Investigation of a novel MEMS orthogonal fluxgate sensor fabricated with Co-based amorphous ribbon core

In this paper, we present a novel MEMS orthogonal fluxgate sensor fabricated by standard micro fabricated technology. The sensor mainly consists of a three-dimensional solenoid pick-up coil and a meander-shaped Co-based amorphous ribbon core. The experimental results demonstrate that the sensitivity and noise can be optimized by tuning operation conditions with excitation current amplitude and frequency. The fabricated sensor exhibits a maximum sensitivity of 575 V/T, a wide linear range of ± 480 μT, and a perming below 0.8 μT for 90 mA rms sinusoidal excitation current at 500 kHz frequency. The equivalent magnetic noise is 0.20 nT/√Hz at 1 Hz, and the RMS noise is 1.09 nT in the frequency range of 0.1-10 Hz under the same excitation. In comparison with other micro fabricated fluxgates in similar dimensions, this device possesses relatively high sensitivity and low noise spectral density.