A review of absorbing boundary conditions for two and three-dimensional electromagnetic scattering problems

The derivation of two- and three-dimensional absorbing boundary conditions (ABCs) for mesh truncation in the partial differential equation solution of electromagnetic scattering problems is briefly reviewed. The approximate 2-D ABC is compared with its exact counterpart and ways are suggested by which the ABCs can be improved. A direct application of the Wilcox expansion to the mesh truncation problem that bypasses the ABC altogether is discussed. The question of using a conformal (as opposed to cylindrical) outer boundary is addressed, and the ABC for this geometry is derived for 2-D scattering and guided wave problems