Calculating Measurement Uncertainty w/ Two-Port Calibration

Here is an example of calculating/estimating the measurement error after a two-port calibration has been done. HP provides numbers on the network analyser data sheets for effective directivity, source and load match, tracking, and crosstalk/isolation, sometimes for several different calibration kits. The errors when measuring our example DUT filter has been greatly reduced (0.5 dB reflection error, 0.06 dB transmission error). Phase errors would be similarly small. Note that this is a worst-case analysis since it is unlikely all the errors would add in phase. A less conservative approach to calculating measurement uncertainty would be to use a root-sum-squares (RSS) method. Refer to RSS Method for details