Accuracy factors in microwave noise parameter measurements

The authors have investigated various factors responsible for inaccuracies in microwave noise parameter measurements, including the number of source admittances, the position of the admittances on the Smith chart in relation to DUT (device under test) parameters, the accuracy of the source admittances and device S-parameters, and the effect of changing noise source impedances. It is shown that the test source impedances do not need to be grouped around the impedance for minimum noise. Calibration and DUT S-parameter accuracy is shown to be important to the noise parameter accuracy. A novel algorithm has been implemented which corrects for different noise source ´on´ and ´off´ impedances. The feasibility of noise parameter measurements with less than 0.1-dB variations of F/sub min/ with frequency with high throughput has been shown.<>