Title:
SURFACE ACOUSTIC WAVE FILTER, DEMULTIPLEXER, AND COMMUNICATION DEVICE
Document Type and Number:
WIPO Patent Application WO/2018/139598
Kind Code:
A1
Abstract:
A SAW filter comprises a substrate including a piezoelectric substrate, a transmission filter, and an additional resonator. The transmission filter is a ladder-shaped filter for filtering and outputting a signal from the transmission terminal to an antenna terminal. The transmission filter comprises a ladder-shaped connection of one or more serial resonators and one or more parallel resonators disposed on the piezoelectric substrate. In the transmission filter, the initial-stage resonator is a serial resonator. The additional resonator includes an IDT electrode disposed on the piezoelectric substrate which is connected to the transmission terminal in a stage prior to the transmission filter and which is connected to any of one or more GND terminals. The additional resonator has a resonance frequency and an antiresonance frequency that are positioned outside a pass-band of the transmission filter.
Inventors:
URATA TOMONORI (JP)
Application Number:
PCT/JP2018/002542
Publication Date:
August 02, 2018
Filing Date:
January 26, 2018
Export Citation:
Assignee:
KYOCERA CORP (JP)
International Classes:
H03H9/145; H03H9/64; H03H9/25; H03H9/72
Domestic Patent References:
| WO2014167755A1 | 2014-10-16 | |||
| WO2017159834A1 | 2017-09-21 |
Foreign References:
| JP2015139217A | 2015-07-30 | |||
| JPH09135145A | 1997-05-20 |
Attorney, Agent or Firm:
IIJIMA, YASUHIRO (JP)
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