Fujitsu Corporation

Taiyo Yuden Co., Ltd.

Fujitsu Media Devices Limited

Other

Fujistu Media Devices Limited

Shogo Inoue

Takashi Matsuda

Jun Tsutsumi

Masanori Ueda

Masafumi Iwaki

Motoaki Hara

Seiichi Mitobe

Michio Miura

Satoru Matsuda

Yasuhide Iwamoto

Osamu Ikata

Tokihiro Nishihara

Kazunori Inoue

Kentaro Nakamura

Suguru Warashina

Hidetaro Nakazawa

Kazuhiro Watanabe

Yoshio Satoh

Osamu Kawachi

Koichi Wada

Shinji Taniguchi

Xiaoyu Mi

Kazuhiro Matsumoto

Masahiko Imai

Toshio Nishizawa

Yasufumi Kaneda

Go Endo

Takayuki Yamaji

Motoyuki Tajima

Kenya Hashimoto

Jyouji Kimura

Masatsune Yamaguchi

Toshihiko Murata

Tatsuya Omori

Masufumi Iwaki

Mosanori Ueda

Hiroyoshi Yasuda

Yasutomo Tanaka

A surface acoustic wave device includes: a pair of comb-type electrodes that are provided on a piezoelectric substrate and include electrode fingers and dummy electrode fingers, the electrode fingers of one of the pair of comb-type electrodes facing the dummy electrode fingers of the other comb-type electrode; and additional films that are provided to cover gaps between tip ends of the electrode fingers and tip ends of the dummy electrode fingers and to overlap with at least one of first through third groups in which the first and second groups respectively include the electrode fingers and the dummy electrode fingers located at opposite sides of the gaps in a first direction in which the electrode fingers extend, and the third group includes the electrode fingers located at sides of the gaps in a second direction that crosses the first direction.

Surface acoustic wave device and filter with additional covering films

A duplexer includes a reception filter that is connected between a reception terminal and an antenna terminal and includes one or a plurality of series resonators that are acoustic wave resonators, and a transmission filter that is connected between a transmission terminal and the antenna terminal and includes one or a plurality of acoustic wave resonators, a resonance frequency of a first series resonator that is one of the one or the plurality of series resonators and is closest to the antenna terminal in the reception filter being higher than an upper limit frequency of a reception band of the reception filter.

Duplexer

A duplexer includes: a transmit filter that is connected between an antenna terminal and a transmit terminal and has a plurality of acoustic wave resonators; a receive filter that is connected between the antenna terminal and a receive terminal and has a plurality of acoustic wave resonators; and a delay line or a longitudinal coupling type resonator that is connected in parallel with at least one of the plurality of acoustic wave resonators of the transmit filter and the plurality of acoustic wave resonators of the receive filter and has at least two IDTs (Interdigital Transducers).

Duplexer, filter and communication module

A surface acoustic wave device includes: a pair of comb-like electrodes formed on a piezoelectric substrate, each of which includes electrode fingers, dummy electrode fingers and a bus bar to which the electrode fingers and the dummy electrode fingers are connected, the electrode fingers and the dummy electrode fingers of one of the pair of comb-like electrodes facing the dummy electrode fingers and the electrode fingers of the other com-like electrode, respectively; and additional films extending in the form of a strip in a first direction in which the electrode fingers are arranged side by side, each of the additional films covering at least parts of gaps defined by ends of the electrode fingers of one of the pair of comb-like electrodes and ends of the dummy electrode fingers of the other comb-like electrode.

Surface acoustic wave device and filter

In a filter, two parallel resonators that are adjacent to each other are connected, in parallel, to a first portion of the signal line that connects a pair of two adjacent series resonators, at least one parallel resonator is connected, in parallel, to a second portion of the signal line that connects a different pair of two adjacent series resonators, a first inductor is connected to one parallel resonator of said two parallel resonators in series, a second inductor is connected to one parallel resonator of said at least one parallel resonator in series, a third inductor is connected to said two parallel resonators and said at least one parallel resonator, the first and third inductors' total inductance is different from the second and third inductor's total inductance.

