YX128°-LiNbO_3 SAW传感器IDT的有限元仿真

FEM simulation of a YX128°-LiNbO_3 SAW sensor

为研究高频环境下的二次效应,建立了SAW传感器叉指谐振器(IDT)的二维周期有限元模型.以YX128°-LiNbO3高频SAW传感器为分析对象,定量分析了不同电极设计参数下的电极二次效应;通过谐响应分析,得到了传感器IDT电学导纳与传感器中心频率的关系,提取了IDT的谐振频率和逆谐振频率.结果表明,随着敷金比MR或电极高度EH的增大,表面波的模态频率降低,相应的表面波的速度也会降低.相同电极高度下,随着敷金比的增大,频率截止带逐渐变宽,对应的电极反射率逐渐变大.仿真提取的谐振频率为973MHz,逆谐振频率为1002MHz.

To study the electrode second order effects （ESOE） at high frequency, a two-dimensional periodic finite element model of SAW sensor IDT was developed. Taking a YX128°-LiNbO3 high frequency SAW sensor as the simulation object, the ESOE with different electrode design parameters were quantitatively analyzed. The relationship between the electrical admittance of sensor IDT and the center frequency was analyzed via the harmonic response analysis, and the resonance and anti-resonance frequencies of the IDT were extracted. Results indicate that the modal frequency and the velocity of surface wave decrease as the metallization ratio （MR） or the electrode height （EH） increases. At the same EH, stopband gets wider and reflection ration of electrode increases with the increasing MR. The resonance frequency and the anti-resonance frequency extracted from the simulation are 973 MHz and 1 002 MHz respectively.