Admittance of a solid cylindrical antenna

Abstract

The problem of calculating the current and admittance of a solid cylindrical antenna is of great practical interest. Yet, unlike the hollow tubular antenna, the above subject has found little attention in the literature. In the present paper, the solution to this problem is constructed in two steps. The first of these involves the derivation of an expression for the reflection coefficient at the end of a semi-infinite solid cylinder, which is obtained by solving a modified Wiener–Hopf equation using a newly-developed technique. Convenient expressions for the current and admittance of the antenna are derived next by considering multiple-reflection phenomena at the ends of the antenna. These expressions are further simplified for thin antennas, i.e. for [Formula: see text], and it is shown that the effect of the end caps, as reflected in the admittance of such an antenna, is to increase its effective length by approximately 0.26a.