On the uncertainty of network analysis methods for the calibration of electrical impedance standards at high frequency

Network analysis methods allow to determine the frequency dependence of impedance standards in the so-called LF-RF gap (roughly from 100kHz to 100MHz). Several papers in literature applied the methods on four terminal-pair gas-dielectric capacitors, for which lumped-parameter electrical models have been developed. The methods ask to perform several measurements with a vector network analyzer (VNA), and to perform calculations in the complex field. The uncertainty expression of the measurement outcome becomes an issue, the calculations involved being impossible to be carried out by hand. We propose here to extend a new software (VNA Tools II) by writing dedicated analysis program. The propagation of uncertainty through the measurement model can thus be performed in an automated way by taking into account the strong correlations between the individual VNA readings. Examples of application of the analysis on measurements performed with the so-called S-matrix method are given.