Linearly polarized radial line slot array antenna with wideband return loss performance using a multisleeve coaxial transition

The purpose of this letter is two-fold: 1) to propose an effective wideband coaxial transition for linearly polarized radial-line slot-array antennas consisting of a set of sleeves surrounding a monopole probe; and 2) to formulate an efficient technique for fast transition optimization taking into account all parts of the antenna. The technique basically obtains an equivalent reflection coefficient of the whole slot array as seen from the transition, thus reducing significantly the unknowns involved in the full-wave description of the problem and hence the optimization time.