A novel SAW sensor for temperature and pressure measurement

For the typical applications of automotive tire pressure monitoring system (TPMS), a novel sensor based on surface acoustic wave (SAW) is reported in this paper. According to the theory of SAW delay line, the effect of temperature and pressure on the sensor can be reflected by variations of the radio frequency (RF) echo signals. The accurate measurement of temperature and pressure can be achieved by introducing a weight factor in the data process. Test results in certain ranges of pressure and temperature demonstrate that the sensor is able to measure temperature (0-200 kPa) and pressure (20-100°C) at the same time. For SAW sensors the temperature measurement accuracy can reach 0.05°C and the pressure measurement accuracy can reach 7.2 kPa. In TPMS, where reliability and durability are really demanding, the reported sensor has its practicability and potential market with its advantages of simple structure, and wireless and passive working mode.