Experimental Characterization and Modeling of Acoustic Wave Propagation Loss Associated with SAW IDT Resonators

In this study, the physical behavior of a surface acoustic wave resonator is formulated with the aid of a distributed four-port transmission line circuit model. Propagation losses of surface acoustic waves are modeled based on frequency-variant circuit model parameters (i.e., resistance, conductance, and attenuation). Furthermore, the loss resulting from metal fingers and leakage toward the bulk substrate are modeled by means of series resistance and frequency-variant parallel conductance, respectively. In addition, the attenuation of highfrequency spurious resonances is modeled using a frequency-variant damping factor. The validity of the proposed model is verified by test filters fabricated on 42°YX-LiTaO3 (piezoelectric substrate). The S-parameters calculated using the proposed model show excellent agreement with the experimental S-parameters measured at the wafer level.