Large-signal modeling of GaAs MESFET operation

Abstract

A numerical modeling technique is described which allows the accurate large-signal characterization of highly doped (>10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">23</sup> m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> ) GaAs MESFET's. A rigourous two-dimensional numerical analysis is used to extract the FET terminal currents. Specially formulated finite difference equations are used to produce stable, accurate, and efficient solutions. By embedding the device in a simple circuit model, a two, terminal time domain response is obtained which is Fourier analyzed to produce a "device surface". The technique is applied to the analysis and design of a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ku</tex> -band monolithic microwave Oscillator, using a 0.5-µm gate length MESFET. A simple equivalent circuit model is proposed which predicts an output of 4 dBm at 16.2 GHz for this oscillator.