Perfectly Matched Layer Formulation of the INBC-FDTD Algorithm for Electromagnetic Analysis of Thin Film Materials

The impedance network boundary condition (INBC)-based finite-difference time-domain (FDTD) method has been widely used for electromagnetic analysis of highly conductive thin film materials. In the INBC-FDTD formulation, the electromagnetic field variations inside the thin film material are taken into account mathematically and thus extremely small FDTD grids are not necessary for the FDTD modeling of the material. Therefore, computational efficiency of the INBC-FDTD formulation is significantly better than other FDTD formulations. Albeit with this great advantage, the INBC-FDTD formulation cannot be fully employed for thin film materials because the corresponding perfectly matched layer (PML) formulation has not been reported in literature. In this work, we propose a PML formulation suitable for the INBC-FDTD algorithm. Numerical examples illustrate that the proposed PML-INBC-FDTD formulation can yield good absorption performance and also it can improve computational efficiency while maintaining numerical accuracy.