Accuracy Improvements in Microwave Noise Parameter Determination

An improved method for the determination of noise parameters from several noise figure measurements on arbitrary source reflections is presented. By applying a transformation algorithm to the measured data, the influence of measurement errors is substantially reduced. The straight forward method needs no iterative estimation of the noise parameters. Synthetic measurements with random measurement errors associated to the measured noise figures as well as to the measured source reflection coefficients were investigated. It is shown, that the magnitude of the source reflection coefficients used for noise figure measurements should be smaller than 0.8, regardless of the magnitude of the optimum noise source reflection coefficient. The new determination method was implemented in a commercial noise parameter system where the measurement capabilities for small transistors was improved considerably.