Unified Frequency-Dependent Split-Step FDTD Formulations Based on the Complex-Conjugate Pole-Residue Pairs Model

Unified and efficient frequency-dependent split-step finite difference time domain (SS-FDTD) formulations are presented. In the proposed formulations, the complex-conjugate pole-residue (CCPR) pairs model is adopted in the FDTD implementation of the domain's frequency-dependent relation with the minimal additional auxiliary variables. In addition, the formulations allow modeling different dispersive materials, such as Debye, Drude, and Lorentz, in the same manner. A numerical example is included to show the validity of the formulations.