Setting this device apart, according to its developers is not only its rapid response, but also its high sensitivity and compact size — all of which are critical for the early detection of CWAs.

Schematic of SAW chemical sensor. Source: Microsystems & Nanoengineering. DOI: 10.1038/s41378-023-00627-8

To accomplish this, the researchers built a passive, wireless sensor system using surface acoustic wave (SAW) technology. The sensor, which specifically targets a simulant for nerve agents called dimethyl methylphosphonate (DMMP), operates at 433 MHz, using a fluoroalcohol polysiloxane (SXFA) coating on a lithium niobate substrate, thus enhancing sensitivity and stability under assorted environmental conditions.

Further, the core of the system surrounds a YZ lithium niobate substrate outfitted with metallic interdigital transducers (IDTs) along with an attached antenna. The team explained that the SXFA coating's interaction with DMMP affects the SAW's properties — for example, its velocity — thereby paving the way for precise detection. The team suggests that the design of the sensor system ensures stable operation within a 0 to 90 cm transmission range, resiliency across a temperature range of -30° C to 100° C and relative humidity levels up to 60%.

Thanks to its passive wireless design, the sensor system is reportedly capable of operating in inaccessible or hazardous areas where chemical threats exist.

An article detailing the sensor system, “A passive wireless surface acoustic wave (SAW) sensor system for detecting warfare agents based on fluoroalcohol polysiloxane film,” appears in the journal Microsystems & Nanoengineering.