正弦波エッジによるスカラー平面波の散乱

摘要

The scattering of a scalar plane wave by a half plane with a sinusoidal edge positioned at the xz-plane is treated by the method of the geometrical theory of diffraction and the far scattered field at a field point (r, v, p) is obtained where v is an angle measured from the edge(z-axis) and φ is the azimuth in the xy-plane. The normal incidence of a plane wave to the z-axis is assumed. The scattered wave exists in a certain specific range of the scattering angle v and the range becomes wider with increasing a ratio h/Λ where h and Λ are the height and period of the edge, respectively. The scattring pattern have peaks at specific scattering angles v, which agree with diffraction angles calculated by the well-known grating formula. It is shown that the results agree qualitatively with results obtained by using the physical optics approximation.%正弦波エッジを持つxz面に置かれた半平面によるスカラー平面波の散乱をGTD法で取り扱い，点（r，v，φ）における遠方散乱界を求めた．平面波はz軸に垂直に入射すると仮定した．散乱波はエッジから測った散乱角汐のある範囲にだけ存在する．その範囲はh/Λの増大とともに広がる．ここで在とΛはそれぞれエッジの振幅と周期である．散乱パターンはある特定の散乱角vでピークを持つ．