Modeling and Simulation of Wireless Passive Pressure Sensors Based on Surface Acoustic Wave Resonators

The surface acoustic wave (SAW) resonator is modeled according to the coupling-of-mode (COM) model of the interdigital transducer (IDT) and the reflectance of the reflector. With the COM model of the SAW resonator, the SAW resonator admittance is derived and its variation with the frequency is simulated. The resonance admittance is the peak of the admittance curve. In resonance condition, the output signal of the SAW resonator is the maximum of all the output signals with different frequency input signals. The pressure on the surface of the SAW resonator substrate can change the velocity and wavelength of the SAW propagating along the substrate, so the resonance frequency will change with the pressure. According to the relation between the pressure variation and the resonance frequency shift, the wireless passive pressure sensor based on the SAW resonator is modeled and simulated. The model of the wireless passive pressure sensor can simulate the frequency variation with the pressure well, and it can be used as an effective tool for designing and analyzing the pressure sensor based on SAW resonators