Abstract
After reviewing some of the basic properties of spheroidal wave functions, the theory of radiation from a prolate spheroid antenna is considered. Particular attention is given to the complicating inftuence of a confocal plasma sheath whose properties may be either constant or depend on the polar angle coordinate. The effects of the compressibility of the plasma and the inftuence of a d—c magnetic field are also considered, using very idealized models. Among other things, it is indicated that a spheroidal structure may be strongly resonated (in a single mode) if the surface impedance has a special form.