Surface acoustic wave magnetostrictive effect for current sensing

Surface Acoustic Wave(SAW) magnetostrictive effect provides a fast and highly-sensitive current detection method,but the coercive force inside the magnetostrictive film results in obvious hysteresis error of the sensor.The strippatterned design of magnetostrictive film can reduce the coercivity inside the film during magnetostriction and suppress the hysteresis phenomenon,so as to realize SAW current detection with high sensitivity and low hysteresis error.Based on the finite element method and Coupled Mode Theory(COM),the magnetostrictive effect of SAW current sensor with strip-patterned FeCo film is analyzed,the sensor response is simulated to determine the optimal structural parameters.To verify the theoretical analysis,the SAW current sensor with a frequency of 150 MHz is developed experimentally,and the sensor test system is established by combining the differential oscillation circuit and the Helmholtz coil.The experimental results show that the strip-patterned design of magnetostrictive film greatly reduces the hysteresis error,and significantly improves the sensor sensitivity.