A 26GHz 22.2DBM Variable Gain Power Amplifier in 28NM FD-SOI CMOS for 5G Antenna Arrays

A 26 GHz power amplifier (PA) targeting millimeter wave 5G mobile systems is presented. The two stage PA, integrated in a complete transmitter in a 28 nm FD-SOI CMOS process, only occupies a die area of 0.144 mm
²
. It uses stacking of two transistors to handle high voltage swing, and a transformer based power combiner at the output to reduce output load impedance. The first stage, the pre-PA (PPA), has 31 unit cells, that can accurately set the gain from 14.7-33.1 dB. The design has been optimized for device stress to provide function for $> \pmb{10}$ years. Saturated output power and 1 dB compression point reach state-of-the-art performance of 20.6/22.2dBm and 18.8/20.7 dBm for 1.5/ 1.8 V supply respectively. For 1.5 V supply, PAE is peaking at 22.6 % and AM-PM is below 5 degrees up to the 1 dB compression point.