基于有限元法与超胞法的结构声表面波缺陷态分析

Analysis of Defect States for Spoof Surface Acoustic Waves Based on Finite Element Method and Supercell Method

简要介绍了有限元法与超胞法相结合计算结构声表面波缺陷能带结构的方法,理论上分析了缺陷型表面声子晶体的声限制和声波导。表面声子晶体由刻有周期性凹槽的刚性板构成,通过改变晶体中某一格点或某一排格点的几何参数可以构建点缺陷和线缺陷。利用有限元法与超胞法能够十分方便地计算出表面声子晶体的点缺陷和线缺陷对应的缺陷带结构以及特定频率声波局域在点缺陷与线缺陷的本征压力场。通过分析缺陷能带结构与本征压力场,可以直观地了解缺陷型表面声子晶体中的声限制和声波导。

The point defect and line defect band structure of spoof surface acoustic waves were calculated by the finite element method and the supercell method,and acoustic confinement and waveguiding of surface phononic crystals with defect states were analyzed theoretically. The surface phononic crystal is composed of rigid surface with periodic grooves. Point defects and line defects can be introduced by changing the geometrical parameters of single groove in the core center or one row of grooves.Furthermore,combining the finite element method and the supercell method,it is very convenient to calculate the band structure of point defects and line defects,and obtain the eigen-pressure field of spoof surface acoustic waves which localized in the point defects and the line defects with specific frequency.By analyzing the defect band structure and eigen-pressure field diagram,we can intuitively understand the acoustic confinement and acoustic waveguides in the surface phononic crystal with defect states.