A Wide-Band High Isolation Dual-Circularly Polarized Microstrip Antenna Array

wide-band dual-circularly polarized transceiver antenna with high port isolation is proposed in this paper. The antenna element uses M-shaped and U-shaped microstrip lines to excite the quasi-cross-shaped aperture to achieve wide-band and lower cross-polarization level. Dual-circular polarization is accomplished via the sequential rotation technique. To obtain high port isolation of the antenna, phase cancellation technique and decoupling structure are utilized. The measurements show that the impedance bandwidth with reflection coefficient less than -10 dB is larger than 34.5% (4.6-6.5 GHz) for left-hand circular polarization (LHCP) port and 29.8% (4.86-6.5 GHz) for right-hand circular polarization (RHCP) port, while the 3 dB axial ratio bandwidth for LHCP and RHCP is greater than 29.1% (4.8-6.4 GHz) and 32.7% (4.7-6.5 GHz), respectively. The port isolation of the antenna is higher than 30 dB in 4.5-6.5 GHz band. The peak gain is about 12 dBic.