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本文所提出的方法是基于用低频导纳分析仪测出试样导纳随频率变化的数据,再藉助于契比雪夫函数的最小二乘式来处理上述数据,从而建立起一个精确的导纳圆。一旦由计算机解出此圆方程,就能获得串联谐振频率 f_(?)、并联谐振频率 f_p、平面耦合系数 K_p、机械品质因数 Q_m、介电常数ε以及样品的等效电路 L_1、C_1、R_(?)和 C_0等。此外,为了改进测量灵敏度,又提出一种差分电容技术,把样品的静态电容从动态部分分离出来,并用这个方法成功地测出具有极低 K_p 的掺钆钛酸铅压电陶瓷的某些电特性。
The proposed method is based on the low-frequency admittance analyzer to measure the change of admittance with the frequency of the sample data, and then use the Chebyshev function least-square to deal with the above data to establish an accurate admittance round. Once the circle equation is solved by the computer, the series resonant frequency f_ (?), The parallel resonant frequency f_p, the planar coupling coefficient K_p, the mechanical quality factor Q_m, the dielectric constant ε, and the equivalent circuit L_1, C_1, R_ (?) And C_0 and so on. In addition, in order to improve the measurement sensitivity, a differential capacitance technique is also proposed to separate the static capacitance of the sample from the dynamic one and to successfully measure some of the power of the doped gadolinium titanate piezoelectric ceramics with very low K_p by this method characteristic.