Design Of A New Kind Of High-precision Magnetic Sensor Based On Giant Magneto-impedance(GMI) Effect

The magnetic sensor based on giant magneto-impedance(GMI) effect becomes one of the hot points on magnetic sensor research in recent years. Compared with other kinds of magnetic sensors, the magnetic sensor has the advantage of miniaturization, high sensitivity, quick response, high temperature stability and low power consumption. As a new kind of high-precision magnetic sensor, the magnetic sensor based on giant magneto-impedance(GMI) effect could be widely used in magnetic fields such as aerospace engineering,national defense and military,geological exploration,industrial test,traffic control,biomedical technologies and so on.From the definition of GMI effect, this paper derives the the impedance value of amorphous materials in theory. Then this paper discusses the factors influencing the impedance value of amorphous material and explains the GMI effect in theory. After that, it summarizes how the production process and methods of amorphous materials affect the GMI effect. From the point of practical design, it discussed the relationship between GMI effect and the specific physical form of sensitive material, the selection of frequency, the structure parameters and so on.In the previous research, the paper designs and realizes the hardware of the magnetic sensor based on GMI effect, including the design of magnetic sensor’s probe and signal processing circuits. The magnetic sensor’s probe adopts longitudinal excitation, selecting Fe-based nano-crystalline ribbon. The section of circuit consists of signal generating circuit, peak detection circuit, filter circuit, differential amplifier circuit, feedback circuit and bias circuit. After design and welding, each function module of the magnetic sensor based on GMI effect is debugged. And it gives the specific experimental steps and experimental results.Finally, the completed magnetic sensor based on GMI effect has carried on the overall debugging and calibration, then each index of the magnetic sensor is given. The experimental results show that the sensitivity of the magnetic sensor based on GMI effect is 176.3 m V/u T. Moreover, the magnetic sensor has the characteristics of high linearity, low repeatability error, low hysteresis error and small size.