不等长多导体传输线模型串扰问题分析

不等长多导体模型为电力电子系统中传输线的一种常见结构,其串扰问题关系到整个系统的正常运行。采用时域有限差分格式对传输线方程进行差分离散,并结合基尔霍夫定律,对不同多导体系统连接位置进行处理,推导出多导体传输线上电压电流迭代公式,实现了整个模型上全部电压电流的同步求解,并通过算例验证了该方法在分析电大尺寸传输线电磁干扰问题时的有效性。     

基于传输线方程的多根非平行传输线串扰分析

非平行结构的传输线在电力电子系统中普遍存在,当其上通有电压和电流信号时,会在周围传输线上产生串扰响应。采用时域传输线方程建立多根非平行传输线之间的串扰模型,结合FDTD方法,分析在脉冲集总源激励下受扰导线始端和终端负载上的串扰电压响应特性,将其结果与仿真结果对比,验证了该方法的正确性。研究结果表明,非平行结构中受扰线始端和终端负载上的串扰电压响应随着传输线离地面高度的增大而增大,随着传输线之间夹角的增大而变小,且减小的趋势逐渐减弱,从而为线缆间的串扰防护提供了参考依据。     

屏蔽腔体中多导体传输线串扰抑制的仿真研究

屏蔽腔体中的传输线串扰是典型的电磁干扰问题,消除或减少串扰是非常必要的。在此建立了腔体内多导体传输线的串扰模型,采用电磁仿真软件研究抑制传输线间串扰的方法,分析受扰线终端接有滤波器前后的串扰电压时频响应特性。仿真结果表明,传输线终端接上相应频带的滤波器,可以滤除传输线上除工作信号以外的干扰信号,为电子系统线缆电磁防护设计提供参考依据。     

对垂直交叉线中串扰的分析

用修正后的传输线方程对垂直的导体间的串扰进行了频域模拟，通过反傅立叶变换得到时域信号。模拟表明，虽然垂直放置可使串扰幅度大幅度降低，但交叉线中仍有较强的干扰，串扰幅度与各端接入的负载有很大关系，对干扰的原因进行分析。为了证明结果的正确性，对平行导体间的串扰用时域有限差分法和本方法进行模拟，得到一致的结果。该文对实际应用有参考价值。     

城际列车线缆串扰分析

用矩量法求解多导体传输线的分布参数,采用多导体传输线理论,建立了串扰模型,并用CST电缆工作室对线缆建模,验证了传输线模型的正确性,并利用所构建模型分析了城际列车上电源线NHWL1-3.5与信号线NH-WL1-1.25的线缆间距、线缆长度以及线缆端接负载对串扰的影响。     

降低电缆内导线间串扰电压的优化方法

本文根据分布参数传输线理论导出了电缆内平行多导线间串扰电压的传递函数矩阵表达式；构造了导线间串扰电压最小的优化目标函数；利用可变多面体算法进行了优化设计；根据计算结果提出了降低串扰电压的新方法。计算结果与已有的实验结果吻合。     

电缆束中编织屏蔽线的抗干扰分析

本文在直导线的串扰分析的基础上，运用多导体传输线模型，对编织屏蔽线的串扰问题进行了深入研究，建立了屏蔽线的抗干扰预测模型，并设计了敏感线被屏蔽情况的串音干扰电压，计算结果表明编织屏蔽线对电磁耦合干扰控制是很有效的。     

基于FFT的传输线串扰时域响应分析与实验研究

基于传输线分布参数结点导纳方程和快速傅立叶反变换方法,仿真分析了传输线串扰电压响应及传输线参数和端接阻抗对串扰电压峰值的影响.发现在不考虑传输线终端负载电阻的电感影响时,仿真结果中振荡不明显,在考虑电感时仿真结果振荡较明显.基于实验室研究设备,对共地平行传输线间的串扰电压和电流进行了实验研究,并将部分实验结果与理论仿真结果进行了比较.结果显示:在考虑传输线终端负载电感时的仿真波形与幅度和测量结果的波形与幅度基本一致,仿真的脉冲宽度要大于测量脉冲宽度,仿真结果峰值略大于测量峰值.     

