压电传感器在谐波模式下的响应特性

Response characteristic of the harmonic model in a piezoelectric sensor

该文以阻抗分析法研究了压电石英晶体(PQC)中的3次和5次谐波的响应特性,结果表明,PQC的高次谐波的频率对表面质量变化高度敏感,3次和5次谐波的频率-质量系数分别为基频模式的频率-质量系数的3倍和5倍。当与液体接触时,PQC的基频和谐波的谐振频率随(ρη)1/2增加而线性下降,其中ρ和η分别为溶液的密度和粘度,基频、3次和5次谐波模式所对应的斜率(F0/(ρη)1/2)之比为1∶1.68∶1.96。基频和谐波的动态电阻随(ρη)1/2增加而线性升高,基频、3次和5次谐波模式所对应的斜率(Rm/(ρη)1/2)之比为1∶1.85∶2.01。高次谐波模式中的纵波效应较弱,其强度约为基频模式中纵波强度的5%。就质量响应而言,PQC的基频、3次和5次谐波的信噪比接近。

The response characteristic of the third and fifth harmonic models in a piezoelectric quartz crystal（PQC） was investigated by an impedance analysis method.It was shown that the frequencies of the harmonics in a PQC are highly sensitive to the changes in surface mass loading.The frequency-mass coefficients in the third and fifth harmonic models are 3 and 5 times of that in the fundamental frequency model,respectively.For a PQC in a liquid phase,the resonant frequencies（f0） in fundamental frequency and harmonic models reduce linearly with increasing（ρη）1/2,where ρ and η are the density and viscosity of the liquid,respectively.The ratio of the slopes（R0/（ρη）1/2） in the fundamental frequency,third and fifth harmonic models are 1：1.68：1.96.The motional resistances（Rm） in fundamental frequency and harmonic models increase linearly with increasing（ρη）1/2.The slopes（Rm/（ρη）1/2） in the fundamental frequency,third and fifth harmonic models are 1 ：1.85 ：2.01.The longitudinal wave effect is weak in the harmonic models.The intensity of the longitudinal wave in the harmonic models is about 5% of that in the fundamental frequency model.With respect to mass effect,the signal-to-noise ratio in the fundamental frequency and harmonic models are similar.