A High-Sensitivity Magnetic Field Sensor Based on PDMS Flexible Resonator

Abstract

High-sensitivity resonator magnetic sensing requires a significant magnetostrictive response, while the narrow linewidth mode of a high-Q resonator can provide a high-precision frequency resolution. Therefore, a polydimethylsiloxane (PDMS) flexible resonator with both a low Young’s modulus and high optical transmittance is an ideal platform for realizing high-sensitivity magnetic sensing. Based on the sandwich structure of the PDMS flexible resonator, the mechanism of the magnetic field sensitivity of the PDMS flexible resonator sandwich structure is studied, and the impact of changes in the refractive index and radius on the sensor device is analyzed. In order to optimize the sensitivity of the sensor, when an external magnetic field acts on the sandwich structure, the impacts of three aspects on the sensitivity of the sensor are simulated and analyzed: different coupling positions of PDMS flexible resonator, different radii, and PDMS mixing ratios. The trend of sensitivity change is obtained, and the physical explanation of the sensitivity trend is analyzed. By optimizing these three aspects, the magnetic field sensitivity is eventually calculated as 19.02 nm/mT. Based on the existing experimental conditions and the preparation technology of the PDMS flexible resonator, the measured magnetic field sensitivity is 4.23 nm/mT.