Increased efficiency in QAM power amplifiers

A dynamic biasing procedure designed to improve the average dc-rf conversion efficiency of power amplifiers employing multi-level modulation schemes such as QAM is investigated. In this technique, the gate bias voltage is adjusted in accordance with the phasor currently being transmitted. Simulations show promising results for a 1 W class-A mode power amplifier. A system to address the distortion issue and dynamic bias control is proposed.