Murata Manufacturing Co., Ltd.

Hitachi Maxell, Limited

Masakazu Tani

Kenichiro Yoshida

Norihisa Yoshimoto

Yoshiyuki Makita

Shouzo Sugiyama

Hajime Kando

Morio Takeuchi

Hideki Tsukamoto

Akihiro Nakamura

Yusuke Naniwa

Kousuke Amano

Jyunichi Shimizu

Shinji Arakawa

Hirotsugu Mori

Hitoshi Tada

Yukiya Yamaguchi

Teruhisa Shibahara

Shigeru Tsuchida

Kei Matsutani

Yasuaki Shin

Takashi Ogami

Manabu Nakahori

Hiroki Shonai

In a radio-frequency circuit, a first switch is connected to an antenna terminal. A second switch is connected to the first switch and is connected to the antenna terminal via the first switch. A first filter is connected to the first switch without having the second switch interposed therebetween and allows a radio-frequency signal of a first communication band to pass through the first filter. A second filter is connected to the first switch via the second switch and allows a radio-frequency signal of a second communication band to pass through the second filter. The second communication band is higher than the first communication band. The radio-frequency circuit further includes an inductor. The inductor is not connected in series with the first filter and is connected in series with the first switch and the second switch between the first switch and the second switch.

Radio-frequency circuit, radio-frequency front-end circuit, and communication apparatus

A multiplexer includes first, second, and third filters with first, second, and third frequency bands different from each other, a first connection point connected to a common terminal, a second connection point connected to one end of the first filter and one end of the second filter, a first switch that switches connection and disconnection between the first and second connection points, a reactance element whose one end is connected to a signal path connecting the second connection point and the first switch, a second switch that switches connection and disconnection between the other end of the reactance element and the first connection point, and a third switch that switches connection and disconnection between one end of the third filter and the first connection point. The first and second frequency bands are adjacent to each other among the first, second, and third frequency bands.

Multiplexer, radio frequency front-end circuit, and communication device

A multiplexer includes a common terminal, reception output terminals (and), a filter () that is connected between the common terminal and the reception output terminal (), a filter () that is connected between the common terminal and the reception output terminal () and has a pass band different from a pass band of the filter (), and an impedance matching circuit that is arranged between the common terminal and the filter (). The impedance matching circuit includes a parallel-arm resonator that is connected between a node (N) on a path connecting the common terminal to the filter () and a ground.

Multiplexer, front end module, and communication device

A multiplexer includes a common terminal, a first reception output terminal, a second reception output terminal, a first filter that is connected between the common terminal and the first reception output terminal, a second filter that is connected between the common terminal and the second reception output terminal and that has a passband different from that of the first filter, and an impedance matching circuit that is disposed between the common terminal and the second filter. The impedance matching circuit includes a serial arm resonator disposed in series on a path connecting the common terminal to the second filter.

Multiplexer, front-end module, and communication device

A multiplexer () includes: a filter (L) that is arranged between a common terminal () and an input/output terminal () and that has a first pass band; a filter (H) that is arranged between the common terminal () and an input/output terminal (), that is formed of at least one acoustic wave resonator, and that has a second pass band located at a higher frequency than the first pass band; and a capacitor (C) that is serially arranged on a connection path between the common terminal () and the filter (H). When the filter (H) is regarded as a capacitance, the Q value of the capacitor (C) in the first pass band is higher than the Q value of the capacitance in the first pass band.

Multiplexer, radio-frequency front end circuit, and communication device

A radio-frequency module includes a mounting substrate having a first main surface; a first power amplifier that is mounted on the first main surface and that amplifies a first transmission signal in a first frequency band; a second power amplifier that is mounted on the first main surface and that amplifies a second transmission signal in a second frequency band different from the first frequency band; a first output matching circuit that is mounted on the first main surface and that receives the first transmission signal amplified by the first power amplifier; and a second output matching circuit that is mounted on the first main surface and that receives the second transmission signal amplified by the second power amplifier. The first output matching circuit and the second output matching circuit are mounted along a second direction intersecting with the first direction.

Radio-frequency module and communication apparatus

Filtersandhaving respective pass bands different from each other, a common terminal to which a terminalof the filterand a terminal of the filterare connected, and an inductor of which one end is connected to the terminaland another end is connected to the common terminal. The filterincludes a longitudinally coupled resonator formed of a resonatorand resonatorsanddisposed on both sides of the resonator, in which the resonatoris connected to the terminal, and a parallel resonator of which one end is connected to the resonatorand another end is connected to a ground electrode, and the resonatorand the parallel resonator of the resonators included in the filterare connected to a signal path between the resonatorand the terminal

Multiplexer, high-frequency front-end circuit, and communication device

A multiplexer includes a common terminal, a first acoustic wave filter having a first frequency band as a pass band, and having a first input/output terminal connected to the common terminal, a second acoustic wave filter having a second frequency band higher than the first frequency band as a pass band, and having a second input/output terminal connected to the common terminal, an inductance element, and a first capacitance element. The first acoustic wave filter has a parallel resonator of which one end is connected to the first input/output terminal and another end is connected to a ground electrode, and the first input/output terminal is connected to the common terminal via the inductance element, and the first capacitance element is connected between a signal path between the one end of the parallel resonator and the inductance element, and a ground electrode.

