ELECTROMAGNETIC SCATTERING FROM OBJECTS COMPOSED OF MULTIPLE HOMOGENEOUS REGIONS USING A REGION-BY-REGION SOLUTION

This paper presents an efficient procedure to calculate the electromag netic field scattered by an inhomogeneous object consisting of N + 1 l inear isotropic homogeneous regions. The procedure is based on surface integral equation (SIE) formulations and the method of moments. The m ethod of moments is used to reduce the integral equations for each hom ogeneous dielectric region into individual matrices. These matrices ar e each solved for the equivalent electric current in terms of the equi valent magnetic current. A simple algebraic procedure is used to combi ne these solutions and to solve for the magnetic current on the outer dielectric surfaces of the scatterer. With the magnetic current determ ined, the electric current on the outer surface of the scatterer is ca lculated. Because the matrix corresponding to each dielectric region i s solved separately, we call this procedure the region-by-region metho d. The procedure is simple and efficient. It requires less computer st orage and less execution time than the conventional MM approach, in wh ich all the unknown currents are solved for simultaneously. To illustr ate the use of the procedure, the bistatic and monostatic radar cross sections (RCS) of several objects are computed. The computed results a re verified by comparison with results obtained numerically using the conventional numerical procedure as well as via the series solution fo r circular cylindrical structures. The possibility of nonunique soluti ons has also been investigated.