Cavity‐backed self‐phased circularly polarized antenna based on stepped‐width dipole with wide axial ratio beamwidth

Abstract

AbstractA cavity‐backed self‐phased circularly polarized (CP) antenna based on stepped‐width dipoles with wide axial ratio beamwidth is proposed for global positioning system (GPS) applications. The radiator of the antenna consists of two pairs of stepped‐width dipoles, contributing to the CP radiation. The working principle of CP radiation is elaborated by using two simplified models. Then, a feeding network consisting of a Y‐shaped structure and two pairs of identical coplanar striplines (CPSs) is utilized to feed the radiator. Moreover, a cavity‐backed reflector is employed in this antenna to achieve a unidirectional radiation with wide axial ratio (AR) beamwidth. Measured results show that the proposed antenna achieves a wide impedance bandwidth of 43% from 1.37 to 2.12 GHz with Return Loss > 15 dB, and a 3‐dB axial ratio (AR) bandwidth of 6.98% from 1.52 to 1.63 GHz. Particularly, the antenna shows a right‐hand circular polarization (RHCP) radiation with wide 3‐dB AR beamwidth of 205° and 215° in the XOZ and YOZ plane at the center frequency of 1.575 GHz, respectively.