高次泛音比法测定厚度振动机电耦合系数

压电振子低频振动模式的高次泛音易与厚度振动模式的基频相耦合,导致厚度振动的基音串联谐振频率不能精确测量(或无法测量),造成传统泛音比法测定压电振子的机电耦合系数的精度和一致性变差或无法进行测定。为了克服传统泛音比法的这一弊端,提出了测定压电振子厚度振动机电耦合系数的高次泛音比法。此法通过测定3次和3次以上的高次串联谐振频率,用高次泛音比来测定压电振子厚度振动机电耦合系数。实验表明,与传统泛音比法相比,高次泛音比法具有精确度高和一致性好的明显优势。为了便于高次泛音比法的应用,提供了高次泛音比和机电耦合系数的对应表。

Higher Overtone Ratio Method for Measuring the Electromechanical Coupling Factor of a Thickness Vibration

The easier coupling of the thickness fundamental resonance with the higher overtone of low-resonant modes leads to a bad measurement accuracy of the thickness series resonance frequencies or a failure of the resonance frequency measurement,resulting in deteriorating the accuracy and the identity of the electromechanical coupling factor determined by the traditional overtone ratio method.To overcome the shortcoming of the traditional overtone ratio method,a higher overtone ratio method to determine the thickness vibration electromechanical coupling factors was presented.The higher overtone ratio method determine the thickness vibration electromechanical coupling factors by measuring third-tone and higher-tone series resonance frequencies.Experiments showed that the higher overtone ratio method has a distinct advantage over the measurement accuracy and the identity of the electromechanical coupling factor in comparison with the traditional overtone ratio method.To facilitate the application of the higher overtone ratio method,a contrast table between the higher overtone ratio and the electromechanical coupling factors was provided.