Abstract: A radio frequency circuit includes an antenna connection terminal, an input terminal, an output terminal, a filter having a pass band including at least part of a transmission band of Band A for FDD, a filter having a pass band including at least part of a reception band of the Band A, and a switch that includes terminals. The antenna connection terminal is connected to the terminal. The filter is connected between the terminal and the input terminal. The filter is connected between the terminal and the output terminal. The switch is configured to switch between first connection, second connection, and third connection. In the first connection, the terminal is connected to the terminal and the terminal is not connected to the terminal. In the second connection, the terminal is connected to the terminal and the terminal is not connected to the terminal.

Abstract: A radio frequency front-end circuit includes a first filter that is a frequency variable filter connected to a first select terminal of a switching circuit, and a second filter connected to a second select terminal of the switching circuit. The switching circuit includes a first switch that switches over conduction and non-conduction between a common terminal and the second select terminal. The first filter includes a serial arm resonance circuit connected to the first select terminal, a parallel arm resonator, and a frequency varying circuit. The frequency varying circuit includes a capacitor and a third switch connected in parallel to each other, and is connected in series to the parallel arm resonator. The frequency varying circuit shifts a frequency of the first filter depending on conduction and non-conduction of the third switch.

Abstract: 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.

Abstract: A radio frequency front-end circuit includes a frequency variable filter connected to a select terminal of a switching circuit, and a filter connected to a select terminal of the switching circuit, the switching circuit including a switch that switches over conduction and non-conduction between a common terminal and the select terminal, the filter including a serial arm resonance circuit connected to the select terminal, a parallel arm resonator, and a frequency varying circuit that is a circuit including a capacitor and a switch connected in parallel to each other, and that is connected in series to the parallel arm resonator, wherein the frequency varying circuit shifts a frequency of the filter depending on conduction and non-conduction of the switch, and an on-resistance of the switch is smaller than an on-resistance of the switch.

Abstract: 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.

Abstract: A dielectric substrate is provided with first and second conductor openings communicating with each other via a first slit, and third and fourth conductor openings communicating with each other via a second slit, and the slits intersect each other. With this structure, two resonant modes including an even mode in which magnetic field vectors are directed from the first to third conductor openings and from the fourth to second conductor openings, and an odd mode in which magnetic field vectors are directed from the third to second conductor openings and from the first to fourth conductor openings, or two resonant modes including an X mode in which magnetic field vectors are directed from the first to second conductor openings, and a Y mode in which magnetic field vectors are directed from the third to fourth conductor openings are generated.

Abstract: A dielectric substrate is provided with first and second conductor openings communicating with each other via a first slit, and third and fourth conductor openings communicating with each other via a second slit, and the slits intersect each other. With this structure two resonant modes including an even mode in which magnetic field vectors are directed from the first to third conductor openings and from the fourth to second conductor openings, and an odd mode in which magnetic field vectors are directed from the third to second conductor openings and from the first to fourth conductor openings, or two resonant modes including an X mode in which magnetic field vectors are directed from the first to second conductor openings, and a Y mode in which magnetic field vectors are directed from the third to fourth conductor openings are generated.

Abstract: In a high-frequency transmission line that is used in a high-frequency band such as the microwave band or the millimeter wave band, at least one resistive film is disposed in a plane that is substantially perpendicular to an electric field of an operating transmission mode, and the resistive film attenuates, by dielectric loss, an unwanted mode having an electric field that is perpendicular to the electric field of the operating transmission mode.

Abstract: In a complex circuit board, the positional relationships between element portions, including an electrode pattern, a dielectric substrate and a magnetic substrate, can be adjusted as desired, and the complex circuit board can be miniaturized. The complex circuit board includes a dielectric substrate and a magnetic substrate, a space being provided between the magnetic substrate and the dielectric substrate, and an electrode pattern provided between the dielectric substrate and the magnetic substrate, a capacitance element portion of the electrode pattern being provided adjacent or in contact with or spaced a predetermined distance from the dielectric substrate, and the inductance element portion of the electrode pattern being provided adjacent or in contact with or spaced a predetermined distance from the magnetic substrate.

