Mixed surface impedance boundary condition for FDTD simulations

摘要

Surface impedance boundary condition (SIBC) is a potential way to improve the efficiency of the finite-difference time-domain (FDTD) method. However, it is still seldom used in FDTD simulations, especially for complicated problems. In this study, the authors propose a novel SIBC, the perfect electric conductor (PEC) backed SIBC (PEC-SIBC). It is a combination of SIBC and PEC. This character makes it possible to integrate PEC-SIBC with the conventional FDTD method. The authors derive the updating equations of PEC-SIBC for a one-dimensional (1D), 2D and 3D problems. Then, the authors verify the validity of PEC-SIBC with a 1D example and analyse the complexity with a 2D example. The comparison for a 1D configuration indicates that PEC-SIBC is a little more accurate than the traditional SIBC. For a 2D example, the SIBC is used to replace a lossy dielectric medium located in the middle of the problem domain. The complexity analysis indicates that PEC-SIBC is much easier and more practical to use than the traditional SIBC.