Improved use of the UK waveguide noise standards

摘要

Historically, the development of the UK waveguide standards at the same time as the development of the radiometer in each frequency band has meant that the standard and the radiometer have developed as a single unit. In particular, the standard is operated and controlled by the same system and software as the radiometer. This means that each standard can only be used with its associated radiometer. Advances in the characterisation of adaptors and tapers has led to a situation where this is no longer the ideal solution and a new approach where the standard is used and controlled separately is described here. The new approach means that it is now possible to perform a waveguide calibration using a coaxial radiometer with minimal increase of uncertainty. Furthermore, it has also been demonstrated that with the use of calibrated adaptors, this method can produce a lower uncertainty for coaxial noise source calibrations.