Thinned Spiral-Configuration Ka-Band SATCOM Phased-Arrays with Diffraction-Limited Beams and Wide Scan Angles

This paper presents a new method for thinning phased-arrays with a circular area which results in diffraction-limited performance and in wide scan angles without triggering large grating lobes. The technique relies on synthesizing a spiral pattern which requires only 50% of the element count of a fully populated (circular) phased-array having the same outside diameter. Measurements done at 29 GHz of a Ka-band SATCOM transmit phased-array show excellent patterns with low sidelobes and low grating lobes, and with wide scan angles (up to ±60°). Also, both arrays have a near identical frequency response. Application areas are in lowering the cost of LEO SATCOM user terminals while still maintaining excellent patterns and scan angles.