A GaAs HBT programmable linear power amplifier

A three-stage power amplifier with a novel programmable linearization input stage is proposed and designed. The input stage with dual feedback loops can predistort the input signal to compensate the gain compression and phase distortion attributed from the following stages. The power amplifier demonstrated a peak PAE of 62% at the output power of 30.5dBm operating at 1.75GHz to 1.95GHz. At 27dBm output power level the adjacent channel power rejection ratio (ACPR) is less than -44dBc at a 1.25MHz offset frequency.