Analysis of heterogeneous electromagnetic scatterers: research progress of the past decade

A review of the current status of integral equation and finite element (FEM) (including time domain) modeling as applied particularly to penetrable bodies is provided. The direct numerical solution of the appropriate frequency-domain partial differential equations is an alternative that has recently been the focus of much effort by the research community and appears to offer computational advantages over the integral equation formulations. These frequency-domain approaches require the solution of a matrix equation; the direct time-domain solution of partial differential equations offers a third formulation that does not require a matrix solution and may be more efficient for electrically large structures. The author summarizes the development of these modeling procedures and attempts to identify some of the unresolved issues associated with their development