Practical 3-D contour/staircase treatment of metals in FDTD

The standard finite-difference time-domain (FDTD) method incorporates an inaccurate staircase representation of perfect electric conductors. More accurate, contour-type update formulas have been proposed. These approaches suffer from bookkeeping complexity, difficulties in mesh generation, and stability problems. Only simplified special cases have been implemented in three dimensions. A new contour-like FDTD algorithm is presented. Subcell formulas and staircase logic are combined to produce a three-dimensional (3-D) algorithm that is simple, robust, and fully automatic.