Quantifying Receiver Nonlinearities in VNA Measurements for the WR-15 Waveguide Band

Scattering (
${S}$
)-parameters are fundamental to numerous microwave quantities, including antenna factors, microwave power, and phase. The uncertainty in
${S}$
-parameter measurements is influenced by the test setup, including instrument noise, drift, and position of the cables. In this article, we present a model to assess the uncertainty in
${S}$
-parameter measurements due to nonlinearity in the receivers of a vector network analyzer (VNA). We developed a model that describes the nonlinearity of raw wave parameters and can be propagated through the corrected
${S}$
-parameters. We designed an experiment to extract the parameters of our model for a test setup from measurements of a series of devices under test and demonstrated our model for the WR-15 rectangular waveguide band. This model can correct for or assess uncertainties due to receiver nonlinearity on
${S}$
-parameter measurements and is agnostic to the calibration method used. Using our model, we assess the effects of receiver nonlinearity on calibration error coefficients and the corrected
${S}$
-parameters of one- and two-port devices under test (DUTs).