We present graphically a novel FET synthesis technique based on the derivative structure observed in real GaAs MESFETs. The synthesis allows the generation of continuously differentiable linear or nonlinear transfer characteristics.

We present an analysis of a 4-FET Transconductor at medium frequencies, using a more realistic GaAs MESFET model, to calculate optimum device widths to minimise 2nd order distortion. Provisional analytical results are compared with SPICE simulations using the Parker Skellern model. A multi-FET Frequency Doubler is similarly analysed to calculate optimum device widths for high fundamental rejection and optimum load for 3rd order distortion nulling. The high frequency degradation of the 4-FET Transconductor is discussed. Simulated performance of two high frequency distortion compensated Linearised Isolator designs, together with a variation of the Frequency Doubler, show good performance at high frequencies.>

The non-linearity demonstrated by a circuit is a function of the device nonlinearity, its parasitic components and the circuit components in which it is embedded. We demonstrate that the common source stage, which is used extensively for Device Characterisation, presents a very complex form of Device-Circuit Interaction, which makes reliable extraction of its intrinsic non-linear parameters extremely difficult. We show how pulse measurements can provide a straight forward access to parameters needed for Volterra Analysis and show the true nature of output conductance.>

Described is an alternative simple description of FET drain current that provides the flexibility of an extra parameter which can be chosen to approximate the Shockley expression or general power law. An empirical polynomial expression which uses only integer powers is used to provide computational efficiency. The expression gives the designer a more accurate FET model which is consistent for both large- and small-signal simulations.>