The incorporation of a MEMS-based magnetic compass with portable electronics or even wrist-watches provides additional customer-demanded features such as personal navigation, and motion sensing functionalities to these devices. A number of magnetic sensors, such as flux gate magnetometers and Hall-effect devices, have been reported to be sufficiently sensitive to the Earth's magnetic field for use in this application. However, the power requirement of these devices is typically prohibitive for a long-term, portable application[1]. Earlier, we reported an electrostatically-driven micromachined resonator incorporating a permanent magnet. It exhibited very low power consumption with sensitivity high enough for measuring the earth's magnetic field[2]. However, electrostatically driven micro devices require relatively high operating voltage[3], incompatible with CMOS driving circuitry. In this paper, we report an all-magnetic MEMS-based resonant compass, driven electromagnetically by an excitation coil and sensed using a Hall-effect sensor. The magnetic amplification provided by the resonator makes it potentially suitable for compact, low voltage portable navigation systems.
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