This paper proposed a dual polarized patch array antenna for millimeter-wave 5G base stations. The antenna operating at 28 GHz band is designed on 12-layer PCB lamination. A stacked patch topology was applied to secure the wide bandwidth of the antenna. In addition, in order to increase the gain of the patch antenna, a substrate-integrated cavity composed of via walls was applied. 8-element antenna array configuration was proposed for active antenna base station with vertical beam steering. Through simulated and measured results, it is determined that the proposed array antenna has good performance suitable for 5G base stations.