Accession Number : ADP005645


Title :   Uniform Geometrical Theory of Diffraction


Corporate Author : OHIO STATE UNIV COLUMBUS ELECTROSCIENCE LAB


Personal Author(s) : Pathak, P H


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/p005645.pdf


Report Date : Jun 1987


Pagination or Media Count : 21


Abstract : Keller's geometrical theory of diffraction (GTD) represents a major breakthrough in solving a wide variety of electromagnetic (EM) radiation and scattering problems at high frequencies. In particular, the GTD is an extension of geometrical optics to include a class of diffracted rays via a generalization of Fermat's principle. These diffracted rays are initiated, for example, from geometrical and electrical discontinuities in a scatterer, or from points of grazing incidence on smooth convex parts of the scattering surface. However, being a purely ray optical theory, the original GTD is overcome via the uniform version of the GTD (i.e., UTD) which requires the diffracted field to make the total high frequency field continuous across the optical shadow boundaries. The UTD solutions for the diffraction by edges and smooth convex surfaces are reviewed in detail after introducing the basic concepts of GTD. Results based on a few additional UTD solutions are also presented together with a few selected applications of these UTD solutions to predict the EM radiation and scattering from complex structures.


Descriptors :   *ELECTROMAGNETIC SCATTERING , *DIFFRACTION , *TARGET CLASSIFICATION , NATO , EDGES , SHADOWS , GRAZING , CONVEX BODIES


Subject Categories : Target Direction, Range and Position Finding
      Radiofrequency Wave Propagation


Distribution Statement : APPROVED FOR PUBLIC RELEASE