扩散硅谐振式压力传感器同频干扰的建模与消除

Model and Elimination for Co-Channel Interference in Diffused Silicon Resonant Pressure Sensor

为简化谐振式微机械压力传感器的制备工艺,提出了一种采用扩散硅作为谐振梁的压力传感器,并采用电磁激励实现传感器的闭环控制。实验中发现:由于采用扩散硅材料,传感器受到较为严重的同频干扰影响,因此,消除传感器的同频干扰成为需要解决的一个主要问题。通过对采用扩散硅作为谐振梁的压力传感器微结构进行分析,建立了传感器主要噪声来源同频干扰的等效电路模型,据此提出一种新的不对称双端激励解决方法。实验结果表明,该方法可有效地降低传感器的同频干扰,传感器的信噪比由1.53提高至35,为传感器闭环激励和检测提供了有效的手段。

The processes to accomplish the resonant micro-machined pressure sensor are more difficult and complex so that the sensor was applied to limited fields. To simplify the processes for this kind of pressure sensor, a novel microstructure pressure sensor with the diffused silicon as the resonant beam was proposed and the electromagnetic excitation was applied to realize the close-looped control for the sensor. It is founded that the sensor was affected by the high co-channel interference during the close-looped control testing. So how to eliminate the co-channel interference is the main problem for the sensor. Therefore, the microstructure of the micro-machined pressure sensor was analyzed at first, and then the equivalent circuit model of the main noise source co-channel interference was brought up, finally a novel measure with nonsymmetrical excitation was proposed. Experiments show that this measure can eliminate the co-channel interference of the sensor and the S/N ratio is improved from 1.53 to 35, which provide the effective ways to close-looped excitation and detection for the sensor.