1. 6 GHz lamb wave acoustic filters based on A1-mode lithium niobate thin film resonators with checker-shaped electrodes.
- Author
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Tong, Xin, Zou, Yang, Wen, Zhiwei, Liu, Zesheng, Luo, Tiancheng, Zhou, Jie, Liu, Huajun, Ren, Yuqi, Xu, Qinwen, Liu, Wenjuan, Liu, Yan, Cai, Yao, and Sun, Chengliang
- Subjects
LAMB waves ,STANDING waves ,ACOUSTIC filters ,IMPEDANCE matching ,SOUND waves - Abstract
The first-order antisymmetric (A1) mode lamb wave resonator (LWR) based on Z-cut LiNbO
3 thin films has attracted significant attention and is widely believed to be a candidate for next-generation reconfigurable filters with high frequency and large bandwidth (BW). However, it is challenging for traditional interdigitated electrodes (IDTs) based LWR filters to meet the requirement of a clean frequency spectrum response and enough out-of-band (OoB) rejection. To solve the problem, we propose LWRs with checker-shaped IDTs for the design of filters that meet the Wi-Fi 6E standard. By taking advantage of checker-shaped IDTs with unparalleled boundaries, the fabricated 6-GHz resonators successfully suppress higher-order A1 spurious modes, demonstrating a spurious-free impedance response and a high figure-of-merit (FOM) up to 104. Based on the demonstrated checker-shaped electrode design, the filter features a center frequency (f0 ) of more than 6 GHz, a 3 dB BW exceeding 620 MHz, and an excellent OoB rejection >25 dB, consistent with the acoustic-electric-electromagnetic (EM) multi-physics simulations. Furthermore, through the capacitance-inductance matching network technology, the filter's voltage standing wave ratio (VSWR) is successfully reduced below 2, showing an excellent 50 Ω impedance matching. This study lays a foundation for ultra-high-frequency and ultra-wideband filters for the Wi-Fi 6/6E application. [ABSTRACT FROM AUTHOR]- Published
- 2024
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