Accurate prediction of intermodulation distortion in GaAs MESFETs

Abstract

A previously proposed look-up-table based mathematical approach forthe modeling of micowave active devices, the Nonlinear Integral Model, is applied for the prediction of intermnodulation distortion (IMD) in GaAs MESFETs. Theoretical considerations and experimental results show that the intermodulationcharacteristics of GaAs MESFETs can be predicted with excellent accuracy by using the proposed model together with suitable electron-deviceoriented interpolation techniques, directly on the bases of conventional measuremerts (DC characteristics and biastfrequency dependent small-signal S-parameters).

A modified Volterra series approach for nonlinear dynamic systems modeling

“…Relatively short duration of nonlinear memory phenomena is commonly encountered in devices whose response must be necessarily "fast," as happens for instance in sample-hold devices or electron devices when described in a voltage controlled form. 6 Thus, the accuracy of the nonlinear dynamic model in (37) [11, nonlinear integral model, (NIM )]) obtained by truncating the modified Volterra series to the first term has been experimentally verified for field-effect transistors operating at microwave frequencies under strongly nonlinear operation [10], [16]- [18]. The extension of the model in (37) to the case of two-port electron devices is straightforward since it is sufficient to consider (37) as a matrix description where and are the vectors of port currents and voltages, and , suitable 2 2 matrices.…”