Even when frequency characteristics are changed in association with multiple communication bands, an attenuation required for a specific frequency band outside a pass band is obtained. A frequency-variable filter () includes multiple series-arm resonators (), multiple parallel-arm resonators (), a variable capacitor (), and an inductor () having a fixed inductance. The multiple series-arm resonators () and the multiple parallel-arm resonators () are connected in a ladder shape. The variable capacitor () is connected in series with the parallel-arm resonator (). The fixed inductor () is connected in series with the parallel-arm resonator ().

Ladder-type frequency-variable filter, multiplexer, radio-frequency front end circuit, and communication terminal

Even when frequency characteristics are changed in association with multiple communication bands, an attenuation required for a specific frequency band outside a pass band is obtained. A multiplexer includes a transmission filter, a reception filter, and a common connection point. An antenna-side end of the transmission filter and an antenna-side end of the reception filter are connected to the common connection point. The transmission filter includes multiple resonators including a parallel-arm resonator and a variable capacitor that is connected in series with the parallel-arm resonator. An inductor for forming an attenuation pole is provided between the antenna-side end of the reception filter and the common connection point. By the inductor for forming an attenuation pole and the reception filter, which is capacitive, an attenuation pole at a frequency close to or equal to a specific frequency outside the pass band of a transmission signal is formed.

Multiplexer, radio-frequency front end circuit, and communication terminal

A first attenuation circuit is connected between a node and ground, and the node is located between a ladder resonance circuit and a transmitter-side terminal. A second attenuation circuit is connected between a first parallel arm resonator of the ladder resonance circuit and ground and is connected in series to the first parallel arm resonator. The first attenuation circuit includes a second parallel arm resonator and a first switch that switches between a first state in which the second parallel arm resonator is connected to the node and a second state in which the first switch is open. The second attenuation circuit includes a capacitor and a second switch that switches between a first state in which the capacitor is connected to the first parallel arm resonator and a second state in which the first parallel arm resonator is connected to ground.

Variable frequency filter, radio frequency front-end circuit, and communication terminal

A variable filter circuit includes: a series arm connected in series between a signal input terminal and a signal output terminal; a parallel arm connected between the series arm and a ground terminal that has a resonator; and a variable reactance portion in the parallel arm, and the resonator of a parallel arm at an initial stage connected to the signal input terminal that has a resonant frequency fr and an anti-resonant frequency fa that satisfy 100&#xd7;(fn&#x2212;fr)/(fa&#x2212;fr)&#x2264;23.9(%) for communication bands for each of which a stop band is set so as to be close to a high-frequency side of a pass band, among the plurality of communication bands, where a resonant frequency is fr, an anti-resonant frequency is fa, and a cutoff frequency at a high-frequency side of a pass band of each communication band is fn.

Variable filter circuit

A frequency-variable filter includes a filter unit and matching circuits. The filter unit includes frequency-variable resonance circuits that include piezoelectric resonators. The matching circuits have a circuit configuration in which a real number component of an impedance increases as the frequency increases. For example, the matching circuits have an L-type circuit configuration that includes a reactance element connected in shunt to the side of the filter unit and that includes an inductor and a capacitor. As the filter unit includes the piezoelectric resonators, the real number component of the impedance increases as the pass band shifts to a high-frequency side, but the real number component of the impedance increases as the frequency increases in the matching circuits as well. Thus, the impedance matching is achieved.

Frequency-variable filter

A high-frequency filter () includes a first input-output terminal (P), a second input-output terminal (P), a variable frequency filter (), and a fixed frequency filter (). The variable frequency filter () and the fixed frequency filter () are connected in series and coupled between the first input-output terminal (P) and the second input-output terminal (P). The variable frequency filter () is a filter capable of varying a passband and an attenuation band. The fixed frequency filter () is a filter having a fixed passband and a fixed attenuation band. The passband of the fixed frequency filter () is set so as to be at least partially overlapped with multiple passbands realized by the fixed frequency filter ().

High-frequency filter

A high-frequency filter () includes resonators (, and), an inductor (), and a switch (). The resonator () is connected between a first input/output terminal (P) and a second input/output terminal (P). One end of the inductor () is connected between the resonator () and the first input/output terminal (P). One end of the resonator () is connected to the other end of the inductor (). The switch () selects either a connection portion that connects the inductor () and the resonator () or the resonator () and connects either the connection portion or the resonator (), which has been selected, to a terminal of the resonator () on the side of the second input/output terminal (P). The switching between the connection modes of the switch () changes the circuit configuration of the high-frequency filter ().

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Kyoto, Japan

Masakazu Tani