Face Centered Anisotropic Surface Impedance Boundary Conditions in FDTD:Improved performance of staircased mesh for shielding problems

We present a new face centered approach to the collocation of the fields for the application of a surface impedance boundary condition (SIBC). This approach deals with the ambiguities in the surface normal that arise at the edges on stair-cased surfaces.. The accuracy of the new scheme is compared to edge based and conformal approaches using both planar sheet and spherical shell test cases. Stair-casing effects are evaluated and the face-centered scheme exhibits significantly less error than the edge based approach.