高功率体声波谐振器的自热效应及其修正

Self-heating effect and its modification of high power bulk acoustic-wave resonators

为了在高功率体声波谐振器的设计中考虑自热效应的影响,提出一种声-电磁-热多物理场协同仿真方法 ,来模拟自热导致的频率偏移,并针对此频率偏移的消除问题,提出了相应的修正方案。首先,由常用的Mason模型设计出满足谐振频率要求的初始谐振器。接着,通过声-电磁-热多物理场协同仿真得到自热导致的频率偏移。然后,初步调整压电层厚度,来抵消此频率偏移。最后,对调整后的谐振器迭代进行声-电磁-热多物理场协同仿真,以确定压电层厚度的调整量。结果表明:自热效应会导致高功率体声波谐振器的谐振频率明显下偏(谐振器案例的频率偏移量为3 MHz),通过减薄压电层厚度(案例中为1.7nm)可彻底消除此频率偏移。所提出的高功率体声波谐振器的修正方案能有效地解决自热效应导致的谐振频率偏移问题。

In order to study self-heating effects in the design of high-power bulk acoustic-wave resonators,an acoustic electromagnetic thermal multiphysics co-simulation method was proposed to simulate frequency shifts caused by self-heating.A corresponding design modification scheme was proposed to eliminate these frequency shifts.First,an initial resonator that satisfies the resonant frequency requirement was designed from the commonly used Mason model.Then,the frequency shifts caused by self-heating were obtained through acoustic electromagnetic thermal multiphysics co-simulation.Next,the frequency shifts were eliminated by adjusting the preliminary thickness of the piezo-layer.Finally,the acoustic electromagnetic thermal multiphysics co-simulation was performed iteratively on the adjusted resonator to determine the final thickness adjustment of the piezo-layer.The results show that the self-heating effect causes the resonant frequency of the high-power bulk acoustic-wave resonator to shift downward significantly(the frequency shift of the resonator case was 3 MHz),and this frequency shift can be completely eliminated by reducing the thickness of the piezo-layer(1.7 nm for the resonator case).The proposed scheme for design modification of high-power bulk acoustic-wave resonators can effectively solve the problem of frequency shifts resulting from self-heating.