Scattering by a circular aperture in a dielectric-loaded conducting spherical shell

The problem considered deals with the scattering of a plane wave by an infinitely thin perfectly conducting spherical shell with a circular aperture of arbitrary subtended angle and loaded with a dielectric shell whose permittivity may be different outside the shell from inside. The fields in both regions are expanded in terms of spherical wave functions and the proper boundary conditions are imposed. The modal expansion coefficients are approximated by applying the least square error method to the equations resulting from matching the fields at the aperture. The scattering pattern and radar cross section are presented for a wide range of parameter variations.<>