Estudio del efecto de las impedancias fuera de banda sobre la intermodulación en un amplificador a FET utilizando un modelo gran señal

Abstract

GaAs Field Effect Transistors are widely used for medium- and high-power amplifiers. This kind of amplifiers have great influence in the performance of a communication system, as far as cost, power consumption, and signal degradation of the transmitter are concerned. Thus, accurate nonlinear models of the transistors are needed in order to predict their behaviour. In this paper, a large-signal continuous model is extracted from measurements of a transistor. Then, a simple amplifier based on the device has been designed, and simulations are carried out in order to predict the performance of a power amplifier built with this type of transistor. Finally, effects arising from baseband and 2nd-harmonic load impedances are analysed by a load-pull method, and their influence on the IMD behaviour is discussed.