基于EIT技术的气流传感器及其实验研究

Gaseous flow sensor based on EIT and its experimental study

提出了一种新型的、基于电阻抗断层成像技术进行气流传感的微机电(MEMS)传感器结构,其基本构造为覆盖在加热器件之上的半导体硅薄膜以及位于硅薄膜四周的16个金属电极.首先,在金属电极对中注入电流,并根据相邻测试规则测量其他电极对间的电压;然后,改变电流注入位置并测量电压,得到208个电压值;最后,利用成像软件将电流和电压参量转换为电阻率分布图像.气流流动所导致的热场分布变化将引起薄膜电阻率的分布发生变化.气流传感实验结果表明,气流方向、速度的变化能够采用图像的方式清晰、直观地进行描述.研究结果为MEMS传感器设计提供了新的方案与技术.

A novel structure of micro-electro-mechanical gaseous flow sensor based on electrical impedance tomography（EIT） is developed.The gaseous flow sensor consists of a silicon film over the heater and 16 metal electrodes surrounding the film.First,the excitation current is injected through a couple electrode and voltages are measured between other electrodes.Then,the sites of the electrodes of current are changed and the voltages are measured again.208 voltage values are obtained.Finally,these values of the currents and voltages are transformed to the resistivity distribution image by using imaging software.The change of thermal field by gas flowing can induce the distribution change of the film＇s resistivity.The experiment results show that the change of the speed and direction of flow can be truly and clearly described with images,which provides a novel method and technique for the design of micro-electro-mechanical gaseous flow sensor.