A Circularly Polarized U-Slot Array with High Polarization Purity and Wide Axial Ratio Beamwidth

A circularly polarized antenna array with high-polarization purity and wide axial ratio beamwidth is proposed. The antenna element is a circularly polarized asymmetric U-slot patch. A sequential rotation technique has been implemented that not only improves the circular polarization performance of the array, it also resolves the issue of beam pattern tilt in asymmetric U-slot antenna configurations. The proposed 2 ×2 planar array achieves a gain of 13 dBic with a 54 degree axial ratio beamwidth.