Measurements of the input admittance of thick spheroidal antennas in conductive mediums.

A measuring apparatus and experimental procedures have been developed to test the validity of a theoretically derived equivalent-circuit representation of the input admittance of prolate spheroidal antennas immersed in a general isotropic homogeneous medium. The experimental results reported are in excellent agreement with theoretical predictions and validate the possibility of computing antenna response by means of a very simple equivalent circuit. This is particularly important when the antenna is used for diagnostic purposes. With regard to the latter application, experiments have shown the opportunity of further investigations, both theoretical and experimental, especially to minimise the effect of the feeding connections on the antenna behaviour.