A Package-Less Saw Rfid Sensor Concept For Structural Health Monitoring

Surface acoustic wave sensors are a promising solution for structural health monitoring applications. They can withstand extreme operating conditions. However, they often fail in operation due to housing issues. In this work, we propose to use an innovative package-less structure in order to fully get rid of the latter. The package-less concept is based on a multilayer substrate whose thicknesses have been designed to ensure an acoustic mode propagating far from the sensor surface and a sensor that can be wirelessly interrogated at 2.45 GHz. The sensitivity to temperature of the guided acoustic mode velocity was determined using finite element simulation. From this calculation, the temperature sensitivity of the sensor was evaluated. In addition, coupling of modes parameters and time signature of the sensor were estimated. The obtained results, limitations and expected technical challenges are discussed as a closure.