Characterizing WR-8 waveguide-to-CPW probes using two methods implemented within the NIST Uncertainty Framework

We individually characterize and provide uncertainties for a pair of WR-8 rectangular waveguide-to-coplanar waveguide (CPW) probes over a frequency range of 90 to 140 GHz utilizing two methods implemented within the NIST Microwave Uncertainty Framework. The first method consists of a two-tier approach, where a vector network analyzer (VNA) calibration is first performed in rectangular waveguide, and then a second-tier calibration is performed on-wafer. The second method determines the scattering parameters of the probes from two one-tier calibrations. We show that the two methods yield nearly equivalent results and uncertainties.