ABSTRACT

Hybrid and asymptotic methods of diffraction theory used when the electric size of a scatterer is large are based on the use of a solution for the radiation pattern of a cylindrical wave, which appears when a plane wave is scattered by an edge with a given boundary condition. The expression of the radiation pattern of a wave scattered by the edge of a half-plane with generalized semitransparent boundary conditions has not been obtained using the Sommerfeld integral technique. The use of the solution for the semitransparent case allows us to expand the asymptotic methods to scatterers with semitransparent edges. In this article, based on solving the problem of the scattering of a plane wave by a half-plane with the generalized semitransparent boundary conditions using the Sommerfeld integral technique, we derive a solution for the far-field of the cylindrical wave scattered by the semitransparent edge. Based on the obtained solution, we derive an expression for the calculation of an amendment to the physical optics approximation, which allows us to extend the physical theory of diffraction method to scatterers with semitransparent edges. We apply the uniform asymptotic theory of diffraction method to the problem of cylindrical-wave scattering by the semitransparent half-plane.

摘要

当散射体的电尺寸较大时使用的衍射理论的混合和渐近方法基于对圆柱波辐射方向图的解决方案，该解决方案在平面波被给定边界条件下的边缘散射时出现。使用Sommerfeld积分技术尚未获得在广义半透明边界条件下由半平面边缘散射的波的辐射方向图的表达式。在半透明情况下使用解决方案可以使我们将渐近方法扩展到具有半透明边缘的散射体。在本文中，基于使用Sommerfeld积分技术解决具有广义半透明边界条件的平面波在半平面上的散射问题，我们推导了半透明边缘散射的圆柱波远场的解决方案。基于获得的解决方案，我们导出了用于计算对物理光学近似的修正的表达式，这使我们能够将衍射方法的物理理论扩展到具有半透明边缘的散射体。我们将衍射方法的统一渐近理论应用于半透明半平面对圆柱波的散射问题。