表面局域态对一维声子晶体中水平剪切波传输特性的影响

Influence of the Surface Localized Modes on the Transmission Property of Shear Horizontal Waves Propagation through the 1D Phononic Crystals

利用传递矩阵法,研究了一维声子晶体表面存在的表面局域态对水平剪切波传输特性的影响。由于表面局域态的存在,声波的透过率出现共振峰。共振峰的极值与入射角度和声子晶体层数有关,合适的入射角度和层数可以使声波完全透射。当入射角在一定范围内连续变化时,在较宽频率范围内均出现较大透过率。声子晶体的这一特性可以应用于高性能的阻抗匹配材料和声波滤波器中。

The influence of the surface localized modes on the transmissivity of shear horizontal waves propagation through the 1D phononic crystals was studied using the transfer matrix method. The particular resonance peak in transmissivity function is found due to the surface localized mode. The magnitude of the peak depends on both the number of periodic (N) of the phononic crystal and the oblique angle (θ) of incidence. For a special N and θ, the acoustic wave can be resonantly transmitted through the phononic crystal into solid thin film detector without any attenuation, in spite of the large acoustic mismatch between the substrate and detector. These resonant peaks will be found in a wider frequency range when the incidence angle changes in some ranges continually. The property of the phononic crystal may be useful for the impedance matching material and high-frequency acoustical filter.