双层敏感对称微纳结构的阵列式SAW微压力传感机理研究

SAW micro-force sensing technology is an important method to measure the micro pressure in micro-gaps. The bulk wave interference and sidelobe effect of SAW sensors are crucial issues to be solved. In this project, we present an array SAW micro pressure sensing mechanism, which is based on the double-layer sensitive symmetric micro-nano structure. In detail, first, the upper-lower symmetry sensitive micro-nano structure is adopted to establish the finite element or boundary element hybrid model of SAW micro pressure sensors. Moreover, the influence of the piezoelectric material and the structure parameters on the insertion loss and side-lobe effect is explained. The mechanism of the interference between the upper and the lower symmetric micro-nano structure spacing, the quality factor, and the low wave attenuation are analyzed, and the mechanism of interference suppression is revealed. Second, we optimize the model by inferring the temperature field and pressure field distribution of the piezoelectric substrate from experimental results. This is used for thermal steady state analysis and compensation. Third, the design of array structure and effective measurement are studied. Uncertainty in measurement based on the Monte Carlo method is analysed. The design structure and peripheral test circuit are optimized to form the array sensing mechanism based on the double-layer sensitive symmetry micro-nano structure. The outcomes of the project and the testing platform will provide theoretical basis，improve the sensitivity of sensing and technical support for the structure optimization of SAW sensors and the multi-parameter coupling in environments under disturbance.

SAW微压力传感技术已成为微接触面间微压力大小测量的重要手段，该类传感器的体声波干扰和旁瓣效应是亟待解决的重要课题。本项目提出基于双层敏感对称微纳结构的阵列式SAW微压力传感机理：（1）搭建上下层敏感对称微纳结构的SAW微压力传感的有限元/边界元混合模型，解明压电材质及结构参数对体声波干扰和旁瓣效应的影响，分析上下层对称微纳结构、待测介质品质因数与低波衰减间的关联机制，揭示该结构可抑制干扰的机理；（2）研究流体-结构和热-结构多域耦合模型，算法优化并实验推定压电基片的温度场、压力场分布方法，进行热稳态分析及补偿；（3）研究阵列式设计及有效性测量，基于蒙特卡洛法对不确定度进行分析，并优化设计结构和外围测试电路，形成双层敏感对称微纳结构下的阵列式传感机理，提高传感精度。项目研究的传感机制，搭建的测试平台，为SAW传感器结构优化及内外部环境扰动下的多参数耦合提供了理论基础和技术支撑。

SAW微压力传感技术已成为微接触面间微压力大小测量的重要手段，本项目提出基于双层敏感对称微纳结构的SAW微压力传感机理：（1）搭建上下层敏感对称微纳结构的SAW微压力传感的有限元/边界元混合模型，根据余弦平方函数加权叉指换能器结构的基本结构和基本原理，提出分裂式余弦平方函数加权叉指换能器和基于MSC的双余弦平方函数加权叉指换能器两种结构，以此抑制旁瓣干扰和体声波干扰等方面的问题；（2）研究SAW微压力传感器外界环境扰动状态，并研究SAW传播时受外界流体环境扰动导致相关参数不稳定、影响测量数据等问题。针对传感器外部流体扰动特性指标，对声表面波及其外部流体域进行有限元分析，得到声表面波微压力传感器测量数据与流体域变化联系，从而进行热稳态分析及补偿；（3）分析天线设计性能参数，与SAW工作原理结合，设计声表面波传输匹配天线。通过HFSS软件仿真天线各结构长度对工作频率和特性指标的影响，优化天线参数设计。基于蒙特卡洛法对不确定度进行分析，并优化设计结构和外围测试电路，形成双层敏感对称微纳结构下的阵列式传感机理，提高传感精度，为SAW传感器结构优化及内外部环境扰动下的多参数耦合提供了理论基础和技术支撑。