INTEGRATED RESONANT MAGNETIC-FIELD SENSOR

The present paper introduces a magnetic-field sensor based on a resona ting single-crystal silicon structure. The excitation of the resonator is achieved by the Lorentz force generated by a sinusoidal current fl owing through a rectangular coil deposited on the surface of the struc ture. The amplitude of the vibration, which is proportional to the mag netic field, is detected by sensing capacitors. A capacitive feedback loop is used to enable the sensor to have a large dynamic range. Becau se of the high quality factor of the resonator, the expected lower mea suring limit is in the nT range. The manufacture of the sensor include s micromachining, glass processing and common bipolar technologies. By adapting these techniques, it is possible to produce sensitive device s at a relatively low unit cost.