Repeatability study of commercial harmonic phase standards measured by a nonlinear vector network analyzer

In this paper, we present the first published repeatability study of commercial harmonic phase standards (HPS) measured by a nonlinear vector network analyzer. Specifically, we measure two harmonic phase standards, one of which is specified to 20 GHz and the other to 50 GHz. By performing 5 calibrations and making 100 measurements from 600 MHz to 19.8 GHz at each calibration, we determine the repeatability bounds for the complex wave-variable vectors and associated phases and magnitudes of each harmonic component. We also compare the mean phase values to those supplied by the manufacturer. While we achieve standard uncertainties of no greater than 0.73°, we find significant variations in the mean values with changing HPS conditions and show evidence of a substantial thermal contribution.