Complex microwave noise parameter measurement using a coaxial radiometer

A technique has been described for the measurement of the complex noise parameters of an active device using a computer controlled coaxial radiometer designed for noise source calibration. The uncertainties on the measured parameters are fully traceable to National Standards. The current values yield an uncertainty of +or-0.2 dB in noise figure at the 95% confidence level. This is limited largely by the uncertainty on the primary noise standard to which all the noise source calibrations are traceable. This primary standard will be replaced in the near future and a lower uncertainty level is predicted. The system used is limited to the frequency band 10 MHz to 18 GHz, but the technique can in principle be applied to any total power radiometer.