Dielectric Hemispherical Aerials Excited in the TM-Symmetric Mode at Microwave Frequencies

Abstract

The electromagnetic boundary-value problem of a lossless dielectric sphere embedded in another lossless dielectric medium, excited by a δ-function electric field symmetrical about the z-axis and applied normally over the equatorial plane, is solved. The field components of the electric and magnetic fields on the surface are theoretically calculated and verified experimentally. Making use of the values of these field components on the surface of a dielectric hemisphere used as an aerial, the surface currents on the aerial are calculated. Expressions for the radiation pattern and gain of such an aerial are derived using Schelkunoff’'s equivalence principle. The calculated radiation patterns and gains of several aerials of different diameters are experimentally verified.