SAW Sensor

S. Liu, P. Wang, and H. Sun
University of Massachusetts Lowell, Lowell, MA, USA

In this paper we study the porous media coating (PMC) effect on the surface acoustic wave (SAW) sensor for chemical detection. Intensive research for SAW sensor is focused on using high surface polymer coating such as nanofibrous film to improve the sensitivity and to shorten response time for in situ trace level detections. A theoretical analysis shows the PMC can provide a higher and faster sensing response while still maintain reasonable transmission loss. A numerical model is developed by using COMSOL Multiphysics and is compared with the prediction from theoretical analysis. The key parameters such as porosity, viscoelastic properties and thickness are correlated with SAW sensing response including transmission loss and frequency shift in this work. It is concluded that PMC based SAW sensor demonstrates higher frequency shift and sensitivity compared with the one with traditional solid film coating. PMC based SAW sensing device holds a great potential in enhancing SAW sensor performance for onsite and trace level detection of chemical analytes.