Murata Manufacturing Co., Ltd.

Norio Taniguchi

Tadamasa Ushiroku

Yasunori Kishimoto

Toshiaki Takata

Michio Kadota

Yuichi Takamine

Takeshi Nakao

Masakazu Mimura

Masashi Omura

Mitsuyoshi Hira

Shuji Yamato

Tomohisa Komura

Tomio Kanazawa

Mitsuo Takeda

Miki Takamiya

Tatsurou Nagai

A composite filter device includes a first filter and a plurality of second filters with different passbands. End portions of the first filter and the plurality of second filters are connected to a common connection. The first filter includes a piezoelectric substrate made of LiNbO, an IDT electrode provided on the piezoelectric substrate, and a dielectric layer provided on the piezoelectric substrate so as to cover the IDT electrode. The first filter utilizes a fundamental wave of Rayleigh waves. The passband of the first filter is arranged in a frequency band that is lower than any of the passbands of the plurality of second filters.

Filter device

A SAW duplexer includes a first SAW filter having a passband with a relatively low frequency, and a second SAW filter having a passband with a relatively high frequency. The first and second SAW filters each have a ladder-shaped circuit configuration. A bridging inductor is connected in parallel to at least one serial arm resonator in the second SAW filter. The bridging inductor includes a coiled portion provided on a multilayer package substrate. The coiled portion is defined by connecting first to third wires provided on first to third layers by via-hole conductors. First, third, and fifth via-hole conductors that define a coil return wire portion are disposed inside the coiled portion.

SAW duplexer having a bridging inductor in a multilayer package

In a longitudinally coupled resonator SAW filter apparatus, one end of each N first longitudinally coupled resonator SAW filter, where N is an integer equal to or greater than 2, is connected in parallel to an unbalanced signal terminal, the first N longitudinally coupled resonator SAW filters are connected in a cascade arrangement to M second longitudinally coupled resonator SAW filters, where M is an integer equal to or greater than 1, the M second longitudinally coupled resonator SAW filter are connected to first and second balanced signal terminals, and N and M are selected such that N&#x3e;M.

Surface acoustic wave filter apparatus and branching filter

A branching filter includes a first filter with a relatively low passband and having a first temperature property-improvement thin film, and a second filter with a relatively high passband and having a second temperature property-improvement thin film. In the branching filter, the thickness of the first temperature property-improvement thin film is different from that of the second temperature property-improvement thin film such that the temperature coefficient of frequency of the first filter is greater than that of the second filter.

Demultiplexer and surface acoustic wave filter

A surface acoustic wave branching filter reduces deterioration of the insertion loss and improves the isolation characteristics. The surface acoustic wave filter includes first ends of a first acoustic wave filter, having a relatively low passband, and a second acoustic wave filter, having a relatively high passband, connected to a first common terminal which is connected to an antenna. A resonator of the first surface acoustic wave filter, among a plurality of parallel-arm resonators and a plurality of series-arm resonators, which is closest to the first common terminal is a parallel-arm resonator. The capacitance of the parallel-arm resonator that is closest to the first common terminal is less than &#xbd; of the capacitance of the other parallel-arm resonators.

Surface acoustic wave duplexer

A surface acoustic wave branching filter includes a first filter and a second filter each including a plurality of surface acoustic wave resonators arranged in a ladder circuit configuration. The first filter in which the frequency range of the passband is relatively low is provided on a first piezoelectric substrate, and the second filter in which the frequency range of the passband is relatively high is provided on a second piezoelectric substrate. The first piezoelectric substrate and the second piezoelectric substrate are rotation Y-cut X-propagation LiTaOsubstrates, and the cut angle of the first piezoelectric substrate is greater than the cut angle of the second piezoelectric substrate.

Surface acoustic wave device having two piezoelectric substrates with different cut angles

A surface acoustic wave apparatus includes a first filter and a second filter, which are integrated into one package, and, filter signal terminals of the first and second filters are connected to package signal terminals of the package through different paths which are insulated from each other. A signal line extended from filter signal terminals is connected to one common terminal outside the package. The signal line and the common terminal define a coupling section. An inductance device is connected in parallel to the coupling section as a matching circuit.

