Numerical analysis of electromagnetic wave scattering and interaction based on frequency-domain integral equation and method of moments techniques

This paper discusses numerical modeling of electromagnetic wave scattering and interaction by general arbitrary-shaped two- and three-dimensional material objects in free space based on the frequency-domain integral equation method. Depending on the type of material object modeled, straightforward electromagnetic boundary value problems can be set up in terms of a set of coupled integro-differential equations with unknown surface equivalent current distributions. These unknown surface equivalent currents are determined by a numerical technique based on the method of moments (MOM) which involves reducing the exact coupled integro-differential equations to a corresponding partitioned dense matrix equation. Various electromagnetic fields (penetrating, near scattered, and far scattered) as well as the radar cross section can be calculated once the unknown surface current distributions are determined.

Canonical two- and three-dimensional scattering and interaction examples are reported which illustrate the capabilities of this method for analyzing arbitrary-shaped objects comprised of conducting, dielectric, and anisotropic materials. For specific geometries, both the induced surface current distribution and the corresponding radar cross section are presented with either analytical or code-to-code validations. The paper concludes with a discussion of means to extend the applicability of the integral equation modeling technique to the case of electrically-large material objects.