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

This article presents a broadband millimeter-wave (mm-wave) linear power amplifier (PA) to support 5G and beyond wireless communication. An asynchronously tuned coupled resonator (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 proposed ideas. The measured PA realizes 76%
$S_{21}\,\,-$
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.,
$n$
257–
$n$
261. The measured
$\vert $
AM−PM
$\vert $
is less than 4° over 24−43 GHz. The large-signal measurement results show that the PA realizes 18.7−20.3-dBm
$P_{\mathrm {sat}}$
, 16.8−19-dBm OP1dB, 24.9%−35.5% PAEmax, and 20.6%–29.7% PAEP1dB 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
$P_{\mathrm {out}}$
/PAE of 11.0 dBm/8.7% with −25.2-dB EVMrms at 24 GHz. The proposed PA achieves a compact size with a core area of 0.088 mm2, making it very suitable for large-scale phased array beamformers.