Investigation on the characteristics of the envelope FDTD based on the alternating direction implicit scheme

This letter presents numerical characteristics of recently developed the envelope FDTD based on the alternating direction implicit scheme (envelope ADI-FDTD). Through numerical simulations, it is shown that the envelope ADI-FDTD is unconditionally stable and we can get better dispersion accuracy than the traditional ADI-FDTD by analyzing the envelope of the signal. This fact gives the opportunity to extend the temporal step size to the Nyquist limit in certain cases. Numerical results show that the envelope ADI-FDTD can be used as an efficient electromagnetic analysis tool especially in the single frequency or band limited systems.