Abstract: A radio frequency module includes a module board including a first principal surface and a second principal surface on opposite sides thereof; a transmission power amplifier; a control circuit configured to control the transmission power amplifier; a first transmission filter and a second transmission filter; and a first switch configured to switch connection of an output terminal of the transmission power amplifier between the first transmission filter and the second transmission filter. The control circuit is disposed on the first principal surface, and the first switch is disposed on the second principal surface.

Abstract: A radio frequency module includes a module board including a first principal surface and a second principal surface on opposite sides thereof, a transmission power amplifier, a control circuit that controls the transmission power amplifier, and a first inductor connected to an output terminal of the transmission power amplifier. The control circuit is disposed on the first principal surface, and the first inductor is disposed on the second principal surface.

Abstract: A radio-frequency front-end circuit includes first and second radio-frequency switches and filters. The first radio-frequency switch includes a first antenna-side terminal and a plurality of first filter-side terminals selectively coupled to the first antenna-side terminal. The second radio-frequency switch includes a second antenna-side terminal and a plurality of second filter-side terminals selectively coupled to the second antenna-side terminal. Some of the filters are multiplexer filters and each includes a common terminal. The common terminals of the filters are coupled individually to some of the first filter-side terminals of the first radio-frequency switch. The second antenna-side terminal of the second radio-frequency switch is coupled to the remaining one of the first filter-side terminals of the first radio-frequency switch.

Abstract: A radio frequency circuit includes a first acoustic wave filter that is connected to a common terminal and includes a first acoustic wave resonator, a first LC filter that is connected to the common terminal via the first acoustic wave filter and includes at least one of an inductor or a capacitor, a second acoustic wave filter that is connected to the common terminal and includes a second acoustic wave resonator, and a second LC filter that is connected to the common terminal via the second acoustic wave filter and includes at least one of an inductor or a capacitor.

Abstract: 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.

Abstract: A radio-frequency circuit includes a first switch which includes a common terminal, a first selection terminal, and a second selection terminal, and switches between connecting the common terminal and the first selection terminal and connecting the common terminal and the second selection terminal; a first low-noise amplifier including an input terminal connected to the first selection terminal, and a second low-noise amplifier including an input terminal connected to the second selection terminal. The frequency band in which the first low-noise amplifier amplifies a radio-frequency signal by at least a predetermined gain includes the frequency band in which the second low-noise amplifier amplifies a radio-frequency signal by at least a predetermined gain.

Abstract: A front-end circuit includes a primary circuit and a diversity circuit, the primary circuit includes transmission paths 51 and 52 for transmitting a signal in a band A and in a band B, respectively. Transmission and reception of a signal in the band B are performed by a TDD system in the transmission path 52. The diversity circuit includes a switch, and reception paths 53 and 54 that receive a signal in the band A and in the band B, respectively. When reception signals in the band A and in the band B are simultaneously transmitted, and when a reception signal in the band A and a transmission signal in the band B are simultaneously transmitted, the switch causes the diversity antenna and each of the reception path 53 and the reception path 54 to be in a conductive state.

Abstract: A radio-frequency front-end circuit includes first and second filters, and first and second band elimination filters. The first filter is connected between an antenna common terminal and a first input-output terminal, and has a first frequency band as a pass band. The second filter is connected between the antenna common terminal and a second input-output terminal, and has a second frequency band as a pass band. The first band elimination filter is connected between the antenna common terminal and a third input-output terminal, and has the first frequency band as a stop band. The second band elimination filter is connected in series with the first band elimination filter between the antenna common terminal and the third input-output terminal, and has the second frequency band as a stop band.

Abstract: A radio-frequency module utilizing carrier aggregation includes a switch circuit that includes one input terminal and three or more output terminals and that simultaneously connects the input terminal and each of two or more output terminals selected from the output terminals, signal paths that propagate signals of corresponding frequency bands, band pass filters in the signal paths, and variable matching circuits in the signal paths. The circuit states of the variable matching circuits are changed in accordance with a combination of two or more signal paths simultaneously connected to the input terminal.

Abstract: A radio frequency front-end circuit includes a multiplexer including filters with different pass bands and including a first acoustic wave filter and a first terminal of each of the filters being connected in common, a second acoustic wave filter including a pass band within the pass band of the first acoustic wave filter, and a switch including a common terminal connected to a second terminal of the first acoustic wave filter and selective terminals including a selective terminal connected to the second acoustic wave filter. Each of an acoustic wave resonator of the first acoustic wave filter located closest to the switch and an acoustic wave resonator of the second acoustic wave filter located closest to the switch, is a serial arm resonator.

