Modeling of High-Sensitivity SAW Magnetic Field Sensors with Au-SiO2 Phononic Crystals

Abstract

The development of high-sensitivity magnetic field sensors is crucial for precise magnetic field detection. In this context, a theoretical model is presented for a highly sensitive surface acoustic wave (SAW) magnetic field sensor incorporating phononic crystal (PnC) structures composed of Au pillars embedded within a SiO₂ guiding layer. Rectangular and triangular PnC configurations are studied and their potential for improving sensor performance are assessed. In the design, the PnC is integrated into the SiO₂ guiding layer to preserve the continuous magnetostrictive layer, enhancing its interaction with the SAW. Results from the simulations indicate that the proposed sensor can achieve a nearly two orders of magnitude increase in sensitivity compared to a continuous delay line of similar dimensions, and an eightfold improvement over a previous sensor design with PnCs composed of magnetostrictive pillars. This improved performance is attributed to the enhanced interaction between the SAW and the continuous magnetostrictive layer, driven by resonance effects within the PnC. These findings highlight the significant potential of incorporating PnCs into SAW sensors for future high-performance magnetic field sensing.