Derivation of The Measurement Deviations Caused by Two-Port VNA Hardware Features

In this paper, the deviation contributions influenced by actual vector network analyzer (VNA) hardware features are determined. The raw and final measured values are regarded as multivariate functions of the error terms based on the widespread short-open-load-thru (SOLT) 12-term error model, with the linear terms of Taylor’s series near the ideal values of the error terms taken as reasonable estimations of the error. The calculated and ideal values of the error terms obtained in calibration steps are hence substituted to derive the deviation contributions of those terms to the raw and final measurement result. Two different VNAs (Keysight 5227A and Ceyear 3671E) are utilized to measure the network under test with known parameters serving the same calibration steps. In the research, reflection tracking error has the greatest influence on the raw measured values, but only the load mismatch error is a deviation contributor to the final measured values. The correctness and effectiveness of the method are verified by comparing the measurement results.