A bilateral comparison of on-wafer S-parameter measurements at millimeter wavelengths

This paper reports on a comparison of measurements that has taken place recently between two UK-based measurement facilities - the University of Leeds and the National Physical Laboratory. The comparison involved making complex S-parameter measurements of a commercially available co-planar waveguide calibration substrate. Most measurements were made at frequencies up to 65 GHz, although some measurement data was obtained up to 110 GHz. Subsidiary investigations also looked at measurement repeatability and the effects of using different VNA calibration schemes. A breakdown of the likely error processes affecting these measurements as a function of frequency is also given leading to rudimentary uncertainty estimates for such measurements.