DETERMINATION OF PHEMTS MICROWAVE NOISE PARAMETERS ONLY BY MEANS OF THE SMALL-SIGNAL EQUIVALENT-CIRCUIT AND EXPERIMENTAL COMPARISONS

The purpose of this paper is to develop an analytical method in order to model the noise parameters of pseudomorphic HEMT's. The principal i nterest of this method is that it does not need adjustable parameters and it only needs the knowledge of the components of the small signal equivalent circuit. It takes into account all the thermal noise source s associated to the resistors and the noise of the channel is describe d by a noise current source with a spectral density 4kT(0)(g(m) + g(ds )). The theoretical results are compared to our measurements but also to other measurement technique involving a part of modelization (Dambr ine [7]). We show that the agreement is excellent for the four noise p arameters as well versus the frequency as versus the bias.