Design of Small Circularly Polarized Patch Antenna

A new method to reduce the lateral size of the circularly polarized (CP) patch antenna is presented. It is implemented by attaching two sets of vertical right-angle bended stubs to the diagonal corners of the slotted square patch. To demonstrate the effectiveness of this method, three antennas with different lengths of bended stubs are designed and tested. The smallest one has a size reduction of 77.7% in comparison to the conventional half-wave circularly polarized patch antenna. It has impedance bandwidth (VSWR ≤ 2) of 7.9%, axial ratio (AR) bandwidth (AR ≤ 3 dB) of 1.53% and peak gain of 4.7 dBic.