Abstract:In order to achieve a kind of high-performance current sensor with high sensitivity and low temperature drift, this paper put forward a kind of new current detection method combined the surface acoustic wave (SAW) technology with magnetostrictive effect, analyzed its sensitive mechanism and improved its temperature characteristic. This SAW current sensor used 128oYX-LiNbO3 as piezoelectric substrate, and SiO2 thin layer whose temperature coefficient polarity is opposite to improve the temperature stability, and one of the SAW delay lines was sputtered with rare-earth giant magnetostrictive TbDyFe film to detect current. The magnetic field of the desired current induces the TbDyFe film’s magnetostrictive strain and ?E effect, changes the SAW propagation characteristics. Based on the theory of acoustic wave propagation in layered medium, this paper analyzed the SAW propagation characteristics in the TbDyFe film/SiO2/piezoelectric substrate layered structure under given current conditions, especially analyzed the TbDyFe and SiO2 film thickness’s effects on the sensor response. The results show that the temperature coefficient of delay(TCD) of the SAW current sensor based on magnetostrictive effect is 18 ppm/oC, and highest sensitivity can reaches 58.1995KHz/A when the TbDyFe and SiO2 thin film thickness are respectively 0.5um and 2um, shows excellent temperature stability and high sensitivity.