Measurement of vibrating frequency of a cantilever using low frequency impedance-loaded SAW sensor

Health monitoring of a structure is important for safety life. If the structure has damage, vibration frequency changes. Normally, an acceleration sensor is used for monitoring the vibration frequency. However, the acceleration sensor needs a battery for the operation. A surface acoustic wave (SAW) device works with an optimum signal and does not need a battery. In this paper, an impedance-loaded SAW sensor is applied for measurements of a vibrating frequency. A variable capacitor and pressure sensors are connected to a reflector on the SAW device as external sensors. The obtained results indicate that the impedance-loaded SAW sensor can monitor the vibrating frequency of a cantilever.