Linearity improvement of three-way Doherty amplifier using power tracking bias supply method

Abstract

This letter presents highly linear three-way Doherty power amplifier (DPA) using power tracking bias supply method. The drain biases of carrier and peaking amplifiers and the gate biases of peaking amplifiers are adoptively controlled by the power tracking circuit according to average power levels of the input signal. For validation, a three-way DPA is implemented using 30-W Si LDMOSFETs and tested for two-tone and 1-carrier WCDMA signals at 2.14 GHz. The measured results show the notable linearity improvement over a wide output power range. (c) 2008 Wiley Periodicals, Inc.