Design of a double feed circularly polarized rectangular microstrip patch antenna on a circular asymmetrical carrier

Circular symmetrical ground planes such as square and circular ones are always utilized in the design of circularly polarized antennas. However, carriers in practical applications are mostly circular asymmetrical, which will impose an effect on the circular polarization performance of the circularly polarized antenna. The characteristics of a circularly polarized microstrip patch antenna with a circular asymmetrical ground plane are analyzed through simulation in this paper. The reason for deterioration of the circular polarization performance is discussed, on the basis of which an improved method is proposed to design a dual-feed circularly polarized rectangular microstrip patch antenna on a circular asymmetrical carrier. The antenna is fabricated and measured. Measured results show that performance of the antenna is remarkably improved.