Fujitsu Media Devices Limited

Fujitsu Corporation

Kabushiki Kaisha Toshiba

Seiichi Mitobe

Shogo Inoue

Takashi Matsuda

Masanori Ueda

Michio Miura

Satoru Matsuda

Koichi Wada

Osamu Kawachi

Yasuhide Iwamoto

Naoyuki Mishima

Toshio Nishizawa

Yasufumi Kaneda

Youichi Masuda

Yasuo Ebata

Satoshi Ichikawa

Toshihiko Murata

Hirohisa Tanaka

Motoyoshi Takase

Kouta Ookubo

Hiroyoshi Yasuda

A filter includes a first filter that is connected between an input node and an output node and is a surface acoustic wave filter, and a second filter that is provided between the input node and the output node and is connected in parallel with the first filter. The first filter has a total number N1 of pairs of electrode fingers of interdigital transducers and the second filter having a total number N2 of pairs of electrode fingers of interdigital transducers, in which N1 is greater than N2.

Filter having multiple surface acoustic wave filters connected in parallel

A filter includes a parallel resonator having first comb electrodes provided on a piezoelectric substrate and a first dielectric film that covers the first comb electrodes, and a series resonator having second comb electrodes provided on the piezoelectric substrate and a second dielectric film covers the second comb electrodes and is made of a material identical to that of the first dielectric film. The first dielectric film has a different thickness from that of the second dielectric film.

Acoustic wave device, resonator and filter

An acoustic wave device includes a piezoelectric substrate, a resonator having comb electrodes that are provided above the piezoelectric substrate and excite an acoustic wave, and a capacitor that is provided above the piezoelectric substrate and is connected in series or parallel with the resonator, the capacitor including electrodes that horizontally face each other above the piezoelectric substrate. The electrodes of the capacitor are further from the piezoelectric substrate than the comb electrodes of the resonator.

Acoustic wave device and filter using the same

An acoustic wave device includes a piezoelectric substrate, a first dielectric film formed on the piezoelectric substrate, and electrodes that are provided on the first dielectric film and excite an acoustic wave, the electrodes including electrode fingers. At least a part of the first dielectric film is cut out between adjacent electrode fingers among the electrode fingers.

Acoustic wave device and filter

A duplexer includes: a first filter that is connected to a common terminal and a first terminal, and includes a first series-arm resonator; a second filter that is connected to the common terminal and a second terminal; a first inductor that is connected in parallel to the first series-arm resonator; a mounting unit that has the first filter and the second filter mounted thereon; a first inductor line that is provided on the mounting unit, and connects the first inductor and the first series-arm resonator; and a first terminal line that is provided on the mounting unit, and connects the first filter and the first terminal. In this duplexer, the directions of currents flowing through the first inductor line and the first terminal line cross each other.

Filter and duplexer

An acoustic wave device includes a piezoelectric substrate, comb electrodes formed above the piezoelectric substrate, and a first dielectric film provided so as to cover the comb electrodes, the first dielectric film having empty spaces associated with fingers of the comb electrodes.

An acoustic wave device includes a piezoelectric substrate, a first dielectric film provided on the piezoelectric substrate, electrodes that are provided on the first dielectric film and excite an acoustic wave, and a second dielectric film that is provided so as to cover the electrodes and is thicker than the electrodes.

A balanced filter includes: a filter that has at least one unbalanced signal terminal; a balun that is a lumped parameter balun that inputs or outputs signals with different phases generated based on a signal input or output from the unbalanced signal terminal of the filter, the balun being formed with an integrated passive device; and a mounting unit in which the filter and the balun are flip-chip mounted.

Balanced filter and duplexer

A surface acoustic wave apparatus has a configuration by which the spurious of the higher-order transverse modes is suppressed and a SAW excitation intensity distribution is not changed in the propagation direction. The surface acoustic wave apparatus has at least one interdigital transducer, which is disposed such that a plurality of comb-shape electrodes respectively connected to common electrodes are interleaved, wherein a region with the plurality of interleaved comb-shape electrodes has a first overlapping region with a overlapping length constant over a whole area along a propagation direction of a surface acoustic wave and a second overlapping region formed on at least one side of the first overlapping region with a overlapping length weighted in the propagation direction of the surface acoustic wave, and wherein an overlapping-length weighting envelope curve in the second overlapping region has at least two changing points in the propagation direction of the surface acoustic wave.

Surface acoustic wave apparatus

A surface acoustic wave apparatus has a configuration by which the spurious of the higher-order transverse modes is suppressed and a SAW excitation intensity distribution is not changed in the propagation direction. The surface acoustic wave apparatus has at least one interdigital transducer; a region with the plurality of interleaved comb-shaped electrodes is formed with two regions which are a first overlapping region and a second overlapping region with overlapping-lengths weighted along a propagation direction of a surface acoustic wave; the first overlapping region and the second overlapping region are in contact or overlapped in a direction vertical to the propagation direction of the surface acoustic wave; and in either the first or the second overlapping region, an overlapping-length weighting envelope curve has at least two or more changing points in the propagation direction of the surface acoustic wave.

An elastic boundary wave device includes a LiNbOsubstrate, an electrode exciting an elastic wave and provided on the substrate, and a silicon oxide film provided on the substrate to cover the electrode, and parameters of the elastic boundary wave device have any one of ranges, where '&#x3b8;' is a rotation Y cut angle of the substrate, 'a' is a ratio of copper density with respect to a density of a material used as the electrode, &#x201c;&#x3bb;&#x201d; is a wavelength of the elastic wave excited by the electrode, &#x201c;h&#x201d; is a film thickness of the electrode, &#x201c;H&#x201d; is a thickness of the silicon oxide film.

Elastic boundary wave device, resonator, and filter

An acoustic boundary wave device includes a first medium having piezoelectricity, electrodes that are provided on the first medium and excite acoustic waves, a second medium made of a material different from the first medium and provided on the first medium so as to cover the electrodes, and a third medium that has a heat conductivity higher than that of the second medium and is provided so as to contact an upper surface of the second medium and at least a part of side surfaces of the second medium.

Acoustic boundary wave device, resonator and filter

A surface acoustic wave device having a given impedance includes multimode type filters connected in series. A composite impedance of the multimode type filters defines the given impedance of the surface acoustic wave device.

Surface acoustic wave device

Transducers are connected in parallel on a piezoelectric substrate. Each of the transducers is constituted of RSPUDTs. The RSPUDTs include SPUDTs that are opposed to each other such that their propagation directions are opposite to each other. The SPUDTs have a unidirectional electrode structure having a propagation characteristic.

Surface acoustic wave device utilizing opposite propagation direction regions and resonant mode coupling

There is provided an apparatus that shows a much better transmission function characteristic in a signal passing band, and a low insertion loss. A plurality of pairs of electrode fingers constitute a first split electrode group of , . . . . Further, a plurality of pairs of electrode fingers constitute a second split electrode group of , . . . . The pairs of electrode fingers of both the groups are interleaved. The pairs of electrode fingers include electrode fingers of a width narrower than &lgr;/8 (&lgr; indicates the wavelength of a surface acoustic wave serving as the operation central frequency), and electrode fingers of a width wider than &lgr;/8, and the distance between the centers of the adjacent electrode fingers differs from &lgr;/4.

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Yokohama, Japan

Seiichi Mitobe