A Compact 19.7- to 43.8-GHz Power Amplifier With 20.3-dBm Psat and 35.5% PAE in 28-nm Bulk CMOS

Abstract

This article presents a broadband millimeter-wave (mm-wave) linear power amplifier (PA) to support 5G and beyond wireless communication. An asynchronously tuned coupled res- onator (ATCR) circuit model is introduced to effectively design PA’s non-ideal transformer-based broadband output matching network (OMN). Two adaptive feedback linearizers (AFLs) and multi-gated transistor (MGTR) techniques are adapted to optimize the linearity. Both amplitude-to-amplitude (AM−AM) and amplitude-to-phase modulation (AM−PM) distortion are improved over one octave with these techniques. A prototype PA is implemented in 28-nm bulk CMOS to verify the pro- posed ideas. The measured PA realizes 76% S21 −3-dB fraction bandwidth (FBW) from 19.7 to 43.8 GHz, fully supporting five operating bands in 5G new radio (NR) frequency range 2 (FR2), i.e., n257–n261. The measured |AM−PM| is less than 4◦ over 24−43 GHz. The large-signal measurement results show that the PA realizes 18.7−20.3-dBm Psat, 16.8−19-dBm OP1dB, 24.9%−35.5% PAE max, and 20.6%–29.7% PAE P1dB over 22−40 GHz. For 5G NR FR2 200-MHz 64-QAM signals [9.7-dB peak-to-average power ratio (PAPR)], the PA achieves an average Pout/PAE of 11.0 dBm/8.7% with −25.2-dB EVM rms at 24 GHz. The proposed PA achieves a compact size with a core area of 0.088 mm 2, making it very suitable for large-scale phased array beamformers.