US 9,203,378 B2Granted

Elastic wave filter, and duplexer and electronic device using same

AssigneeSkyworks Panasonic Filter Solutions Japan Co., Ltd.

InventorsJoji Fujiwara, Tetsuya Tsurunari, Hiroyuki Nakamura, Rei Goto

Life of this patent

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Abstract

An elastic wave filter includes first and second longitudinally coupled elastic wave filters. The first filter includes a first pair of grating reflectors, first to fifth IDT electrodes arranged in ordinal order between the grating reflectors along a propagation direction of elastic waves, a first unbalanced terminal, and first and second balanced terminals. The second filter has a second unbalanced terminal, and third and fourth balanced terminals, the first and second unbalanced terminals being electrically connected to each other, the first and third balanced terminals being electrically connected to a first JO terminal, and the second and fourth balanced terminals being electrically connected to a second JO terminal. The first and second balanced terminals, and the third and fourth balanced terminals, output signals opposite in phase to each other. A first signal at the first JO terminal is opposite in phase to a second signal at the second IO terminal.

Claims19

Dependent claims

An elastic wave filter comprising:

a first longitudinally coupled elastic wave filter having a first unbalanced signal terminal, a first balanced signal terminal, and a second balanced signal terminal, the first longitudinally coupled elastic wave filter including a first pair of grating reflectors, first, second, third, fourth, and fifth IDT electrodes arranged in ordinal order between the grating reflectors of the first pair of grating reflectors along a propagation direction of elastic waves in the first longitudinally coupled elastic wave filter;
and
a second longitudinally coupled elastic wave filter having a second unbalanced signal terminal, a third balanced signal terminal, and a fourth balanced signal terminal, the first and second unbalanced signal terminals being electrically connected to each other, the first and third balanced signal terminals being electrically connected to a first input/output terminal, and the second and fourth balanced signal terminals being electrically connected to a second input/output terminal, the first and second balanced signal terminals outputting signals opposite in phase to each other, the third and fourth balanced signal terminals outputting signals opposite in phase to each other, and a first signal at the first input/output terminal being opposite in phase to a second signal at the second input/output terminal.

An elastic wave filter device comprising:

first, second, and third input/output terminals;
a piezoelectric substrate;
a first longitudinally coupled elastic wave filter formed on the piezoelectric substrate, the first longitudinally coupled elastic wave filter including first and second reflectors, and first, second, third, fourth, and fifth IDT electrodes arranged in ordinal order between the first and second reflectors along a propagation direction of elastic waves in the first longitudinally coupled elastic wave filter, one end of each of the first, third, and fifth IDT electrodes being electrically connected to the first input/output terminal, and the other end of each of the first, third, and fifth IDT electrodes being electrically connected to ground, one end of each of the second and fourth IDT electrodes being electrically connected to ground, the other end of the second IDT electrode being electrically connected to the second input/output terminal, and the other end of the fourth IDT electrode being electrically connected to the third input/output terminal;
and
a second longitudinally coupled elastic wave filter formed on the piezoelectric substrate, the second longitudinally coupled elastic wave filter including third and fourth reflectors, and sixth, seventh, eighth, ninth, and tenth IDT electrodes arranged in ordinal order between the third and fourth reflectors along a propagation direction of elastic waves in the second longitudinally coupled elastic wave filter, one end of each of the sixth, eighth, and tenth IDT electrodes being electrically connected to the first input/output terminal, and the other end of each of the sixth, eighth, and tenth IDT electrodes being electrically connected to ground, one end of each of the seventh and ninth IDT electrodes being electrically connected to ground, the other end of the seventh IDT electrode being electrically connected to the second input/output terminal, and the other end of the ninth IDT electrode being electrically connected to the third balanced signal terminal.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/845,547Filed 18 Mar 2013 · division
Priority: JP 2008-06538814 Mar 2008
Published: US 2013/0214872 A122 Aug 2013
Granted: 1 Dec 2015
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

H03H 9/725
Networks using surface acoustic waves: duplexers
H03H 9/0023
Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators: networks for transforming balanced signals into…
H03H 9/0071
Being electrically parallel: the balanced terminals being on the same side of the tracks
H03H 9/6436
Coupled resonator filters: having one acoustic track only

Family

PCT/JP2009/000972Parent of this division · filed 4 Mar 2009
US 2013/0214872 A1Pre-grant publication · published 22 Aug 2013
Application12/921,580Parent of this division
US 8,427,259 B2Parent of this division
US 2011/0006855 A1Published application
US 9,203,378 B2This patent

From the US filing history. Foreign family members aren’t listed.