Dispersion and Maximum Time Step of 2D ADI and CN ID-FDTD

This paper reviews ADI ID-FDTD and CN ID-FDTD methods, the implicit FDTD methods based on isotropic dispersion finite difference (IDFD) scheme reported in [1] and [2]. The dispersion relations of each method are derived by solving the eigenvalue problem of iteration matrix in spatial spectral domain, and it is identified to induce the equal dispersion relations that presented in [1] and [2] through Fourier analysis. In addition, the maximum time steps of ADI ID-FDTD and CN ID-FDTD methods are mentioned.