A Broadband Circularly Polarized Crossed-Dipole Antenna

Abstract

A unidirectional broadband circularly polarized (CP) crossed-dipole antenna is presented in this communication. This antenna has a simple feeding structure, which uses an unequal power network. It can simply realize 90° phase shift and four equal power divisions. The study of the antenna performance with different geometric parameters has been conducted. Working band of designed antenna covers the BeiDou Navigation Satellite System, GPS, and GLNOSS bands. An optimized antenna is designed and measured, the measured results agree well with the simulated results. The results show good performance of impendence bandwidth is approximately 66.2% (1.01-2.01 GHz), the 3-dB axial-ratio bandwidth (ARBW) of approximately 41.3% (1.21-1.97 GHz). Moreover, the measured bore-sight antenna gain is stable and varying not too much, which average value is 6.0 dBic with less than 1.5-dB variation within the 3-dB ARBW.