Microwave scattering by turbulent air

A system for measuring the power scattered by a region of thermally turbulent air is described, and its performance is analyzed. Also described is the equipment used to generate the turbulent region and the temperature fluctuations therein. The experimental procedure can be summarized by stating that it consisted in measuring the fluctuations of the null in the interference pattern of an antenna array composed of two antennas excited out of phase, when thermally turbulent air, of known properties, was interposed between the receiving and transmitting systems. The measured and calculated receiver response due to scattering by the turbulent air is compared, and it is noted that they agree at least within an order of magnitude. The experiment described shows that a measurement of the angular dependence of the signal scattered by turbulent air is within the possibilities of available techniques, although a more elaborate measuring system and higher microwave power levels would be required.