| Popis: |
In this work, the relation between temperature coefficient of frequency (TCF) and wavelength (λ) of a shear horizontal surface acoustic wave (SH-SAW) resonator in lithium niobate-on-insulator (LNOI) platform is investigated numerically and experimentally. Proposed device achieves a low TCF of -18.5 ppm/K, quality factor (Q max ) of 1360, and effective electromechanical coupling factor $\left({k_{{\text{eff}}}^2}\right)$ of 21.2%, yielding a high figure-of-merit $\left({{\text{FOM1}} = k_{{\text{eff }}}^2\cdot{Q_{\max }}}\right)$ of 288. The dispersive behavior of the TCF was first analyzed based on finite element method (FEM), which reveals the strong correlation between TCF and the thickness of LN (h LN ) and SiO 2 (h SiO2 ) thin films. To confirm our observations, three prototyped SH-SAW devices with λ of 2.8, 4, and 6 μm were fabricated and characterized, showing TCFs approximately -86, -45, and -18.5 ppm/K, respectively, for both series and parallel resonance frequencies. The results captured through experiments fits well with the trends predicted in the FEM simulations. Furthermore, the proposed resonator (λ = 6 μm, TCF = -18.5ppm/K, FOM1 = 288) exhibits a very competitive performance among state-of-the-art thin film LN/LT resonators. |
