A Wideband Circularly Polarized L-Probe Coupled Patch Antenna for Dual-Band Operation

This paper presents the design and testing of a dual-band circularly polarized patch antenna. The portion of the antenna for upper band operation consists of two stacked circular patches that are supported by the plastic posts in the air. They are excited by four L-probes that are located sequentially under the circumference of the lower patch. For lower band operation, a larger circular patch is added below the upper band patches. It is also coupled by four L-probes sequentially. The proposed antenna has an impedance bandwidth of 43.9% (SWRles2) and a 3-dB axial ratio bandwidth of 33% for the lower band, while an impedance bandwidth of 55.2% (SWRles2) and a 3-dB axial ratio bandwidth of 44.7% can be obtained for the upper band. Both bands have a peak gain of around 7.8 dBi.