A 39-GHz Phase-Inverting Variable Gain Power Amplifier in 65-nm CMOS for 5G Communication

This letter presents a 39-GHz phase-inverting variable gain power amplifier (VGPA) for 5G communication. Adopting a Gilbert structure-based variable gain amplifier (VGA) stage, the VGPA realized the dB-linear gain control characteristic as well as 180° phase inversion. At 0°/180° phase states, the 39-GHz VGPA achieves the maximum gain of 38.7/38.9 dB with gain tuning range of 5.6/5.2 dB, respectively. Over 38–43 GHz, the phase inversion error is limited within 5.9°, and the rms phase error is less than 3.6°/2.2°. Meanwhile, with the metal interleaving coplanar transformer matching network, this VGPA achieves 17.7/17.6-dBm Psat and 13.2/13.36-dBm OP1 dB, with the power added efficiency (PAE) of 35%/34.5% and 13.6%/14.4% at the saturation and 1-dB compression points, respectively. Over the gain control states, the OP1 dB fluctuation is less than 0.3 dB. Implemented in a 65-nm CMOS process, the proposed VGPA consumes 150 mW with a chip area of 0.3 mm2.