WIDEBAND SINGLE-FEED CIRCULARLY POLARIZED ANTENNA

Abstract

In this paper, a novel wideband single-feed circularly polarized patch antenna is presented. The antenna consists of an L-shaped probe, four parasitic patches perpendicular to the probe, and a planar reflector. By modifying the structure of the patches, two orthogonal radiation modes are created to realize the circular polarization in the broadside direction. This antenna exhibits a wide impedance bandwidth of 82.4% from 2 GHz to 4.8 GHz for the voltage standing wave ratio (VSWR) ≤ 2a nd a 3-dB axial ratio (AR) bandwidth of 56.2% from 2.11 GHz to 3.77 GHz, over which the antenna gains vary from 5.7 dBic to 9.7 dBic. The measured results agree well with the simulated ones. In this paper, in order to enhance the bandwidth of the single-feed circularly polarized antenna, a novel patch antenna with parasitic elements is presented. This antenna is composed of an L-shaped probe and four parasitic patches located perpendicularly to the probe. By slicing pairs of rectangular and L-shaped slots on the patches, wide impedance bandwidth and 3-dB axial ratio bandwidth can be achieved. Experimentally, the proposed antenna delivers an impedance bandwidth of 82.4% and a 3-dB axial ratio bandwidth of 56.2%. Compared with the single-feed patch antennas in (3-7), this antenna has a much wider axial ratio bandwidth of 56.2%.