Phase distortion mechanism of a GaAs FET power amplifier for digital cellular application

Abstract

A conventional class AB amplifier with high efficiency has phase distortion which is not suitable for a pi /4-shift quadrature phase shift keying (QPSK) signal. A new nonlinear GaAs FET model, instead of the conventional large signal GaAs FET model, is presented. It incorporates the phase distortion mechanism in a class AB amplifier. Using the results of the analysis, the authors designed a low phase distortion power amplifier by optimizing circuit parameters and device parameters, which had a low phase variation of less than 2 degrees .< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>