A 40% PAE Frequency-Reconfigurable CMOS Power Amplifier With Tunable Gate-Drain Neutralization for 28-GHz 5G Radios

作者：Ali Sheikh Nijam; Agarwal Pawan; Renaud Luke; Molavi Reza; Mirabbasi Shahriar; Pande Partha Pratim; Heo Deukhyoun^*

来源：IEEE Transactions on Microwave Theory and Techniques, 2018, 66(5): 2231-2245.

DOI：10.1109/TMTT.2018.2801806

• Class-AB
• CMOS
• error vector magnitude (EVM)
• 5G
• frequency reconfigurable
• high efficiency
• millimeter wave (mm-wave)
• multiband
• phased array
• power amplifier (PA)
• quadrature amplitude modulation (QAM)
• switched substrate-shield tunable inductor
• transformer-feedback neutralization
• tunable coupling coefficient
• tunable neutralization
• 28 GHz

In this paper, a high-efficiency frequency-reconfigurable CMOS power amplifier (PA) design technique is presented at 24 and 28 GHz using integrated tunable neutralization and matching networks. To cope with the adverse effects of gate-drain capacitance (Cgd) in millimeter-wave (mm-wave) CMOS PAs in deep-submicrometer technologies, we propose a reconfigurable coupling-coefficient-based transformer. This technique provides optimum neutralization of Cgd in a common-source configuration, while enabling tunable neutralization in a frequency reconfigurable PA. Furthermore, to reconfigure the PA's input and output matching networks, a low-loss frequency-reconfigurable matching topology using a switched substrate-shield inductor is proposed. The adopted matching network addresses the high loss in a conventional frequency reconfigurable matching approach, while facilitating high efficiency in the proposed PA design. Using the proposed techniques, a class-AB PA is fabricated in a 65-nm CMOS technology. This prototype achieves measured saturated power-added efficiency (PAE(sat)) of 42.6%, saturated output power (P-o,P- sat) of 14.7 dBm at 24 GHz, and 40.1% PAE(sat), and 14.4 dBm P-o,P- sat at 28 GHz while occupying an active area of only 0.11 mm(2). At 24 and 28 GHz, the PA is tested under 16 and 64-quadrature amplitude modulation (QAM) signals with 250 MHz of channel BW. The PA achieves modulated PAE of 15.2%/14.1%, error vector magnitude of -26.4/-26.6 dB, and adjacent channel leakage ratio of -30/-32 dBc at an average output power of 7.1/7 dBm for a 64-QAM signal with 250-MHz BW at 24 and 28 GHz, respectively. To the best of the author's knowledge, the design presents one of the highest PAEs among mm-wave CMOS PAs reported to date, while it also supports multiband operation.

• 出版日期2018-5