Technical aspects of SAW gas sensors application in environmental measurements

Abstract

The development of semiconductor technology and computer methods allows for the improvements in air pollutions measurement techniques. Besides the traditional techniques of air pollution measurement such as chromatography or dynamic olfactometry, the electronic nose (EN) gains increasing attention in this area. EN is a device which imitates the human olfactory sense. The main component of the device is an array of many nonspecific gas sensors. In this article, the most frequently used types of gas sensors in scientific studies were shortly characterised as: metal oxide semiconductors (MOS), conducting polymers, quartz microbalances (QCM) and surface acoustic wave (SAW) sensors, and others. Both their advantages and disadvantages were summarised. Technical aspects of measurements using SAW gas sensors arrays were presented, as well as measurement circuits were described.