Coded wireless temperature sensors with design specified sensitivity

ASR&D has developed a patented surface acoustic wave (SAW) temperature sensor with individual sensor identification codes and design-controlled temperature sensitivity. Temperature sensitivities demonstrated during this work range from -165ppm/°C to +680 ppm/°C, all on YZ lithium niobate, a piezoelectric substrate with an inherent temperature sensitivity of magnitude 94ppm/°C. A set of 32 individually identifiable coded SAW temperature sensor devices were developed. Wireless measurements confirmed the ability to selectively detect any single sensor out of the combined response of multiple sensors. The wireless electronic reader system currently being developed at ASR&D is a single-channel reader that can be manually adjusted to select any one sensor out of a group of up to 32 sensors simultaneously operating in the field of view (FOV) of the reader. This system avoids code collision problems typical of prior coded SAW wireless sensor systems, and can be extended to read 32 or more sensors operating in the FOV of one reader, at ranges of up to 100 feet, with sampling times of 1-10 msec.