Filter, duplexer and communication module

A resonator includes: a first comb-shaped electrode including a first bus bar, first electrode fingers coupled to the first bus bar and extending in an extension direction, and first dummy electrode fingers coupled to the first bus bar; and a second comb-shaped electrode including a second bus bar, second electrode fingers coupled to the second bus bar, extending in the extension direction, and facing the first dummy electrode fingers through first gaps, and second dummy electrode fingers coupled to the second bus bar and facing the first electrode fingers through second gaps, wherein 0.5&#x3bb;&#x2266;&#x394;D where &#x394;D represents a distance in the extension direction between at least two gaps that are at least adjoining two of the first gaps or/and at least adjoining two of the second gaps, and &#x3bb; represents pitches of the first electrode finger and the second electrode finger.

Resonator, filter, and duplexer

A duplexer includes: a first filter of which first and second ends connect to a common terminal and a first terminal respectively; and a second filter having a passband higher than that of the first filter, a first end and second end thereof connecting to the common terminal and a second terminal respectively, wherein a phase shifter is located neither between the first filter and the common terminal nor between the second filter and the common terminal, the second filter is a ladder-type filter including piezoelectric thin film resonators connected in a ladder shape, a propagation constant in a direction perpendicular to a thickness direction of a piezoelectric thin film in the piezoelectric thin film resonator is a real number at frequencies lower than a resonance frequency of the piezoelectric thin film resonator, and a resonator at a first stage is a parallel resonator in the second filter.

An acoustic wave filter includes: at least a parallel resonator, wherein at least one of the parallel resonator includes a piezoelectric substance, an IDT located on the piezoelectric substance, and reflectors located on the piezoelectric substance so as to sandwich the IDT, and a distance between a first electrode finger that is an electrode finger closest to the reflector among electrode fingers of the IDT and a second electrode finger that is an electrode finger closest to the IDT among electrode fingers of the reflector is less than 0.25(&#x3bb;+&#x3bb;) where a period of the electrode fingers of the IDT is &#x3bb;and a period of the electrode fingers of the reflector is &#x3bb;.

Acoustic wave filter, duplexer, and module

A filter includes: first series resonators and first parallel resonators that are connected in a ladder shape between an input terminal and an output terminal; a first inductor that is connected in parallel to at least one first series resonator; one or more second parallel resonators that are provided separately from the first parallel resonators, are connected between the input terminal and the output terminal, and have a resonance frequency and an anti-resonance frequency at frequencies lower than a passband formed by the first series resonators and the first parallel resonators; wherein an attenuation region is formed by a first attenuation pole formed by the at least one first series resonator and the first inductor and a second attenuation pole formed by a resonant response of the one or more second parallel resonators.

Filter and duplexer

A filter includes: acoustic wave resonators connected between an input terminal and an output terminal; and a cancel circuit including an input connection portion and an output connection portion connected so that the cancel circuit is connected in parallel to at least a part of the acoustic wave resonators, wherein the cancel circuit includes a first acoustic wave resonator connected between a node between the input connection portion and the output connection portion and a ground.

Filter, duplexer, and communication module

A ladder filter includes at least one series resonator connected in series between an input terminal and an output terminal, at least one parallel resonator connected in parallel with the at least one series resonator, and an inductor connected in parallel with the at least one series resonator. The at least one series resonator and the inductor generate a first attenuation pole at a frequency equal to or lower than a frequency band defined by the at least one series resonator and the at least one parallel resonator. The first attenuation pole is located at a frequency that is equal to or higher than a resonance frequency of a parallel resonator that is included in the at least one parallel resonator and has a highest resonance frequency and that is equal to or lower than a high-frequency end of the pass band.

Ladder filter, duplexer and module

A ladder filter includes at least one series resonator connected in series between an input terminal and an output terminal, at least one parallel resonator connected in parallel with the at least one series resonator, an additional resonator connected in series between the at least one series resonator and one of the input terminal and the output terminal, and an inductor connected in series to the additional resonator, the additional resonator having a resonance frequency higher than an anti-resonance frequency of the at least one series resonator.

According to an aspect of the invention, each of a filter, a duplexer and a communication module includes a plurality of series resonators connected to a signal line in series and a plurality of parallel resonators connected to the signal line in parallel. At least two of the plurality of parallel resonators are connected to the signal line between two of the plurality of series resonators in parallel, inductors are respectively connected to the at least two parallel resonators, and the inductors have different inductances from each other.

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Kawasaki, Japan

Shogo Inoue