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US 7,135,944 B2Granted
Branching filter having both saw ladder and dual mode filters, and electronic apparatus using the branching filter
AssigneesFujitsu Media Devices Limited, Fujitsu Limited
InventorsYasuhide Iwamoto, Shogo Inoue, Osamu Ikata, Jun Tsutsumi
Life of this patent
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Abstract
A duplexer includes two surface acoustic wave filter having different band center frequencies, and a phase matching circuit that matches the phases of the two surface acoustic wave filters to each other. In this duplexer, one of the two surface acoustic wave filters is a ladder type surface acoustic wave filter, while the other one of the two surface acoustic wave filters includes two or more dual-mode type surface acoustic wave filters that are connected in parallel.
Claims36
A duplexer comprising:
- two surface acoustic wave filters that are connected to a common terminal and have different band center frequencies;
- and
- a phase matching circuit that matches the phases of the two surface acoustic wave filters to each other,
- one of the two surface acoustic wave filters being a ladder type surface acoustic wave filter, while the other one of the two surface acoustic wave filters including a plurality of dual-mode type surface acoustic wave filters equal to three or more and connected in parallel.
1 more element
A duplexer comprising:
- two surface acoustic wave filters that are connected to a common terminal and have different band center frequencies;
- and
- a phase matching circuit that matches the phases of the two surface acoustic wave filters to each other,
- the two surface acoustic wave filters and the phase matching circuit being housed in a laminated package, and
- one of the two surface acoustic wave filters being a ladder type surface acoustic wave filter, while the other one of the two surface acoustic wave filters including a plurality of dual-mode type surface acoustic wave filters equal to three or more and connected in parallel.
2 more elements
An electronic device comprising:
- an antenna;
- a duplexer that is connected to the antenna;
- and
- a transmission system and a reception system that are connected to the duplexer,
- the duplexer including two surface acoustic wave filters that is commonly connected to the antenna and has different band center frequencies, and a phase matching circuit for matching the phases of the two surface acoustic wave filters to each other, and
- one of the two surface acoustic wave filters being a ladder type surface acoustic wave filter, while the other one of the two surface acoustic wave filters including a plurality of dual-mode type surface acoustic wave filters equal to three or more connected in parallel.
3 more elements
Dependencies are inferred from the claim text.