Novel Circularly-Polarized Antenna Array Using Patch Elements With 90° Phase Difference

A novel circularly polarized (CP) antenna array using patch elements with 90° phase difference is presented with the center frequency designed at 5.5 GHz. First, a patch antenna element with non-radiating edge feed is designed. Next, in order to obtain a 90° phase difference, a double-layer patch antenna is designed. A parasitic patch is added to the original antenna to introduce one more resonant mode, resulting in the 90° phase difference. Finally, these two kinds of antenna elements are placed perpendicularly to form a circularly polarized antenna array. With the use of the non-radiating edge feed, the future feed network is simplified. The simulation results show that the axial ratio (AR) bandwidth is 9.7% $(5.27-5.81 \mathrm{GHz})$ and the maximum CP peak simulated gains 10.1 dBic.