NFRAD - Review of the New Nist Noise Measurement System

The National Institute of Standards and Technology (NIST) has completed design and testing of a new noise measurement system. The new system is capable of measuring noise temperature at multiple frequencies about ten times faster than previous NIST systems. This system will also be used to measure the noise parameters of amplifiers. Required reflection coefficients used to calculate mismatch and asymmetry are no longer measured by a six-port reflectometer in each noise measurement. Instead, they are measured with a vector network analyzer and stored in lookup tables. We have tested radiometers in the frequency ranges 4-8 GHz, 8-12 GHz, and 12-18 GHz. The system tests will be discussed as well as measurements and uncertainty analysis.