Innovative surface acoustic wave devices: A solution for real time monitoring and self-cleaning cascade impactor

Abstract

This paper presents a comparative study of three types of surface acoustic waves sensors used for particulate matter detection along with a theoretical study tackling the possibility to switch to innovative materials called Piezoelectric-on-Insulator. These sensors are placed in a cascade impactor as impaction plates. Monitoring their phase variation allows us to measure the quantity of fine particles present in the air with high accuracy. Until now, the sensors used in our prototype are built on quartz substrate and present a sufficient sensitivity to fine particles. One major concern in our application is the fouling of the sensor’s surface with particles upon long periods of exposure. This shaped our drive to develop a self-cleaning sensor relying on other substrates with stronger electromechanical coupling coefficient (k2) [1]. Hence, the aim of this study is to demonstrate the possibility of using strongly coupled modes on different piezoelectric substrates for an accurate PM detection. Among these, different POI substrates are considered to assess their physical and acoustic properties, especially in terms of k2 and thermal stability, for further optimization enabling their exploitation in the self-cleaning system that is being developed.