5-GHz Antisymmetric Mode Acoustic Delay Lines in Lithium Niobate Thin Film

Ruochen Lu, Yansong Yang, Ming Huang Li, Michael Breen, Songbin Gong

Research output: Contribution to journalArticlepeer-review


We present the first group of acoustic delay lines (ADLs) at 5 GHz using the first-order antisymmetric (A1) mode in Z-cut lithium niobate thin films. The demonstrated ADLs significantly surpass the operation frequencies of the prior art with similar feature sizes because of their simultaneously fast phase velocity, large coupling coefficient, and low loss. In this article, the propagation characteristics of the A1 mode in lithium niobate are analytically modeled and validated with finite element analysis. The design space of A1 ADLs is then investigated, including both the fundamental design parameters and those introduced from the practical implementation. The implemented ADLs at 5 GHz show a minimum insertion loss of 7.9 dB, an average insertion loss (IL) of 9.1 dB, and a fractional bandwidth around 4%, with group delays ranging between 15 and 109 ns and the center frequencies between 4.5 and 5.25 GHz. The propagation characteristics of A1 mode acoustic waves have also been extracted for the first time. The A1 ADL platform can potentially enable wideband high-frequency passive signal processing functions for future 5G applications in the sub-6-GHz spectrum bands.

Original languageEnglish (US)
Article number8901450
Pages (from-to)573-589
JournalIEEE Transactions on Microwave Theory and Techniques
Issue number2
StatePublished - Feb 2020


  • A1 mode
  • acoustic delay line (ADL)
  • fifth generation (5G)
  • lithium niobate
  • microelectromechanical systems
  • new radio (NR)
  • piezoelectricity

ASJC Scopus subject areas

  • Radiation
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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