An Integrated MEMS Magnetic Gradiometer Rejecting Vibrations and Stray Fields
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Author
Gasparin, Enrico
Hoogerwerf, Arno
Bayat, Dara
Spinola Durante, Guido
Petremand, Yves
Tormen, Maurizio
Despont, Michel
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DOI
10.1109/ESSERC62670.2024.10719515
Abstract
Due to electrification, magnetic sensors are increasingly
deployed in magnetically polluted environments. To reject
stray fields, differential sensing schemes are typically used. In
this paper, we rely instead on a single-point gradiometric sensing
scheme based on the force exerted on a magnet, which is directly
related to the magnetic field gradient. Unlike the prior art,
our concept uses a differential MEMS force-sensing mechanical
transducer. The overall sensor rejects not only magnetic stray
fields, but also mechanical disturbances such as vibration and
gravity. It is the first single-point MEMS gradiometer that can
operate unshielded in various orientations. Our prototype realization
achieves a noise density of 4 nT/mm/√Hz in a ±300 μT/mm
measurement range. We demonstrate its operational effectiveness
in a bus-bar current sensing application. Finally, the paper
discusses the remaining weaknesses and provides an outlook for
MEMS-based magnetic sensors.
Publication Reference
European Solid-State Circuits Conference ESSERC 2024, Bruges, Belgium 9-12, pp. 532-535
Year
2024-09-09
Sponsors
InnoSuisse