Abstract: A directional coupler includes a main line, a sub-line, a coupling terminal, a terminal circuit, a first switching circuit, and a second switching circuit. The first switching circuit and the second switching circuit respectively connects the first end and the second end of the sub-line alternately to the coupling terminal and to the terminal circuit. The first switching circuit connects the first end to the coupling terminal at a time that differs from a time at which the first switching circuit disconnects the first end from the terminal circuit. The first switching circuit disconnects the first end from the coupling terminal at a time that differs from a time at which the first switching circuit connects the first end to the terminal circuit.

Abstract: A directional coupler includes a first main line, a second main line, first sub-lines, second sub-lines, a first output terminal, a second output terminal, a first inductor, and a second inductor. The first output terminal is configured to be coupled to the first sub-lines. The first output terminal is configured to output a first detection signal corresponding to a first radio-frequency signal transferred through the first main line. The second output terminal is configured to be coupled to the second sub-lines. The second output terminal is configured to output a second detection signal corresponding to a second radio-frequency signal transferred through the second main line. The first inductor is provided in a first signal path including the first output terminal. The second inductor is provided in a second signal path including the second output terminal.

Abstract: A directional coupler includes a main line and a sub-line electromagnetically coupled to each other, a variable termination circuit that is connected to one end of the sub-line and that has a variable impedance, a variable matching circuit that is connected to the other end of the sub-line and that has a variable impedance or a variable attenuator that has a variable attenuation, and a control circuit that controls the impedance of the variable termination circuit and that controls the impedance of the variable matching circuit or the attenuation of the variable attenuator. The control circuit includes a non-volatile memory and controls the impedance of the variable termination circuit in accordance with data stored in the memory.

Abstract: A directional coupler includes a conductor serving as a primary line disposed in a multilayer body and conductors serving as a plurality of secondary lines that are disposed in the multilayer body and each of which is capable of being electromagnetically coupled to the conductor serving as the primary line. A facing area where the conductor serving as the secondary line and the conductor serving as the secondary line face each other is smaller than a facing area where the conductor serving as the secondary line and the conductor serving as the primary line face each other. A distance between the conductor serving as the secondary line and the conductor serving as the secondary line is longer than a distance between the conductor serving as the secondary line and the conductor serving as the primary line.

Abstract: A directional coupler (2) includes a main line (11), a sub-line (12), a variable terminator (13), and a variable filter circuit (15). The variable terminator (13) is a variable impedance circuit that terminates one end portion of the sub-line (12). The variable filter circuit (15) is connected to the other end portion of the sub-line (12). The variable filter circuit (15) may include a filter, a bypass path, and a switch which is connected to at least one of the filter and the bypass path.

Abstract: A directional coupler includes a main line, sub-lines, and a switch. The sub-lines are located at positions that enable the sub-lines to be electromagnetically coupled to the main line. The switch is coupled between an end portion sand an end portion of the sub-line. The switch is configured to switch connection of the end portion and the end portion between a shorted state and an open state.

Abstract: A directional coupler includes a main line, a first sub-line to be electromagnetically coupled to the main line, a second sub-line to be electromagnetically coupled to the main line, and a coupling terminal configured to output a detection signal corresponding to a radio frequency signal that is transmitted through the main line, the first sub-line and the second sub-line are different in length from each other, and connection between the first sub-line and the coupling terminal and connection between the second sub-line and the coupling terminal are switched.

Abstract: A directional coupler includes a main line through which a signal is transmitted, first and second sub-lines that are selectively coupled to the main line, and a common output port that outputs a detection signal generated by the signal transmitted through the main line, wherein a first degree of coupling between the main line and the first sub-line is different than a second degree of coupling between the main line and the second sub-line.

Abstract: A dielectric having a first main surface and a second main surface facing each other, a main line provided on a side of the first main surface in contact with the dielectric, and a sub line provided on the side of the first main surface in contact with the dielectric are included, the dielectric has a first portion in contact with the main line and a second portion in contact with the sub line, and when the first main surface is viewed in a plan view, between the first portion and the second portion, a third portion having a relative dielectric constant changing along a direction intersecting with the main line and the sub line is located.

Abstract: A directional coupler includes a main line, a first sub-line to be electromagnetically coupled to the main line, a second sub-line to be electromagnetically coupled to the main line, and a coupling terminal configured to output a detection signal corresponding to a radio frequency signal that is transmitted through the main line, the first sub-line and the second sub-line are different in length from each other, and connection between the first sub-line and the coupling terminal and connection between the second sub-line and the coupling terminal are switched.

Abstract: A filter module includes a first ground terminal, a second ground terminal, a low pass filter, and a second inductor. The low pass filter includes a first inductor provided in an input/output path of signal, a first capacitor provided in a first path connecting a first node and the first ground terminal, and a second capacitor provided in a second path connecting a second node and the second ground terminal. The second inductor is connected in series to the second capacitor in a path connecting the second capacitor and the second ground terminal. The first path and the second path are not connected to each other by any path except the one between the first node and the second node.

