Effect of Thickness Ratio of Double Layered Thickness-Shear Resonator on Temperature Characteristics of Resonance Frequency

The factor dictating the temperature characteristic of the double layered thickness-shear resonator was investigated by evaluating the resonators with different thickness ratios. Using Ca
₃
TaGa
₃
Si
₂
O
₁₄
[CTGS], one of the Langasite-type piezoelectric single crystal, double layered resonators with thickness ratios x = 0.25 and 0.5 were fabricated and the temperature dependence of their resonance frequency were measured at −30 to 80°C. As a result, the temperature characteristics for the resonator with x = 0.25 exhibited different profiles depending on the order of resonance mode, on the other hand, those for the resonator with
$x$
= 0.5 exhibited no difference among all of the order. Comparing these results with the wave propagation model in the resonator, it was found that the thickness ratio of two layers at the region effectively contributing to the electric field output was deeply related to the deviation of the temperature characteristics.