Title :
Simultaneous measurement of CO2 and humidity using a pair of SAW devices and cluster-analysis pattern recognition
Author :
Hoyt, Andrea E. ; Ricco, Antonio J. ; Bartholomew, John W. ; Osbourn, Gordon C.
Author_Institution :
Microsensor R&D, Sandia Nat. Labs., Albuquerque, NM, USA
Abstract :
We use a pair of polymer-coated 97-MHz ST-quartz surface acoustic wave (SAW) delay lines to simultaneously determine the concentrations of CO2 and relative humidity (RH) in the gas phase at room temperature. The SAW response of a CO2 permeable polyimide is rapid and reversible for CO2 from 0.03 to 97% of one atm, with some interference from humidity; a layer of the hydrophilic polymer poly(N-vinylpyrrolidone) responds mainly to humidity. Visually-empirical region-of-influence (VERI) pattern recognition (PR) is used to select the optimum pair of films and to evaluate the robustness of the sensor pair to errors
Keywords :
biomedical ultrasonics; carbon compounds; chemical engineering computing; gas sensors; humidity sensors; medical signal processing; membranes; pattern recognition; polymer films; surface acoustic wave delay lines; surface acoustic wave sensors; ultrasonic delay lines; ultrasonic transducer arrays; 97 MHz; CO2; CO2 permeable polyimide; SAW device pair; SAW response; SiO2; cluster-analysis pattern recognition; energy-efficient indoor climate control; errors; gas phase; humidity; hydrophilic polymer; medical applications; optimum pair; poly(N-vinylpyrrolidone); polymer-coated ST-quartz surface acoustic wave delay lines; relative humidity; respiration monitoring; room temperature; scuba applications; simultaneous measurement; visually-empirical region-of-influence pattern recognition; Acoustic measurements; Acoustic waves; Delay lines; Humidity; Interference; Pattern recognition; Polyimides; Polymers; Surface acoustic waves; Temperature;
Conference_Titel :
Solid State Sensors and Actuators, 1997. TRANSDUCERS '97 Chicago., 1997 International Conference on
Conference_Location :
Chicago, IL
Print_ISBN :
0-7803-3829-4
DOI :
10.1109/SENSOR.1997.635484
