Thinned Spiral and Diffused-Configuration Ka-Band SATCOM Phased Arrays With ±60° Beam Scanning

In this article, we propose a novel method for thinning phased arrays with circular apertures, utilizing a spiral configuration of elements. A comparative study is presented between two types of thinned planar arrays-spiral and conventional diffused thinned arrays. The performance of these arrays is verified using four different filled fractions, occupying 64%, 50%, 32%, and 25% of the element count of an 812-element circular aperture. The measurements were conducted primarily at 29 GHz using a Ka-band satellite communication (SATCOM) transmit phased array. The results demonstrate that both types of arrays exhibit wide scan angles of up to +/- 60 degrees while keeping the sidelobe levels (SLLs) below -12.5 dB. Specifically, spiral arrays are capable of achieving near-diffraction-limited patterns at wide scan angles. Additionally, both arrays exhibit a similar frequency response to the reference aperture, thus maintaining the operation bandwidth. Application areas are in low-earth orbit (LEO) SATCOM phased arrays or mm-wave imaging systems with a reduced number of elements with diffraction-limited beams and where higher SLLs may be tolerated.