Small and low-loss intermediate frequency surface acoustic wave filters using zinc oxide film on quartz substrate

Michio Kadota, Hajime Kando

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)

Abstract

A ZnO/quartz substrate is expected to be applied to a intermediate frequency (IF) surface acoustic wave (SAW) filter for which a small size, a low insertion loss, and a good temperature coefficient of frequency (TCF) are necessary because it has a large ks and an excellent TCF. However it was clarified that the SAW filter consisting of a single solid electrode or single-phase unidirectional transducer (SPUDT) on ZnO/quartz substrate often has a large spurious response due to the Love wave. The new cutting angle and the propagating direction (26-27°Y-X) for quartz were developed in order to suppress the spurious response. The developed W-CDMA IF 380 MHz filter was mounted on a small package of 3.2 × 5.0 mm2. It had a low loss of 5.8 dB, and high adjacent channel selectivity (ACS) of 36.1 dB/35.0 dB. Then, the developed N-CDMA IF 183 MHz filter was mounted on a small package of 5 × 7 mm2. It had a low loss of 4.3 dB. In both cases, the frequency shift per 1°C was less than 0.37 ppm/°C.

Original languageEnglish
Pages (from-to)3139-3142
Number of pages4
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume42
Issue number5 B
DOIs
Publication statusPublished - 2003 May

Keywords

  • CDMA
  • Quartz
  • SAW
  • TCF
  • Temperature coefficient
  • ZnO

ASJC Scopus subject areas

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

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