Orthogonal Fluxgate Sensor Fabricated With a Co-Based Amorphous Wire Embedded Onto Surface of Alumina Substrate

The orthogonal fluxgate sensor with a novel structure is presented in this paper for the first time. To overcome a weakness (tiny and flexible) of an amorphous wire in mass production, the sensor proposed in this study is composed of a pickup coil and a CoFeSiB amorphous wire which was embedded onto the surface of alumina substrate. We demonstrate that the fundamental mode operation can be achieved, and the sensitivity is enhanced by adding a suitable bias to excitation current. We present there is a close correspondence between the impedance resonance frequency and the optimal frequency of the sensor output. This can be explained with the equivalent circuit of the pickup coil and the maximum power transfer theorem. The experimental result says the operation frequency has to be decided by measuring the impedance of the pickup coil. The maximum sensitivity of the fabricated sensor at the optimal operation frequency is 0.8 V/Oe with the excitation current of 25 mA and DC bias of 15 mA.