FDTD discretization of Maxwell's equations on a face-centered-cubic grid

Maxwell's equations are discretized on a Face-Centered-Cubic (FCC) lattice instead of simple cubic to improve grid isotropy of the numerical simulation. Explicit update equations and numerical dispersion expressions are derived. The method is tested by simulating a dipole in a large computational domain to demonstrate the improved grid isotropy of the FCC lattice compared to the cartesian (standard Yee) grid. Also, a rectangular resonator is simulated, and the resonant frequencies are found to show the accuracy of the method.