Surface acoustic wave gyroscope

设计了一种工作频率为15 MHz、波型为瑞利波、压电衬底为LiNbO3 128 Y-cut的表面声波陀螺仪。一个数字转换器（IDT：称为“发生器IDT”）的电极和两个反射器排列在一起，在表面上产生驻波。两个idt（称为“传感器idt”）和两个用于接收二次波的反射器垂直地排列在产生主驻波的电极上。微扰电极设置在idt之间。该陀螺仪的工作原理是在基片旋转的情况下接收扰动电极激发的二次波。利用等效电路模型估计出转速为2 π rad/s的输出电压为几十mV。该传感器的电极为铝和铬，尺寸为25mm × 45mm。在传感器IDT上，通过测量导纳特性与频率的关系，发现其抗谐振频率与发电机IDT的谐振频率不同，且Q因子较低。因此，输出电压将降低到100毫伏以下。并观察了微扰电极的散射波。这些散射波由传感器idt检测到。通过振动测量，发现了一些与我们设计的振动条件不同的扰动电极。此外，主驻波形成不明显。因此，由于输出电压过低，使用振动台检测陀螺仪的输出。随着表振动频率的锁定，传感器IDT的输出被放大。但是，不幸的是，还没有检测到输出电压。

A surface acoustic wave gyroscope using an operation frequency of 15 MHz, a wave mode of Rayleigh wave and a piezoelectric substrate of LiNbO3 128ﾟ Y-cut was designed. Electrodes of an interdigital transducer (IDT : called "generator IDT") and two reflectors are aligned for generating a standing wave on the surface. Two IDTs (called "sensor IDTs") and two reflectors for receiving a secondary wave are aligned perpendicularly into the electrodes which generate the primary standing wave. Perturbation electrodes are arranged between the IDTs. A principle of this gyroscope is receiving the secondary wave excited by the perturbation electrodes with rotation of the substrate. An output voltage of few tens of mV with rotation rate 2pi rad/s was estimated by using equivalent circuit models. This sensor with electrodes of aluminum and chromium and the size of 25mm x 45mm was fabricated by using photo-process.On sensor IDT,a different anti-resonance frequency from a resonance frequency of generator IDT and low Q factor was found from measuring admittance characteristic versus frequency. Therefor, output voltage will be decreased to less than one hundred muV.And waves scattered by the perturbation electrodes were observed. These scattered waves were detected by the sensor IDTs. Some perturbation electrode with different vibration condition from our design were found by vibration measuring. Further, the primary standing wave was not formed clearly. Thus, a vibrating table was used to detect the output of the gyroscope, for the output voltage was too low. The output of sensor IDT was amplified with locking in the frequency of table vibration. But, unfortunately, the output voltage could not detected yet.