This paper presents a new modeling approach accounting for the nonlinear description of low-frequency dispersive effects (due to thermal phenomena and traps) affecting electron devices. The theoretical formulation is quite general and includes as particular cases different models proposed in the literature. A large set of experimental results, oriented to microwave GaN power amplifier design, is provided to give an exhaustive validation under realistic device operation.

This paper presents a new original approach to power amplifier design, which is mainly based on low-frequency nonlinear empirical electron device (ED) characterization. The proposed technique enables the same level of accuracy provided by expensive load-pull measurement systems to be obtained through a relatively simple and low-cost setup. Moreover, ED currents and voltages related to reliability issues can be directly monitored. Different experimental examples based on power GaAs and GaN field-effect transistors are provided to demonstrate the validity of the proposed approach.

A technology-independent large-signal model of electron devices, the nonlinear integral model (NIM), is proposed. It is rigorously derived from the Volterra series under basic assumptions valid for most types of electron devices and is suitable for harmonic-balance circuit analysis. Unlike other Volterra-based approaches, the validity of the NIM is not limited to weakly nonlinear operation. In particular, the proposed model allows the large-signal dynamic response of an electron device to be directly computed on the basis of data obtained either by conventional measurements or by physics-based numerical simulations. In this perspective, it provides a valuable tool for linking accurate device simulations based on carrier transport physics and harmonic-balance circuit analysis algorithms. Simulations and experimental results, which confirm the validity of the NIM, are also presente

The purpose of this letter is to present an experimental analysis of the temperature effects on the small-signal equivalent circuit of a GaN HEMT. With the aim of contributing to the exploration and advancement of this technology for high-power and high-temperature applications, the major intrinsic RF figures of merit together with the positive derivative of the real parts of the impedance parameters versus frequency are deeply investigated versus ambient temperature.

In this paper, a new model formulation is presented that correctly accounts for low-frequency dispersion (i.e., trapping and thermal phenomena) affecting field-effect transistors (FETs). In particular, for the first time a behavioral description is applied only to the intrinsic current generator, enabling the correct measurement-based evaluation of the intrinsic device operation. The model, which is by construction technology independent, has been extensively validated considering a GaN FET. This choice is justified by the large interest around this technology and by the presence of dispersion effects that must be accurately accounted for.