Weak Magnetic Sensors Based On Fe-based Amorphous Ribbons Gmi Effect

With the emergence of the Giant Magnetic-Impedance (GMI) effect, the miniaturization, high sensitivity, quick response, and low power consumption of the magnetic sensor in the field of weak magnetic measurement become possible. It has an enormous foreground of application. Then, a weak magnetic sensor based on GMI effect in Fe-based amorphous ribbon is designed in this paper.Firstly, the theory of GMI effect and two analytic methods are introduced, then the influence factors and operating principle of the sensor based on the GMI effect in Fe-based amorphous ribbon are analyzed in detail. With the test on characteristic of the sensitive component, the turns of coil, the excitation frequency and the length of amorphous ribbon are confirmed. Next, the framework and the experimental system of the micro-magnetic sensor are designed, which is composed of the excitation signal circuit, wave detector circuit, amplifier filter circuit, negative feedback circuit, bias circuit, data acquisition and processing circuit, data transmission, storage and display circuit based on SCM, and corresponding functional software etc. In this paper, anti-interference measures of hardware and software are also designed. At last, the global debugging of the sensor system and the static calibrations are accomplished, and the static characteristics of the sensor are given.The experimental result shows that the sensor system, which can measure the static weak magnetic field ranging from -210uT to 210uT, has an excellent linearity, high sensitivity and good repeatability, and could reach the??uirements of the specification.