Covariance-matrix-based Uncertainty Propagation Analysis For S-parameter Measurements And Application

Along with the rapid development of modern wireless communicationtechnology, vector network analyzer (VNA), which is used to characterizevarious parameters of high frequency and microwave signals, has been widelyutilized. As an effective and directive measurement instrument for networkparameters, the VNA measurement uncertainty analysis has its own significance.So far, many microwave physical parameters, such as power, time-domainvoltage or current waveform which are determined by S-parameters. While mostof the VNA uncertainty propagation analysis is focus on the value of S-parameter itself, and the method of S-parameter uncertainty propagate to thephysical parameters has not been analyze. In this case, it is inevitable to explorean effective method on the further propagation of VNA uncertainty.This thesis does some research on relevant studies and puts forward theVNA S-parameter measurement uncertainty analysis principle based on thecovariance matrix. Firstly, this thesis introduces S-parameter measurementplatform in detail and VNA measurement uncertainty sources, which mainly dueto the systematic and random effects. The ultimate source of the uncertaintycaused by systematic effects is the calibration standards. Secondly, VNAmeasurement uncertainty propagation process has been given according to theVNA calibration process, and the general expression formulas of the VNAmeasurement uncertainty propagation have been derived. Finally, the thesischooses calibration process of two instruments, which are the microwave powermeter calibration and broadband harmonic phase reference calibration, toanalyze the further propagation of the uncertainty. It is according to thecharacteristics of vector correction and parameter calculation that based on thereflection coefficient measured by VNA. Monte Carlo simulation has been alsoused to verify the proposed method.It is a difficult task to analyze the uncertainty of microwave instrument, theuncertainty described in this thesis is just one of the sources of uncertainty.There are other sources like temperature, humidity and other environmentalchanges on devices.