Surface acoustic wave device with reflection electrodes having pitches that vary
AssigneeFujitsu Media Devices Limited
InventorsOsamu Kawachi, Satoshi Orito, Takuya Abe
Life of this patent
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Abstract
A surface acoustic wave device includes: a substrate; a pair of reflection electrodes that are formed on the substrate; and drive electrodes that are interposed between the reflection electrodes. In this surface acoustic wave device, the pitches in each of the reflection electrodes vary according to a predetermined variation pattern. With this structure, the suppression on spurious signals and the shape factor (the sharpness of the cut-off region of the pass band) can be improved at the same time.
Claims24
A surface acoustic wave device comprising:
- a substrate;
- a pair of reflection electrodes formed on the substrate;
- and
- a plurality of drive electrodes interposed between the pair of reflection electrodes,
- each of the reflection electrodes having pitches that vary according to a respective given variation pattern, and
- wherein each of the reflection electrodes has a variation pattern that exhibits a peak in the middle of a corresponding one of the reflection electrodes.
A surface acoustic wave device comprising:
- a pair of reflection electrodes formed on a substrate;
- and
- a plurality of drive electrodes interposed between the pair of reflection electrodes,
- each of the reflection electrodes being divided into blocks, and
- at least two of the blocks having different pitches from each other,
- wherein the block located in the middle of the plurality of blocks in each of the reflection electrodes has the largest or smallest pitch.
A surface acoustic wave device that has longitudinally coupled multi-mode resonators, each of the resonators comprising:
- a pair of reflection electrodes that are formed on a substrate;
- a plurality of drive electrodes interposed between the pair of reflection electrodes,
- each of the reflection electrodes having pitches that vary according to a predetermined given variation pattern,
- wherein a first resonator of the resonators has a different variation pattern from that of a second resonator of the resonators.
Dependencies are inferred from the claim text.