Attenuation and fluctuation of millimeter radio waves

This paper contains a resume of the millimeter propagation measurements conducted by the Electrical Engineering Research Laboratory of The University of Texas. These measurements were made at wavelengths of 8.6 millimeters and 4. 3 millimeters, and more recently and as yet unreported, at a wavelength of 3.35 millimeters. The 8.6 and 4.3 millimeter measurements were made at elevations of 0.25 kilometer and 4 kilometers above sea level. The path lengths ranged from 3.5 miles to 61 miles. The 3.35 millimeter measurements were made at an elevation of 0.25 kilometer over a path length of 7.5 miles. The measured oxygen and water vapor attenuations at the three millimeter wavelengths are compared to theoretical attenuations. Spectra of scintillations are shown and several of the refraction characteristics are noted. A comparison of the propagation of the millimeter wavelengths with that of 3.2 centimeter wavelength is also made.