Developments in coaxial power standards at NPL

A 2.4 mm twin line coaxial calorimeter is the first microwave power standard in this line size to be developed at the National Physical Laboratory (NPL). The design is based on a twin line coaxial calorimeter where RF power dissipated in one load is measured in terms of a DC power dissipated in a similar load with its effective efficiency derived from a thermal and electrical analysis of the twin lines. The calorimeter will provide traceable power measurements from DC to 50 GHz between power levels of 0.1 and 10 mW with an uncertainty ranging from 0.5% at 10 MHz to 2.3% at 50 GHz at the 1 standard deviation level.