High-frequency analysis of EM scattering from a conducting sphere coated with a composite material

The asymptotic high-frequency solution for the scattered field produced by a plane wave incident on a perfectly conducting sphere coated with a thin composite material is considered. In the shadow region, the high-frequency scattered field is entirely associated with the usual creeping-wave diffraction. In the lit region, the scattered field can be expressed as a sum of geometrical optics (GO) and creeping-wave diffraction terms. The field in the caustic regions, where the ray solution fails, is excluded. The appropriate formula for each term is derived, and the result is presented in a form suitable for computation. Numerical results for the bistatic scattering patterns of the coated sphere show excellent agreement with the rigorous eigenfunction solutions.>