Improving the accuracy and metrological support of power meters in the frequency range from 37.5 to 178.6 GHz

To satisfy the needs for metrological support of power measurements in the frequency range from 37.5 to 178.6 GHz, the device has been developed and designed for automated measurements, calibrations and verification of wattmeters with high accuracy and the ability to adapt to various types of devices under investigation. This paper presents the composition, diagram andgeneral principle of the device. A description of the structure of isothermal calorimetric converters of autocompensation type with dry load and reference body, which are the basis of the device, is given. The implemented algorithms for converting and replacing microwave power with direct current power of the developed calorimetric wattmeters are presented. The measures taken at the manufacturing stage to minimize sources of measurement uncertainty are described. To assess the accuracy of measuring the absorbed power, a mathematical model of the conversion factor has been compiled. Corrections have been introduced into this mathematical model to improve the measurement accuracy of the reproducible microwave power. The obtained basic metrological and technical characteristics of calorimetric wattmeters and comparison equipment of the device are presented. The obtained metrological and technical characteristics correspond to the current level of standard equipment.