二维声子晶体平板成像中的通道特征
Scattering channel in focus imaging of two-dimensional phononic crystal panel
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摘要: 利用多重散射理论分析了钢,水声子晶体平板成像过程.发现平板成像中的散射波会聚具有散射通道特征.对于确定的声源位置,不同入射角信号对应不同的通道;耦合进入通道的信号强度也不相同.小角度入射波能较强地耦合进入通道;大角度入射波在入射表面受到强烈散射,较弱地耦合进入通道.非理想成像情况下,不同入射角信号通过平板成像的位置不同,因而形成像差.声源位置改变,对应的通道亦随之改变.散射通道与声子晶体的各向异性能带结构和多重散射密切相关.Abstract: By using multiple-scattering theory (MST), the imaging process was investigated in steel/water phononic crystal panel with negative refraction. It was found there are some channels for the scattering waves propagating in the panel. For a given source location, the scattering channel changes with incident angle and so does the strength of signal coupled to the channel. While small-angle incident wave can be coupled into the channel perfectly, large-angle incident wave which is strongly scattered in the incident surface can be coupled into the channel only weakly. In the non-ideal imaging case, imaging position changes with the angle of incidence signal, it further causes imaging aberration. These scattering channels are closely related to the anisotropic band structure of the crystal panel and multiple scattering of the rods, and vary with position change of the sound source.
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