Switched-Coupler Measurements for High Power FR Calibrations
J. W. Allen
Calibration of RF power sensors at levels greater than 10 mW and uncertainties on the order of 2 % need not require complex calorimetric methods. Using a series of cascaded directional couplers makes it possible to compare a high-power RF sensor against a calibrated, low-power, bolometer mount. For power levels up to 1 kW, typical uncertainties are on the order of 2 % or better. This paper describes the design and operational theory behind the new high-power measurement system recently developed at the National Institute of Standards and Technology (NIST). This new system makes use of the established low-power bolometer calibration service, and extends our measurement capability up to 1 kW in the 2 MHz to 1000 GHz frequency range.
microcalorimeter, microwave calorimeter, microwave power measurement, microwave power standard waveguide, microwave power standard