Stochastic model and drift dependence of long term stability of type N precision coaxial terminations

This paper discusses a stochastic model fitting process for the determining the calibration interval of precision Type N coaxial terminations. The measurements were taken weekly and over a six month period. The calibration of the vector network analyzer employs one-port error correction model using a sliding load. The observed drift rate is computed using linear regression. A second-order drift was observed. This paper describes possible causes of this mechanism by analyzing the partial differential equations of the one-port error correction model. Discussions on the dependence of long term stability and calibration model are provided.