This paper presents a cavity PCB process-based Ka-band phased array with offset-fed aperture coupled patch antenna. To reduce a wire bonding loss in the interconnection between the chip and PCB, the antenna is designed using a cavity-processed PCB, and the height of the cavity area is matched to the height of the chip to minimize the bonding length. In addition, the presented antenna is fed by aperture coupling which has advantages in process and utilization compared to via feeding. However, as the frequency increases, there is little space on the PCB, which makes the aperture coupling feeding not be applied normally. Therefore, in this paper, offset-fed aperture coupling is analyzed and experimentally verified. The presented antenna has a peak gain of about 16 dBi at 28 GHz and is capable of beam steering in a range of about ± 30 degrees.