A New Waveguide Flow Calorimeter for Levels of 1-20 W

A new dual waveguide flow calorimeter power meter used as a master reference standard in a top-echelon calibration laboratory is described. It operates at 1-20-W level and has been produced in 9 standard waveguide sizes from WG10 (WR284, R32) to WG22 (WR28, R320). These all have a VSWR 1.05 and a flat and stable RF/dc substitution efficiency over the full waveguide bandwidth. Referring only to dc standards, the Effective Efficiency Factor can be measured with built-in facilities. Comparison measurements with U. K. national standards have shown agreement within ±0.2 percent over 3 years.