Hydrogen Sulfide Surface Acoustic Wave Gas Detector

Abstract

A surface acoustic wave (SAW) hydrogen sulfide (H S) gas detector has been designed, fabricated an3 tested. The detector consists of twin SAW delay lines fabricated on a single LiNbO substrate. Each delay line is confi uredas an is coated with a sputfered film of activated tungsten trioxide (WO$ while the other is uncoated and used as a stable reference. Phase dela changes due to the mass loadin stress and elecrric field effects induced by the 82s gas sorbed on the WO3 film result in corre ponding frequency shifts which are directly proportional to the as concentration. Gas detector properties time and shape of the response curve gignature). The detector was found to be quite stable and s stematic responses to concentrations less than 18 parts per billion were observed. oscillator. The propa ation path o 9 one delay line