Miniaturized Dual-Mode SAW Filters using 6-inch LiNbO<sub>3</sub>-on-SiC for 5GNR and WiFi 6
Pengcheng Zheng, Shibin Zhang, Jin‐Xu Xu, Xiaoli Fang, Yang Chen, Kai Huang, Dongchen Sui, Xiu Yin Zhang, Xin Ou
Abstract
In this work, low-loss and wide-band surface acoustic wave (SAW) filters in the frequency range of 3.3 to 6.3 GHz were demonstrated on 6-inch X-cut LiNbO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> -on-SiC substrate fabricated by the ion-slicing process. Further, the SAW filter with n77 and n79 dual-band response or n79 and WiFi 6 dual-band response was demonstrated for the first time in a compact footprint of < 1 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , respectively. The shear horizontal (SH) and longitudinal leaky (LL) dual-mode excitation as well as their preferred in-plane orientations are analyzed using the finite element method. The fabricated SH-SAW filter aiming at the n77 band shows a large 3-dB bandwidth (BW) of 495 MHz and a low insertion loss (IL) of 0.85 dB. The LL-SAW filters aiming at WiFi 6 band feature scalable center frequencies (f <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> ) from 5.34 to 6.1 GHz, 3-dB BWs between 330 and 402 MHz, and ILs between 1.32 and 1.74 dB. All devices, including the dual-band filters, share the same two-step manufacturing process and the device wavelengths (λ) are above 1.0 µm. This dual-mode SAW technology using LiNbO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> -on-SiC shows the strong potential for miniaturized and low-cost front-ends in 5G and WiFi 6 bands.