A radio frequency nonreciprocal network based on switched acoustic delay lines

Ruochen Lu, Tomas Manzaneque, Yansong Yang, Liuqing Gao, Anming Gao, Songbin Gong

Research output: Contribution to journalArticle

Abstract

This paper demonstrates the first nonreciprocal network based on switched low-loss acoustic delay lines. The four-port circulator is built upon a recently reported frequency-independent, programmable, nonreciprocal framework based on switched delay lines. The design space for such a system, including the origins of the insertion loss (IL) and harmonic responses, is theoretically investigated, illustrating that the key to better performance and low-cost modulation signal synthesis lies in a large delay. To implement a large delay, we resort to in-house fabricated low-loss, wideband lithium niobate (LiNbO3)SH0 mode acoustic delay lines employing single-phase unidirectional transducers. The four-port circulator, consisting of two switch modules and one delay line module, has been modularly designed, assembled, and tested. The design process employs time-domain full circuit simulation, and the results match well with measurements. An 18.8-dB nonreciprocal contrast between IL (6.6 dB) and isolation (25.4 dB) has been achieved over a fractional bandwidth of 8.8% at a center frequency 155 MHz, using a record low switching frequency of 877.19 kHz. The circulator also shows 25.9-dB suppression for the intramodulated tone and 30 dBm for IIP3. Upon further development, such a system can potentially lead to future wideband, low-loss chip-scale nonreciprocal radio frequency systems with unprecedented programmability.

Original languageEnglish (US)
Article number8641432
Pages (from-to)1516-1530
Number of pages15
JournalIEEE Transactions on Microwave Theory and Techniques
Volume67
Issue number4
DOIs
StatePublished - Apr 2019

Keywords

  • Acoustic delay line
  • SH0 mode
  • full-duplex radios
  • lithium niobate
  • magnetless circulator
  • microelectromechanical systems
  • nonreciprocity
  • piezoelectricity
  • simultaneous transmit and receive (STAR)

ASJC Scopus subject areas

  • Radiation
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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