High frequency passive micro-magnetic sensor based on surface acoustic wave transponder and giant magnetoimpedance sensitive element

This paper presents a high frequency micro-magnetic field sensor composed of a surface acoustic wave (SAW) transponder and a giant magnetoimpedance (GMI) sensitive element. The coupling-of-mode(COM) method is used to design and optimize the structure of the SAW transponder. An amorphous wire as the GMI element is used to conjunct with the SAW transponder. The experiment result shows the magnetic sensitivity of the sensor of 1.13 dB/Oe changes when the magnetic sensitivity does not exceed 2.0 Oe. For the two-dimension intensity measurement of the magnetic field, a two-dimension SAW-GMI sensor is developed and tested.