GaN HEMT noise modeling based on 50-Ω noise factor

The extraction of a high-frequency ivalent circuit model plays a fundamental role for the development of any emerging transistor technology. Indeed, an equivalent circuit can provide a valuable support for microwave engineers to ensure a fast and reliable optimization of both device fabrication and circuit design. As far as gallium nitride (GaN) HEMTs are concerned, research efforts have been mostly focused on determining equivalent circuits able to reproduce their large-signal behavior. Nevertheless, an increasing amount of interest is also being devoted to noise equivalent circuits, due to the interesting GaN technology noise performance. Within this context, the purpose of the present paper is to extract and fully validate an accurate noise model for GaN HEMTs based on a simple, fast, and reliable extraction procedure. The noise model is obtained by assigning an equivalent noise temperature to each resistor of the small-signal equivalent circuit. The accuracy of the extracted noise model is confirmed by the good agreement between measured and simulated high-frequency noise parameters.