Research on experiments and the FDTD method of multi-conductor transmission lines for transient analysis

In order to research the transient electromagnetic process of some parallel wire structures, the multi-conductor lines (MTL) can be modeled and the finite difference-time domain (FDTD) method can be used. In this paper, an experimental method to determine the per-unit-length parameters by measuring the input impedance for the short- and open-circuit cases is introduced by using an impedance analyzer. For the convenience to treat with the frequency-dependent parameters, the vector fitting method is adopted in FDTD method. Based on a recursive algorithm for time-domain convolution, the corresponding voltage and current recursion formulations in the FDTD method are presented. Some examples are given. By comparing the calculated results with the results of measurement and EMTP, the FDTD method proposed is very efficient. The proposed method can be extended to signal integrity analysis.