脉冲法测压电振子厚度模机电耦合系数kt

本文讨论了圆片形压电振子的脉冲响应电压.该电压包括一个按指数衰减的脉冲电压和一个高频衰减振荡,前者是由于振子的夹持电容向电路中电阻放电形成,后者是由于振子的压电效应产生的.当外加激励的脉宽和电路的电阻为适当值时,压电振子的高频振荡幅度只和它的机电耦合系数k有关,从而提出了一个测试压电振子的厚度模机电耦合系数k_t的新方法.该方法所需的设备简单,结果准确,通过对一些样品的测试,与传统方法测试的结果很相近.

IMPULSE RESPONSE MEASUREMENT THE ELECTROMECHANICAL COUPLING FACTOR kt OF THICKNESS MODE PIEZOELECTRIC RESONATOR

The pulse response voltage of a piezoelectric circular disk resonator excited by an external voltage is discussed. The voltage is the superposition of a pulse exponential decay resulted principally from the discharging of the clamped capacity of the resonator through R, the resistance of the circuit, and a decaying high frequency oscillation resulted from the piezoelectric effect of the resonator by the applied pulse voltage.lt is shown that the amplitude of the high frequency oscillation is dependent on the electromechanical coupling factor K of the resonator when adequately adjusting the width of the initial pulse voltage and R, the resistance of the circuit. A new method for measuring thickness model electromechanical coupling factor k_t of the piezoelectric resonator is presented.The advantages of this method are simpler equipments and exact results. It is found that the measuring results of some samples using this method are in good agreement with the data obtained from measuring with the conventional method.