Broadband omni-directional circularly polarized antenna based on vertically and horizontally polarized elements

摘要

This paper presents a broadband omnidirectional circularly polarized antenna design using combination of broadband omnidirectional vertically and horizontally polarized radiating elements. The vertically polarized (VP) component is a modified version of ultra-wideband (UWB) monopole antenna and the horizontally polarized (HP) element is a recently-developed omnidirectional HP antenna using planar folded dipoles. The two radiating elements are fed by a carefully designed broadband Wilkinson power divider Schiffman phase shifter to achieve the required power division and phase shift over the entire band for the entire band between the two polarizations. The simulation shows that the proposed antenna has a 10 dB return loss bandwidth of 59.1% (1.11-2.04GHz), and the bandwidth for the maximum 3 dB axial ratio for all azimuth directions is 49.7% (1.21-2.01GHz).