High gain and high PAE power amplifier by employing adaptive bias control circuit for resonant WPT

In this paper, high-efficiency power amplifier is implemented using adaptive bias control circuit for the wireless power transmission (WPT). The high efficiency power amplifier uses the Class-E amplifier structure because the efficiency of the WPT system is strongly affected by the efficiency of power amplifier. The adaptive bias control circuits consist of the directional coupler, power detector and operation amplifier. And the high gain two-stage amplifier using the drive amplifier is performed for the low input stage of power amplifier. The proposed power amplifier using the adaptive bias control circuit can have high efficiency at lower power level.