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

Sangeun Jang,Kyung-Young Jung

doi:10.1109/access.2021.3107528

Abstract

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.

Highlights

T HE finite-difference time-domain (FDTD) method has been popularly employed for a variety of research areas including dispersion-engineered metamaterials, plasma, photonics, and biomedical applications [1]–[7]
We propose the perfectly matched layer (PML) formulation suitable for the impedance network boundary condition (INBC)-FDTD algorithm in order to fully employ the INBC-FDTD algorithm for electromagnetic analysis of thin film materials
The proposed PML-INBC-FDTD result is in good agreement with the FDTD result while the conventional INBC-FDTD result is inconsistent with the FDTD result

Summary

INTRODUCTION

T HE finite-difference time-domain (FDTD) method has been popularly employed for a variety of research areas including dispersion-engineered metamaterials, plasma, photonics, and biomedical applications [1]–[7]. In the standard FDTD method, very refined spatial grids are usually used, which leads to overwhelming computational resources [17]. To tackle this problem, the impedance network boundary condition (INBC)FDTD formulation was presented [18]. The INBC-FDTD formulation was successfully used to analyze shielding effectiveness of highly conductive thin film materials [19]–[21]. S. Jang et al.: PML-INBC-FDTD for Electromagnetic Analysis of Thin Film Materials in complex media without spurious reflections [22]–[24]. We propose a PML formulation suitable for the INBC-FDTD algorithm. Numerical examples are employed to illustrate that the proposed PML-INBC-FDTD formulation can effectively absorb electromagnetic waves.

PML-INBC-FDTD FORMULATION

CONCLUSION