基于二维声子晶体的体声波谐振器仿真分析

Simulation of film bulk acoustic resonator based on two-dimensional phononic crystals

提出了一种基于声子晶体的新型体声波谐振器结构,利用声子晶体在其带隙范围内对弹性波具有高反射率、低透射率的特点,将声子晶体作为体声波谐振器底部的声反射层。首先计算出了4种不同结构声子晶体的带隙特性,并使用有限元软件COMSOL Multiphysics对基于声子晶体的体声波谐振器结构进行建模仿真,得出了主要结论。当体声波谐振器工作频率在声子晶体带隙范围内时,直接以声子晶体作为体声波谐振器的衬底,仿真得到的阻抗曲线较为平滑,且Q值为858.09,有效机电耦合系数为6.32%。

A new structure of film bulk acoustic resonator(FBAR)based on phononic crystal(PnC)was proposed.The phononic crystal was used as the acoustic reflection layer at the bottom of the bulk acoustic wave resonator,which has the characteristics of high reflectivity and low transmittance of elastic wave in its band gap.The band gap characteristics of four kinds of phononic crystals with different structures were calculated by the finite element software COMSOL Multiphysics.The main conclusions are as follows.If the bulk acoustic resonator is working within the band gap of the phononic crystal,PnC can be used as the bottom acoustic reflection layer of the FBAR.With using PnC as the acoustic energy reflect structure,the impedance curve of FBAR is smooth,and the quality factor is closed to traditional FBAR with a value of 859 and effective mechanical coupling coefficient of 6.32%.