单位长度电感, 与理论分析得到的结果相比较验证了导线间距越小, 近邻效应对单位长度电感的影响越大.最后, 计算考虑了近邻效应的耦合微带线的电感矩阵, 并将它与其他不考虑近邻效应的方法得到的结果相比较, 说明近邻效应对传输线电感矩阵的影响.     

外方内圆传输线特性阻抗的推导及应用

文章对外方内圆不平衡传输线特性阻抗的计算方法进行了分析和推导,同时介绍了外方内圆传输线的实际应用。     

用多极理论分析特种截面传输线

本文应用多极理论分析一类特殊结构的TIM传输线，给出用多极理论分析这类传输线问题的使用规则。实例计算结果表明，用多极理论分析这类特种截面的传输线问题，不仅具有较高的计算精度，而且可以很方便地应用于传输线工程问题的设计与计算。     

传输线网络瞬态响应灵敏度分析

在传输线网络瞬态响应灵敏度分析之中,提出了一种基于NILT的新的分析方法。该方法将传输线及其效应连同电子元器件及单元电路作为一个整体,根据传输线在电路中的拓扑关系,将传输线网络瞬态响应灵敏度分析问题转化为求解传输线网络瞬态响应问题,以及传输线ABCD矩阵对电路参数的偏导数问题。通过将ABCD矩阵进行级数展开,极大地简化了ABCD矩阵对电路参数偏导数的计算以及传输线网络瞬态响应灵敏度的分析。本文方法不需要对耦合传输线进行解耦,具有简单、精确、高效等特点,算例结果表明了本文方法的有效性。     

Transient field coupling and crosstalk in lossy lines witharbitrary loads

We extend the transient scattering analysis of a lossy multiconductor transmission line to the evaluation of the interference produced by a field illuminating the line. The external interference is described by suitable voltage wave sources that are readily computed in the time domain and do not affect the structure of the transient scattering equations. The proposed formulation fully exploits the advantages of the transient analysis based on the line matched scattering parameters, dealing effectively with low-loss lines and helping the understanding of the interference mechanism through the physical interpretation of the results. The simplicity and efficiency of our approach is evidenced by means of a numerical example of the external interferences on a realistic nonlinearly loaded highly mismatched 3-conductor interconnect     

Fast transient analysis of incident field coupling to multiconductor transmission lines

Due to the rapid surge in operating frequencies and complexity of modern electronic designs, accurate/fast electromagnetic compatibility/interference analysis is becoming mandatory. This paper presents a closed-form SPICE macromodel for fast transient analysis of lossy multiconductor transmission lines in the presence of incident electromagnetic fields. In the proposed algorithm, the equivalent sources due to incident field coupling have been formulated so as to take an advantage of the recently developed delay extraction based passive transmission line macromodels. Also, a method to incorporate frequency-dependent per-unit-length parameters is presented. The time-domain macromodel is in the form of ordinary differential equations and can be easily included in SPICE like simulators for transient analysis. The proposed algorithm while guaranteeing the stability of the simulation by employing passive transmission line macromodel, provides significant speed-up for the incident field coupling analysis of multiconductor transmission line networks, especially with large delay and low losses.     

低压电力线载波通信结合滤波器设计

低压电力线作为载波通信信道时,其通信特性并不理想,各种负载、用电设备及外界都将引起大量的噪声,给电力线载波通信带来了严重的干扰问题,从而影响电力线通信系统的性能。为了保证载波通信信号和数据的有效传输,通过电路分析并设计一种低压电力线载波通信结合滤波器,经仿真与实验该滤波器能有效过滤低压电力线载波通信信道中的各种干扰信号,从而达到了保证载波通信信号和数据的有效传输的作用。     

HFC网络噪声干扰的分析

对HFC传输网络中的电磁波噪声干扰，设备本身产生的噪声，HFC网络上行通道噪声，传输线路上从外界入侵的噪声以及终端用户噪声干扰所产生的原因进行分析。     

Influence of microwave scattering by power transmission lines ondigital radio communications