Surface acoustic wave apparatus and communication apparatus

A surface acoustic wave duplexer includes a transmission-side surface acoustic wave filter and a receiving-side surface acoustic wave filter which are connected to an antenna terminal, and the transmission-side surface acoustic wave filter and the receiving-side surface acoustic wave filter are mounted on a package material. The surface acoustic wave duplexer further includes a high-frequency wave element which is connected to the transmission-side surface acoustic wave filter and the receiving-side surface acoustic wave filter, and at the same time, has two trap attenuation poles at the higher frequency side than at least the transmission-side pass band and the receiving-side pass band.

Surface acoustic wave branching filter

A ladder filter includes series arm resonators and parallel arm resonators which are alternately connected to each other. The series arm resonators include a first series arm resonator connected in parallel with an inductor and a second series arm resonator not connected to the inductor. The ladder filter satisfies the relationship of fsr&#x3c;fsrwhere fsrrepresents the resonant frequency of the first series arm resonator and fsrrepresents the resonant frequency of the second series arm resonator.

Ladder filter, branching filter, and communication apparatus

A surface acoustic wave duplexer includes a first filter including a ladder filter and a second filter including a ladder filter with a pass band that is different from that of the first filter. Inductors are connected in parallel with respective series resonators of both first and second filters.

Surface acoustic wave duplexer and communication apparatus having the same

A surface acoustic wave filter device includes a surface acoustic wave filter element having a ladder type circuit electrically connected and mechanically fixed to a package by a face down mounting method. A micro-strip line connected to series arm resonator and/or a parallel arm resonator is provided inside the package, whereby excellent filter characteristics are provided by the addition of the inductance component thereof.

Surface acoustic wave filter device

A surface acoustic wave branching filter includes a first surface acoustic wave filter chip having a relatively low center frequency and a second surface acoustic wave filter chip having a relatively high center frequency which are joined to a chip mounting surface of a packaging member. A bump of the second surface acoustic wave filter chip is joined to a signal wiring pattern disposed on the chip mounting surface of the packaging member. The signal wiring pattern is configured to have a pattern portion that is in closer proximity to a ground wiring pattern than to the bump.

A ladder circuit type SAW filter device includes series arm resonators and parallel arm resonators that are defined by SAW resonators. Among the parallel arm resonators, a first parallel arm resonator that is connected to one of an input end and an output end and a second parallel arm resonator that is connected to a junction between two series arm resonators have the relationship of Cp &times;2<Cp , where Cp represents the capacitance of the first parallel arm resonator and Cp represents the capacitance of the second parallel arm resonator. The inductance of an inductor that is connected to the second parallel arm resonator is equal to or less than the inductance of the inductor that is connected to the first parallel arm resonator. The SAW filter device has superior steepness of filter characteristics in the lower range of a pass band and outstanding attenuation in a stop band.

A branching filter is a surface acoustic wave device in which a first filter having a relatively low bandpass frequency and a second filter having a relatively high bandpass frequency are connected to a common terminal. A junction-side resonator that is included in the second filter and that is connected in closest proximity to the common terminal is connected in series. The resonant frequency f of the junction-side resonator is higher than the center frequency f , which is the center of the passband, of the second filter, and is more preferably set so as to satisfy the expression: f &plus;BW&times;0.2&lE;f &lE;f &plus;BW&times;0.7, where BW is the bandwidth of the passband.

Surface acoustic wave device and communication apparatus

A surface acoustic wave filter includes a piezoelectric substrate and a plurality of surface acoustic wave resonators mounted on the piezoelectric substrate. The plurality of surface acoustic wave resonators are connected so as to constitute a lattice-type circuit having series-arm resonators and lattice-arm resonators, and a capacitance ratio &ggr; value of the lattice-arm resonators and a capacitance ratio &ggr; value of the series-arm resonators are made different from each other.

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Shiga-ken, Japan

Norio Taniguchi