Precise determination of open circuit capacitance of coplanar probes for on-wafer automatic network analyser measurements

When coplanar probes are used, the open circuit reflection standard in the SOLT calibration technique is usually the most questionable of the four. This standard is described in the ´cal kit´ as a capacitance, the value of which is determined in a ´cut and try´ way. A more direct method is proposed by the authors.