Model of a surface acoustic wave sensing system based on received signal strength indication detection

Surface acoustic wave (SAW) sensing systems based on the received signal strength indication (RSSI) detection principle have recently gained considerable research attention because of their distinct advantages and disadvantages. However, the test mode requires constant sweeping, which severely limits the system's dynamic response; to overcome this limitation, an effective solution is to establish a suitable eigenvalue search strategy to replace naive sweeping. To this end, a basis for this process is established in this study. Furthermore, the mechanism of the SAW sensing system based on RSSI detection is analyzed, a system model is established by introducing sequence signal superposition, and the model's validity is verified via experiments. Signal variations at each stage and model errors are analyzed, and the system's timing parameters are optimized. Finally, using the SAW torque sensor, an optimized torque measurement prototype is designed and the system's effectiveness is verified through static torque experiments. A complete model of the measurement system can be simulated through this model; it provides the basis for an eigenvalue search strategy and can act as a simulation model or design basis for other researchers building RSSI-detection-based SAW sensing systems. (paper)