A 27-GHz Continuous Class-F Power Amplifier with AM-PM Compensation in 65 nm CMOS Process

A 27-GHz continuous class-F (CCF) power amplifier (PA) fabricated in 65-nm CMOS process is presented in this paper. The harmonically tuned networks are adopted at drain terminals for waveform rectification. By reducing the overlaps between voltage and current waveforms, the power added efficiency (PAE) can be boosted accordingly. An NMOS pre-distortion linearizer applied at gate terminal is used for AM-PM compensation. Due to negative phase deviation with low insertion loss, the AM-PM distortion resulted from overdriven mode can be improved without degrading the large signal performance. This CCF PA successfully achieves 9.9-dB small-signal gain, 18.4 dBm $P_{sat}$ with 37.7% $PAE_{max}$, and 17.8 dBm OP1dB with 37% $PAE_{1dB}$ at 27 GHz continuous wave (CW) measurement. In addition, under the modulated scheme of 64-QAM with 1.5 Gbps data rate centred at 27 GHz, this CCF PA achieves −25.2 dB EVM with average output power ($P_{o, avg}$) of 13.9 dBm and average PAE of 24.4%.