Electromagnetic induction readout silicon-on-insulator MEMS resonant magnetometer

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.