交错叠层型介质栅电磁带隙结构的特性

Characteristics of electromagnetic band-gap structure with stratified crossed dielectric gratings

用平面波展开法分析计算了适合三维应用的正交和斜交叠层型电磁带隙 (EBG)结构。提供了阻带宽度与各结构、材料参数的关系曲线,为工程设计提供了优 选结构的参考数据。从大量计算数据中归纳出:(1)这两种结构都不存在三维全方 向带隙;(2)对于传播方向与层面的法线的夹角不超过一定范围(约20°)的平面电磁 波存在公共阻带;(3)对于传播方向与层面的夹角不超过一定范围(约14°)的平面电 磁波,60°斜交介质栅在两个约120°的角域内(分角线沿菱形栅格的短对角线)也存 在公共阻带,正交介质栅结构逊于斜交介质栅结构;(4)上述传播方向基本垂直于和 基本平行于层面两种情况下的各自的公共阻带,随着传播方向从角域的中心向边缘 改变,由包含到交叠到分立,取决于层叠介质栅的具体结构和媒质参数。对某文献中 的柴堆式EBG结构进行了验证性仿真,所得结果与文献中的数据相符。

In this paper, the band-gap characteristics of 3-D EBG structure consisting of orthogonal or non-orthogonal stratified dielectric gratings were analyzed and calculated by using the method of plane waves expansion. The curves of stop-bandwidth vs. geometric and constitutive parameters were provided as the optimal structure data for engineering design. The conclusions are summarized as: (1) Both orthogonal grating structure and non-orthogonal grating structure do not possess a complete band-gap for all wave-vectors; (2) For the wave-vector around the normal of grating-plane (&le20°), a common stop-band exists; (3) For the wave-vector close to the grating-plane (&le14°) within two120° in azimuth (while the bisector is parallel to the shorter diagonal of rhombic grating-net) of the non-orthogonal structure, a common stop-band exists too, which better than orthogonal one; (4) The common stop-bands in the case-2 and in case-3 are involved, then overlapped, and then separated each other, when the wave-vector is changed from the center to edge of valid angular region, and quantitatively depend on the geometric and constitutive parameters of gratings. To verify validity of the algorithm, the dielectric woodpile EBG structure was analyzed and the computational results were almost the same as the data in the reference.