A Polarization Reconfigurable Circular Patch Antenna with Tuning Stub and Crescent Slot

A polarization-reconfigurable patch antenna designed for future 5G application operating in the ka band is introduced. This study focuses on designing and analyzing a circular-shaped microstrip patch antenna, utilizing a Rogers RT Duroid 5880 substrate, to achieve diversity polarization. The antenna is designed with dimensions of 24 mm × 20 mm × 0.80 mm. The antenna consists of a circular radiating element with crescent-shaped slots, fed by a microstrip transmission line, and incorporates two stubs, each integrated with independently controlled PIN diodes. The polarization can be toggled between right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP) by switching the states of the PIN diodes. Simulation results show that the antenna operates between 26.63 GHz and 29.76 GHz with a reflection coefficient below -10 dB. The antenna exhibits a gain exceeding 6 dBi across all polarization states throughout the entire designed frequency range. Additionally, it achieves a good axial ratio (less than 3 dB) in both RHCP and LHCP modes over the 27.82-28.36 GHz range and acquires axial-ratio bandwidth (ARBW) of 1.82%. It’s simple design and ease of simulated make it an excellent candidate for high-speed data transmission and 5G ka band applications.