Theory and Analysis of High-Sensitivity Acceleration Sensing Based on 2-D Phononic Crystals

Acceleration sensing is widely applied from consumer electronics to inertial navigation. Conventional accelerometers are mainly based on capacitive or optical principles. However, these approaches either suffer from limited sensitivity or face challenges in integration. Therefore, it is imperative to develop novel acceleration sensing systems based on new physical principles. This article explores 2-D phononic crystals (PnCs) for highsensitivity acceleration sensing. It introduces a novel approach where ultrasound is utilized for the first time to sense acceleration through the PnCs structure. Defective PnCs create a resonant cavity that produces sharp transmission peaks within the band gap. Acceleration causes a frequency shift in these peaks. The research employs the plane wave expansion (PWE) method and the finite element method (FEM) to calculate the band structure and transmission spectra of the PnCs. Both numerical and experimental results demonstrate that this approach is suitable for acceleration sensing, with the experiment achieving a sensitivity of 276 Hz/g, a measured bandwidth of 152 Hz, and a theoretical noise estimation of 7.01 ng/√Hz. Moreover, it is expected to reach the order of 105 Hz/g with the microfabrication techniques in the future. This innovative application of PnCs demonstrates significant potential across a range of microelectromechanical system (MEMS) sensors.