Efficiency Enhancement of mm-Wave Power Amplifiers Using Envelope Tracking

• Published in: IEEE microwave and wireless components letters 2011-03, Vol.21 (3), p.157-159
• Main Authors: Yan, J J, Presti, C D, Kimball, D F, Young-Pyo Hong, Chin Hsia, Asbeck, P M, Schellenberg, J
• Format: Article
• Language: English
• Subjects: Amplifiers; Applied sciences; Bandwidth; Circuit properties; Drains; Efficiency; Electric, optical and optoelectronic circuits; Electronic circuits; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronics; envelope tracking (ET); Envelopes; Exact sciences and technology; Frequency modulation; Gain; Gallium arsenide; linearity; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Microwaves; millimeter wave power amplifier (PA); MMICs; Modulators; Noise levels; Peak to average power ratio; peak-to-average ratio; Power amplifiers; Power efficiency; Power generation; Signal convertors; Tracking
• ISSN: 1531-1309; 2771-957X; 1558-1764; 2771-9588
• DOI: 10.1109/LMWC.2010.2102747

This letter presents a 44 GHz GaAs MMIC-based power amplifier (PA) which uses envelope tracking (ET) techniques for efficiency enhancement. Digital pre-distortion (DPD) is also employed to achieve high linearity. For a 7.6 dB PAPR 64QAM 20 MHz bandwidth signal (data rate 120 Mb/s) at an output power of 23.8 dBm, the measured EVM was 2.0% and ACPR1 was better than -40 dBc. Power efficiency enhancement of more than 5.7 times for the final MMIC stage (from 1.22% to 7%) was measured, using an external drain modulator. To the authors' best knowledge, this is the first time envelope tracking has been applied to PAs in the millimeter wave regime.