A method for evaluating power transmission line interference with microwave radio communication circuits due to microwave scattering is presented and used to predict digital radio transmission performance degradation. Numerical results show that the effects of power line screening on highly efficient digital radio systems are more serious than on analog (FM) radio systems since power lines cause quadrature distortion and intersymbol interference as well as average level reduction. An experimental result using a communication satellite beacon shows that conductors within the first Fresnel zone cause the interference     

多回高压输电线路产生的无线电干扰分析

在规划设计，中关村软件园东侧将建设包括4回220kV四分裂导线，6回110kV单导线构成的10回高压输电线路，为了评估该高压线路走廊对软件园的电磁环境影响。在简述高压输电线路由于电晕产生的无线电干扰的基础上，分析单回220kV四分裂导线。220kV不采用分裂导线两种情况下的无线电干扰水平，由此估计该10回输电线路产生的无线电干扰水平，结果表明，该高压线路走廊产生的无线电干扰水平符合国家标准GB15707-1995《高压交流架空送电线无线电干扰限值》相应的要求。     

传输线的反射干扰

在数字信号处理系统中,时钟信号和数字信号传输因传输始端和终端阻抗不匹配而引起反射干扰,使传输信号的波形出现上冲、下降和振荡。为了抑制这种因阻抗不匹配引起的反射,本文首先从产生这种反射的原因和造成的重大危害分析,提出了反射干扰这一亟待解决的问题;接着从传输线的阻抗特性以及阻抗匹配原理出发,提出了始端和终端阻抗匹配原则,最后给出了几种减小和抑制反射干扰的方法,实践证明使用阻抗匹配这一方法在减小反射干扰是十分有效的。     

Modal dispersion compensation by using digital coherent receiver with adaptive equalization in multi-mode fiber transmission

Modal dispersion compensation is demonstrated by using electrical adaptive equalization for a multi-mode fiber (MMF) transmission with multipath interference resulting from mode conversion caused by axial deviations in the transmission line. We reveal that we can realize a 20 km 50 μm-core GI-MMF transmission even if mode conversions are intentionally introduced by two 5 μm axial deviations in the transmission line.     

Stretchable Twisted‐Pair Transmission Lines for Microwave Frequency Wearable Electronics

Stretchable electrical interconnects based on serpentines combined with elastic materials are utilized in various classes of wearable electronics. However, such interconnects are primarily for direct current or low‐frequency signals and incompatible with microwave electronics that enable wireless communication. In this paper, design and fabrication procedures are described for stretchable transmission line capable of delivering microwave signals. The stretchable transmission line has twisted‐pair design integrated into thin‐film serpentine microstructure to minimize electromagnetic interference, such that the line's performance is minimally affected by the environment in close proximity, allowing its use in thin‐film bioelectronics, such as the epidermal electronic system. Detailed analysis, simulations, and experimental results show that the stretchable transmission line has negligible changes in performance when stretched and is operable on skin through suppressed radiated emission achieved with the twisted‐pair geometry. Furthermore, stretchable microwave low‐pass filter and band‐stop filter are demonstrated using the twisted‐pair structure to show the feasibility of the transmission lines as stretchable passive components. These concepts form the basic elements used in the design of stretchable microwave components, circuits, and subsystems performing important radio frequency functionalities, which can apply to many types of stretchable bioelectronics for radio transmitters and receivers.     

基于热成像摄像机的输电导线微风振动监测技术

导线微风振动的存在严重威胁着输电线路的正常运行。鉴于此,输电导线微风振动监测系统的监测设备应具备抗磁能力强、精确度高、安装简易的特点。设计了一种基于热成像摄像机和图像处理技术的输电导线微风振动在线监测方案,详细阐述了该方案在硬件和软件部分的实现方法。此设计可以在线实时、准确地测量导线的动弯应变大小,并且具备抗电磁干扰的能力,有效保证了输电导线微风振动的监测需求。