FDTD Formulation Based on High-Order Surface Impedance Boundary Conditions for Frequency-Dependent Lossy Multi-Conductor Transmission Lines

A finite-difference time-domain (FDTD) formulation for a uniform frequency-dependent lossy multi-conductor transmission line (MTL) is presented. It is based on a distributed parameter MTL model using partial resistances and partial inductances. In order to consider both skin and proximity effects, the partial internal impedances are computed with a boundary element method (BEM) formulation, enforcing a high-order surface impedance boundary condition (SIBC). The proposed FDTD formulation is numerically validated with two test cases.