Design of a Single-fed Gain-enhanced Circularly Polarized Patch Antenna for Microwave Power Transmission

A high-gain single-fed circularly polarized (CP) microstrip patch antenna for microwave transmission systems is proposed in this paper. Two narrow rectangular slots are added to the rectangular microstrip patch to enhance the antenna gain. The patch is rotated by 90∘ to form a cross microstrip patch antenna, and a pair of narrow microstrip strips are added at the edge of the cross patch along the -45∘ diagonal direction of the antenna to implement circular polarization. Two short rectangular microstrip lines are added on both sides of the narrow microstrips to adjust the phase of the current to further reduce the axial ratio (AR) value. The designed antenna model is simulated, fabricated and measured. The results of the measurement show that the antenna has a gain of 11.3 dB at the resonance frequency of 5.8 GHz, and the CP AR is 2.73 dB. The antenna can be applied to microwave power transmission systems and other personal wireless communication systems.