Suppression of Spurious Modes in Lithium Niobate A1 Resonators Using Dispersion Matching

This work presents an improved design that exploits dispersion matching to suppress the lateral spurious modes in the thin-film lithium niobate first-order antisymmetric Lamb wave mode (A1) resonators. The dispersion matching in this work is achieved by micro-machining the lithium niobate thin film to balance the electrical and mechanical loading of electrodes. The fabricated devices based on the proposed method exhibit spurious-free responses with a maximum Q
_3dB
of 692 and k
_t
²
of 28%. The demonstrated method herein could overcome a significant hurdle that is currently impeding the commercialization of A1 devices.