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Main Authors: Anusorn, Taran, Barrera, Omar, Kramer, Jack, Anderson, Ian, Yao, Ziqian, Chulukhadze, Vakhtang, Lu, Ruochen
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2505.18388
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author Anusorn, Taran
Barrera, Omar
Kramer, Jack
Anderson, Ian
Yao, Ziqian
Chulukhadze, Vakhtang
Lu, Ruochen
author_facet Anusorn, Taran
Barrera, Omar
Kramer, Jack
Anderson, Ian
Yao, Ziqian
Chulukhadze, Vakhtang
Lu, Ruochen
contents This article presents an approach to control the operating frequency and fractional bandwidth (FBW) of miniature acoustic filters in thin-film lithium niobate (TFLN). More specifically, we used first-order antisymmetric (A1) mode lateral-field-excited bulk acoustic wave resonators (XBARs) to achieve efficient operation at 20.5 GHz. Our technique leverages the thickness-dependent resonant frequency of A1 XBARs, combined with the in-plane anisotropic properties of 128$^\circ$ Y-cut TFLN, to customize filter characteristics. The implemented three-element ladder filter prototype achieves an insertion loss (IL) of only 1.79 dB and a controlled 3-dB FBW of 8.58% at 20.5 GHz, with an out-of-band (OoB) rejection greater than 14.9 dB across the entire FR3 band, while featuring a compact footprint of 0.90 $\times$ 0.74 mm2. Moreover, an eight-element filter prototype shows an IL of 3.80 dB, an FBW of 6.12% at 22.0 GHz, and a high OoB rejection of 22.97 dB, demonstrating the potential for expanding to higher-order filters. As frequency allocation requirements become more stringent in future FR3 bands, our technique showcases promising capability in enabling compact and monolithic filter banks toward next-generation acoustic filters for 6G and beyond.
format Preprint
id arxiv_https___arxiv_org_abs_2505_18388
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Practical Demonstrations of FR3-Band Thin-Film Lithium Niobate Acoustic Filter Design
Anusorn, Taran
Barrera, Omar
Kramer, Jack
Anderson, Ian
Yao, Ziqian
Chulukhadze, Vakhtang
Lu, Ruochen
Signal Processing
This article presents an approach to control the operating frequency and fractional bandwidth (FBW) of miniature acoustic filters in thin-film lithium niobate (TFLN). More specifically, we used first-order antisymmetric (A1) mode lateral-field-excited bulk acoustic wave resonators (XBARs) to achieve efficient operation at 20.5 GHz. Our technique leverages the thickness-dependent resonant frequency of A1 XBARs, combined with the in-plane anisotropic properties of 128$^\circ$ Y-cut TFLN, to customize filter characteristics. The implemented three-element ladder filter prototype achieves an insertion loss (IL) of only 1.79 dB and a controlled 3-dB FBW of 8.58% at 20.5 GHz, with an out-of-band (OoB) rejection greater than 14.9 dB across the entire FR3 band, while featuring a compact footprint of 0.90 $\times$ 0.74 mm2. Moreover, an eight-element filter prototype shows an IL of 3.80 dB, an FBW of 6.12% at 22.0 GHz, and a high OoB rejection of 22.97 dB, demonstrating the potential for expanding to higher-order filters. As frequency allocation requirements become more stringent in future FR3 bands, our technique showcases promising capability in enabling compact and monolithic filter banks toward next-generation acoustic filters for 6G and beyond.
title Practical Demonstrations of FR3-Band Thin-Film Lithium Niobate Acoustic Filter Design
topic Signal Processing
url https://arxiv.org/abs/2505.18388