SAW sensor for detection of hydrocarbons. Numerical analysis and experimental results

Urbańczyk

2013

Acta Phys. Pol. A

Self Cite

This paper presents the results of the analysis of surface acoustic waves sensor equivalent model. They were the sensor response of the surface acoustic waves sensor in the steady state gas: H2, CO2, NO2, NH3, CnHm, CO. Thin layer of WO3 has been used as a sensor layer. Impedance replacement of sensor layer, taking into account the prole of the concentration of gas molecules in the layer, has been implemented into the equation of Ingebrigtsen, which enabled us to obtain analytical expressions for the relative changes in surface wave velocity in the steady state. The results of the analysis show that there is an optimum thickness of layer sensor for which an acoustoelectric eect (change in the acoustic wave velocity) is the highest.

Section: Introductionmentioning

confidence: 99%

Numerical Optimization of Structures SAW Gas Sensors

Urbańczyk

2013

Acta Phys. Pol. A

Self Cite

Numerical and Experimental Analysis of the Response of a SAW Structure with WO3 Layers on Action of Carbon Monoxide

Urbańczyk²,

Pustelny³

et al. 2015

Archives of Acoustics

The paper presents the results of an analysis of gaseous sensors based on a surface acoustic wave (SAW) by means of the equivalent model theory. The applied theory analyzes the response of the SAW sensor in the steady state affected by carbon monoxide (CO) in air. A thin layer of WO3 has been used as a sensor layer. The acoustical replacing impedance of the sensor layer was used, which takes into account the profile of the concentration of gas molecules in the layer. Thanks to implementing the Ingebrigtsen equation, the authors determined analytical expressions for the relative changes of the velocity of the surface acoustic wave in the steady state. The results of the analysis have shown that there is an optimum thickness of the layer of CO sensor at which the acoustoelectric effect (manifested here as a change in the acoustic wave velocity) is at its highest. The theoretical results were verified and confirmed experimentally.

Numerical Analysis of Sensitivity of SAW Structure to the Effect of Toxic Gases

Pustelny

Wszołek

et al. 2016

Archives of Acoustics

The paper presents the results of numerical analysis of the SAW gas sensor in the steady and nonsteady states. The effect of SAW velocity changes vs surface electrical conductivity of the sensing layer is predicted. The conductivity of the porous sensing layer above the piezoelectric waveguide depends on the profile of the diffused gas molecule concentration inside the layer. The Knudsen's model of gas diffusion was used.Numerical results for the effect of gas CH4 on layers: WO3, TiO2, NiO, SnO2 in the steady state and CH4 in the non-steady state in recovery step in the WO3 sensing layer have been shown. The main aim of the investigation was to study thin film interaction with target gases in the SAW sensor configuration based on simple reaction-diffusion equation.The results of the numerical analysis allow to select the sensor design conditions, including the morphology of the sensor layer, its thickness, operating temperature, and layer type. The numerical results basing on the code elaborated numerical system (written in Python language), were analysed. The theoretical results were verified and confirmed experimentally.