This paper presents significant frequency scaling of acoustic filter technology to 50 GHz. This achievement is enabled by the P3F LiNbO3 multilayer stack, in which piezoelectric thin-films of alternating orientations are transferred in sequence, thereby allowing efficient exploitation of high-order modes with high quality factor (Q) and coupling coefficient (k2) in a thicker piezoelectric stack. The demonstrated filter is comprised of twelfth-order symmetric (S12) mode lateral-field-excited bulk acoustic wave resonators (XBARs), built on a 4-layer periodically poled piezoelectric (P3F) 128 Y-cut lithium niobate (LiNbO3) stack. The filter exhibits 3.3 dB insertion loss (IL) and a fractional bandwidth (FBW) of 2.9%. The miniature design, with a footprint of 0.36 mm2, makes it promising for future wireless front-end applications. These results represent the highest frequency acoustic filters reported to date, setting a new benchmark in piezoelectric filter technology. Upon further development, the platform could enable filters further into the FR2 range, essential for next-generation communication systems.
@article{arxiv.2506.22549,
title = {50 GHz Piezoelectric Acoustic Filter},
author = {Omar Barrera and Jack Kramer and Lezli Matto and Vakhtang Chulukhadze and Sinwoo Cho and Michael Liao and Mark S. Goorsky and Ruochen Lu},
journal= {arXiv preprint arXiv:2506.22549},
year = {2026}
}