机载线缆间的串扰耦合分析

串扰是机载设备间互联线缆干扰耦合的重要因素。以混合模S参数为基础,建立单线-双绞线模型以模拟机载设备之间的动力线缆对信号线产生的串扰耦合。在此模型基础上提出串扰耦合测试方案,搭建串扰耦合测试系统,并根据测试获得的耦合系数评估单线-双绞线线间串扰耦合强弱。通过测试比较,对影响因素进行分析,结果表明,距地高度对线间串扰影响不大,线间距对线间串扰耦合影响显著,因此在条件允许下尽可能增加设备间互联线缆的间距可有效抑制串扰耦合。     

降低电缆内导线间串扰电压的优化方法

本文根据分布参数传输线理论导出了电缆内平行多导线间串扰电压的传递函数矩阵表达式;构造了导线同串扰电压最小的优化目标函数;利用可变多面体算法进行了优化设计;根据计算结果提出了降低申扰电压的新方法。计算结果与已有的实验结果吻合。     

Time-domain modeling of electromagnetic field coupling to finite-length wires embedded in a dielectric half-space

The transient behavior of a single straight line embedded in a dielectric half-space and illuminated by the electromagnetic pulse (EMP) is analyzed directly in the time domain using the wire antenna approach. The formulation is based on the corresponding space-time Hallen integral equation. The effects of a two-media configuration are taken into account via the Fresnel reflection and transmission coefficient, respectively. The space-time Hallen integral equation is handled by the time-domain version of the indirect Galerkin-Bubnov boundary element method. The transient response obtained using the direct time-domain approach is compared with the results obtained via an indirect frequency-domain analysis method. Some illustrative numerical results are presented in the paper. Numerical results obtained via the different approaches agree satisfactorily, i.e., the maximum deviation between the results is around 6%.     

A stable solution of time domain electric field Integral equation for thin-wire antennas using the Laguerre polynomials

In this paper, a numerical method to obtain an unconditionally stable solution of the time domain electric field integral equation for arbitrary conducting thin wires is presented. The time-domain electric field integral equation (TD-EFIE) technique has been employed to analyze electromagnetic scattering and radiation problems from thin wire structures. However, the most popular method to solve the TD-EFIE is typically the marching-on in time (MOT) method, which sometimes may suffer from its late-time instability. Instead, we solve the time-domain integral equation by expressing the transient behaviors in terms of weighted Laguerre polynomials. By using these orthonormal basis functions for the temporal variation, the time derivatives can be handled analytically and stable results can be obtained even for late-time. Furthermore, the excitation source in most scattering and radiation analysis of electromagnetic systems is typically done using a Gaussian shaped pulse. In this paper, both a Gaussian pulse and other waveshapes like a rectangular pulse or a ramp like function have been used as excitations for the scattering and radiation of thin-wire antennas with and without junctions. The time-domain results are compared with the inverse discrete Fourier transform (IDFT) of a frequency domain analysis.     

带负载导线的电磁脉冲响应数值方法研究

现有的细导线算法[1,2,3]只能处理导线两端开路情形,在其基础上提出了一种修正的方法,该方法可以用来计算细导线两端带有负载时电磁脉冲对导线的响应,负载包括电容和电感.在该方法中,导线被分成理想导线、负载和地三个部分,分别用不同的偏微分方程描述,并得到可直接进行计算的差分方程.使用该方法给出了一计算实例,并对计算的结果进行了分析.     

Transient response of nonlinearly loaded wires in a two media configuration

The transient behavior of thin wires with nonlinear resistive load in the presence of a dielectric half-space is analyzed directly in the time domain. The nonlinear wire problem is formulated by the space-time Hallen integral equation. The effect of a two-media configuration is taken into account via the space-time reflection coefficient appearing within the Green function. The resulting integral equation is handled by the space-time boundary integral equation method. The transient response for the case of a thin wire isolated in free space computed by this direct time-domain approach is compared with results obtained by another method solved using data derived from frequency-domain analysis. Results for various other configurations are also presented.     

