Fast Anisotropic Metasurface Analysis in FDTD using Surface Susceptibility Model

The FDTD methods combined with Surface Susceptibility Model (FDTD-SSM), compared to traditional brute force metasurface simulation, have been proved efficient and accurate for fast metasurface analysis. However, the present work is limited to scattering elements that are either isotropic or that have diagonal surface susceptibilities. This paper proposes a necessary extensions of Finite Difference Time Domain equations to analyze general anisotropic metasurfaces which have off-diagonal surface susceptibility tensors. At last, the Surface Susceptibility Model simulation results are validated by geometrical structure simulation results.