点缺陷阵列对声子晶体波导定向辐射性能的影响

将点缺陷阵列应用于声子晶体波导,提出一种具有高定向辐射性能的复合声子晶体波导. 基于有限元法的数值分析表明,附加到声子晶体波导表面的点缺陷阵列可激发出作为次级声源的谐振模. 谐振模辐射的声波与波导出射端口直接辐射的声波相互干涉,可以使声子晶体波导的法向辐射声压提高161.21%、发散角减小85.35%. 当点缺陷的数目增大到一定程度后,波导的定向辐射性能不再有明显的改善. 该研究为改善波导的定向辐射性能提供了一种新方法. 关键词： 声子晶体波导 点缺陷 谐振模 定向辐射

The influence of point defect array on directional emission of phononic crystal waveguide

A novel composite waveguide is proposed to improve the directional emission of phononic crystal waveguide by introducing a point defect array. The finite element simulations indicate that the point defects attached to the output surface of phononic crystal waveguide produce resonant modes, which act as secondary radiation sources. The interferences of sound wave radiated from these radiation sources and waveguide can enhance the normal radiation intensity by 161.21% and reduce the half-power angular width by 85.35%. In addition, when the number of the point defects is large enough, the directivity approaches a steady value. The investigation provides a new method to improve the directional emission of phononic crystal waveguide.