High-efficiency X-band MMIC GaN power amplifiers with supply modulation

This paper presents measurement results on supply-modulated X-band 0.15μm gate width GaN HEMT MMIC power amplifiers for OFDM signals. Two PAs at 10GHz with 4 and 10W output powers show peak CW efficiencies of 69% and 55%, with gains of 8.5 and 20.4 dB respectively. Supply modulation trajectories are designed by static characterization of each MMIC PA, and the drain modulation is performed though both a linear broadband modulator and a high-efficiency 5-MHz switching modulator. The PAs are tested in four modes: (1) with a constant 20-V supply and the 18-MHz OFDM signal input through the drive; (2) pure envelope tracking; (3) signal-split supply modulation; and (4) envelope elimination and restoration (EER) with a 5-MHz switching modulator. Average PAE and composite power added efficiencies are compared, reaching 65.4% and 35%, respectively, with the 4-W PA and a linear modulator.

[1]  P. Asbeck,et al.  High-Efficiency Envelope-Tracking W-CDMA Base-Station Amplifier Using GaN HFETs , 2006, IEEE Transactions on Microwave Theory and Techniques.

[2]  Narisi Wang,et al.  60% efficient 10-GHz power amplifier with dynamic drain bias control , 2004, IEEE Transactions on Microwave Theory and Techniques.

[3]  L.E. Larson,et al.  Design of wide-bandwidth envelope-tracking power amplifiers for OFDM applications , 2005, IEEE Transactions on Microwave Theory and Techniques.

[4]  Raymond S. Pengelly,et al.  The Doherty power amplifier , 2015, 2015 IEEE MTT-S International Microwave Symposium.

[5]  Mark P. van der Heijden,et al.  A 19W high-efficiency wide-band CMOS-GaN class-E Chireix RF outphasing power amplifier , 2011, 2011 IEEE MTT-S International Microwave Symposium.

[6]  Peter M. Asbeck,et al.  High Efficiency WCDMA Envelope Tracking Base-Station Amplifier Implemented with GaAs HVHBTs , 2008, 2008 IEEE Compound Semiconductor Integrated Circuits Symposium.

[7]  D. Maksimović,et al.  High-Frequency PWM Buck Converters Using GaN-on-SiC HEMTs , 2014, IEEE Transactions on Power Electronics.

[8]  D. Maksimovic,et al.  Codesign of PA, Supply, and Signal Processing for Linear Supply-Modulated RF Transmitters , 2012, IEEE Transactions on Microwave Theory and Techniques.