Accession Number : ADA193752

Title :   Rapid-Scanning Fourier Transform Spectrometer for Studies of Propagation of Near-Millimeter-Wave Radiation through Clear Air and Fog.

Descriptive Note : Final rept. 28 Apr 80-30 Sep 87,

Corporate Author : GEORGIA INST OF TECH ATLANTA

Personal Author(s) : Bohlander, R A ; Larsen, J W ; Lamm, D R ; Blyler, M L ; Weeks, D E

PDF Url : ADA193752

Report Date : 01 Mar 1988

Pagination or Media Count : 83

Abstract : A system has been developed to measure relative atmospheric transmission for the near-millimeter wave range of frequencies, 60-100 GHz. A 400 m long propagation range has been established. A transmitter/receiver system at one end of a link incorporates a rapid-scanning Fourier transform spectrometer. It involves a novel mirror drive which moves both interferometer mirrors simultaneously. The interferometric section is a polarizing Martin-Puplett type. The grid polarizers are made photolithographically. The source is a hot mercury lamp in a cavity, and the detector, an InSb photoconductive element. Scans of 7.5 GHz resolution require about 0.2 sec. A dihedral retroreflector 200 m from the transmitter/receiver reflects the signal back and completes the link. Calibration spectra are obtained from a short path to a second retroreflector. System tests are described.

Descriptors :   *RADIO TRANSMISSION, *ATMOSPHERIC PHYSICS, AIR, ATMOSPHERES, CALIBRATION, DRIVES, FOG, GRIDS, HIGH TEMPERATURE, INTERFEROMETERS, INTERFEROMETRY, MERCURY LAMPS, MILLIMETER WAVES, MIRRORS, PATHS, POLARIZERS, RETROREFLECTORS, SHORT RANGE(TIME), SIGNALS, SPECTRA, TRANSMITTANCE, TRANSMITTER RECEIVERS, FOURIER SPECTROMETERS, EXTREMELY HIGH FREQUENCY, ELECTRONIC SCANNERS, PHOTOLITHOGRAPHY, INDIUM ANTIMONIDES

Subject Categories : Radiofrequency Wave Propagation
      Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE