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-Perot 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.