Envelope tracking power amplifier with static predistortion linearization

An efficiency enhanced power amplifier is presented. The amplifier uses envelope tracking (ET) technique and static predistortion to achieve high linearity. The effects of drain voltage modulation to experimental amplifier's gain, phase as well as bandwidth are measured using simple single-tone tests and discussed. Then the amplifier's ET performance is evaluated. The complete envelope tracking system uses 16 QAM modulated 1 MHz bandwidth signals. The amplifier's single-tone power added efficiency (PAE) was measured to be 38% with 20 dBm output power and average PAE for 16 QAM was 39% with average output power of 20 dBm. The amplifier achieved roughly 25 dBc ACPR, which improved to roughly 50 dBc after adding predistortion.