Field Concentrator Based Resonant Magnetic Sensor

A novel resonant magnetic sensor based on the combination of a mechanical resonator and a magnetic field concentrator with two gaps is reported. In contrast to previous Lorentz force based resonant magnetic sensors, a high sensitivity is achieved without modulated driving current and complex feedback electronics. Furthermore, compared to magnetic moment based resonant magnetic sensors, the new concept requires no permanent magnet. The novel sensing principle is discussed and a macroscopic proof-of-concept structure is presented. Simulation and test of the macroscopic sensor result in a high sensitivity of 140 kHz/T at a magnetic flux density of 1.5 mT. For low magnetic fields, the sensitivity depends linearly on the magnetic flux density.