Enlarging Rayleigh Elimination Window through Modulating Substrate and LiNbO3 Cut Angle for Fabricating LNOI-Based Spurious-Free Wideband SAW Filters
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2022-10-10 |
| Journal | 2022 IEEE International Ultrasonics Symposium (IUS) |
| Authors | Huiping Xu, Sulei Fu, Junyao Shen, Rongxuan Su, Honglang Li |
| Institutions | Tsinghua University, National Center for Nanoscience and Technology |
| Citations | 7 |
Abstract
Section titled “Abstract”Lithium niobate on insulator (LNOI) platform attracts much attention in recent years for its potential to fabricate wideband surface acoustic wave (SAW) filters using the shear horizontal (SH) mode. However, the coexistence of Rayleigh mode can deteriorate the performance of SH-based filters, and thus implementing a systematical investigation of the influences of the substrates and the LN cut angles on the Rayleigh elimination window (REW) is necessary to evaluate the advantageous designing parameters for a target spurious-free filter. In this work, the REW of rotated YX-LN/SiO <inf xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”>2</inf> /substrate (including SiC, Si, Al <inf xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”>2</inf> O <inf xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”>3</inf> , diamond and quartz) platform is studied through finite element method (FEM), and it is found that the LN/SiO <inf xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”>2</inf> /SiC shows a wider REW since the Rayleigh mode can be totally eliminated in a window range (hC <inf xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”>u</inf> /λ) of Cu electrode normalized thickness of 0.08 when θ is between 18° and 24°. Resonators and filters with different hC <inf xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”>u</inf> /λ were fabricated on 15°, 20° and 25°YX-LN/SiO <inf xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”>2</inf> /SiC and verified the simulation results, and among which the filters built on 20° and 25°YX-LN/SiO <inf xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”>2</inf> /SiC are spurious-free and exhibit 3-dB fractional bandwidth (FBW) of about 20% and minimum insertion loss (IL <inf xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”>min</inf> ) of about 1.2 dB, respectively.