A new noise measurement method of noise parameters at microwave frequencies

Abstract

This paper proposes a new method for noise parameter measurement of microwave devices. Instead of measuring the noise figure, the optimum source impedance /spl Gamma//sub opt/ is determined by measuring the noise powers corresponding to cold impedances, then, the minimum noise figure F/sub min/ (or minimum effective noise temperature T/sub min/) and noise conductance G/sub n/ are determined by connecting a calibrated hot noise source. Measurements with highly mismatched impedances (magnitude of the reflection coefficient close to one |/spl Gamma/|/spl ap/1) are possible, which is not the case with the classical method. Automatic tuner and isolators used in the classical method are no longer necessary. Using the method described, noise measurement system cost can be reduced and measurement time minimized.