嵌入压电基底蜂窝状声子晶体声表面波带隙特性

Properties of surface acoustic wave bandgaps in honeycomb phononic crystal embedded with piezoelectric substrate

提出了将部分镍圆柱体镶入128°YX-LiNbO_(3)基底的二维蜂窝状压电型声子晶体。用有限元法结合低反射边界条件计算并分析了该结构的能带结构与传输损失。结果显示:与倒圆锥体结构相比,镶入型结构具有更低的声表面波(SAW)带隙,原因是将部分柱体嵌入到基底中增加了共振体的质量。通过分析带隙边缘处振动本征模态结合传输损失发现,第一SAW带隙是由局域共振机理打开,第二SAW带隙同时具有Bragg散射特性和局域共振特性。应用质量弹簧振动系统估算了第一SAW带隙的起始频率,结果为82.98 MHz。此外,讨论了柱体几何参数对带隙特性的影响。该研究为微米尺度SAW声子晶体的带隙调控奠定了一定基础。

A kind of two-dimensional honeycomb piezoelectric Phononic Crystal(PC) with partial nickel cylinders embedded in 128°YX-LiNbO_(3) substrate is proposed.The band structures and transmission loss of the PC are simulated and analyzed using the Finite Element Method(FEM) in combination with low reflection boundary conditions.The results show that the embedded PC has lower SAW band gap than the inverted cone PC.The reason is that embedding part of the cylinder into the substrate increases the mass of the resonator.The vibration eigenmodes at the band gap edges and transmission losses are analyzed.It is found that the first SAW band gap is opened by the local resonance mechanism,and the second SAW band gap has both Bragg scattering and local resonance characteristics.The initial frequency of the first SAW bandgap is estimated by using the mass-spring vibration system,and the result is 82.98 MHz.Furthermore,the effect of cylinder geometry parameters on the bandgap characteristics is discussed.The research lays a foundation for the band gap regulation of micron-scale SAW phononic crystals.