Sensitivity of surface acoustic waves devices

摘要

The Surface Acoustic Waves (SAW) devices are widely used as filters, delay lines, resonators and gas sensors. It is possible to use it as mechanical force. The paper describes sensitivity of acceleration sensor based on SAW using the Rayleigh wave propagation. Since characteristic of acceleration SAW sensors are largely determined by piezoelectric materials, it is very important to select substrate with required characteristics. Researches and numerical modeling based on simply sensor model include piezoelectric beam with unilateral free end. An aggregated mass is connected to the one. The dimension and aggregated mass are various. In this case a buckling stress and sensitivity are changed. Sensitivity in main and perpendicular axis are compare for three sensors based on SiO_2, LiNbO_3, Li_2B_4O_7. Influences of phase velocity, electromechanical coupling constant and density on sensitivity are investigated. Some mechanical parameters (Young's modulus, dynamic strength) of the substrates in dynamic work mode are researched using sensor model and Rayleigh model of vibrations without vibration damping. The model is useful because it simply determines dependencies between sensor parameters and substrate parameters. Differences between measured and evaluated quantities are less then 5%. Researches based on sensor models, which fulfilled mechanical specifications similarly to aircraft navigation.