Scaling Surface Acoustic Wave Filters on LNOI platform for 5G communication

We demonstrate surface acoustic wave (SAW) filter suitable for 5G communication through the construction of the LiNbO 3 film bonded on insulator (LNOI) platform of 32° Y-X LN/SiO 2 /poly-Si/Si. Through finite element method, the acoustic energy confinement is verified and a spurious mode mitigation through electrode thickness modulation is proposed. Resonator fabricated on LNOI using Al/Cu/Ti multilayer electrode demonstrate electromechanical coupling factor (K ² ) of 24.1%, maximum Bode-Q (Q max ) of 2987 at resonance frequency of 3816 MHz. Besides, two type of SAW filters with center frequency over 3.5 GHz were then successfully realized, and the fractional bandwidth are 29.4% and 19.6%, which meets the requirement of n77 and n78 full band, respectively. Finally, the frequency can be extended over 5 GHz, while the K ² and Q max keeps at 21.6% and 574.