The AB-C Doherty power amplifier. Part I: Theory
Article first published online: 3 NOV 2008
Copyright © 2008 Wiley Periodicals, Inc.
International Journal of RF and Microwave Computer-Aided Engineering
Volume 19, Issue 3, pages 293–306, May 2009
How to Cite
Colantonio, P., Giannini, F., Giofrè, R. and Piazzon, L. (2009), The AB-C Doherty power amplifier. Part I: Theory. Int J RF and Microwave Comp Aid Eng, 19: 293–306. doi: 10.1002/mmce.20350
- Issue published online: 6 APR 2009
- Article first published online: 3 NOV 2008
- Manuscript Accepted: 20 JUL 2008
- Manuscript Received: 20 MAR 2008
- Doherty Amplifier;
- power amplifier;
- high efficiency;
- active load modulation
In this article, the complete theoretical analysis of a Doherty amplifier employing a Class AB bias condition for the Main and a Class C one for the Auxiliary devices, respectively, is presented. Starting from the simplified model of an active device, the analysis of the AB-C Doherty behavior is carried out as a function of the input signal. In particular, the proposed approach is based on the analysis of the output drain current waveforms generated by the two active devices, while assuming a Tuned Load configuration (i.e., short circuit condition) for higher harmonic terminations. A closed form formulation is derived in order to directly design an AB-C Doherty amplifier, while fully understanding the basis of its physical behavior. Finally, which Doherty parameters can be chosen by the designer or have to be implicitly fixed are discussed and clarified. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.