The influence of tilted structure on the performance of LiTaO3-POI multilayer SAW resonators
The aim of this study is to investigate the effect of tilted structure on the transverse mode spuriousness of SAW resonators on LiTaO3-POI multilayer substrates. Utilizing the finite element method (FEM),two single-port resonator models were developed with half-periods (P) of 0.98μm and 1.42 μm and apertures size of 40P. Subsequently,a series of tilting angles of 0°,2.5°,5°,7.5°,10°,12.5°,15°,17.5°,and 20° were simulated and analyzed. Based on the simulation results,the resonator layout was drawn,and the tape-out was tested. The results show a high consistency between the measured and simulated data. Under the same half-period condition,the transverse mode spurious suppression ability of the SAW resonator is first enhanced and then weakened at larger tilt angle within a certain range. Simultaneously,the electromechanical coupling coefficient experiences a steady decline by escalating tilt angles. Oppositely,the impedance ratio exhibits an initial augmentation followed by diminish,reaching a maximum value at tilt angles of precisely 2.5° and 5°,where resonator performance is optimized. In summary,the tilt angle has a significant suppression effect on the transverse modal spurious of the LiTaO3-POI multilayer structured SAW resonator,which provides an important theoretical basis and practical guidance for the design and fabrication of SAW filters. The study concludes that an appropriate tilt angle can effectively enhance the performance of the SAW resonators,which is of great significance for the development of high-performance radio frequency (RF) filters.
LiTaO3-POI multilayer structuretilted structureelectromechanical coupling coefficientimpedance ratio
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