Improvement of Measurement Uncertainty of THz Waveguide Vector Network Analyzers

Even if systematic error terms, i.e. directivity, matching and tracking, in vector network Analyzer (VNA) can be corrected by a calibration process, but it is difficult to ignore the other random error effects, i.e. connection repeatability and flexure effects of cables attached to test ports, etc.. In the THz waveguide VNA using frequency extension modules, LO and RF cables making connection from frequency extension modules to microwave VNA produce a large impact on the uncertainty in the transmission phase measurements. This paper proposes minimization of cable flexure effects of RF and LO cables in the THz VNA using frequency extension modules. Then, VNA error model including the LO and RF cable flexure effects are discussed.