新型表面波电流传感器优化设计

The optimum design of new SAW-based current sensor

本文对结合磁致伸缩效应的新型声表面波电流传感器进行优化设计。传感器采用80 MHz声表面波双通道延迟线型差分振荡器,并在传感通道SAW器件表面声传播路径上溅射磁致伸缩薄膜,利用薄膜材料在电流激发磁场作用产生的磁致伸缩效应引起声传播速度的变化,并以相应振荡器频率的变化来表征待测电流。通过对不同磁致伸缩材料(FeCo和FeNi)以及薄膜厚度的传感效应进行分析,用以为传感器的优化设计提供思路,并通过实验进行验证,实验结果显示,相对于FeCo而言,采用FeNi作为敏感材料的电流传感器具有良好的重现性、线性度以及较高的灵敏度。

In this paper,a novel SAW current sensor based on the magnetostrictive effect was optimal designed.This SAW current sensor used80MHz SAW dual-channel delay liner differential oscillator,and magnetostrictivefilm was deposited on the SAW propagation path.The magnetic field of the desired current inducesthe film’s magnetostrictive strain,changes the SAW phase velocity,then the corresponding differential oscillationfrequency change was used to evaluate the applied current.The sensor effects of different magnetostrictivematerials(FeCo and FeNi)and film thickness were analyzed to provide ideas on the optimization design of thesensor,and also were verified by experiments.The experimental results show that,comparing to the FeCo,thecurrent sensor with FeNi as sensitive film has good repeatability,linearity and high sensitivity.