Characterization Of Millimeter Wave Propagation Through A Turbid Atmosphere

Atmospheric effects on the propagation of electromagnetic waves are usually described in terms of intensity fluctuations, angle-of-arrival fluctuations, and the mutual coherence function (HCF). Experimental determination of these statistical quantities is usually accomplished by forming a time average of instantaneous field measurements and assuming ergodicity to obtain an ensemble average. This paper reviews two experimental approaches used to obtain such data, viz., the long-baseline interferometric method and the quasi-optical method; emphasis will be placed on the latter method. In addition, sampling of the atmospheric temperature and humidity fluctuations, which give rise to the electromagnetic fluctuations, is analyzed. Finally, a 1.6-km propagation range employing the quasi-optical method and the meteorological sampling considerations mentioned above will be described. The range is completely instrumented to provide the relevant meteorological and electromagnetic para-meters needed to characterize propagation at frequencies near 300 (Hz in a turbulent atmos-phere.