Diffraction of a plane wave by a rectangular hole in a thick conducting screen

The method of the Kobayashi potential (KP) is applied to evaluate an electromagnetic field diffracted by a rectangular hole in an infinite conducting screen with a finite thickness. Since the KP method yields an eigenfunction expansion of the present geometry, the solution satisfies the proper edge condition and we obtain a highly accurate and fast convergent result. Numerical results are obtained for various physical quantities, such as the transmission coefficient, magnitudes of waveguide modes excited in the hole, and aperture field distributions, as well as the far-field patterns. The results of the transmission coefficient and waveguide modes are presented as functions of the thickness to illustrate the effects of the screen thickness on the transmission property.