Comparing accuracy of waveguide VNA measurement calibrated by TRL calibration using different length of line standard in terahertz band

We have evaluated the measurement uncertainty for rectangular waveguide Vector Network Analyzer (VNA) measurements in the WM-250 (WR 1.0), 750 GHz - 1.1 THz frequency band. We developed a new waveguide flange design for precise connections and dimensional measurements to establish traceability to SI in VNA measurements. TRL calibration method is useful for VNA calibration in the millimeter wave frequency region, but TRL line standards become thin, fragile and then increment of the risk of breakage of line standard at connection/reconnection cycle. This is the total investigation of measurement uncertainty for VNA measurement at Terahertz band comparing between both calibrations performed by single thin line and double thick lines as TRL line standards.