Ring-shaped Lamb Wave Resonator based LiNbO3 Film with A1/A3 Mode Resonance above 6/17 GHz

This paper presents a ring-shaped Lamb wave resonator based 300 nm-thick Z-cut LiNbO
3
thin film. The proposed structure applied the alternative voltage along both the x and y direction by arranging ring-shaped electrodes, thus exciting the two-dimensional Lamb waves by utilizing both the e
24
and e
15
piezoelectric constants. The measured impedance results show first order asymmetric mode (A
1
) mode resonance above 6 GHz with effective electromechanical coupling coefficient (K
²
eff
) of 8.91%, and third order asymmetric mode (A
3
) mode resonance above 17 GHz with K
²
eff
of 1.77%. In the meanwhile, the proposed structure realized a static capacitance (Co) of 0.13 pF within an active region area at 200×200 µm
²
, which has great potential for 50 Ω impedance match within a miniature size applied in super high frequency, spurious modes free RF front-ends filters.