Electromagnetic induction readout silicon-on-insulator MEMS resonant magnetometer

Abstract

This paper presents a micromechanical (MEMS) resonant magnetometer that has been designed to have an electromagnetic induction readout. The MEMS magnetometer is composed of a pair of clamped-clamped beam resonators which together form a U-shaped a magnetic field detection loop through induction. When the resonator oscillates at the anti-phase mode like a double-ended tuning fork (DETF) under the magnetic field, an electromotive force will be generated across the device based on the Faraday's law of induction. Compared with Lorentz force driven MEMS magnetometers which require a bias current, this sensing mechanism provides for lower power consumption. In comparison to a previous device based on the same principle, our device is fabricated by a much simpler 3 mask level process, and possesses a higher sensitivity of 18 mV/T at a required DC drive voltage of only 5 V.