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硅酸镓镧晶体良好的温度特性、相对大机电耦合系数以及高温稳定性等特点,使得利用其制作高温压力传感器具有独特的优势.为了研究SAW谐振频率与外界压力扰动的关系,在相对于参考状态的LAGRANGE坐标描述下,结合叠加偏载的电弹方程和一阶微扰方程,将偏载和扰动引起的机械弹性扰动和压电项同时考虑在内,得到了适用于强压电性基片,常温或高温情况下的通用声表面波压力敏感模型.提出了研究声表面波压力传感器敏感基片优化选择的基本准则和需要综合考虑的性能指标(高机电系数和低温度延迟系数).全面分析了三旋硅酸镓镧压电晶体上分别适用于常温和高温条件下的声表面波压力传感器使用的优化切向.其中,适合常温SAW压力传感器使用的优化基片切向:?1:Φ=0°~0.6°,Θ=144.4°~145.8°,Ψ=23.2°~24.1°;?2:Φ=59.4°~61°,Θ=34.2°~36.2°,Ψ=24.1°~22.3°;?3:Φ=119°~120°,Θ=143.8°~145.5°,Ψ=22.3°~23.5°.适合高温SAW压力传感器应用的基片优化切向:Ⅰ:Φ=8°~30°,Θ=24°~36°,Ψ=4°~25°;Ⅱ:Φ=30°~55°,Θ=144°~158°,Ψ=4°~28°.利用(0,150°,22°)和(0,90°,0)两种切向进行了实验验证,证明理论计算结果与实验值吻合.
The good temperature characteristics, relatively large electromechanical coupling coefficient and high temperature stability of gallium-garnet crystal have unique advantages in using them to produce high-temperature pressure sensor.In order to study the relationship between SAW resonant frequency and external pressure disturbance, State LAGRANGE coordinate description, combined with partial load deflection of the projectile and first-order perturbation equations, the partial load and perturbation caused by the mechanical elastic perturbation and piezoelectric term taken into account, obtained for the strong piezoelectric base The general SAW pressure sensitive model under the condition of ambient temperature or high temperature is proposed, and the basic criteria for optimizing the selection of the SAW pressure sensor substrate and the performance indexes (high mechanical and low temperature delay coefficient) that need considering synthetically are put forward. This paper analyzes the optimized tangential direction of the surface acoustic wave pressure sensor which is suitable for normal temperature and high temperature respectively in the tri-cyclic gallium lanthanum-lanthanum piezoelectric crystal. Among them, the optimal substrate tangential direction for the SAW pressure sensor at room temperature : Φ = 0 ° to 0.6 °, Θ = 144.4 ° to 145.8 °, Ψ = 23.2 ° to 24.1 °; 2 2: Φ = 59.4 ° to 61 °, Θ = 34.2 ° to 36.2 °, Ψ = 24.1 ° to 22.3 ° 3: Φ = 119 ° -120 °, Θ = 143.8 ° ~ 145.5 ° and Ψ = 22.3 ° ~ 23.5 °. The optimal tangential direction of the substrate for high temperature SAW pressure sensor applications is as follows: Ⅰ: Φ = 8 ° ~ 30 °, Θ = 24 ° ~ 36 °, Ψ = 4 ° ~ 25 ° ; Ψ = 30 ° -55 °, Θ = 144 ° -158 °, Ψ = 4 ° -28 ° .There are two tangential directions (0,150 °, 22 °) and (0,90 °, 0) Experimental verification shows that the theoretical calculation results are consistent with the experimental values.