Papers by Keyword: Surface Acoustic Wave

Abstract: The surface acoustic wave (SAW) technique is a precise and nondestructive method to detect the mechanical characteristics of the precision-machined surface. The paper is concerned with the effect of the roughness of the machined surface on the dispersion of surface acoustic waves propagating in the precision-machined surface which indicates mechanical characteristics of the machined surface. The finite element method (FEM) is employed by establishing a series of models with different roughness Ra value to analyze influences from different roughness Ra value on surface acoustic wave dispersion. The models are established by applying a combined method based on fractal theory and wavelet analysis. The simulation results showed that the roughness of machined surface will cause the dispersion of surface acoustic wave propagation, the effect varies with the different roughness Ra values. A critical Ra value influencing on the surface acoustic wave propagation exists. Accordingly, that the factor of roughness should be considered in advance or not, the situation can be determined through studying and determining the critical roughness Ra value above mentioned. Consequently, the study has the important meaning regarding the detection for mechanical characteristics of the machined surface.

Abstract: Droplet mobility actuated by surface acoustic wave (SAW) was demonstrated in this paper. On the surface of the LiNBO₃ substrate, pairs of copper inter-digital transducer (IDT) were fabricated to generate Rayleigh wave at different radio frequency (RF) voltages. The various droplet motions, such as mixing, flowing and atomization were analyzed by adjusting pulse frequency and input power. The experimental results demonstrated that the SAW could function as an atomizer when the input power was higher than 25W. Based on fundamental experiments, a novel driving curve for micro droplets under different driving power was obtained as well.

Abstract: When detecting torque with surface acoustic wave (SAW) resonator sensors, the real strain of the host structure is not exactly consistent with the strain of SAW resonator due to material mismatch and the finite-thickness adhesive problem. A 3-layer (host structure, adhesive, and resonator layer) model is established. Finite-element Analysis (FEA) was used to investigate the strain transfer from the metal substrate to the SAW resonator (SAWR) through a bonding layer. The results show that the values of the strain transfer rate of FEA agree well with the experimental data. It can be concluded that FEA is of great value for SAW sensor design and sensing applications.

Abstract: For amorphous materials such as glass, the fragility of the material can be limited using surface reinforcement by chemical tempering. The principle of chemical tempering consists in forming a superficial compression layer on the surface by immersing the glass in a solution of molten potassium nitrate. In this study, dispersion of surface ultrasonic waves caused by the presence of residual surface stresses was studied. The thickness and the level of the stressed cortical zones were estimated using an inverse method.

Abstract: When detecting torque with surface acoustic wave (SAW) resonator sensors, the real strain of the host structure is not exactly consistent with the strain of SAW resonator due to material mismatch and the finite-thickness adhesive problem. A 3-layer (host structure, adhesive, and resonator layer) model is established. Finite-element Analysis (FEA) was used to investigate the strain transfer from the metal substrate to the SAW resonator (SAWR) through a bonding layer. The results show that the values of the strain transfer rate of FEA agree well with the experimental data. It can be concluded that FEA is of great value for SAW sensor design and sensing applications.

Abstract: Traditional surface acoustic wave touch screen causes high power consumption. The controller that needs to generate driving sound transducer voltage leads to large volume and high cost. It is difficult to become integration of the controller and small and medium size portable information terminal. So a low-power, ultra-light, small and medium size surface acoustic wave touch screen technology solution is proposed. On the touch screen set passive manned sensors and active detection circuit at the same time, the state transition of active detection circuit triggered by passive manned sensors, realize a touch of low power consumption, high precision requirements. In this paper the principal and system structure are discussed and the superiority is given.