Abstract: A directional coupler includes a main line, a secondary line, and a variable terminator. The variable terminator includes a variable inductor. The variable inductor includes a plurality of inductors coupled in series with each other between an end portion of the secondary line and the ground and switches configured to bypass at least one inductor of the plurality of inductors.

Abstract: A directional coupler includes a multilayer body, a conductor (31), and a conductor (32). The conductor (31) is a conductor that is arranged in an insulating layer (21) of the multilayer body and that extends in a certain shape. The conductor (32) is arranged on a side of an insulating layer (22) of the multilayer body opposite the insulating layer (21). The conductor (32) runs parallel to the conductor (31) and is electromagnetically coupled to the conductor (31). The conductor (32) has a winding shape with one or more rounds, and has a conductor portion (321) and a conductor portion (325) that are arranged adjacent to each other with a spacing in a direction orthogonal to a running parallel direction. In plan view of the multilayer body, the conductor (31) is arranged between the conductor portion (321) and the conductor portion (325).

Abstract: A directional coupler includes a main line, a sub-line electromagnetically coupled with the main line, a coupled output terminal, plural filters, filter switching circuits, and plural filter protecting switches. Each of the filter switching circuits is able to connect a corresponding one of the plural filters to one end of the sub-line and to the coupled output terminal. Each of the filter protecting switches is directly connected to a corresponding end of a corresponding one of the plural filters and is able to switch between a connection state and a disconnection state. The connection state is a state in which the corresponding end of the corresponding one of the plural filters is connected to a reference potential. The disconnection state is a state in which the corresponding end of the corresponding one of the plural filters is disconnected from the reference potential.

Abstract: A directional coupler includes a main line, a sub-line, a coupling terminal, a terminal circuit, a first switching circuit, and a second switching circuit. The first switching circuit and the second switching circuit respectively connects the first end and the second end of the sub-line alternately to the coupling terminal and to the terminal circuit. The first switching circuit connects the first end to the coupling terminal at a time that differs from a time at which the first switching circuit disconnects the first end from the terminal circuit. The first switching circuit disconnects the first end from the coupling terminal at a time that differs from a time at which the first switching circuit connects the first end to the terminal circuit.

Abstract: A directional coupler includes a main line for transmitting a high frequency signal, a sub line electromagnetically coupled to the main line, a termination circuit for terminating one end portion of the sub line, and a variable filter that has an input terminal and an output terminal and the input terminal is connected to another end portion of the sub line. The variable filter is a filter unit circuit having one frequency band as a pass band or a stop band, and in the filter unit circuit, a variable passive element for shifting a frequency in the pass band or the stop band is disposed.

Abstract: A bidirectional coupler includes the following elements. A main line and a sub-line are electromagnetically coupled. First and second resistors are each grounded at one end. First and second switches connect the sub-line to the first and second resistors or a third port. A third resistor is disposed between one end of the sub-line and the first switch or between the other end of the sub-line and the second switch. When detecting an input signal, the first switch electrically connects one end of the sub-line to the other end of the first resistor and the second switch electrically connects the other end of the sub-line to the third port. When detecting a reflected signal, the first switch electrically connects one end of the sub-line to the third port and the second switch electrically connects the other end of the sub-line to the other end of the second resistor.

Abstract: A directional coupler includes a main line and a sub-line electromagnetically coupled to each other, a variable termination circuit that is connected to one end of the sub-line and that has a variable impedance, a variable matching circuit that is connected to the other end of the sub-line and that has a variable impedance or a variable attenuator that has a variable attenuation, and a control circuit that controls the impedance of the variable termination circuit and that controls the impedance of the variable matching circuit or the attenuation of the variable attenuator. The control circuit includes a non-volatile memory and controls the impedance of the variable termination circuit in accordance with data stored in the memory.

Abstract: Bidirectional detection is performed with a suppressed increase in return loss at an output terminal. A bidirectional coupler includes a detection port, a main line connected to a first port and a second port, a sub-line, a termination circuit, a switch circuit that switches each of one end and another end of the sub-line to the termination circuit or the detection port, and a matching network disposed between the switch circuit and the detection port and including at least one of a first variable capacitor, a first variable inductor, or a first variable resistor. In a first mode for detecting a first signal, the switch circuit connects the one end of the sub-line to the detection port, and connects the other end of the sub-line to the termination circuit.

Abstract: A directional coupler includes a main line through which a signal is transmitted, first and second sub-lines that are selectively coupled to the main line, and a common output port that outputs a detection signal generated by the signal transmitted through the main line, wherein a first degree of coupling between the main line and the first sub-line is different than a second degree of coupling between the main line and the second sub-line.