Conformal FDTD Modeling of Imperfect Conductors at Millimeter Wave Bands

The Dey-Mittra conformal finite difference time domain (CFDTD) algorithm for perfect electrical conductors is modified for the analysis of finite conductivity conductors at millimeter wave frequencies. Formulas are derived for CFDTD coefficients using voltage state variables and a constant surface impedance boundary condition (SIBC). The approach permits a fast implementation suitable for CUDA type GPU hardware. Accuracy and stability are investigated with respect to the stability constraints on intersection areas introduced by Dey-Mittra and Benkler as well as the distance stability constraints of Zagorodnov that permits 100% Courant temporal sampling. A relaxation of the Zagorodnov distance constraints permits increased accuracy with respect to all alternative area constraints. Analytic solutions are used to judge the performance of the proposed CFDTD modifications for millimeter wave band applications.