In this work, dynamic load modulation of high power amplifiers using a varactor-based tunable matching network is presented. The feasibility of dynamic tuning and efficiency enhancement of this technique is demonstrated using a modular design approach for two existing high efficiency power amplifiers (PA), a 7-W class-E, and a 10-W class-J power amplifier PA at 1 GHz. For this purpose and for each of the PAs, a simple quasi-static inverse model is developed allowing an efficiency-optimized control of the PA and the varactor-based tunable matching network. Modulated measurements using a single carrier WCDMA signal with 11.3 dB peak-to-average ratio (PAR) indicate about 10 to 14 percentage units improvements in the average power-added efficiency (PAE) for the complete architecture.
@article{arxiv.1210.3494,
title = {Varactor-Based Dynamic Load Modulation of High Power Amplifiers},
author = {Ali Soltani Tehrani and Hossein Mashad Nemati and Haiying Cao and Thomas Eriksson and Christian Fager},
journal= {arXiv preprint arXiv:1210.3494},
year = {2012}
}