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US 9,806,693 B2Granted
Duplexer with a ladder filter portion and a specifically connected capacitor or elastic wave resonator
AssigneeMurata Manufacturing Co., Ltd.
InventorYuichi Takamine
Life of this patent
Estimating the term…
Abstract
A duplexer includes a transmission filter with a ladder circuit configuration and a reception filter including a ladder filter portion connected to an antenna terminal and a longitudinally coupled resonator-type surface acoustic wave filter. In the transmission filter, a coupling capacitor is connected between an end portion of an inductor nearer to parallel arm resonators and a wiring line connecting the series arm resonators of the ladder filter portion to each other in the reception filter.
Claims18
A duplexer comprising:
- an antenna terminal;
- a transmission terminal;
- a reception terminal;
- a transmission filter that is connected between the antenna terminal and the transmission terminal and that has a ladder circuit configuration including a plurality of elastic wave resonators;
- a reception filter including a longitudinally coupled resonator filter portion connected between the antenna terminal and the reception terminal and a ladder filter portion connected between the longitudinally coupled resonator filter portion and the antenna terminal;
- wherein
- the transmission filter includes a first series arm resonator, a first parallel arm resonator, and an inductor connected between the first parallel arm resonator and a ground potential;
- the ladder filter portion includes at least two second series arm resonators and a second parallel arm resonator;
- and
- the duplexer further includes a coupling capacitor or an elastic wave resonator connected between a wiring line connecting the second series arm resonators of the ladder filter portion to each other and an end portion of the inductor nearer to the first parallel arm resonator.
7 more elements
Dependencies are inferred from the claim text.