Accession Number:

AD0765383

Title:

Fresnel Diffraction of RF Wavefronts

Descriptive Note:

Final rept. Dec 1971-Feb 1973

Corporate Author:

CALSPAN CORP BUFFALO NY

Personal Author(s):

Report Date:

1973-02-01

Pagination or Media Count:

186.0

Abstract:

The objective of this program was to develop the necessary mathematics including a computer program to predict and define the RF and geometric shadow of any proposed or existing obstruction in the coverage volume of airspace of radar facilities operating in appropriate aeronautical service bands. The RF shadow calculation includes the effects of Fresnel diffraction by a perfectly-conducting rectangular obstruction through the use of Geometric Diffraction Theory. Both the line-of-sight geometrical-optic shadow and Fresnel diffraction effects are calculated by the computer program for arbitrary incidence and observation angles relative to the obstacle. Signal degradation relative to the obstacle-free field, and for desired combinations of transmit and receive polarizations, was described by providing plots of arbitrarily chosen dB levels at chosen observation planes behind the obstruction. Circularly cylindrical, spherical, and convex polyhedron obstructions were also considered but only to determine geometric shadowing. A flight test program was conducted to experimentally validate the computer program using a rectangular obstruction at three different viewing angles. The experimental results were in good agreement with predicted values.

Subject Categories:

  • Air Navigation and Guidance
  • Active and Passive Radar Detection and Equipment
  • Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE