an impedance-matched exponentially-non-uniform axial-mode helical antenna

This paper, using the circuit-geometric features of the method of moments (mom), presents a comprehensive analytical treatment of an exponentially non-uniform helical antenna (enh), mounted on a ground plane of finite extent. earlier investigations reported in the literature established that the introduction of an exponential non-uniformity in the turns spacing of an otherwise uniformly wound helical antenna significantly improves its axial ratio and power gain profiles, but failed to address two important questions; one concerning the influence of the degree of non-uniformity on the antenna performance: and the other, the associated return loss profile, which is of particular importance in practical applications. it is shown in this paper, that when a properly designed impedance matching circuitry is introduced, a return loss of the enh of close to 60 db is achievable; without compromising axial ratio and gain performances.  indeed, axial ratio bandwidth remained unchanged at 54.55% for both the impedance-matched and unmatched enhs, whilst maximum gain changed marginally from 14.19db, for the unmatched enh to 14.18db for the impedance-matched antenna.