Load Matching for Giant Magnetoimpedance Sensor in Coaxial Configuration

Abstract

Operation on the principle of the giant magnetoimpedace (GMI) magnetic field sensor was designed and tested for the case of CoFeSiB amorphous wire of 6 mm length. We considered magnetic field displacement of the order of 10 Oe. Piece of amorphous wire was placed as a central conductor of a coaxial cable. The maximum slope of the sensor GMI characteristic was observed at the terminator resistance RT = 50 Ohm, while the maximum of the GMI ratio variation was observed in the not “matched” (RT = 75 Ohm) but closer to the “short” mode. Amorphous wire placed as a central conductor of a coaxial cable serves as a sensitive element with high sensitivity with respect to applied field making possible to use a simple design with a miniature coil for magnetic field biasing.