Accurate Nonlinear Resistive FET Modeling for IMD Calculations

This work discusses the nonlinear modeling procedures required for intermodulation distortion (IMD) calculations of MESFETs biased in the resistive (linear) region. An automatic full two-sided characterization of Ids(vgs, Vds) is compared against the previously published extraction of Ids(vds) in this problematic region. It is shown that this one-sided Taylor series extraction is insufficient for most applications of the FET in its triode zone, and thus an alternative method is proposed.