Plane wave diffraction by two rectangular holes in a thin conducting screen-Derivation of the exact solution

摘要

The method of the Kobayashi potential (KP) is applied to exactly formulate an electromagnetic field diffracted by two rectangular apertures in an infinite conducting screen with an infinitesimal thickness. Since the KP method yields an eigenfunction expansion of the present geometry, the solution satisfies the proper edge condition and we can obtain a highly accurate and faster convergent numerical result. Therefore, the derived expression serves as the reference solution to evaluate the accuracy of conventional numerical techniques, such as the FDTD method. The expansion coefficients are obtained from the matrix equation whose matrix elements consist of double infinite integrals that include the Bessel functions and trigonometric functions. Since any edge property can be incorporated into our solution, it is possible to obtain fields diffracted by an aperture with more complex geometry by applying the concept of multiple diffraction.