Title :
A 3-bit, 2-watt, digital-analog gallium nitride power amplifier for 64-QAM bandwidth efficient modulation with 25% power savings
Author :
Watanabe, Monte ; LaRocca, Tim
Author_Institution :
Northrop Grumman Aerosp. Syst., Redondo Beach, CA, USA
Abstract :
A 3-bit digital-analog power amplifier using 28-V 0.2-μm AlGaN/GaN HEMT, for high-power, high-rate, linearized transmitters, is presented. Efficient amplification of complex digitally-modulated RF signals is achieved using a constantly active main transistor cell and 3-bit unary-weighted, digitally-controlled auxiliary cells that are enabled/disabled based on signal envelope power. The auxiliary cells efficiently linearize the AM-AM response, compensating for gain compression and extending P1dB by 2.5dB. Dynamic simulations with a 50MHz, 64-QAM signal predict 50% EVMRMS improvement and 25% power savings compared to a Class-A amplifier. Static measurements of the digital-analog power amplifier demonstrate 9.6dB linear gain, 2.2W P1dB, and 39.3% PAEP1dB at 7GHz.
Keywords :
III-V semiconductors; aluminium compounds; gallium compounds; high electron mobility transistors; microwave power amplifiers; 3-bit digital-analog power amplifier; 3-bit unary-weighted cell; 64-QAM bandwidth efficient modulation; AM-AM response; AlGaN-GaN; Class-A amplifier; HEMT; digital-analog gallium nitride power amplifier; digitally-controlled auxiliary cell; digitally-modulated RF signal; frequency 50 MHz; frequency 7 GHz; gain compression; linearized transmitter; power 2.2 W; signal envelope power; size 0.2 mum; transistor cell; voltage 28 V; Aerodynamics; Computer architecture; Gallium nitride; Linearity; Microprocessors; Power amplifiers; Radio frequency; Digital control; gallium nitride; linearization techniques; peak-to-average power ratio; power amplifiers;
Conference_Titel :
Radio Frequency Integrated Circuits Symposium (RFIC), 2012 IEEE
Conference_Location :
Montreal, QC
Print_ISBN :
978-1-4673-0413-9
Electronic_ISBN :
1529-2517
DOI :
10.1109/RFIC.2012.6242270
