同面散射场电容传感器的电极结构与敏感特性

Electrode structure and characteristics of uniplanar scattering-field capacitive sensors

同面散射场式电容传感器极板所产生的电场呈散射状,传统的电磁场理论很难得到精确的解析解,给传感器的设计及性能优化带来很大困难。该文在电磁场分析的基础上,采用有限元分析的方法研究了传感器电极结构与敏感特性之间的关系,并通过实验对分析结果进行了验证。结果表明:在用于金属目标的非接触位移测量时,传感器两电极极板间的距离存在最优值;叉指结构传感器量程和灵敏度均优于普通结构传感器。

The electrode structure of the uniplanar scattering-field capacitive sensor is the essential factor affecting sensor performance. However, the scattering of the electric field makes precise analysis with traditional electromagnetism theory difficult, which complicates the design process, especially performance optimization. Therefore, a finite element analysis was used to solve the electromagnetic equations to analyze the relationship between the electrode structure and the field characteristics. Experiments validated the analytical results. The results indicate that uniplanar electrodes used as the non-contact proximity sensor for a metal target have an optimized gap size between the two electrodes. The interdigitated structure gives better measurement scale and sensitivity than the general two-electrode structure.