AN ANISOTROPIC TWO-DIMENSIONAL SCATTERING CODE

Abstract

A computer code has been developed to predict radar return from two- dimensional cylindrical targets composed of anisotropic, lossy, and inhomogeneous materials. A moment method formulation uses point matching with rectangular domains of pulse basis functions for volumetric elements. Targets may also be composed of thin films including conducting sheets. Particular attention is paid to problems associated with close coupling which involve numerical integration over neighboring domains of basis functions, rectangles which may be very close together as in the case of thin layers of material. Examples are used to show that analytical integration of singularities associated with close coupling gives results which are superior to the numerical approximations used in typical moment method The results are of interest for problems involving isotropic as well as anisotropic targets. For example, when a code which calculates close couplings with numerical approximations is applied to a hollow, conducting cylinder, computed radar return may be distorted by introducing conducting elements close to the interior wall of the cylinder. With analytical treatment of singularities, however, there is no distortion. In another example results from codes are compared for the case of a right circular cylinder coated with anisotropic material. Results in good agreement with a series solution taken from the literature are achieved when analytical treatment of singularities is considered. Finally, for the example of a conducting plate it is shown how analytical treatment of singularities makes good results possible for a minimum number of basis functions. [Vol. 4, No. 2, pp. 49-58 (1989)