Analysis of the numerical dispersion of the 2-D ADI-FDTD method with higher order scheme

The alternating direction implicit (ADI) FDTD method is an unconditionally stable method. The maximum time-step size is not limited by the Courant-Friedrich-Levy (CFL) condition. However, the numerical error such as numerical dispersion increases, when the ADI method is applied. It was proven that higher order scheme could reduce the numerical dispersion error in the conventional FDTD method. In this paper, we investigate the numerical dispersion property of the ADI-FDTD method with higher order scheme. It is found that the numerical dispersion error of the ADI-FDTD method with higher order scheme is smaller than the original ADI-FDTD method.