Exploring Microwave Reconfigurable Intelligent Surface for Wireless VOC Detection: A Comparative Study of Porous and Solid PDMS Interfaces

Abstract

Microwave gas monitoring with a low-profile design and enhanced selectivity remains a persistent challenge. This study introduces an innovative approach employing a real-time wireless reconfigurable intelligent surface (RIS) for comparative investigation of the interaction of two distinct polydimethylsiloxane (PDMS) interfaces, i.e., solid and porous, with acetone gas molecules. The developed PDMS-coated microwave RIS detects varying concentrations of acetone vapor by wirelessly monitoring variations in the resonant characteristics of the resonating RIS beneath the sensitive interface. This PDMS-coated microwave RIS is validated through exposure to incremental (15–75) parts per thousand (ppt) acetone concentrations and demonstrated a sensitivity of ≈4.4 MHz/ppt and ≈4.3 MHz/ppt of acetone for solid and porous PDMS, respectively. Integrating PDMS and microwave-based RIS systems provides a sensitive tool for tracking the interaction of acetone gas and PDMS and demonstrates this system's capability for sensitive gas detection. This study introduces a unique development in the wireless detection of VOCs and presents a compact and passive approach with enhanced sensitivity, making it suitable for monitoring the interaction of polymers and hazardous VOCs. This technology is particularly suited for use in challenging and hard-to-reach environments.