How a new mesh algorithm improves 3D dispersive material modeling

Abstract

A dispersive volume-average polarized effective permittivity (D-VP-EP) algorithm is introduced for the analysis of arbitrarily shaped three-dimensional dispersive materials, utilizing the complex-conjugate pole-residue (CCPR) model within the finite-difference time-domain (FDTD) method. The D-VP-EP employs the fitting algorithm as the preprocessor in the frequency domain, followed by an interpolation algorithm in the spatial domain, to avoid conformal-induced changes in the form of the constitutive equations during subsequent conformal mesh generation. The D-VP-EP algorithm maintains the iterative formulation of conventional CCPR-FDTD while enabling conformal meshing between 2 dispersive materials with an arbitrary number of poles. In scattering simulations of metal-dielectric dispersive bilayer nanosphere and transmission spectrum simulations of a dispersive micro-ring, the D-VP-EP effectively reduces mesh mismatch errors at curved interfaces when compared to volume-averaged or staircase, and only needs 1/16 of the computing resources of the comparison group to achieve the same accuracy.