Development of A Surface Acoustic Wave Delay Line Device for Sensing ICE

In this work, a surface acoustic wave device with delay line pattern with operation frequency of 200MHz was developed for sensing ice. Y-cut 35° quartz was employed as piezoelectric crystal, which exhibits excellent temperature stability. A SiO
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thin-film was coated onto the SAW device after the photolithographic deposition of interdigital transducers (IDTs) to protect the metal electrodes in process of ice formation. The developed SAW sensing chip was characterized by using the high-low temperature chamber. When the temperature in chamber was dropped to the freezing point, a sharp change in frequency of the sensing device was observed because of the mass loading effect from the ice layer. The theoretical results obtained by solving the acoustic wave equations in layered structure oifers a clear explanation for the phenomenon observed. Obviously, fast and distinct response towards ice accretion was achieved from the developed SAW device, which indicates that it is very promising for sensing ice.