Magnetic sensors based on micromechanical oscillators

This paper describes magnetic sensor technology based on the detection of Lorentz force on a micromechani-cal oscillator. Experimental results are presented based on a silicon resonator operating at 105.5 kHz with a quality factor of 13,000. Sensor operation is demonstrated using amplitude modulation (AM) and frequency modulation (FM) readout of the magnetic signal. In AM operation, the noise at the sensor's output is equivalent to 128 nT/rt-Hz and the bandwidth is 4 Hz. In FM operation, the noise at the sensor's output is equivalent to 500 nT/rt-Hz and the bandwidth is 50 Hz.