Etch-A-Sketch filter

This paper demonstrates an “Etch-A-Sketch” filter on a Z-cut lithium niobate (LN) thin-film. The filter consists of two resonators coupled by a reconfigurable phononic crystal that can be programmed by AFM-based post-release piezoelectric domain engineering. Specifically, we demonstrated a band-pass filter at 553MHz with 8.6MHz 3dB bandwidth (BW). Then, we “Etch-A-Sketch” periodically domain inverted patterns on the coupling element which changes the coupling impedance, and reduces the filter BW by 4.6%. This method only requires 80V (magnitude) to achieve domain inversion which is 100x lower than that required for bulk LN, and no DC bias voltage is required during RF operation.