Axially slotted antenna on a spheroid with an isorefractive coating

Abstract

An algebraic solution is presented to the problem of radiation from an axisymmetric slot on a conducting prolate spheroid confocally coated with an isorefractive material, when the slot is excited by a delta gap source. The formulation of the problem is realized by expanding the electromagnetic field in each region in terms of spheroidal vector wave functions and a set of unknown expansion coefficients. Imposing the boundary conditions at the interface between the surface of the spheroid and the isorefractive coating, as well as that between the coating and the medium exterior to the coating leads to a set of simultaneous equations, the solution of which yields the unknown expansion coefficients. Numerical results are presented as normalized power patterns and radiation patterns for isorefractive materials, to show the effects of the coating on the radiation from the antenna.