Accession Number : ADD008622

Title :   Loss-Free Scanning Antenna.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE AIR FORCE WASHINGTON DC

Personal Author(s) : Renau,Jacques ; Curtis,James W ; Nicholson,Donald S ; Hennessey,Frank L

Report Date : 16 Jun 1981

Pagination or Media Count : 5

Abstract : A system for, and a method of, scanning a collimated beam of electromagnetic radiation with a very large primary reflector of an antenna system without loss (i.e., with zero phase error) and without moving the primary reflector. The system is a two dimensional scan, loss-free, Cassegrain antenna system which comprises a stationary, parabolic-shaped, primary reflector, and a smaller, movable, parabolic-shaped subreflector, and also a movable, plane wave, electromagnetic radiation beam source interposed between the two reflectors. It is shown that, without moving the primary reflector, the beam can be scanned over wide angles with no phase error in the plane of scan, provided that the source and the subreflector are rotated about the focal point of the antenna in a specific manner. A unique angular relationship between the source and the subreflector is required for each scan angle, and is taught. The method includes the step of using this antenna system in scanning the beam from the primary reflector, without any phase error and without moving the primary reflector. (Author)

Descriptors :   *Patents, *Cassegrain antennas, Phase control, Beams(Radiation), Plane waves, Electronic scanners, Reflectors, Radiation, Wide angles, Sources, Antennas, Scanning, Losses, Errors, Phase

Subject Categories : Electrical and Electronic Equipment
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE