A Circularly Polarized Cavity-Backed Stacked Patch Antenna for Wide-Angle Beam Scanning Millimeter-Wave Phased Array

This paper presents design and measurement of a circularly polarized cavity-backed patch antenna for a low-profile active electronically scanned array with a beam-scanning capability over a wide angle. The proposed antenna comprises upper patches, a spacer, and pin-fed lower patches to achieve low axial ratio across a wide angle of view and high efficiency. Each component is bonded without any screws, which enhances the manufacturability of the antenna and prevents degradation of the radiation pattern. A 16-element array is fabricated and measured. The measured pattern for co-polarization agrees well with the simulated one, and scan loss is approximately 5.5 dB in the +/- 70 degrees directions. In addition, low axial ratio of approximately 4.5 dB is obtained even in the +/- 70 degrees directions.