Active magnetic shielding with a magnetic field sensor

The shielding effect of a high-sensitivity magnetic field sensor and reverse excitation Helmholtz coil on the unidirectional noise magnetic field component was discussed in this paper. Results indicate that when the Helmholtz coil is small (about the same size as the sensor), a noise magnetic field of 60 Hz, 2.6 × 10^-7 T (p-p) can be reduced to 1.7 × 10^-9 T (p-p), demonstrating the potential efficacy of the active magnetic shielding method.