On the Definition of Reference Planes in Probe-level Calibrations

In this contribution we analyze the definition of reference planes in probe-level calibrations. The removal of the probe type from the calibration definition is presented first analyzing the transition discontinuities and defining to which extent they have to be incorporated in the calibration error terms. Subsequently a commercial calibration, which is defined specific to a probe topology, is considered and its frequency dependent standard response are computed accurately via a 3D EM simulator. These probe independent standard definitions are then used to compare the accuracy achieved on the same structures, (i.e., CPW lines of different lengths) from two different probe topologies. Finally, the data from both probes are compared, using a worst bound metric, to the data achieved when using the probe specific calibration data showing an accuracy improvement for the probe independent approach, validating the improved identification of the reference plane proposed here.