Accuracy improvements in microwave noise parameter measurements

Factors contributing to the accuracy of microwave noise parameter measurements are examined theoretically and experimentally. It is shown that for good accuracy the test source impedances need not be grouped around the impedance that produces the minimum noise figure. System calibration and device under test (DUT) S-parameter accuracy are important to the derived noise parameter accuracy, and the use of a vector network analyzer is advantageous. An algorithm is implemented which avoids errors caused by different noise-source 'on' and 'off' impedances.<>