A Wideband X/Ku/Ka-band SATCOM 8-Channel SiGe Transmit Beamformer Chip in a 16-Element Phased-Array

This paper presents a 5-33 GHz 8-channel transmit beamformer implemented in 90nm SiGe BiCMOS HBT technology. Each channel is composed of a wideband two-stage power-amplifier (PA), a phase-shifter (PS), a variable gain amplifier (VGA) and single-ended to differential converter (S2D). The input RF power is distributed to the 8-channels using a two-stage Wilkinson network and active dividers. The measured small-signal gain is 24-27 dB at 5-33 GHz with 5-bit phase-shifter operation and > 20 dB gain control. A peak OP1dB and OPsat of 13-14 dBm is achieved at Ku-band. The beamformer is attached to a 16-element wideband antenna array and shows scanning performance at 8-30 GHz. To author's knowledge, this work achieves the widest bandwidth Tx beamforming chip. Application areas are ground terminals capable of communications with X, Ku and Ka-band satellite constellations.