Offset-short vector-network-analyzer calibration with simultaneous modeling of calibration standards

We present an improved offset-short vector-network-analyzer calibration method which allows to identify broadband equivalent-circuit models of the offset-short standards and an imperfect thru connection. Our approach is based on the multi-frequency formulation of the vector-network-analyzer calibration problem in which parameters of the models are identified simultaneously with the vector-network-analyzer calibration coefficients at all frequencies. Thus, the impact of the constraints imposed by the models is also reflected in the calibration coefficients. We illustrate our approach with experimental results for an offset-short calibration in coaxial 3.5 mm connector. These results demonstrate that our method reduces the impact of measurement errors, and extends the bandwidth of the calibration.