Numerical Dispersion Characteristics of the Three-dimensional Precise Integration Time-Domain Method

This paper presents a comprehensive analysis of numerical dispersion of a recently developed unconditionally stable three-dimensional time-domain algorithm called the precise integration time-domain (PITD) method. The dispersion relation is derived analytically and the effects of spatial and time steps on the numerical dispersion are investigated. It is found the PITD scheme has advantages over the conventional Yee´s FDTD method in using a large time step and over the ADI-FDTD method in having high computational accuracy. Numerical dispersion errors of the PITD method can be made nearly independent of the time-step size.