Title :
Design for linearizability of GaN based multi-carrier Doherty power amplifier through bias optimization
Author :
Hammi, Oualid ; Sung-Chan Jung ; Ghannouchi, Fadhel M.
Author_Institution :
Electr. Eng. Dept., KFUPM, Dhahran, Saudi Arabia
Abstract :
In this paper, a GaN based symmetrical Doherty power amplifier is designed. The Doherty amplifier bias conditions are optimized for a trade-off between power added efficiency and linearity. The carrier amplifier is biased for linearity and the peaking amplifier bias is chosen for maximum power added efficiency. Measurement results under a four carrier WCDMA drive signal show respectively 43% power added efficiency and -32.5dBc adjacent channel leakage ratio at 6dB output power back-off. Linearization of the designed Doherty PA using baseband digital predistortion led to quasi perfect cancellation of spectrum regrowth while operating at an output power back-off equal to the input signal´s peak to average power ratio.
Keywords :
III-V semiconductors; code division multiple access; gallium compounds; power amplifiers; radiofrequency amplifiers; spectral analysis; wide band gap semiconductors; Doherty PA; GaN; adjacent channel leakage ratio; baseband digital predistortion; bias optimization; carrier WCDMA drive signal; carrier amplifier; gallium nitride based multicarrier Doherty power amplifier; input signal peak to average power ratio; linearity amplifier; linearizability; linearization; output power back-off; peaking amplifier bias; power added efficiency; power added linearity; quasi perfect cancellation; spectrum regrowth; symmetrical Doherty power amplifier; Linearity; Multiaccess communication; Optimization; Power measurement; Predistortion; Spread spectrum communication;
Conference_Titel :
Electronics, Circuits and Systems (ICECS), 2012 19th IEEE International Conference on
Conference_Location :
Seville
Print_ISBN :
978-1-4673-1261-5
Electronic_ISBN :
978-1-4673-1259-2
DOI :
10.1109/ICECS.2012.6463701
