HI i am new at RF characterization techniques . I am currently working on the uncertainty estimation for a measurement based on one port S11 reflection measurement. I download the uncertainty calculator and introduced my analyzer and calibration kit. What i want to know is how i have to apply the uncertainty charts for the S11 magnitude and phase accuracy, as i understand the values of the uncertainty will depend on the S11 measured and the frequency range. On my measurement i make a sweep from 0 to 10 GHz, measuring the S11 at each frequency. Is well done if i add the Magnitude uncertainty an the phase uncertainty from the charts to my measurement equations in function of the S11 value i measure at each frequency ?

It's a bit complicated. The uncertainty in S11 is computed as a linear error term, meaning you have to convert the dB value to linear (or use the LinMag display), then add or subtract the uncertainty in the displayed value, and then convert back to dB to get the actual uncertainty at that particular frequency and value of S11. Example: S11=-10 dB, Linmag is .316. If the uncertainty at .316 is 0.02, then the value of S11 ranges from .336 to .296. or to -10.56 to -9.46 dB; that's right, the uncertainty is unevenly spread (in the dB sense).