Verification of Commercial Probe-Tip Calibrations

We present results of a verification procedure useful in evaluating the accuracy of probe-tip scattering parameter measurements. The procedure was applied to calibrations and measurements performed in industrial laboratories. Actual measurement discrepancies, due primarily to calibration errors, are directly com pared to bounds determined by the comparison method. The results demonstrate the utility of the verification technique as well as serious flaws, particularly at high frequencies, in some conventional calibrations.