A new MESFET nonlinear model

In this paper, a new empirical model for the dc I–V characteristics of a GaAs MESFET transistor is presented. The conventional approach for modeling the dc I–V characteristics of a MESFET transistor adopts the hyperbolic-tangent dependence on Vds through the observation of the Ids versus Vds curve. The derived model is capable of accurately modeling the device current–voltage behavior in different operation regions. The new model equations describe the device drain current as a polynomial of the effective gate–source voltage Veff, which is in turn a rational function of Vgs, and the parameters for the polynomial vary with Vds. Model parameter extraction is made for a 0.5 μm gate-length MESFET device. Measured and modeled results are compared, and good agreement is obtained. A comparison among the proposed model, Curtice's and Chalmers' model, and Parker's model are also made in this paper. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 226–230, 2001.