A MEMS resonant magnetometer based on capacitive detection

In this paper, a MEMS resonant magnetometer based on Lorentz force is presented. The Lorentz force is stimulated by the interaction of an AC current which circulates in a suspended clamped-clamped conducting beam, obtained through a bulk micro-machining, and a 150 mT external static magnetic field. The off-plane (in the z-direction) structure displacement is converted into a capacitance change by a series of interdigitated combs. The frequency of the AC supply current is chosen to be equal to the resonant frequency of the suspended beam, leading to the increase of its deflection magnitude and the overall sensitivity by a factor equal to Q (Quality-factor). Throughout this paper, the first-order resonance frequency and the capacity are simulated with Comsol^® and thereafter compared to the measured values. On the other hand, the quality-factor and the electric model of the sensor are determined from the characterization of the fabricated sensor prototype.