Propagation Constant Measurement Based on a Single Transmission Line Standard Using a Two-port VNA

This study presents a new method for measuring the propagation constant of transmission lines using a single line standard and without prior calibration of a two-port vector network analyzer (VNA). The method provides accurate results by emulating multiline standards. Each line standard is realized by sweeping an unknown network along a transmission line. The network need not be symmetric nor reciprocal, but must exhibit both transmission and reflection. We performed measurements using a slab coaxial airline and repeated the measurements on three different VNAs. The measured propagation constant from all VNAs is nearly identical. By avoiding disconnecting or moving the cables, the proposed method eliminates errors related to connector repeatability, resulting in improved broadband traceability to the SI units.