Two different ways in evaluating the uncertainty of S-parameter measurements

The expression of uncertainty of scattering parameter measurements in vector network analysis is an active research subject, since no full consensus about proper algorithms for such expression has been reached so far. Recently, two software packages have been acquired at INRIM, which allow to perform this task in a metrological framework. In this paper we compare the result of analysis performed by two packages, VNA Tools II and Multiport Measurement Software version 4 (MMS4). Both packages claim to perform uncertainty analyses fully compliant to the Guide of expression of uncertainty in measurement, but following completely different approaches. We organized a comparison by performing, with both packages, analyses of the very same datasets. These have been generated by real measurements on passive standards with a commercial vector network analyzer. Results of the comparison give consistency of the uncertainty analyses performed by the software packages, which can be therefore considered equivalent and mutually validated.