An automatic measurement system for traceable characteristic impedance in coaxial air lines

An automatic measurement system for traceable characteristic impedance of coaxial air lines is introduced. The system is used to measure conductor diameters of air lines with precision connectors. It is composed by inner diameter of outer conductor (IDOC) and outer diameter of the inner conductor (ODIC) measurement setup. In this system, a new automatic measuring technology with capacitance sensor is established for IDOC. As an example, the measurement results of three 2.4mm air lines are shown. Analysis on the uncertainty of conductor diameters and characteristic impedance of coaxial air lines is given finally.