Abstract—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.