A single-aperture duplex antenna with dual circular polarizations

This article proposes a novel design of a compact single-aperture dual circular polarization (CP) antenna with integrated duplexing functions using a phase controllable coupled resonator structure. To the best of the authors’ knowledge, this is the first report of a multifunctional CP antenna with integrated duplexing performance and dual polarizations. The two orthogonal CPs are realized for the two respective filtering channels. Each channel contains a phased filtering power divider forming the dual-feed to a patch to achieve right-hand or left-hand CP (RHCP or LHCP). The required output phases of the dividers are realized by varied configurations of the coupled λ/2-resonator pairs. A duplex-CP-antenna with RHCP/LHCP at the downlink/uplink (2.45/2.7 GHz) is designed, fabricated, and measured. It achieved a 3-dB AR bandwidth of 3.2/7.7% at the downlink/uplink and an isolation better than 20 dB. Meanwhile, the antenna showed expected second-order filtering characteristics at both channels.