Uncertainty-aware frequency estimation algorithm for passive wireless resonant SAW sensor measurement

Passive wireless surface acoustic wave (SAW) resonators have been used as sensor elements for different physical parameters such as temperature, pressure, and force in a number of industrial and medical applications. Their operation is based on measuring the variation of the SAW resonant frequency with a physical parameter. The good measurement practice requires that the measurement uncertainty is estimated and provided together with the measurement result. This paper presents an uncertainty-aware frequency estimation approach, based on representation of the measurement uncertainty with a confidence probability of 95%, which, along with accurately calculating the frequency of the received echo signal, provides a quality evaluation for each measured SAW resonant frequency. The method has been validated by experiments.