3D micromechanical compass

Jukka Kyynäräinen, J. Saarilahti, H. Kattelus, T. Meinander, M. Suhonen, A. Oja, H. Seppä, P. Pekko, H. Kuisma, S. Ruotsalainen, M. Tilli

Research output: Contribution to journalArticleScientificpeer-review

10 Citations (Scopus)

Abstract

We have designed and fabricated micromechanical magnetometers intended for a 3D electronic compass which could be embedded in portable devices. The sensors are based on the Lorentz force acting on a current-carrying coil, processed on a single crystal silicon resonator. Sensors for all cartesian components of the magnetic field vector can be processed on the same chip. The vibration amplitude is detected capacitively and the resonance is tracked by a phase-locked-loop circuit. The fabrication process is based on aligned direct bonding of a double side polished and a SOI wafer. Magnetometers measuring the field component along the chip surface have a flux density resolution of about 10 nT/√Hz at a coil current of 100 μA. Magnetometers measuring the field component perpendicular to the chip surface are currently less sensitive with flux density resolution of about 70 nT/√Hz. Resolution is limited by the fundamental thermomechanical noise. The standard deviation of the signal was less than 1% over a period of 5 days.

Original languageEnglish
Pages (from-to)126-129
JournalSensor Letters
Volume5
Issue number1
DOIs
Publication statusPublished - 1 Mar 2007
MoE publication typeA1 Journal article-refereed

Keywords

  • Magnetic sensors
  • Magnetometers
  • MEMS
  • Micromechanics
  • Resonators

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    Kyynäräinen, J., Saarilahti, J., Kattelus, H., Meinander, T., Suhonen, M., Oja, A., Seppä, H., Pekko, P., Kuisma, H., Ruotsalainen, S., & Tilli, M. (2007). 3D micromechanical compass. Sensor Letters, 5(1), 126-129. https://doi.org/10.1166/sl.2007.040