Huang Shitian, Luo Wenbo, Bai Xiaoyuan, Lv Lu, Pan Xinqiang, Shuai Yao, Wu Chuangui, Zhang Wanli
IEEE Trans Ultrason Ferroelectr Freq Control. 2021 Jul;68(7):2585-2589. doi: 10.1109/TUFFC.2021.3066589. Epub 2021 Jun 29.
A solidly mounted resonator on flexible polyimide (PI) substrate with high-effective coupling coefficient ( K ) of 14.06% is reported in this article. This high K is resulting from the LiNbO (LN) single-crystalline film and [SiO/Mo] Bragg reflector. The quality of LN film fabricated by the crystal-ion-slicing (CIS) technique using benzocyclobutene (BCB) bonding layer was close to the bulk crystalline LN. The interfaces of the Al/LN/Al/[SiO/Mo] Bragg reflector/BCB/PI multilayer are sharp, and the thickness of each layer is consistent with its design value. The resonant frequency and K keep stable when it is bent at different radii. These results demonstrate a feasible approach to realizing RF filters on flexible polymer substrates, which is an indispensable device for building integrated and multifunctional wireless flexible electronic systems.
