A Hybrid Method for Electromagnetic Coupling Problems of Transmission Lines in Cavity Based on FDTD Method and Transmission Line Equation

A time domain hybrid method is presented for efficiently solving the electromagnetic coupling problems of transmission lines in cavity. The proposed method is based on the finite-difference time-domain (FDTD) method and transmission line (TL) equations (FDTD-TL), which can achieve a strong synergism on the computations of field and circuit. The FDTD method with an auto mesh generation technique is employed to obtain the electric fields of transmission lines excited by an incident wave from the outside of the cavity. The electric fields are introduced into the TL equations as additional voltage sources at each time step of FDTD method. The current and voltage responses of terminal loads can be obtained by the TL equations. Two examples are presented to demonstrate the correctness of this method. The high efficiency of this hybrid method is verified by comparing the computation time with the traditional method.