Analysis of internally reflected and diffracted fields in electromagnetic backscattering by dielectric spheroids

Abstract

For a prolate spheroid of arbitrary size various components of the scattering mechanism responsible for the backscattered energy (which is of interest to monostatic radar systems) are analyzed. In the case of a spherical structure, due to the symmetry, the conditions for the existence of glory rays and internal surface waves are straightforward. It is shown that for the prolate spheroid with arbitrary direction of incidence, these conditions are more complex, and it is advantageous to resort to a numerical method of ray tracing. The solution yielded by this numerical method, along with some geometrical arguments, shows that for most of the cases of arbitrary scatterers, the single bounce glory ray will not exist and therefore will not contribute to the backscattered energy. For the axial case of incidence, conditions for the existence of internal surface waves have also been developed. Finally, some results for the approximate backscattered signal incorporating the above components, are presented.