Ultra-High Q of 11000 in Surface Acoustic Wave Resonators by Dispersive Modulation

In this work, a method to reduce the acoustic energy loss has been proposed, and the GHz ultra-high
${Q}$
acoustic wave resonators based on the LiTaO3-on-SiC (LTOSiC) substrate were demonstrated. By modulating the ratio of the LiTaO3 film thickness to interdigital transducer pitch (
${h}_{\textit {LT}}/\lambda {)}$
, the adjoined X and Z polarization components of the guided shear horizontal surface acoustic wave (SH-SAW) can be significantly diminished, and the acoustic energy loss can be effectively reduced. The modulated dispersive SH-SAW resonator shows an excellent Bode-
${Q}$
of 11000 and a Figure of merit (FoM) of 620. In addition, as predicted by the propagation loss of the acoustic delay lines on LTOSiC, high
${Q}$
factors can be achieved when
${h}_{\textit {LT}}/\lambda $
is less than 0.14. These results suggest the feasibility of developing low-loss acoustic devices on the LTOSiC substrate for wireless communications.