Research on magnetic sensors based on magnetic induction and capacitance

Magnetic induction is inherent in our daily interactions with consumer electronics and demonstrates significant potential for measuring weak magnetic fields. In response to the impact of geomagnetic noise on traditional magnetic sensors in weak field measurements, this paper proposes a gradient magnetic field sensor based on the principles of magnetic induction and capacitance. By examining the characteristics of various structures, the final design was determined and validated through simulations. The sensor minimizes geomagnetic interference by fixing a permanent magnet to the proof mass of the sensitive capacitor, constraining the rotation of the magnet to ensure sensitivity only to gradient field forces. Quantitative analysis establishes the relationship between the external gradient magnetic field and the output voltage of the sensitive capacitor. Simulation results indicate that the proposed method offers rapid response and high precision, with a voltage sensitivity of 22. 9 μV(nT ∙ cm^-1) and a gradient magnetic field resolution of 5 nT/cm. Consequently, this device holds promise for applications in weak magnetic field measurement.