A novel wideband circularly polarized dual-fed slot antenna with microstrip feeding network

Abstract

This study presents the design of novel dual-fed circularly polarized (CP) antenna. This antenna consists of a tapered slot, a backside metal plate and a microstrip-fed delay line phase shifter. Based on the analysis of the radiation mechanism of antenna ground plane, the edge shape is optimized as a half-circle type to enhance the bandwidth of antenna gain and CP purity. The proposed antenna possesses a wideband return loss better than 10 dB in the range of 4.18–7.57 GHz, covering the bandwidth of axial ratio lower than 3 dB from 4.25 to 6.75 GHz. The measured antenna gain is approximately 9–10.5 dBic and the radiation patterns are broadside and consistent within the CP operating bandwidth.