Millimeter wave power standards

The millimeter wave power standards were developed at SSIA "Metrology" and entirely modernized, automated, and united as The Power Standard for the Frequency Range (37.5 to 178.6) GHz during 1992 to 1995. The uncertainty (99% confidence level) is 0.5% in the (37.5 to 78.3) GHz band and 1% in the (78.3 to 178.6) GHz band. The standard power meters are based on isothermal calorimeters. The unit of power transfer is effected by means of waveguide comparison assemblies and secondary power standards of the autocompensating type. The periodic comparisons of the standard power meters and of those with the power standard of the Russian Federation (2.59 to 37.5) GHz at the frequency 37.5 GHz show agreement and long-term stability of 0.3%. For an independent control in the short wave-length end of the range a special wide-band transducer is calibrated in a microcalorimeter by direct measurement of its thermal losses and compared afterwards with the power standard.