A Dual-Polarized Aperture-Sharing Phased-Array Antenna for 5G (3.5, 26) GHz Communication

Integrating the sub-6 GHz antenna and the millimeter-wave (mm-wave) antenna in one radiating aperture is a promising approach to support different frequency bands for the incoming communication system. In this article, an mm-wave dual-polarized 64 element phased-array antenna is integrated into the partially reflective surface (PRS) of a sub-6 GHz resonant cavity antenna (RCA). The PRS consists of two multilayer printed circuit boards (PCBs), which are stacked together and connected by solder joints. The thick PRS unit cell is designed with a miniaturized footprint at 3.5 GHz and can also contain a $2\times $ 2 mm-wave active subarray, including four stacked-patch antennas, a beamformer IC (BFIC), and some other input circuits. A copper plate is also inserted in the PRS for thermal control. A prototype antenna is fabricated and measured. Measurement results agree well with the simulation. In the sub-6 GHz band, the proposed antenna demonstrates dual-polarized radiation over the frequency band from 3.45 to 3.58 GHz. In the high-frequency band, the dual-polarized mm-wave array driven by the built-in active beamforming network is capable of scanning ±45° both in azimuth and elevation over the frequency band from 24.5 to 27 GHz.