A Millimeter-Wave Resonant Cavity Antenna With Multibeam and High-Gain Capabilities for 5G Applications

In this article, a technique to obtain a high-gain multibeam antenna for millimeter-wave (mmW) fifth-generation (5G) base stations (BSs) is proposed using the Fabry–Pérot Cavity (FPC) structures. A thin single metallodielectric layer is used as the partially reflective surface (PRS) layer to enhance the radiation performance of the FPC antenna (FPCA) and provide an off-axis pencil beam. As the feeding structure illuminating the PRS layer, a cylindrical cavity is designed using a right-angle-type semi-waveguide (RATSW) structure. An array of coaxial probes is used to obtain beam switching at the azimuth plane by exciting different probes. To confirm the functionality of the proposed FPCA, a prototype is fabricated with five coaxial probes to generate five radiation beams; however, the structure can be extended to provide more antenna beams using higher number of probes. The cavity structure of the proposed antenna is fabricated by the 3-D printing technology as an easy manufacturing process. The measurement results show that multiple switchable beams with high antenna gain are obtained over the desired frequency bandwidth of 27–30 GHz. The maximum measured gain is 19 dBi at 27.5 GHz when a single probe is excited. A conceptional scenario for the potential applications of the proposed antenna in the 5G BSs is presented.