Time Domain Hybrid Method for the Coupling Analysis of Oblique Transmission Line Network Excited by Ambient Wave

Efficient numerical methods which analyse the coupling within an oblique transmission line network (OTLN) excited by electromagnetic wave are still rare in the literature. A novel time domain hybrid method is proposed in this article, in which finite-difference time-domain (FDTD) method, transmission line (TL) equations, Norton's theorem, and interpolation techniques are organically combined. In this method, the terminal loads and connection nodes of OTLN are first shifted to the center lines of FDTD grids, where the loads and nodes are located. Then the OTLN is divided into several independent oblique transmission lines according to the connecting nodes. Finally, the FDTD method combined with TL equations and interpolation techniques is applied to compute the transient responses on each oblique transmission line, and the Norton's theorem is utilized to build the equivalent circuit models of connecting nodes to realize the transmissions of interference signals on these oblique transmission lines. Numerical simulations of OTLN on the perfect conductor (PEC) ground and in a shielded cavity excited by ambient wave are employed to exhibit the accuracy and efficiency of the proposed method. Because the structure of OTLN does not need to be meshed, the proposed method outperforms the conventional FDTD method in both memory usage and computation time.