Accurate Noise Temperature Measurements on Mismatched Semiconductor Devices

A measurement system has been developed, which allows the direct determination of the noise temperature of a mismatched one-port network without the use of passive nonreciprocal components. Furthermore this radiometer has been extended to measure "cold" noise temperatures without any cooling of the radiometer components used. As an example of application, the radiometer is applied to noise temperature measurements of semiconductor devices. A brief outline of the measurement system is given and practical measurement results are compared with theoretical predictions.