The electron device modelling is a research topic of great relevance, since the performances
required to devices are continuously increasing in terms of frequency, power and linearity: new
technologies are affirming themselves, bringing new challenges for the modelling community. In
addition, the use of monolithic microwave integrated circuits (MMIC) is also increasing, making
necessary the availability, in the circuit design phase, of models which are computationally efficient
and at the same more and more accurate. The importance of modelling is even more evident by
thinking at the wide area covered by microwave systems: terrestrial broadband, satellite communications, automotive applications, but also military industry, emergency prevention systems
or medical instrumentations.
This work contains a review of the empirical modelling approach, providing the description of
some well-known equivalent-circuit and black-box models.
In addition, an original modelling approach is described in details, together with the various
possible applications: modelling of nonquasi-static phenomena as well as of low-frequency
dispersive effects. A wide experimental validation is provided, for GaAs- and GaN-based devices.
Other modelling issues are faced up, like the extraction of accurate models for Cold-FET or the
more convenient choice of the data-interpolator in table-based models.
Finally, the device degradation is also treated: a new measurement setup will be presented, aimed
to the characterization of the device breakdown walkout under actual operating conditions for
power amplifiers