  In this work, we present a linear uncertainty (LU) propagation treatment of
measurement and model uncertainties in multiline thru-reflect-line (TRL)
calibration. The proposed method is in accordance with the ISO Guide to the
Expression of Uncertainty in Measurement (GUM). We demonstrate with numerical
simulation based on the Monte Carlo (MC) method that our proposed LU method
delivers identical uncertainty as the MC method but in a more efficient way.
