Time Domain Hybrid Method for the Coupling Analysis of Transmission Line with Junctions

Numerical methods prosed for the coupling effects analysis on transmission line (TL) with junction structure, which are excited by ambient wave, are still rare in the published literature. By combining the finite difference time domain (FDTD) method with TL equations and charge conservation law, a hybrid method with high-efficiency in the time domain is proposed in this work. Within this method, we first decompose the whole structure of TL into two groups, i.e. several independent TL segments and some junction structures. For the TL segments, the TL equations and FDTD method is jointly employed to build the coupling models of each TL segment and obtain the corresponding transient responses. Based on this, the voltages at the junctions are solved by the charge conservation law and FDTD method jointly. By numerical simulation of the case where a transmission line with two junctions on a perfect electrical conductor (PEC) ground is excited by ambient wave, the accuracy of the proposed method is verified by comparing its results with the one obtained by applying commercial simulation software CST.