Miniaturized Thermal Acoustic Gas Sensor Based on a CMOS Microhotplate and MEMS Microphone

Richard Hopper,Phillip Stanley-Marbell,Vasileios Tsoutsouras,Daniel Popa,Florin Udrea

doi:10.3390/proceedings2020056003

Abstract

In this work, we present a novel thermal acoustic gas sensor, fabricated using a CMOS microhotplate and MEMS microphone. The sensing mechanism is based on the detection of changes in the thermal acoustic conversion efficiency which is dependent on the physical properties of the gas. The gas sensor has all the benefits of CMOS technology, including low cost and miniaturization. Here, we demonstrate its application for CO2 gas detection.

Highlights

Thermal acoustic systems are used to generate acoustic waves in gases
Thermal acoustic systems have been used as loudspeakers and as components in systems to convert thermal acoustic power into electrical energy [2], little work has been done to study their application as gas sensors
The sensing mechanism studied in this work relies on the fact that the thermal acoustic conversion efficiency is partly dependent on the physical properties of the gas, namely its thermal effusivity

Summary

Introduction

Thermal acoustic systems are used to generate acoustic waves in gases. A typical system consists of a thermally modulated wire or thin film used to kinetically excite gas molecules [1]. A typical system consists of a thermally modulated wire or thin film used to kinetically excite gas molecules [1]. To maximize the thermal-acoustic conversion efficiency, it is important to minimize the thermal mass of the heated element.

Results

Conclusion