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US 7,030,716 B2Granted
Duplexer having two surface acoustic wave filters on one substrate
AssigneesFujitsu Media Devices Limited, Fujitsu Limited
InventorsJun Tsutsumi, Shogo Inoue, Takashi Matsuda, Masanori Ueda
Life of this patent
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Abstract
A duplexer includes two surface acoustic wave filters that are formed on one substrate, at least one of the two surface acoustic wave filters being a ladder filter. In this duplexer, the positional difference between the centers in the surface acoustic wave propagating direction of each two neighboring comb-like electrodes among comb-like electrodes that form series-arm resonators in the ladder filter is equal to or smaller than a fourth of the length in the propagating direction of the comb-like electrode having the larger number of pairs of electrode fingers of each two neighboring comb-like electrodes.
Claims11
A duplexer comprising
- two surface acoustic wave filters that are formed on one substrate, at least one of the two surface acoustic wave filters being a ladder filter,
- wherein
- the positional difference between the centers in a surface acoustic wave propagating direction of each two neighboring comb-like electrodes among comb-like electrodes that form series-arm resonators in the ladder filter is not equal to zero and is equal to or smaller than a fourth of the length in the propagating direction of the comb-like electrode having the larger number of pairs of electrode fingers of each two neighboring comb-like electrodes.
A duplexer comprising
- two surface acoustic wave filters that are formed on one substrate, at least one of the two surface acoustic wave filters being a ladder filter,
- wherein
- the positional difference between the centers in a surface acoustic wave propagating direction of each two neighboring comb-like electrodes among comb-like electrodes that form series-arm resonators in the ladder filter is equal to or smaller than a fourth of the length in the propagating direction of the comb-like electrode having the larger number of pairs of electrode fingers of each two neighboring comb-like electrodes, and
- a first straight line connecting an input terminal integrally formed with the comb-like electrode forming the input-stage series-arm resonator of the ladder filter to an output terminal integrally formed with the comb-like electrode forming the output-stage series-arm resonator of the ladder filter deviates from the straight line extending perpendicularly to the propagating direction, so that the angle of the first straight line with respect to a second straight line connecting an input terminal to an output terminal provided in a package that accommodates the substrate is smaller than the angle of the second straight line with respect to the straight line extending perpendicularly to the surface acoustic wave propagating direction on the substrate.
1 more element
A duplexer comprising
- two surface acoustic wave filters that are formed on one substrate, at least one of the two surface acoustic wave filters being a ladder filter,
- wherein
- comb-like electrodes that form series-arm resonators in the ladder filter are arranged in the direction perpendicular to a surface acoustic wave propagating direction;
- and
- a first straight line connecting an input terminal integrally formed with the comb-like electrode forming the input-stage series-arm resonator of the ladder filter to an output terminal integrally formed with the comb-like electrode forming the output-stage series-arm resonator of the ladder filter deviates from the straight line extending perpendicularly to the propagating direction, so that the angle of the first straight line with respect to a second straight line connecting an input terminal to an output terminal provided in a package that accommodates the substrate is smaller than the angle of the second straight line with respect to the straight line extending perpendicularly to the surface acoustic wave propagating direction on the substrate.
2 more elements
A duplexer comprising
- two surface acoustic wave filters that are formed on one substrate, at least one of the two surface acoustic wave filters being a ladder filter,
- wherein
- a first straight line connecting the center of a comb-like electrode forming the input-stage series-arm resonator of the ladder filter to the center of a comb-like electrode forming the output-stage series-arm resonator of the ladder filter deviates from the straight line extending perpendicularly to a surface acoustic wave propagating direction, so that the angle of the first straight line with respect to a second straight line connecting an input terminal and an output terminal provided in a package that accommodates the substrate is smaller than the angle of the second straight line with respect to the straight line extending perpendicularly to the surface acoustic wave propagating direction on the substrate.
Dependencies are inferred from the claim text.