A 6.1 GHz Wideband Solidly-Mounted Acoustic Filter on Heterogeneous Substrate for 5G Front-Ends
Hongyan Zhou, Shibin Zhan, Pengcheng Zheng, Liping Zhang, Jinbo Wu, Hulin Yao, Tiangui You, Xin Ou
Abstract
This paper reports a 6.1 GHz wideband solidly-mounted acoustic filter based on the novel LiNbO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> -on-SiC (LNOSiC) substrate for the first time. The well-confined S0 mode waves with high phase velocity and large electromechanical coupling (k <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</inf> ) in LNOSiC were theoretically and experimentally investigated. Compared with conventional surface acoustic wave (SAW) resonators, the resonators using the S0 mode in the transferred single crystal LiNbO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> thin film offer 1.5- to 1.8-fold higher frequencies and 2- to 3-fold larger k <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</inf> , thus enabling 6-GHz filters with a fractional bandwidth of more than 7%. The newly proposed S0 mode devices on the LNOSiC substrate break the frequency limitation (~ 3 GHz) of conventional SAW devices, which are promising for compact, high frequency and large bandwidth 5G RF front-ends.