Exact surface impedance/admittance boundary conditions for complex geometries: Theory and applications

A methodology useful to derive exact and higher order surface impedance/adm ittance boundary conditions (HOI/ABC's) for complex geometries is presented . It is shown that exact surface boundary conditions are always expressed t hrough dyadic integral operators involving the tangential magnetic and elec tric fields all over the surface of the body. Quasi-local surface boundary conditions that include curvature effects are shown to be computable throug h an asymptotic approximation of the integral operators. Finally, an exampl e of a surface admittance boundary condition useful to analyze a structure exhibiting discontinuities along its-surface boundary is presented. Practic al examples to demonstrate the feasibility of the proposed methodology, as well as the accuracy of the resulting surface boundary conditions are also presented.