Fundamentals of the Physical Theory of Diffraction, 2nd Edition

Preface to the First Edition

The physical theory of diffraction (PTD) is a high-frequency asymptotic technique for the investigation of antennas and scattering problems. This monograph presents the first complete and comprehensive description of the modern PTD based on the concept of elementary edge waves (EEWs). Its subject is the diffraction of acoustic and electromagnetic waves by perfectly reflecting objects located in a homogeneous lossless medium.

The basic idea of PTD is that the diffracted field is considered as the radiation generated by scattering sources (currents) induced on objects. Uniform and nonuniform scattering sources are introduced in PTD. Uniform sources are defined as sources induced on an infinite plane tangent to the object at a source point. Nonuniform sources are caused by any deviation of the scattering surface from the tangent plane. For large convex objects with sharp edges, the basic contributions to the scattered field are produced by uniform sources and by those nonuniform sources that concentrate near edges (often called fringe sources).

The integration of uniform sources leads to the physical optics (PO) approximation for the scattered field. The PTD is the natural extension of the PO approximation by taking into account the additional field created by the nonuniform/fringe sources.

The book provides high-frequency asymptotics for the scattering sources and for the scattered field in the far zone. Scattering characteristics are calculated for ...