An improved two-dimensional (2,4) finite-difference time-domain method for Lorentz dispersive media

The credible solution of discretized Maxwell's equations in spaces occupied by Lorentz dispersive media is the main subject of this work. Specifically, we introduce a finite-difference time-domain (FDTD) algorithm with a typical (2,4) structure that features dispersion-relation-preserving characteristics and produces reduced numerical errors in two-dimensional electromagnetic simulations, compared to the standard approach with similar computational requirements. We consider the case of dispersive media with non-vanishing absorption coefficients and investigate different options for the suitable modification of the spatial approximations, so that the accomplished accuracy is optimized for a given computational overhead. The properties of the proposed FDTD technique are thoroughly examined, both theoretically and in numerical tests, and the performance upgrade compared with the conventional solution is assessed.