A Coaxial Radio-Frequency Power Standard

A coaxial calorimeter intended for use as a reference standard of radio-frequency power is described. It is designed to operate at power levels up to 100 mW and frequencies up to 6 GHz. The calorimeter is of the twin-load type; one load being the calorimetric body while the other provides a reference level of temperature. The input connector is a General Radio type 900 precision connector. The sensitivity of the calorimeter is about 50 μV/mW and this has been achieved by means of a multijunction thermopile. The uncertainty in the measured power level has been estimated to vary from ±0.20 percent at low frequencies to ±0.37 percent at 6 GHz.