A Solidly Mounted Resonator Fabricated by LiNbO3 Single Crystalline Film on Flexible Polyimide Substrate.

A solidly mounted resonator on flexible Polyimide (PI) substrate with high effective coupling coefficient (Kt2) of 14.06% is reported in this paper. This high Kt2 is resulting from the LiNbO3 (LN) single crystalline film and [SiO2/Mo]3 Bragg reflector. The quality of LN film fabricated by Crystal-ion-slicing (CIS) technique using Benzocyclobutene (BCB) bonding layer was close to the bulk crystalline LN. The interfaces of the Al/LN/Al/[SiO2/Mo]3 Bragg reflector/BCB/PI multilayer are sharp and the thickness of each layer is consistent with its design value. The resonant frequency and the Kt2 keep stable when it is bended 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 multi-functional wireless flexible electronic systems.