2018 Volume 15 Issue 3 Pages 20171261
The equivalent circuit of multi-conductor transmission lines above lossy ground will be more complex compared with one single transmission line above lossy ground, and many problems of matrices need to be solved. In this paper, for multi-conductor transmission lines above lossy ground, the frequency-domain sections of ground impedance matrix and exciting voltage matrix are approximated as the rational function form by the vector fitting (VF) method. So the time domain results can be obtained conveniently by the Laplace element in HSPICE. The DEPACT macro-models and equivalent sources of external electromagnetic fields are built based on voltage controlled current source and voltage controlled voltage source. Then, combined with these equivalent circuits, the equivalent circuits for multi-conductor transmission lines above lossy ground excited by external electromagnetic fields are presented. The simulation results are compared with the finite difference time domain (FDTD) method and good agreement is obtained. Using this approach, the transient responses for multi-conductor transmission lines above lossy ground with nonlinear or frequency-dependent terminations excited by external electromagnetic fields could be obtained quickly and accurately.