Wideband circularly-polarized aperture antenna arrays utilizing UWB directional coupler

A novel wideband CP antenna array using the UWB directional coupler and sequential rotation technique is presented. The proposed antenna array is composed of two rectangular aperture antennas and a directional coupler as the sequential feeding scheme. The coupler was successfully designed and implemented, where two output port signals of 90°±10° phase difference and 3-dB magnitude imbalance were achieved over a ultra wide band 1.5 - 5.3 GHz. The resultant array showed a 10-dB return loss bandwidth in the 1.7-5.5 GHz band (103%) and a 3-dB axial ratio (AR) bandwidth in the 2.2-5.3 GHz band (82%).