The treatment of thin wires in the FDTD method using a weighted residuals approach

In this contribution, the problem of accurately representing thin wires within the finite-difference time-domain (FDTD) mesh is addressed by means of a method based on the weighted residual (WR) interpretation of the FDTD algorithm. Results for wire dipoles and wire transmission lines, obtained using the proposed method, are presented and compared to those obtained using existing techniques. It is shown that the proposed method yields results which are more accurate and are less dependent on the choice of cell size than other approaches and, in addition, lends itself well to being extended for more complicated structures. Details of the calculation of the update equations are given.     

Modeling and characterization of the bonding-wire interconnection

In this paper, the bonding-wire interconnection has been studied from the points of view of its modeling and electrical characterization. Both singleand double-wire structures have been considered, the latter under the assumption of parallel wires. Two electrical models of the bonding wire are discussed. First, the finite-difference time-domain (FDTD) method is proposed for the rigorous analysis of such structures. This method uses a suitable discretization technique, which accounts for the wire curvature by means of a polygonal approximation. A quasi-static model of the bonding wire, suitable for commercial microwave computer-aided-design tools is then proposed. This model is based on the representation of the structure with four sections of a uniform transmission line and the model parameters are evaluated analytically from the dimensions of the interconnection. Accuracy and applicability of the quasi-static model have been assessed by analyzing several test structures, the reference results being obtained with the FDTD method. Finally, the quasi-static model has been used to provide an extensive electrical characterization of the bonding wire versus its main geometrical parameters. This characterization is given in terms of an equivalent series inductance and two equivalent shunt capacitances forming a π low-pass network. This representation is particularly useful in the matching of the bonding-wire discontinuity     

Detection and Location of Multiple Wiring Faults via Time–Frequency-Domain Reflectometry

In this paper, we propose a high-resolution time–frequency-domain reflectometry technique as a methodology of detection and estimation of faults on a wire. This method adopts the time–frequency cross-correlation characteristics of the observed signal in both the time and frequency domains simultaneously. The accuracy of the proposed method is verified with experiments using a radio-guide-type coaxial cable and comparing it with traditional time-domain as well as frequency-domain reflectometry methods. It is clearly shown here that the proposed algorithm produces excellent results compared to the conventional methods for single as well as multiple fault cables.      

Folded loop antenna for mobile hand-held units

The vertical folded loop antenna, modeled as wire and printed radiating element mounted on a conducting box, simulating a cellular telephone with and without dielectric coating, is analyzed. The finite-difference time-domain (FDTD) method is used to calculate radiation patterns and input impedance. The results are compared with measurements and with NEC data. Very good agreement is obtained in all cases. Parasitic loading is used to enhance the bandwidth of the printed element. The antenna meets the design requirements for existing and future mobile communication systems     

Time-domain analysis of lossy active transmission lines using FDTD method

In this paper, an accurate and efficient method for analysis of a GaAs MESFET including frequency-dependent losses of the electrodes in the time domain is presented. The time domain analysis is obtained based on the fully distributed model using finite-difference time-domain (FDTD) technique, with the assumption of the skin effect losses. The time-domain results are verified using the conventional time-domain to frequency-domain (TDFD) solution technique.     

Transmission link radiation and localized defect contribution

A complete electrical wire link between equipment boxes is analyzed using a theoretical method based on the finite-difference time-domain (FDTD) algorithm. This paper describes how the asymmetry of the transmission line created by different terminations has a direct impact on the radiation level. Thereafter, a transient experimental method is proposed to evaluate the behavior of localized defects on transmission links. The transient results lead to (S) parameters and radiation power. Simulations using the FDTD method validate the experimentation