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

• Published in: IEEE journal of solid-state circuits 2024-08, Vol.59 (8), p.2455-2468
• Main Authors: Zeng, Weisen, Gao, Li, Sun, Ning-Zheng, Li, Hui-Yang, Xu, Jin-Xu, Xu, Hongtao, Xue, Quan, Zhang, Xiuyin
• Format: Article
• Language: English
• Subjects: 5G mobile communication; Broadband; Broadband amplifiers; CMOS; Couplings; Distortion; fifth generation (5G); linearity improvement; millimeter wave; power amplifier (PA); Quadrature amplitude modulation; Symbols; Transformers
• ISSN: 0018-9200; 1558-173X
• DOI: 10.1109/JSSC.2024.3364096

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.