57 efficiency, wide dynamic range linearized heterojunction FET-based power amplifier for wide-band CDMA handsets

摘要

A high efficiency, wide dynamic range linearized power amplifier has been developed for 1.95 GHz wide-band CDMA (W-CDMA) handsets. The amplifier is based on a developed heterojunction FET, and its linearity and efficiency are further improved by incorporating a MMIC predistorter. The output power (P/sub out/) and power added efficiency (PAE) of the amplifier improve significantly from 25.5 dBm and 54.4% to 26.2 dBm and 57.4% respectively after the use of the predistorter, measured at an adjacent channel leakage power ratio (ACPR) of -40 dBc. With bias control, the linearized amplifier also shows an excellent low P/sub out/ (13 dBm) performance, achieving a PAE of 47.7% at the same ACPR criteria. This performance is believed to be the highest PAE reported for W-CDMA handset amplifiers.