Highly-efficient three-stage Doherty power amplifier with adaptive driving amplifier for 3.5 GHz WiMAX applications

Summary form only given, as follows. This paper reports a new three-stage Doherty power amplifier (DPA) with an adaptive driving amplifier. The driving amplifier inserted at the input of the carrier cell controls the input power of the carrier cell to eliminate the gate leakage current at high input power levels. The gate bias voltage of the driving amplifier is adjusted using an envelope tracking technique according to input power levels. For a WiMAX signal, the proposed DPA has the total DE of 39.5 % at an 8-dB BOP.