Low-loss gas sensor for sensor network consisting of SAW resonators with large spaces between IDTs and reflectors

Sensor network has been proposed with the development of mobile communications system such as cellular phone and wireless LAN. To detect CO, environmental gas and hydrogen leakage from future fuel-cell cars, we published the novel SAW sensor with self-temperature-compensated characteristics on the assumption of garage use at -40 to 80 °C. However, the sensor network which operates under extreme low-power consumption requires small losses for delay-line-type sensors. We have developed a new low-loss sensor consisting of lattice-circuit type delay lines which have large spaces between IDTs and reflectors, where reactive films are formed.