A 78-93 GHz Power Amplifier with 19.6-dBm Psat and 12.8 % PAEpeak in 0.1-µm GaAs pHEMT for Radio Astronomical Receiver System

A W-band power amplifier (PA) for radio astronomical receiver LO chain in 0.1-μm GaAs pHEMT technology is presented in this paper. This PA is a 3-stage common source design using transmission lines to implement matching network. In order to increase the bandwidth, two sections matching networks for output are utilized to maintain the matching loci within the Q = 1 contour of Smith chart. A 90 degrees Lange coupler is employed to enhance the bandwidth and to combine the output power. The chip size with all pads is 2×1.5 mm2. From the measurement results, the proposed PA achieves 11.5-dB small signal gain with 15-GHz 3-dB bandwidth (78-93 GHz), saturated output power (P
_sat
) of 19.6 dBm, output 1-dB compression point (OP
_1dB
) of 18.2 dBm, and maximum power added efficiency (PAE
_peak
) of 12.8%.