A linearity-improved multi-band envelope tracking Tx power amplifier under antenna mismatch for mobile applications

Abstract

A linearity-improved multi-band envelope tracking power amplifier (ET PA) with digital predistortion (DPD) under antenna mismatch is introduced based on the advanced mismatch detection and correction technique. An advanced tunable output matching network (TOMN) is utilized to correct the mismatch and to reconfigure the operating band, simultaneously. An advanced phase shifter and an operating algorithm are newly proposed to detect mismatch on the multi-band PA and are realized as a compact integrated circuit (IC), facilitating self-contained operation without external control. The mismatch detector and RF switches for the TOMN were integrated into a single IC using silicon on insulator (SOI) CMOS, which was integrated with a 2-m InGaP/GaAs HBT PA monolithic microwave integrated circuit (MMIC) into a single module. With long-term evolution (LTE) signal, the fabricated ET PA demonstrates a linearity improvement of 2-2.4 dB under 2.5:1 voltage standing wave ratio.