Surface Acoustic Wave Sensor for CWA detection and its potential for space application

초록

Surface acoustic wave (SAW) sensor is a microelectromechanical systems (MEMS) which transduces an input electrical signal into a mechanical wave to be easily influenced by physical phenomena. As a sensor to detect various chemical warfare agents (CWAs) which are crucial for people safety as well as military operation, the responsivity and selectivity of targeted chemical species in the detection of various CWAs, such as nerve agents, blister agents, blood agents, mustard (HD), are important factors due to their lethal natures. To design the sensitive sensor, the detecting layer which can easily react with CWAs is required to possess the function of fast response and high selectivity. In this study, we designed surface acoustic wave (SAW) sensor with an operating frequency of 250MHz by interdigital transducers (IDT) configuration on a quartz substrate [1]. Synthesized POSS was dissolved in ethanol and coated on a SAW device by drop coating method. After drying process, the SAW sensor was mounted the testing equipment with mass flow controller system for sensing test. Also the sensing apparatus was tested under a constant temperature as well as humidity condition to minimize the environmental influence. Also for space application, ultraviolet radiation monitoring using SAW can be very useful to explore the outer space because of the sensitivity of SAW to optical wavelengths through the phenomena known as acoustic charge transport (ACT), which involves the interaction between a surface acoustic wave and photogenerated charge carriers from a photoconducting layer. Also temperature monitoring and other possible sensing technology based on SAW sensors in harsh environment can be suggested for future space applications.