A general finite difference time domain method for hybrid dispersive media model

The shift operator finite difference time domain (SO-FDTD) method is developed to deal with hybrid dispersive media model. First, we have proved that the complex permittivity of hybrid dispersive media model may be described by rational polynomial fraction in j_ω. Then, by introducing z_t defined as a shift operator, the relation between D and E is derived in time domain. The constitutive relation in discretized time domain and the recursive formulation for D and E available for FDTD computation are obtained. Finally, the reflection of an first order Debye and first order Lorentz hybrid dispersive slab is computed. The computed results are in good agreement with the one obtained by analytic method.