Enhanced sensitivity of temperature-compensated SAW-based current sensor using the magnetostrictive effect
Enhanced sensitivity of temperature-compensated SAW-based current sensor using the magnetostrictive effect
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DOI：
10.1088/1361-665x/aa5137
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发表时间：
2017-02-01
影响因子：
4.1
通讯作者：
Du, Zaofu
中科院分区：
文献类型：
--
作者：
Wang, Wen;Jia, Yana;Du, Zaofu
本文提出了一种基于温度补偿表面声波（SAW）的电流传感器，由 SiO2/128 度 YX LiNbO3 压电基板上的 SAW 延迟线图案制成的传感器芯片、沉积在 SAW 传播路径上的磁致伸缩 FeCo 薄膜以及相应的差分振荡配置组成。 FeCo 涂层在施加电流产生的磁场下产生磁致伸缩应变，从而导致 SAW 传播以速度变化的形式发生线性变化。相应的差分振荡频移用于评估测试电流。通过求解层状结构中的耦合机电场方程，同时考虑磁致伸缩效应，确定了最佳的 FeCo 薄膜厚度和产生高电流灵敏度的传感器工作频率，然后通过评估所开发的利用亥姆霍兹线圈的 SAW 电流传感器系统进行实验证实。我们的 300 MHz SAW 传感器具有 500 nm FeCo 涂层和 2:1 的纵横比，可实现 16.6 KHz A(-1) (8.3 KHz m(-1) T-1) 的高灵敏度、出色的线性度和较低的检测限（类似于 0.2 mA）。
A temperature-compensated surface acoustic wave (SAW)-based current sensor was proposed in this contribution, composed of a sensor chip made by SAW delay line patterns on a SiO2/128 degrees YX LiNbO3 piezoelectric substrate, a magnetostrictive FeCo film deposited on the SAW propagation path, and a corresponding differential oscillation configuration. The FeCo coating produced magnetostrictive strain under the magnetic field generated by the applied current, leading to linearity changes in the SAW propagation in the form of velocity change. The corresponding differential oscillation frequency shift was used to evaluate the tested current. By solving the coupled electromechanical field equation in a layered structure while considering the magnetostrictive effect, the optimal FeCo film thickness, and sensor operation frequency yielding high current sensitivity, were determined, and then confirmed experimentally by evaluating the developed SAW current sensor system utilizing a Helmholtz coil. A high sensitivity of 16.6 KHz A(-1) (8.3 KHz m(-1) T-1), excellent linearity, and lower detection limit (similar to 0.2 mA) were achieved with our 300 MHz SAW sensor with a 500 nm FeCo coating and aspect ratio of 2:1.