Broadband T‐bar fed slot antenna array with stable horizontally polarized omnidirectional radiation

Abstract

A broadband horizontally polarized omnidirectional antenna array is proposed, which consists of a circular array of four identical broadband T-bar fed cavity-backed slot antenna elements and a 1-to-4 power divider. The proposed omnidirectional antenna array has a compact diameter of only 0.44λ0, a broad bandwidth of 75.9% (450-1000 MHz) and a favorable omnidirectional radiation pattern in the azimuth plane with a gain variation below 3 dB in the operating band. Moreover, the cavity-backed structure makes the proposed antenna array hardly affected by metal environment and the all metal construction allows for high-power applications, and the reserved cable channel behind the cavities of the antenna elements ensures the extensionality and stability of the proposed array when longitudinal array expansion is needed. Design procedures of the proposed antenna array have been described in detail, simulations and measurements of the proposed antenna array have also been carried out to validate its performance in this article.