Abstract: In a complex circuit board, the positional relationships between element portions, including an electrode pattern, a dielectric substrate and a magnetic substrate, can be adjusted as desired, and the complex circuit board can be miniaturized. The complex circuit board includes a dielectric substrate and a magnetic substrate, a space being provided between the magnetic substrate and the dielectric substrate, and an electrode pattern provided between the dielectric substrate and the magnetic substrate, a capacitance element portion of the electrode pattern being provided adjacent or in contact with or spaced a predetermined distance from the dielectric substrate, and the inductance element portion of the electrode pattern being provided adjacent or in contact with or spaced a predetermined distance from the magnetic substrate.

Abstract: A dielectric transmission line attenuator or terminator, which is used with a dielectric transmission line provided with two conductive plates substantially parallel to each other and a dielectric strip held between the two conductive plates. A resistor film pattern is provided along a surface defined where upper and lower parts of the dielectric strip are divided, and substantially parallel to the two conductive plates. The resistor film pattern and the two conductive plates form a transmission line, and the dielectric transmission line and the transmission line are coupled.

Abstract: In a complex circuit board, the positional relationships between element portions, including an electrode pattern, a dielectric substrate and a magnetic substrate, can be adjusted as desired, and the complex circuit board can be miniaturized. The complex circuit board includes a dielectric substrate and a magnetic substrate, a space being provided between the magnetic substrate and the dielectric substrate, and an electrode pattern provided between the dielectric substrate and the magnetic substrate, a capacitance element portion of the electrode pattern being provided adjacent or in contact with or spaced a predetermined distance from the dielectric substrate, and the inductance element portion of the electrode pattern being provided adjacent or in contact with or spaced a predetermined distance from the magnetic substrate.

Abstract: In a high-frequency transmission line that is used in a high-frequency band such as the microwave band or the millimeter wave band, at least one resistive film is disposed in a plane that is substantially perpendicular to an electric field of an operating transmission mode, and the resistive film attenuates, by dielectric loss, an unwanted mode having an electric field that is perpendicular to the electric field of the operating transmission mode.

Abstract: In a complex circuit board, the positional relationships between element portions, including an electrode pattern, a dielectric substrate and a magnetic substrate, can be adjusted as desired, and the complex circuit board can be miniaturized. The complex circuit board includes a dielectric substrate and a magnetic substrate, a space being provided between the magnetic substrate and the dielectric substrate, and an electrode pattern provided between the dielectric substrate and the magnetic substrate, a capacitance element portion of the electrode pattern being provided adjacent or in contact with or spaced a predetermined distance from the dielectric substrate, and the inductance element portion of the electrode pattern being provided adjacent or in contact with or spaced a predetermined distance from the magnetic substrate.

Abstract: A dielectric nonreciprocal circuit device, which has satisfactory nonreciprocal characteristics obtained by improving the structure of a part supporting magnetic members, is incorporated in a radio device. The dielectric nonreciprocal circuit device has an arrangement such that supporting members for supporting the magnetic members are not located where the magnetic members are abutted against dielectric strips or where the magnetic members are disposed in close proximity to the dielectric strips.

Abstract: In a complex circuit board, the positional relationships between element portions, including an electrode pattern, a dielectric substrate and a magnetic substrate, can be adjusted as desired, and the complex circuit board can be miniaturized. The complex circuit board includes a dielectric substrate and a magnetic substrate, a space being provided between the magnetic substrate and the dielectric substrate, and an electrode pattern provided between the dielectric substrate and the magnetic substrate, a capacitance element portion of the electrode pattern being provided adjacent or in contact with or spaced a predetermined distance from the dielectric substrate, and the inductance element portion of the electrode pattern being provided adjacent or in contact with or spaced a predetermined distance from the magnetic substrate.

Abstract: A dielectric-waveguide attenuator, a dielectric-waveguide terminator, and a wireless apparatus incorporating the same in which the length of a dielectric waveguide is shortened in a direction in which an electromagnetic wave propagates to reduce the size of the overall module. The two parts of a split dielectric strip are placed between an upper conductive plate and a lower conductive plate to form the dielectric waveguide, and a substrate having at least two resistance-film patterns formed thereon is positioned between the two dielectric strips. With this arrangement, the resistance films both attenuate signals and also discontinuously change line impedance at a plurality of places and synthesize the electromagnetic waves reflected at the parts where the line impedance discontinuously changes so that the reflected waves cancel each other.