An Approximate Theory of the Diffraction of an Electromagnetic Wave by an Aperture in a Plane Screen
An Approximate Theory of the Diffraction of an Electromagnetic Wave by an Aperture in a Plane Screen
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平面屏幕孔径衍射电磁波的近似理论
DOI：
10.1049/pi-c.1956.0021
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发表时间：
1956
期刊：
影响因子：
--
通讯作者：
R. F. Millar
中科院分区：
文献类型：
--
作者：
R. F. Millar
提出了一种基于Sommerfeld半平面解的近似衍射理论。结果表明，在某些区域，平面波入射的理想导电半平面对电磁场的散射(在二维问题中)可以认为是由沿半平面边缘的电流和磁流引起的。将这一边缘电流概念推广到任意形状的平面波在无限大的理想导电屏中被任意形状的孔洞绕射的情况，这种近似适用于大孔口，并且可能是渐近的。在这种处理中，忽略了屏幕不同部分散射场之间的相互作用，得到了孔径内切向电场的边缘电流表达式。对圆孔的情况进行了较为详细的研究，得到了轴向和孔径场的分布，并与现有的实验和理论数据进行了比较。实验与理论吻合较好，并随着入射光斑半径与入射波长之比的增大而提高。
An approximate diffraction theory based on the Sommerfeld half-plane solution is developed. It is shown that, in certain regions, the electromagnetic field scattered (in the two-dimensional problem) by a perfectly conducting half-plane with plane waves incident can be conceived as arising from the flow of electric and magnetic currents along the edge of the half-plane. This edge-current concept is extended to the diffraction of normally incident plane waves by an aperture of arbitrary form in a thin, perfectly conducting screen of infinite extent.The approximation is for large apertures and is probably asymptotic. Interaction between the fields scattered by different parts of the screen is neglected in the present treatment.Expressions are obtained for the tangential electric field in the aperture in terms of these edge currents. The case of the circular aperture is studied in some detail, axial and aperture field distributions being derived and compared with the available experimental and theoretical data. Agreement with experiment and theory is fairly close, and improves with increase of the ratio of aperture radius to wavelength of incident radiation.