Research On Modeling Methods Of Microwave Nonlinear Circuits

It is known to us all that microwave power amplifiers under large-signal condition present behaviors with nonlinearity. In order to optimize the microwave power amplifiers, we must construct large-signal nonlinear cicuits and device models. The goal of this paper is to implement the nonlinear modeling of power GaAs FET based on the small-signal model.In order to compensate the traditional nonlinear characteristics, the new method of depicting nonlinearity, nonlinear scattering function, is brought up; meanwhile its characteristics are discussed. After researching on the method of modeling GaAs FET, we introduce a circuital mothod of extracting S parameters. Relied on the existed small-signal model, large-signal nonlinear model of GaAs FET is then constructed via the measurements of I-V curves of GaAs FET. Finally we validate that this model can be used to describe the large-signal characteristics of power transistors with harmonic balance method.