An improved mode-localized lorentz force magnetometer with reduced power consumption

In this work, an improved micro-electro-mechanical system (MEMS) magnetometer based on the mode localization effect is presented. The device consists of weakly coupled resonators (WCRs) and two magnetic field sensing units (MFSUs), coupled via electrostatic negative stiffness introduced by perturbation capacitors. When an external magnetic field is applied to the MFSUs under an excitation current, the resulting Lorentz-force-induced displacement perturbs the energy distribution of the vibrating WCRs. Through the mode localization effect, the Lorentz-force-induced mechanical motion is amplified into a pronounced variation in the amplitude ratio, which serves as a measurable indicator of the external magnetic field strength. Experimental results demonstrate a sensitivity of 510.7 /T, a noise floor of 206 nT/√Hz, a resolution of 244 nT, and a measurement range of 105 mT, all achieved with a low power consumption of 1 mW. Furthermore, it achieves a measurement range-to-noise floor ratio of 5.1 × 10⁵√Hz, which compares favorably with previously reported Lorentz-force MEMS magnetometers and indicates a favorable trade-off between measurement range and noise floor. These performance metrics, together with the device’s miniaturization and low-cost fabrication, indicate its potential applicability in areas such as industrial equipment monitoring, consumer electronics navigation, and battery health management in new energy vehicles.