多层频率选择表面的分析

本文科用矩量法和广义散射矩阵理论分析了平面波入射到多层频率选择表面的电磁散射特性。首先引入广义波导的概念,将单层频率选择表面(FSS)上每个单元看成两个广义波导的接头,广义波导中的本征模是周期性结构中的Floquet模,然后根据等效原理和边界面上切向场量的连续性条件得到了一个关于广义波导中模式系数的方程,用矩量法求解可得波导接头的广义散射参量。最后运用广义散射矩阵理论计算了多层FSS总的散射参量。作为示例,文中对由矩形与圆形孔阵所组成的单层FSS和双层矩形孔阵FSS的散射特性作了计算,数值结果与已有文献中给出的数据极为一致。

Analysis of Multilayered Frequency-Selective Surfaces

In this paper, the electromagnetic scattering characteristics at a plane wave incident on multilayered frequency-selective surfaces (FSS) are analyzed by the method of moments combined with the generalized scattering matrix theory. At first ,an idea of generalized waveguide is introduced ,and each element of the single layer FSS can be taken as a junction between two generalized waveguides. The eigen modes in these waveguides are replaced by Floquet modes in periodic structures. Then according to the equivalence theorem and the continuous condition of tangential components of magnetic field,an equation about the mode coefficients in generalized waveguides can be derived. The method of moments is employed to solve this equation for the generalized scattering matrix of the junction. At last,the total scattering parameters of multilayered FSS are computed using generalized scattering matrix theory. As examples,the reflection and transmission coefficients of single and double-layered FSS composed of rectangular and circular aperture arrays are calculated. Numerical results are found in good agreement with available values in the literatures.