Self-validating passive wireless SAW sensor

The surface acoustic wave (SAW) sensors are very suit for the applications under harsh environmental conditions, which cause temporal failures, signal shadowing, multi-path fading and signal attenuation pose great challenges in the reliability of passive wireless SAW sensor. This paper proposes a method to evaluate measurement uncertainty before operating frequency measurement, deduce the relationship between the measurement uncertainty of resonant SAW sensor and the signal-to-noise ratio (SNR), which is based on the Fisher information matrix and subspace parameters. This estimator can be further used to identify and skip the faulty conditions. The proposed approach is evaluated in simulations and practical experiments.