Calibration accuracy of a 625 GHz on-wafer probe

The accuracy of an on-wafer probe system operating at 625 GHz is analyzed. A weighted least squares analysis is applied to the calibration of a one-port measurement system to propagate the non-systematic errors introduced by probe contact and probe placement variation. The worst-case errors of the 625 GHz on-wafer probe system are found and the combined effects of the VNA extender's power drop-out at the low end of the band with the poor matching of the probe at the high-end results in the 625 GHz probe system being most accurate in the center of the WR-1.5 waveguide band. Between 560 and 625 GHz the worst case error is 0.26 in linear magnitude and 15° in phase for a 0 dB reflection.