Circularly polarized Ka-band radiating element unit-cell for SatCom wide-angle electronically steered phased arrays

This paper presents the design and simulations of a circularly polarized cavity-backed patch antenna for a low profile active electronically scanned Ka-band array with a beam-scanning capability over a wide-angle range (+/- 60°). The proposed unit-cell devoted to aircraft SatCom applications is derived in two versions for both 18-20 GHz and 28-30 GHz bands. It comprises an upper patch coupled to a dual pin-fed lower patch, both separated by a metal grid spacer. By symetrically placing the two input feeds, a similar behavior for both polarizations can be achieved, attaining thus a low axial ratio over a wide-angle range.