Measurement of the magnitude and direction of magnetic field by a micromachined cantilever

This paper presents a new method which can not only measure the magnitude but also the direction of the magnetic field. A structure with a cantilever driven in different modes is used. The magnetic field direction and magnitude are detected by measuring the vibration amplitudes of the different modes for the mechanical cantilever. The vibration mode is activated by an AC current pass through the coil on the cantilever. The displacements of the structure are shown to be a sine and cosine function of the angle of the magnetic field, respectively, and have been verified through experiments. When the vibration amplitudes of different modes of the cantilever are measured, the magnitude and direction of the magnetic field can be gotten.