# The Application of Commercial Surface Acoustic Wave Radio Communication Filters as Transducers for DMMP Sensors

## TL;DR

This study explores using radio communication filters as gas sensors to detect DMMP, a simulant for nerve agents, showing promising performance.

## Contribution

The novel use of commercial SAW resonators as transducers for DMMP detection is demonstrated.

## Key findings

- R433 resonators produced a 20.5 kHz signal within 1 minute of DMMP exposure.
- Both R315 and R433 resonators reacted rapidly to 3 mg/m3 DMMP vapor.
- The sensors generated stable analytical signals in the range of several to several dozen kilohertz.

## Abstract

In the present study, we used two popular radio communication SAW resonators as a base for gas sensors and tested their performance. Taking into account issues related to sensor sensitivity, the possibility of applying a sensor layer, the availability of devices, and other related issues, we selected two popular single-port resonators with center frequencies of 315 and 433 MHz (models R315 and R433, respectively) for testing purposes. Both resonators were equipped with a sensitive film of hexafluoroisopropanol-substituted polydimethylsiloxane, a material that selectively absorbs molecules with a high ability to form basic hydrogen bonds. Fabricated sensors were used to detect trace amounts of dimethyl methylphosphonate (DMMP) vapor, which has often been used in similar studies as a nerve chemical warfare agent simulant. Sensors using both devices loaded with sensor layers of an optimal thickness rapidly reacted to a gas containing DMMP at a concentration of 3 mg/m3, generating a stable analytical signal ranging from several to several dozen kilohertz. In the case of R433, the frequency signal was 20.5 kHz at 1 min from the beginning of exposure to DMMP. The obtained results showed that the used transducers exhibited good performance as a base for gas sensors. Finally, their suitability for sensing applications was confirmed by a comparison with the results obtained in previous similar studies.