Source-pull noise characterization of GaAs pHEMTs

The paper presents results of the four noise parameter measurement of GaAs pseudomorflc high electron mobility transistors (pHEMTs) in the frequency range 0.8-8 GHz. The parameters were determined using an own complex noise characterization method based on the eigth-term linear noise model. The measurements were performed on wafer with the source-pull technique and the state of the art test equipment available for measuring both the noise powers and scattering parameters. From the output noise powers measured in the system for cold and hot states of the noise source, consistent frequency characteristics of the four noise parameters were obtained for the transistors tested. Also the small signal parameters, the insertion power gain and input reflection coefficient of the transistors, determined from the noise measurements, agreed very well with their counterparts calculated using scattering parameters measured. The results show that the complex noise characterization method supported with the novel test equipment can be effectively applied to study noise properties of small-sized transistors.