Measurement and characterization of precision 7 mm and 3.5 mm coaxial air lines at NMC, A*STAR

This paper presents works on measurement and characterization of coaxial air dielectric transmission lines (air lines) at the National Metrology Centre (NMC) of the Agency for Science, Technology and Research (A*STAR) of Singapore. The air line is one of the realizable and calculable impedance standards directly traceable to the national standard of length. Diameters of two beadless air lines of 7 mm and 3.5 mm connectors are measured by using an automated air-gauging system established recently and their characteristic impedances are calculated from measured diameters.