Low-cost broadband circularly polarized patch antenna

A novel single-feed broadband circularly polarized patch antenna is proposed. The proposed antenna has a simple structure, consisting of a corner-truncated square radiating patch, an L-shaped ground plane, and a probe feed. Through a via hole in the vertical ground of the L-shaped ground plane, the radiating patch is easily excited by a probe feed oriented in the same plane as the patch, and circular polarization (CP) radiation over a wide frequency range (>10%) is achieved. Experimental results of a constructed prototype with the center operating frequency at about 2500 MHz showed that the antenna has an impedance bandwidth (1.5:1 VSWR) of about 30%, a 3-dB axial-ratio CP bandwidth of about 10.4%, and a gain level of 8.5 dBi or larger within the CP bandwidth. In addition to the low cost of the proposed antenna due to its simple structure, the obtained CP performance is among the best that have been reported for single-feed single-element patch antennas.