Improving the traceability of coaxial impedance measurements at lower RF in the UK

The authors report on a measurement service introduced recently by NPL at Malvern to provide traceability for impedance, and other complex reflection parameters, for coaxial line terminations fitted with APC-7 connectors at frequencies below 50 MHz. The new service is a result of several improvements made to an existing measurement system. These improvements, including the use of robust statistical techniques to reduce the uncertainty of measurement, are discussed and typical results produced by the enhanced system are presented