Electromagnetic wave scattering from planar periodic metallic surfaces
Abstract
The analysis of infinite periodic planar structures with apertures along some axis is of great importance due to the frequency-selective and polarization selective properties exhibited by them. The properties of these surfaces are dependent on the shape of the aperture and the mutual coupling with nearby elements in the array. The determination of the diffracted powers in the various scattered orders requires an accurate description of the electric and magnetic fields in the plane of the scattering surface. Expanding these field distributions in a modified Fourier Series (F.S), an infinite dimensional system of linear equations is derived by mapping the F.S coefficients of the electric and magnetic fields onto components of a vector and representing each step of the Tsao-Mittra Spectral Iteration process as a matrix multiplication. This system of equations is equivalent to that obtained using the moment method, and is solved using standard techniques. Application of our solution procedure in the one dimensional case, where we have a strip grating, provides an arbitrarily accurate description of the fields for any configuration of the strip grating, which may be of finite or infinite conductivity, and for any angle of oblique incidence of the arbitrarily polarized incident plane wave. In the two dimensional case, our procedure is applicable, and produces accurate results, in the case of many different frequency selective surfaces, unlike various solution procedures which are applicable only in the case of a specific shaped aperture. Scattering for rectangular strip (wire) meshes, circular patches and narrow slots is considered. Comparison of results with those obtained using other methods support the validity of the solution procedure.
Degree
Ph.D.
Advisors
Gallagher, Purdue University.
Subject Area
Electrical engineering
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