Imposing Surface Impedance Boundary Conditions in unstructured FDTD

Implementing Surface Impedance Boundary Conditions (SIBC) for explicit FDTD with unstructured grids needs special attention. In many cases only the primary mesh is available, and in any case the dual mesh topology, if present, is substantially different from the primary mesh. The direct relation of the electric and magnetic field components at the boundary is not available due to their staggered discretization in space and time. One-sided spatial derivatives are used in this work for the discrete Maxwellpsilas equations FDTD updates. Regardless of availability of a dual mesh the problem may be considered first in 1-D to perform numerical error analysis. Examples with Perfect Magnetic Conductor (PMC), resistive SIBC and Maloney-Smith conductor SIBC model are shown.