Scaling Surface Acoustic Wave Filters on LNOI platform for 5G communication
Rongxuan Su, Sulei Fu, Zengtian Lu, Junyao Shen, Huiping Xu, Peisen Liu, Zhibin Xu, Haowei Wang, Shuai Zhang, Rui Wang, Cheng Song, Fei Zeng, Weibiao Wang, Feng Pan
Abstract
We demonstrate surface acoustic wave (SAW) filter suitable for 5G communication through the construction of the LiNbO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> film bonded on insulator (LNOI) platform of 32° Y-X LN/SiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> /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 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) of 24.1%, maximum Bode-Q (Q <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</inf> ) 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 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and Q <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</inf> keeps at 21.6% and 574.