A Method to Improve the Axial Ratio of Microstrip Circularly Polarized Patch Antenna

In order to improve the axial ratio of the circular polarized microstrip patch antenna, a method is proposed in this paper. By changing the size of the rectangular slot loaded on one side of the top corner of the non chamfered patch, the axial ratio of the circular polarized microstrip patch antenna element can be improved by more than 0.6dB. Use this unit to form 2 × 2 array, the array’s axial ratio can be improved by more than 1dB. Finally, the array’s axial ratio is less than 2dB and its gain reaches 10dBic (in 2.4-2.5 GHz). The simulation results are in good agreement with the experimental results.