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A new empirical nonlinear model of GaN-based electron devices is presented in the article. The model takes into account low-frequency dispersion due to self-heating and charge-trapping phenomena and provides accurate predictions at frequencies where nonquasi-static effects are important. The model is based on the application of a recently proposed equivalent-voltage approach and is identified by using pulsed measurements of drain current characteristics and pulsed S-parameter sets. Full experimental validation on a GaN on SiC PHEMT is provided at both small- and large-signal operating conditions. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008. [ABSTRACT FROM AUTHOR]

Theoretical and practical issues concerning the nonlinear dynamic modelling of electron devices are discussed in this article. All the different dynamic phenomena, which are important for the description of the device behaviour, are comprehensively dealt with by means of a unified mathematical derivation. In particular, both the “fast” dynamics associated with charge-storage phenomena at high operating frequencies and the “slow” dynamics of low-frequency dispersion, due to device self-heating and “charge-trapping” effects in deep-bulk and surface regions, are simultaneously taken into account. The result is an empirical, technology-independent and nonquasi-static model of electron devices, suitable for a simple and reliable identification procedure and based on conventional measurements of static characteristics and bias- and frequency- dependent small-signal parameters. The model implementation in the framework of commercially available CAD tools is also outlined in this article. Experimental validation, based on a GaAs p-HEMT, is also presented. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006. [ABSTRACT FROM AUTHOR]

Low-frequency dispersive phenomena due to self-heating and/or “traps” (that is, surface-state densities and deep-level traps) cause important dynamic deviations in the I/V characteristics of III-V devices and they must be taken into account when an accurate large-signal dynamic model is needed. To this end, different low-frequency dispersive I/V models have been proposed by the research community and, quite often, a characterization based on pulsed I/V measurement systems has been suggested as the most appropriate for the identification of model parameters. Unfortunately, besides requiring special-purpose setups, pulsed characterization may suffer from some drawbacks, as discussed in this article. As an alternative, a simple large-signal measurement setup is presented here, which is based on low-frequency sinusoidal excitations and can be easily implemented by means of conventional general-purpose laboratory instrumentation. The proposed setup is successfully adopted in this article to identify the dispersive I/V characteristics of a GaAs PHEMT large-signal model providing excellent prediction of intermodulation distortion at Ka-band frequencies. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005. [ABSTRACT FROM AUTHOR]