差分负载式无线无源声表面波应变传感器研究

在用声表面波(SAW)传感器直接测量应变时，易受到环境温度的干扰，将不可避免地产生力温耦合效应。针对该问题，该文提出了一种新型的外接应变传感器负载，并采用了差分结构的无线无源SAW应变传感器设计方法。传感器采用双通道SAW反射型延迟线作为无线传感系统的应答器，其中一个通道外接力容性应变片作为外接负载传感器以感知应变量，另外一个通道则外接参考负载以差分抵消测试环境温度变化的影响。该文结合耦合模理论，仿真了负载容性应变传感器电容变化引起的SAW传感系统响应特性。最后通过实验验证了这种差分负载式SAW应变传感器的可行性与有效性。

Research on Difference Load Type Surface Acoustic Wave Passive Wireless Strain Sensor

When using the surface acoustic wave (SAW) sensor to measure strain directly, which is vulnerable to ambient temperature interference, the sensor will inevitably produce force temperature coupling effect. Therefore, this paper presents a new type of wireless passive SAW strain sensor design method that is adopting an external load and differential structure. The SAW device in the sensor is used as a transponder for the wireless sensor system, which is adopting the dual channel reflective delay line differential structure. One of the channels, collecting an external capacitive strain gauges used as the external load sensor, senses the strain. And the other one, also collecting an external capacitive strain gauges used as an external reference load, is used to counteract the effects of temperature changes in the test environment. Based on the coupling of modes (COM) theory, this paper has simulated the load sensor capacitance changes caused by the sensor response characteristics. Finally, the feasibility and effectiveness of this differential load SAW strain sensor are verified by experiment.