Scattering of Electromagnetic Wave by aubwavelength Hole in a Perfect Metal Plate
Date Issued
2008
Date
2008
Author(s)
Chen, Hung-Wen
Abstract
The scattering of an oblique electromagnetic wave incident on a subwavelength circular aperture in an infinite perfect conductor plane with a finite thickness is investigated analytically. he theory is based on the duality property of source-free Maxwell equation and the resultant scattering fields are fully expressed in terms of the auxiliary scalar and vector potentials. Both of the TM and TE polarized incidence are considered. There are two regions defined by the analytical method: the near field inner region and the radiation outer region. We use the method by Fabrikant to solve the mixed boundary value problems. Because epsilon=ka which is the product of the incident wave number and the pore radius is a small parameter, we could use the method of matched asympototic expansion to find the multipole structure. The sophisticated three- dimensional interplay between the pore depth and the incident angle is also revealed. The leading term of scattering radiation field due to the hole can be considered as caused by an electric dipole perperdicular to the plane of the hole, and a magnetic dipole parallel to it. When the thickness of the plane goes to zero, the result can be matched with Bethe’s theory.he theory lays the foundation for the future extension to the sattering problem of structured perfect conductor planes.
Subjects
Matched asymptotic expansion
Electromagnetic multipole expansion
Electromagnetic scattering
Diffraction by subwavelength holes.
Type
thesis
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