Low-Loss 5-GHz First-Order Antisymmetric Mode Acoustic Delay Lines in Thin-Film Lithium Niobate

Ruochen Lu, Yansong Yang, Steffen Link, Songbin Gong

Research output: Contribution to journalArticlepeer-review


In this work, we present the low-loss acoustic delay lines (ADLs) at 5 GHz, using the first-order antisymmetric (A1) mode in 128° Y-cut lithium niobate thin films. The ADLs use a single-phase unidirectional transducer (SPUDT) design with a feature size of quarter acoustic wavelength. The design space is analytically explored and experimentally validated. The fabricated miniature A1 ADLs with a feature size of 0.45 μ \text{m} show a high operating frequency at 5.4 GHz, a minimum insertion loss (IL) of 3 dB, a fractional bandwidth (FBW) of 1.6%, and a small footprint of 0.0074 mm2. The low IL and high operating frequency have significantly surpassed the state-of-the-art performance of ADLs. The propagation characteristics of A1 acoustic waves have also been extracted. The demonstrated designs can lead to low-loss and high-frequency transversal filters for future 5G applications in the sub-6-GHz bands.

Original languageEnglish (US)
Article number9201380
Pages (from-to)541-550
Number of pages10
JournalIEEE Transactions on Microwave Theory and Techniques
Issue number1
StatePublished - Jan 2021


  • 5G mobile communication
  • Acoustic devices
  • delay lines
  • microelectromechanical systems
  • piezoelectric devices
  • thin-film devices
  • transversal filters

ASJC Scopus subject areas

  • Radiation
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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