A 5.5 GHz S3 Mode Plate Acoustic Wave Resonator Using Lithium Tantalate Thin Film

Acoustic wave resonators using plate acoustic wave in the lithium tantalite (LiTaO
3
) thin film shows the potential of relating high frequency with a suitable quality factor (Q). The effect of the LiTaO
3
thickness on the plate wave characteristics is investigated in this work. A high frequency resonator using third symmetric lamb wave (S
3
) mode in a composite plate of 36° YX-cut LiTaO
3
and silicon dioxide (SiO
2
) has been fabricated as a wave-length (λ) is 4 μm. The series resonant frequency (f
s
), Q
s
and Q
p
of the proposed resonator are 5.5 GHz, 419 and 816, respectively. This work demonstrated that the S
3
mode based composite thin film of LiTaO
3
and SiO
2
is suitable for high-frequency devices with high Q.