Implementation and Derivation of Conformal Absorbing Boundary Conditions for the Vector Wave Equation

A rigorous implementation, in an edge-based finite element formulation, of a second-order absorbing boundary condition (ABC) is presented for the solution of the 3-D scattering problem when the boundary S terminating the mesh is conformal to the object. Numerical experiments performed on a cone-sphere and a cylinder with hemispherical caps are presented that justify the use of this ABC. A high-order ABC is derived in the locally planar approximation, and its performances are evaluated for the analytical case of the sphere, which serves to address a number of important issues pertaining, e.g., to the accuracy with which the creeping waves are taken into account when an ABC is utilized.