Shear Horizontal Surface Acoustic Wave FIR Filters in Lithium Niobate on Insulator

This work demonstrates a digitally weighted FIR filter based on guided SH0 acoustic waves in thin film lithium niobate (TFLN) on insulator. An input interdigitated transducer (IDT) is used to launch the acoustic wave. Output IDTs, or taps, are spaced corresponding to a unit delay of 100 ns with the output taps demonstrating the ability to implement a FIR filter. In contrast with previous work, this FIR filter architecture enables digitally tunable FIR amplitude and phase post-fabrication.