Automatic Noise Temperature Measurement through Frequency Variation

The dependence of two-port noise temperature on the source reflection factor does not lend itself to easy automated measurement. This paper shows that a noise analysis performed over a small frequency interval centered about the frequency of interest and with a source circuit having fast phase variations leads to a straightforward solution of the problem. The conditions for applying the procedure are broad enough to enable measuring most components like transistors and amplifiers over the entire microwave range. An example of practical implementation is presented.