Recent and Future Developments in Millimetre and Sub-millimetre Wavelength Measurement Standards at NPL

With the rapidly growing interest in millimetre-wave and sub-millimetre-wave systems, the lack of traceability for measurements at these wavelengths is becoming ever more of a problem. Making comparable measurements of fundamental parameters, such as power, is very difficult and no proper calibrations traceable to SI realisations are available. At NPL, work undertaken in the 1980s led to the development of the photo-acoustic power meter by QMC, London (now marketed commercially by Thomas Keating) but this does not easily address measurements of power in waveguide. NPL also has comprehensive standards (power, S-parameters, noise and attenuation) in waveguide up to 110 GHz but nothing (until recently) at higher frequencies.