HIGH-FREQUENCY SURFACE CURRENTS INDUCED ON A SPHERICAL REFLECTOR BY THE EDGE-DIFFRACTION OF OBLIQUELY INCIDENT WAVES

An explicit expression of the high-frequency surface current excited o n a perfectly conducting spherical cap by the edge-diffraction of an o bliquely incident wave is derived. The result is given in the GTD term inology and shows the influence of the incidence angles on the transfe r functions. To this end the real (physical) space is embedded into a twofold extended abstract space in which an equivalent canonical probl em is established, This latter yields a system of dual integral equati ons whose kernels were not previously treated. By inverting these new kernels, the system of dual equations is reduced to two independent Wi ener-Hopf problems. From the asymptotic solutions of these problems, o ne derives the expression of the edge-excited current along with the k nown geometrical optics term. The resutlt can be used directly in prac tical applications. If the incident ray becomes normal to the edge, th en the resulting expressions are reduced to the already known expressi ons. The basic idea and general formulas used here can also be used to solve other diffraction problems with similar geometry.