中文摘要：

提出一种基于声子晶体线缺陷波导的多通道结构来实现声波定向激发。一束入射声波在该结构中传播时被分割成多束分支,这些分支声束到达输出端时具有相等的相位,进而在输出端产生具有高度准直形态的辐射场分布。该辐射场分布的半高宽具有反比于结构中通道数的特点。数值模拟结果与实验结果同时验证了这种结构的声定向效应。相对于大多数已有的声波定向方案,这种结构具有简单从而易于制备的优点。

英文摘要：

A multi-channel structure based on line-defect waveguide of sonic crystal is proposed to obtain directional acoustic emission. An incident acoustic wave can be split into multiple beams in the structure which then emit at output ports with the same phase,leading to a highly directional radiation pattern. The full width at half maximum（ FWHM） of emission pattern is inversely proportional to the number of channels in the structure. Beaming effect of the designed structure is verified both numerically and experimentally. Compared to most of the existing schemes for acoustic emission,this structure is very simple thus is easier for fabrication.