A unified FDTD approach for electromagnetic analysis of dispersive objects

Abstract—In order to obtain a unified approach for the Finite-Difference Time-Domain (FDTD) analysis of dispersive media described by a variety of models, the coordinate stretched Maxwell’s curl equation in time domain is firstly deduced. Then the FDTD update formulas combined with the semi-analytical recursive convolution (SARC) in Digital Signal Process (DSP) technique for general dispersive media are obtained. In this method, the flexibility of FDTD in dealing with complicated object is retained; the advantages of absolute stability, high accuracy, less storage and high effectiveness of SARC in treating the linear system problem are introduced, and a more unified update formulation for a variety of dispersion media model including Convolution Perfectly Matched Layers (CPML) absorbing boundary is possessed. Therefore it can be applied to analysis of general dispersive media provided that the poles and corresponding residues in dispersive medium model of interest are given. Finally, three typical kinds of dispersive model, i.e., Debye, Drude and Lorentz medium are tested to demonstrate the feasibility of presented approach. 1