A note on the stability of the FDTD implementation of the graphene conductivity modeled by a [2/2]-Pade function

Abstract

Recently, a [2/2]-Pade function has been used for implementing the graphene conductivity in the finite difference time domain (FDTD) algorithm. In this paper, it is shown that the employed temporal discretization methodology introduces additional stability restriction other than the conventional Courant-Friedrichs-Levey (CFL) constrain. To overcome this drawback, alternative FDTD implementation, based on the bilinear Z-transformation, is presented. The method is equally applicable to both the graphene interband and intraband conductivity terms. Numerical examples are included to verify these findings. (C) 2017 Elsevier GmbH. All rights reserved.