Diffraction of the creeping waves generated on a perfectly conducting spherical scatterer by a ring source

To analyze the diffraction of high frequency waves one turns often to the geometrical theory of diffraction (GTD) whose aim is to describe this phenomenon in terms of certain factors. These factors involve, among the others, several diffraction coefficients showing the modifications to be considered when a ray is transformed into another one at a diffraction point. The aim of this paper is to analyze the diffraction of creeping waves generated on a perfectly conducting spherical reflector, and thereby to obtain explicit expressions for certain coefficients related to the diffractions occurring at the edges of spherically curved reflectors. The analysis is performed by using an integral transform technique recently developed by one of the authors. Various ray contributions are isolated, and fairly simple nonuniform expressions for the diffraction coefficients are obtained.