Accession Number : AD0474398

Title :   PROPAGATION FACTORS AT 3.2 MILLIMETERS.

Descriptive Note : Technical documentary rept.,

Corporate Author : AEROSPACE CORP EL SEGUNDO CA LAB OPERATIONS

Personal Author(s) : Hoffman, L. A. ; Wintroub, H. J. ; Garber, W. A.

Report Date : OCT 1965

Pagination or Media Count : 101

Abstract : Communications systems operating at 3.2 mm are feasible for short horizontal path lengths of the order of 50 km with only a minimum of required transmitting power (0.1 to 1 W). These systems can be small and rugged and will operate under most weather conditions, except perhaps for conditions of moderate to heavy rainfall and extremes of humidity. The bandwidth limitation of the medium has not yet been established, but it is known to be greater than 30 Mc/s. On the assumption that 90% of the attenuation takes place in the first 10 km of the atmosphere, groundspace communications systems can be designed with components that will be useful at elevation angles as low as 10 deg. The 3.2-mm wave window is useful for space communication (including such applications as radar and navigation) and astronomical observations for elevation angles exceeding about 10 deg. Thick clouds and rain adversely affect this capability, especially at the lower elevation angles. Present technology is capable of providing millimeter-wave sources with significant power outputs (up to 100 W, average) such that the millimeter-wave region may assume an important role in space communications. This potential for the millimeter-wave region is due to the fact that the combination of a large bandwidth and a low inherent noise level is difficult to match at either the longer wavelengths or optical wavelengths. (Author)

Descriptors :   (*MILLIMETER WAVES, PROPAGATION), (*SPACE COMMUNICATIONS, MILLIMETER WAVES), ATTENUATION, DATA TRANSMISSION SYSTEMS, BROADBAND, PARABOLIC ANTENNAS, MICROWAVE RELAY SYSTEMS, ATMOSPHERIC MOTION, BEAMS(ELECTROMAGNETIC), ABSORPTION, CLOUDS, FOG, RAINFALL, VOICE COMMUNICATIONS, WIND, OXYGEN, WATER VAPOR, ANTENNA RADIATION PATTERNS, ATMOSPHERIC REFRACTION, TROPOSPHERE, NOISE, FEASIBILITY STUDIES, SCINTILLATION.

Subject Categories : Radiofrequency Wave Propagation
      Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE