Application of plasma-polymer-film-coated sensors to gas identification using linear filters

Abstract A chemical sensing system that uses a new type of sensor film and digital signal processing of sensor dynamic responses is described. It consists of quartz-crystal microbalances coated with plasma-polymer films. The sensor dynamic responses include information about the target gases, and are described by linear filters the coefficients of which reflect the sensor's dynamics and which can extract the dynamic parameters, even when the gas concentrations change, using multiple sensors with different dynamic characteristics. This method is applicable to various uses under practical conditions. The application of the proposed method to a fire-alarm system is described. This system can discriminate between the gases from burning polyvinyl chloride (PVC) cables and circuit boards, Finally, some simulation results indicate that it is significant for these sensors to have different dynamic properties when the sensors' outputs are greatly disturbed by noise.