Accuracy estimation of mixed-mode scattering parameter measurements

The pure-mode vector network analyzer (PMVNA) provides direct measurement of differential circuits. Residual error models are derived for the PMVNA and a traditional four-port vector network analyzer (FPVNA). The residual error models are used to calculate the maximum and root-mean-square uncertainties in measurements of mixed-mode scattering parameters of a typical differential amplifier. The uncertainties produced by the PMVNA are compared to the transformed mixed-mode S-parameters of the FPVNA. The PMVNA is shown to have lower uncertainty when measuring differential devices.