二維週期表面阻抗特性研究

Abstract

我們利用二維表面阻抗( two-dimension impedance surface )來模擬二維週期結構( two-dimension periodic structure )，以研究其散射( scattering )特性。關於此類問題之研究歷史可追朔至1965年A. Hessel及A. A. Oliner兩位教授利用一維表面阻抗之模型，配合嚴格之數學理論，成功地解釋了伍德奇變( Wood’s anomaly )之現象。本研究主要將上述一維週期表面阻抗之研究推廣至二維結構，並且利用精確之波模匹配法( method of mode matching )處理此三維邊界值問題( three-dimension boundary-value problem )。此外，我們業已發展電腦程式來計算，並獲得豐富的數值結果，尤其是對於平面波入射二維週期表面阻抗之伍德奇變現象做審慎之驗證；此種經由散射空間諧波耦合至表面波的物理機制，將可提供作為電波吸收之應用。

We present here an exact formulation for the three-dimensional boundary-value problem of plane wave scattering by a two-dimensionally periodic impedance surface in a uniform medium. The scattering characteristics of such a structure are rigorously analyzed in terms of the complete set of both TE- and TM-polarized plane waves in the uniform medium. Extensive numerical results are given to illustrate physical phenomena associated with the structure.