High-Gain Shared-Aperture Patch Phased Array and Reflectarray Antenna

A dual-band shared-aperture antenna, integrating a patch phased array and a reflectarray antenna (RA), is presented in this paper. The X-band phased array uses stacked patches as radiators, while the Ka-band RA also employs patches but with various sizes to achieve the desired phase compensation, placing above the X-band array. In addition, the upper ones of stacked patches serve as the ground plane for Ka-band RA operation. Due to this configuration, the X-/Ka-band shared-aperture operation is realized with high-gain property. The proposed shared-aperture antenna achieves an active VSWR below 3 in 10.2 ~12 GHz during ±45° beam scanning in E/H planes. Moreover, the 3-dB gain bandwidth is 16.6% (27.1 ~32.0 GHz), with a peak gain of 26.2 dBi at 29 GHz, corresponding to an aperture efficiency of 53%.