Millimetre wave primary noise standards in waveguide bands 18–170 GHz

Accurate measurement of millimetre wave systems in terms of their noise performance is dependent on the evolution of appropriate and convenient standards. The popular use of noise diodes as a transfer standard have limitations in terms of their frequency coverage and absolute accuracy. Consequently significant errors arise in the calibration of sensitive radiometers and other low noise components or instruments. A convenient laboratory cryogenic primary standard is described which allows improved accuracy whilst extending the prior art to frequencies as high as 170 GHz.