High-Gain Dual-Band Resonant Cavity Antenna for 5G Millimeter-Wave Communications

A high-gain dual-band resonant cavity antenna (RCA) for the fifth-generation (5G) millimeter-wave (MMW) communications is presented in this letter. The proposed antenna provides the high gain and large gain-bandwidth product over the 28 GHz band and the 38 GHz band. The heights of the second- and third-order resonant in the RCA are optimized for dual-band operation. Improvements on the gain and the bandwidth are achieved in both bands when stepped rings are added. The gain is further increased with a circular patch on a partially reflective surface, which is made by a substrate of high permittivity. Finally, a prototype is designed, simulated, and verified through measurement. Good performance is achieved: in the 26.5–28 GHz band, the bandwidth is 5.5% and the peak gain is 20.3 dBi; in the 37.5–39.4 GHz band, the bandwidth is 4.9% and the peak gain is 20.4 dBi. The proposed antenna has the features of low cost and easy fabrication as well.