General ADE formulations of SC-PM for modelling multi-term dispersive FDTD applications

General and efficient auxiliary differential equation (ADE) formulations of the stretched-coordinate perfectly matched layer (SC-PML) absorbing boundary conditions are presented for truncating open region multi-term dispersive finite-difference time-domain (FDTD) applications. In the proposed formulations, appropriate digital-filtering techniques are used for efficient implementations of the constitutive relations of the dispersive materials in the discrete-time domain. The validity of the new formulations has been demonstrated by computing wave propagation in a two-term Lorentz dispersive domain.