A Wideband Differentially Fed Circularly Polarized Slotted Patch Antenna with a Large Beamwidth

A wideband differentially fed circularly polarized (CP) antenna featuring a slotted patch design with a large beamwidth is presented. The final design of the differentially fed CP antenna, aimed at achieving high gain and a wide axial ratio (AR) bandwidth, involves coupling a differential bending dipole antenna to the slotted patch in the same plane. The presented differentially fed CP antenna demonstrates characteristics of a large AR beamwidth, as verified by simulation and experiment. The measured AR beamwidths of 132.3° in the xoz plane (phi = 0°) and 116.2° in the yoz plane (phi = 90°) are realized at 5.5 GHz. The measured result exhibits broadband performance with a -10-dB impedance bandwidth of 78.8% (3.81–8.76 GHz), a 3-dB AR bandwidth of 36.7% (4.78–6.93 GHz), and a maximum gain of 10.2 dBic.