Analysis of Plate Acoustic Waves Resonance Properties Using Thin Plate of LiNbO₃/SiC

In recent years, to realize high-performance filters for mobile communication systems like 5G and beyond, numerous researchers have developed thin layered structures of surface acoustic waves, bulk acoustic waves, and plate acoustic wave structures with free surfaces on both sides of thinned piezoelectric films. While there are many reports on the superiority of plate wave modes, it is undeniable that strength and heat dissipation pose significant challenges with independently thin piezoelectric films, hindering practical implementation. Therefore, in this study, we proposed a plate wave resonator with a new structure where the piezoelectric film is supported on the bottom surface by a thin film of cubic silicon carbide, known for its high strength and heat dissipation properties. However, this might slightly reduce the coupling coefficient. Nevertheless, our examination revealed that we could maintain performance with an effective electromechanical coupling coefficient of over 20% while achieving a high velocity, approximately 1.4 times higher than that of conventional plate wave resonators.