ST-X石英基片上铬栅阵中单根栅条反射系数实验研究

精确的栅条反射系数对于声表面波器件的设计至关重要。本文利用网络分析仪的时域功能,采用短脉冲方法实验研究了ST-X石英基片上铬栅阵中单根栅条的反射系数。并推导出计算反射系数的公式。实验测量了不同铬膜厚度条件下单根指条的反射系数,再对实验结果作最小方差法拟合,得到反射系数随铬膜厚度变化的表达式,即反射系数中压电短路贡献和铬的力学负载贡献之和。最后将实验结果与采用有限元方法计算的理论结果比较,发现两者基本吻合。

Experimental study on the reflection coefficient of chromium gratings strip on a ST-X quartz

The strip reflection coefficient,which includes not only amplitude information but also phase information,is a key parameter in Surface Acoustic Wave(SAW)device design.In this paper,the experimental study on the reflection coefficient of chromium grat- ings strip is implemented on using the impulse response method with the aid of network an- alyzer time function.The reflection coefficient experimental expression is derived first. Then,experiments are implemented to measure reflection coefficients with different chromi- um strip thickness.Finally,by means of minimum variance curve fitting method,the rela- tionship of the reflection coefficient v.s.chromium thickness is obtained,which shows that both piezoelectric short-circuiting and mass loading contributions to the reflection coeffi- cient is determined.Experimental result agrees well with theoretical result by Finite Ele- ment Method(FEM).