Ultra‐wideband SAW sensors and tags

Abstract

A sensor system using ultra‐wideband frequency technology and passive surface acoustic wave (SAW) sensors/tags has been demonstrated experimentally. The system operates with a frequency bandwidth of 500 MHz, which results in compressed RF pulses of about 2 ns duration, including just a few sinusoids with amplitude modulation. A correlation method is developed to measure the delay between two echoes with high resolution, avoiding the phase ambiguity problem. For temperature, deformation or other measurand a simple structure including only two reflectors is sufficient. This method is used in a system which simultaneously remotely measures a few temperature sensors with a resolution of 0.1°C. The operation of the system in a strongly reflecting environment (inside a metal box) is demonstrated.