Activate Zeolite Filter: A gas sensor signal stabilization and enhancement

Abstract

In this report, we investigate zeolite as a humidity filter by optimizing its heating temperature providing constant humidity to the gas sensor chip. The metal oxide semiconductor (MOS) based gas sensor signals are prone to humidity and temperature variations which causes difficulty in distinguishing the sensor response. The baseline drift of MOS sensor, their signal stability and repeatability are achieved by heated zeolite filter assembly as part of packaged sensor. The sensor package consists of a sandwich of zeolite powder and nichrome wire, which controls the humidity and temperature of the sensor. With the packaged filter and sensor assembly, the recorded humidity and temperature near the sensor chip are 35±5% RH and 40±5°C when the external humidity and temperature is varying from 30 to 80% RH and 21 to 35°C. NO 2 sensor is investigated with and without the filter for proof of concept to check the sensor stability and repeatability.