Surface acoustic wave duplexer composed of SiO2/Cu electrode/LiNbO3 structure having convex and concave portions

Yasuharu Nakai, Takeshi Nakao, Kenji Nishiyama, Michio Kadota

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

The transition bandwidth of 20MHz between the transmission (Tx: 1850-1910MHz) and the receiving (Rx: 1930-1990MHz) bands of personal communication service (PCS) handy phones in the United States (US) is very narrow compared with those of other systems. We have already realized surface acoustic wave (SAW) duplexers with sizes of 5.0 × 5.0 × 1.7 and 3.0 × 2.5 × 1.2 mm3 for PCS handy phones in the US with an excellent temperature coefficient of frequency (TCF) by using a shear horizontal (SH) wave on a flattened SiO2/Cu electrode/36-48° YX-LiTaO 3 structure and a Rayleigh wave on a SiO2/Cu electrode/120-128° YX-LiNbO3 structure. Although the surface of the above-mentioned structures is flattened SiO2, we have also studied the shape of the SiO2 surface. As a result, in addition to increasing the stop-band width, which corresponds to the reflection coefficient, the TCF and power durability have been improved by forming convex portions on the surface of the SiO2 over the interdigital transducer (IDT) gaps.

Original languageEnglish
Article number07GG02
JournalJapanese journal of applied physics
Volume48
Issue number7 PART 2
DOIs
Publication statusPublished - 2009 Jul 1

ASJC Scopus subject areas

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

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