Wideband Phased Array System at K-Band for Satellite Down-link Applications

This paper presents a wideband electronically steerable circularly polarized receive phased array antenna system at K-band (17.7 GHz to 20.2 GHz) for satellite downlink applications. A scalable 64-element antenna array module in a multi-layered PCB is designed using a dual-polarized proximity-fed square-ring patch radiator with stacked circular-ring patch as the antenna element. For circular polarization (CP) radiation, the two feeds are excited orthogonally in 90° out of phase with each other. To enhance CP performance, each 2 × 2 antenna subarray is excited in a sequentially rotated manner with one Rx beamforming core chip. The 64-element array module with aperture size of 60mm × 60mm demonstrates a measured 12.5° half-power beam width (HPBW), around 22 dBic antenna gain and less than 2.5 dB axial ratio (AR) across the frequency band. The beam can be steered to ±60° in all planes without grating lobes. Furthermore, to demonstrate the scalability, a 256-element phased array is prototyped and measured.