SCATTERING OF ELECTROMAGNETIC WAVES BY ULTRA-SONIC BEAMS
Abstract
Efforts were made to determine the feasibility of non-line-of-sight microwave communication systems, using ultrasonic scattering transmission. Factors affecting the scattering of radio waves by sonic beams are discussed from the point of existing theory. Among the significant factors are: changes in the refractive index of air, the angles of incidence and of reflection of a radio beam relative to a sonic beam, the collimation or half power beamwidth of the sonic beam, and distortion of a plane or spherical sonic wave caused by various meteorological phenomena. A review of sonic sources is presented with the theory of the forced air vibrator type of source expanded. In essence, it combines the advantages of the siren with those of the mechanical vibrator, and hence was selected for this study. The experimental tests and evaluation of a prototype forced air vibrator were initiated and serve as the basis for out-ofdoors experiments aimed at measuring quantitatively the scattering of a radio beam in the 30-34 kmc region by an ultrasonic beam in the 10-12 kc region. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 15, 1961
- Accession Number
- AD0267219