Temperature measurements with Ultra-Wideband SAW sensors

The Ultra-Wideband (UWB) technology applied to Surface Acoustic Wave (SAW) tags and sensors potentially brings many benefits [3]. The chip size can be reduced and the number of stored information increased. The interrogation signal energy is spread over a broad spectrum B so that the interrogation signal power levels are very low at any particular frequency. Matching to signal filtering can be used, to obtain a short pulse of1B duration and to improve signal to noise ratio. We have developed prototypes of a ultra wide frequency band SAW tags/sensors operating in a frequency range from 200 MHz to 400 MHz with compressed pulse duration of about 5 ns. The prototypes have been characterized in the temperature range - 5 °C to +130 °C, and the temperature has been measured with precision around 0.1 °C. Remote wireless measurements are now under way with the signals generated by the “Tektronix AWG7122B” and the sensor responses measured at 1.5 m with EM interrogation signal level in order of micro Watt. First experimental results for the 2 GHz is are presented.