Toward a Novel Remote Pressure Sensor: Influence of Static Magnetic Fields on the Resonance Frequency of Magnetostrictive Microcantilevers

Abstract

This contribution presents the concept of a novel miniature pressure sensor that can be queried wirelessly. The sensor consists of a monomorph magnetostrictive microcantilever (MSMC) and a magnetized membrane. The distance between membrane and cantilever and therefore the biasing magnetic field strength varies with the applied pressure. The advantage of the sensor is that the aimed quantity is the bending/resonance frequency, which solely depends on the biasing magnetic field strength. We report on the fabrication of a MSMC with a size of 1500 μm × 72 μm × 5 μm and we present two different methods to determine the resonance frequency of the cantilever. One approach is the so-called peak and hold method, where the resonance frequency is determined by measuring the frequency response. In the second method applied, the impulse response of the cantilever is evaluated. We demonstrate that the resonance frequency of the cantilever can be shifted in a range of up to 13% by applying a biasing magnetic dc field of 35 kA/m. In addition, the measured quality factor of the cantilever reveals the low damping. The obtained results show that the fabricated MSMC is applicable for the proposed miniature pressure sensor.