Wireless pressure and temperature measurement using a SAW hybrid sensor

A passive pressure and temperature sensor unit based on the combination of a SAW reflective delay line with a high-Q capacitive pressure sensor is presented. Due to a symmetric arrangement of the impedance loaded splitfinger interdigital transducer (IDT) between two reference reflectors a temperature corrected evaluation of the pressure signal is enabled. A prototype of a tire pressure sensor unit is shown. In combination with a wheel arch antenna and a conventional transceiver unit a typical signal-to-noise rate of 20 dB resulting in a pressure accuracy of /spl plusmn/15 kPa was measured.