Absorbing-boundary conditions using perfectly matched-layer (PML) technique for three-dimensional TLM simulations

This paper describes the algorithm that interfaces the three-dimensional (3-D) transmission-line matrix (TLM) with an absorbing-boundary condition (ABC) based on the perfectly matched-layer (PML) approach. The algorithm uses a coupling between the TLM symmetrical condensed node (SCN) network and a finite-difference approximation of the PML equations. Examples are presented in scattering problems and S-parameter characterization of discontinuities. Excellent results are found even with absorbing walls located in the region of evanescent waves. Absorption performances obtained are significantly superior to ABC´s based on the one-way equation approach and currently used for TLM simulations. Finally, it is found that for all tested situations, the algorithm is numerically stable