Over-determined offset short calibration of a VNA

Abstract

Electromagnetic modeling of coaxial 1:85mm and 1:0mm standards for Vector Network Analyzer (VNA) calibration shows only limited accuracy. The approach presented in this paper can overcome this accuracy limitation. Instead of handing over the standards’ S-parameters to the calibration algorithm, parameterized models of the standards are used as input into the calibration algorithm. The technique is demonstrated with an offset short calibration where the unknown phase constant of the short’s parameterized model is estimated with the calibration algorithm. No assumptions on the frequency dependency of the phase constant are needed. Further on we describe the best constellation of the offset shorts’ reflection coefficients in the Smith chart when calibrating a one-port.