Abstract: A composite filter device includes bandpass filters whose respective one ends are electrically connected in common. A first bandpass filter of the bandpass filters includes a first filter, a switch, a second filter, and an impedance element that is electrically connected to the switch and having an impedance value larger than the input impedance value of the second filter. The switch is configured to be switched between a first state in which the first filter and the second filter are electrically connected and a second state in which the first filter and the impedance element are electrically connected.

Abstract: A radio-frequency module utilizing carrier aggregation includes a switch circuit that includes one input terminal and three or more output terminals and that simultaneously connects the input terminal and each of two or more output terminals selected from the output terminals, signal paths that propagate signals of corresponding frequency bands, band pass filters in the signal paths, and variable matching circuits in the signal paths. The circuit states of the variable matching circuits are changed in accordance with a combination of two or more signal paths simultaneously connected to the input terminal.

Abstract: A radio-frequency module utilizing carrier aggregation includes a switch circuit that includes one input terminal and three or more output terminals and that simultaneously connects the input terminal and each of two or more output terminals selected from the output terminals, signal paths that propagate signals of corresponding frequency bands, band pass filters in the signal paths, and variable matching circuits in the signal paths. The circuit states of the variable matching circuits are changed in accordance with a combination of two or more signal paths simultaneously connected to the input terminal.

Abstract: A radio-frequency front-end circuit includes first and second filters, and first and second band elimination filters. The first filter is connected between an antenna common terminal and a first input-output terminal, and has a first frequency band as a pass band. The second filter is connected between the antenna common terminal and a second input-output terminal, and has a second frequency band as a pass band. The first band elimination filter is connected between the antenna common terminal and a third input-output terminal, and has the first frequency band as a stop band. The second band elimination filter is connected in series with the first band elimination filter between the antenna common terminal and the third input-output terminal, and has the second frequency band as a stop band.

Abstract: In a band pass filter, a first elastic wave resonator includes a first base board type and a first electrode configuration significantly improved or optimal for frequency characteristics of the first elastic wave resonator, and a second elastic wave resonator includes a second base board type and a second electrode configuration significantly improved or optimal for frequency characteristics of the second elastic wave resonator. A first attenuation pole provided by the first elastic wave resonator and a second attenuation pole provided by the second elastic wave resonator is steeper than if the first elastic wave resonator and the second elastic wave resonator that have different frequency characteristics include electrodes having the same configuration on the same types of base boards.

Abstract: In a high frequency module, in addition to a main transmission path in which a high-frequency signal propagates in first filter elements, a sub transmission path is defined by inductive coupling or capacitive coupling between a first inductor and a matching element or by inductive coupling between the first inductor and a second inductor. The sub transmission path has different amplitude characteristics and phase characteristics from those of the main transmission path depending on a degree of the inductive coupling or capacitive coupling, and transmission characteristics as a high-frequency module are adjustable by adjusting the amplitude characteristics and the phase characteristics of the sub transmission path.

Abstract: A switch circuit includes first and second switches. The first switch includes a first common terminal and at least two first selection terminals selectively connected to the first common terminal. The second switch includes at least one second common terminal and at least one second selection terminal selectively connected to the at least one second common terminal. One of the at least two first selection terminals and the at least one second common terminal are connected to each other via a path passing through a first multiplexer. Another one of the at least two first selection terminals and the at least one second common terminal are connected to each other via a bypass path bypassing the first multiplexer.

Abstract: A radio-frequency front-end circuit includes a first filter that has a first pass band and is connected to an antenna common terminal, a second filter that has a second pass band and is connected to the antenna common terminal, a switch that includes a common terminal and selection terminals, the common terminal being connected to the first filter, and a third filter that is connected to one of the selection terminals and is disposed between the switch and an input/output terminal. A reflection coefficient of the first filter alone in the second pass band viewed from the antenna common terminal is larger than a reflection coefficient of the third filter alone in the second pass band viewed from the antenna common terminal.

Abstract: A radio frequency front-end circuit includes a multiplexer including filters with different pass bands and including a first acoustic wave filter and a first terminal of each of the filters being connected in common, a second acoustic wave filter including a pass band within the pass band of the first acoustic wave filter, and a switch including a common terminal connected to a second terminal of the first acoustic wave filter and selective terminals including a selective terminal connected to the second acoustic wave filter. Each of an acoustic wave resonator of the first acoustic wave filter located closest to the switch and an acoustic wave resonator of the second acoustic wave filter located closest to the switch, is a serial arm resonator.

Abstract: A multiplexer includes a n number (n is an integer equal to three or more) of filters that are individually provided in the n number of paths commonly connected at a common junction point, and that have different pass bands from one another. In the multiplexer, (n?1) filters among the n number of filters except for the first filter have impedances of which imaginary components cancel each other at a pass band frequency of the first filter when viewed from the common junction point in a state of the n number of paths being not commonly connected.