Contactless and local measurement of temperature fluctuations at 60 GHz

The study is aimed at reviewing the possibilities provided by millimetre waves for local and contactless measurement of temperature fluctuation Delta T. The authors propose to measure the noise temperature of oxygen molecules with a 60 GHz radiometer, allowing contactless measurement. The most original feature of the device is within the open resonator used as a sensor which allows local measurement. Moreover, for atmospheric measurements, the influence of water droplets can be easily taken into account by using microwave frequencies (see Rayleigh´s formulation for water droplet/wave interaction). The accuracy obtained on air temperature fluctuations is about 1 K (0, 5 K) for a response time of 0, 5 s (4 s) between 100 K and 400 K.