A Scalable Circularly-Polarized 256-Element Ka-Band Phased-Array SATCOM Transmitter with ±60° Beam Scanning and 34.5 dBW EIRP

This paper presents a scalable 256-element Ka-band switchable dual-polarizrd phased-array SATCOM transmitter (TX). The phased-array can generate linear, rotated linear, clockwise and counter-clockwise polarization which can be selected by setting the phased shifters in the beamformer chips. The low-cost design uses FR-4 based printed circuit board (PCB), surface mount technology (SMT) and silicon beamformer chips. The phased-array can scan to ±60° in the elevation plane with a 3-dB beamwidth of 7° and 34.5 dBW EIRP at broadside. It has a measured 3-dB instantaneous axial-ratio bandwidth of 2 GHz and is scalable without grating lobes to allow economical construction of larger phased-arrays. The compact size of (14 × 11.5 cm) makes it suitable for a low-cost Ka-band SATCOM terminal.