High-frequency edge reflection type resonators with excellent temperature characteristics

Michio Kadota, Tetsuya Kimura, Daisuke Tamasaki

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

Currently, some duplexers are required to have a good temperature coefficient of frequency (TCF). An Al electrodes/36-48° YX-LiTaO3 substrate, which is used for most surface acoustic wave (SAW) duplexers, does not have a good TCF. Its TCF can be improved by depositing a SiO2 film with a positive TCF on a transversal SAW filter consisting of a substrate with a negative TCF such as LiTaO3 and LiNbO3. However, resonator-type SAW devices combining a SiO2 film, Al electrodes, and a LiTaO3 substrate do not show good frequency characteristics because of their small reflection coefficient and so on. It is considered as a countermeasure that a resonator using the reflection of a shear horizontal (SH) wave at substrate edges will show good frequency characteristics because its reflection coefficient is very large regardless of the Al electrode and SiO 2 films thicknesses. It has been difficult to obtain a high-frequency edge reflection resonator using ordinary machining techniques because it requires extremely fine substrate edges. However, a high-frequency edge reflection resonator with a good TCF and excellent frequency characteristics has been realized using our newly developed method of obtaining fine edges.

Original languageEnglish
Pages (from-to)4749-4753
Number of pages5
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume46
Issue number7 B
DOIs
Publication statusPublished - 2007 Jul 26
Externally publishedYes

Keywords

  • Edge reflection
  • Excellent TCF
  • High-frequency
  • SH wave

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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