Scaling Factors of ID-FDTD Scheme for Dispersive Media Based on the Auxiliary Differential Equation (ADE) Method

The isotropic-dispersion finite-difference time domain (ID-FDTD) scheme is modified for a dispersive medium. The proposed ID-FDTD scheme is based on the ADE method. In this correspondence, three typical dispersive media are considered: Debye, Drude, and Lorentz media, for which scaling factors are formulated. The dispersion property is then examined, and the accuracy of the proposed scheme is verified by consideration of two scattering problems.