用于粘弹性液相传感的强耦合压电体声波器件高频振动研究

Working in viscoelastic liquid phase with large damping, the quality factors of traditional quartz crystal bulk acoustic wave(BAW) devices dramatically decay, which makes the frequency stability and sensing resolution decrease obviously. A key method is to replace quartz crystal by the crystals with high piezoelectric constants. However，the emergence of the spurious modes of the devices work in viscoelastic liquid, the lack of the analytical model for vibrations of BAW devices with high piezoelectric coupling factors in nonlinear viscoelastic liquid, and the unclearness of the sensing mechanism become critical and urgent problems. This study launches following research points:(a) To reveal the generation mechanism of spurious modes and to obtain an effective method suppressing the spurious modes of the devices working in viscoelastic liquid phase by building the high-frequency vibration analytical model; (b) To investigate the influence law of the nonlinear rheological properties on vibrations of the devices by building the analytical model, and to clarify the sensing mechanism of the devices working in nonlinear viscoelastic liquid by deriving the characteristic damping of energy dissipation, providing new ideas and methods for investigating the sensing mechanism of BAW devices in complex medium; (c) To verify the theoretical results by designing and testing the piezoelectric biosensors based on crystals with high piezoelectric constants. Breaking through the limitation of the BAW method on sensing in viscoelastic liquid phase with large damping, the research results can provide reliable analysis method on high frequency vibrations for the sensors working in viscoelastic liquid phase, extend BAW method to the application field of nonlinear viscoelastic liquid phase and are of significance.

在大阻尼粘弹性液相中，传统的石英体声波器件谐振品质因数衰减严重，频率稳定性和传感分辨率显著下降。用强压电耦合的晶体材料代替石英晶体是解决该难题的关键所在。然而，强压电耦合器件在粘弹性液相中复杂寄生模态的出现、器件在非线性粘弹性流体中分析模型的缺乏，及由此导致的传感机制模糊等成为亟待解决的重要问题。本项目拟开展:(a)通过建立高频振动分析模型，揭示粘弹性液相中器件寄生模态的产生机理并提出有效抑制方法；(b)通过建立模型探究非线性流变特性对器件振动的作用规律，利用推导能量损耗特征阻尼的新方法阐明其传感机制，为复杂介质中的体声波传感机制探索提供新的思路和途径；(c)通过设计及测试强耦合生物传感器对理论结果进行验证。本项目突破体声波方法在大阻尼粘弹性液相传感中的局限，为粘弹性液相强耦合器件提供可靠的高频振动分析方法，将体声波方法拓展到非线性粘弹性液相传感中，具有重要意义。

传统的石英体声波器件在大阻尼液相负载下工作时，谐振品质因数降低明显，其导致器件频率稳定性和传感分辨率显著下降。强压电耦合晶体替代石英晶体是解决这一难题的关键所在。强耦合压电体声波器件在粘弹性流体中工作时分析模型的缺乏，导致其寄生振动模态明显，并且其传感机制模糊，影响到其在粘弹性液相传感中的应用。本项目开展了以下工作: 建立了强耦合压电体声波器件在粘弹性流体中的寄生模态分析模型，揭示了复杂寄生模态的产生机理；通过建立模型阐明了强耦合体声波器件在非线性粘弹性流体中的高频振动特性；揭示了强耦合压电器件在非线性粘弹性流体中的传感机制，通过设计强耦合压电液相生物传感器，对理论分析方法和传感机制进行了实验验证。本项目为粘弹性液相强耦合体声波器件提供了可靠的高频振动分析方法，突破了体声波方法在大阻尼粘弹性液相传感中的局限，并拓展了体声波方法在传感领域的应用范围，具有重要意义。

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