Development of a Love Wave Based Device for Sensing Icing Process with Fast Response

This work addresses the theoretical and experimental investigations of a Love wave based device employing waveguide structure of SiO2/36 degrees YX-LiTaO3 for sensing icing process. The mass loading effect induced by the icing process modulates the acoustic wave propagation, and corresponding changes in device frequency can be collected to evaluate the icing process. The waveguide structure confines the acoustic wave energy into SiO2 thin-film, which contributes well to the improvement of the mass loading sensitivity. The corresponding sensing mechanism was analyzed by solving the acoustic propagation equations in layered structure. The sensing device patterned by delay-line on 36 degrees YX-LiTaO3 substrate with SiO2 guiding layer was photolithographically developed as the sensor element, and characterized by using the high-low temperature chamber. The icing process was simulated by dropping appropriate water on top of the device surface. Very clear and fast frequency response was observed from the proposed sensing device in the icing process, and also, the influence of SiO2 guiding layer thickness on sensor response was also investigated.