Characterizing artefact standards for use with coaxial vector network analyzers at millimeter-wave frequencies

Traceability for vector network analyzer (VNA) measurements in coaxial lines smaller than 2.4 mm is problematic. The common method for traceability is to use precision coaxial air lines as primary standards. Since slotless lines are not commercially available in lines of this size, the air lines used are difficult to connect, extremely delicate, and expensive to replace. This paper describes a method of characterizing artefacts to use as standards, including specially designed and manufactured air-dielectric shielded open-circuits of various offset lengths as well as offset short-circuits and well-matched loads available in commercial VNA calibration kits. This will provide traceability using more robust and easier to use standards for calibration of the VNA. The proposed method is illustrated by measurement results obtained in 1.85 mm coaxial line (to 65 GHz.).