Abstract: A PA module includes a previous stage amplification element to amplify a high-frequency signal, a posterior stage amplification element to amplify the high-frequency signal amplified by the previous stage amplification element, and a variable filter circuit arranged between the previous stage amplification element and the posterior stage amplification element and to vary a pass band and an attenuation band in accordance with a frequency band of the high-frequency signal, in which the variable filter circuit includes a filter portion and switches, the previous stage amplification element, the switches, and the posterior stage amplification element are arranged on a mounting surface of a substrate, the filter portion is stacked and arranged so as to overlap with at least one of the previous stage amplification element, the switches, and the posterior stage amplification element when the substrate is viewed in a plan view.

Abstract: A radio-frequency signal amplifier circuit that is used in a front-end circuit and that propagates a radio-frequency transmission signal and a radio-frequency reception signal is described. The amplifier circuit has an amplifier transistor, a bias circuit, a resistor, and an LC series resonance circuit. The LC series resonant circuit has one end that is connected to a node between the resistor and a signal input terminal, and has another end that is connected to a grounding terminal. A resonant frequency of the LC series resonance circuit is included in a difference frequency band between the frequencies of the transmission signal and the reception signal.

Abstract: A PA module (10A) includes a previous stage amplification element (12) to amplify a high-frequency signal, a posterior stage amplification element (13) to amplify the high-frequency signal amplified by the previous stage amplification element (12), and a variable filter circuit arranged between the previous stage amplification element (12) and the posterior stage amplification element (13) to vary a pass band and an attenuation band in accordance with a frequency band of the high-frequency signal, in which the variable filter circuit includes a filter portion (16) and switches (14 and 15) to vary the pass band and the attenuation band of the variable filter circuit, and the previous stage amplification element (12) and at least a part of the switches (14 and 15) are formed in one chip using a chip A, the posterior stage amplification element (13) are included in a second chip which is different from the chip A.

Abstract: A semiconductor substrate includes emitter electrodes for multiple high-frequency amplifying transistors. An insulating substrate includes multiple land electrodes, ground electrodes, and multiple inductor electrodes. The land electrodes are formed on the front surface or near the front surface of the insulating substrate, and are joined to the respective emitter electrodes. The ground electrodes are formed inside the insulating substrate. Each of the inductor electrodes couples a corresponding one of the land electrodes to any of the ground electrodes in such a manner that the lengths of the coupling to the ground electrodes are individually determined.

Abstract: A high-frequency amplifier module includes a semiconductor substrate and an insulating substrate. The semiconductor substrate includes multiple emitter electrodes, each of which is coupled to the emitter of a corresponding one of high-frequency amplifying transistors. The insulating substrate includes a common ground electrode, ground terminal electrodes, and thickness-direction coupling electrodes. The common ground electrode is formed on or near the front surface of the insulating substrate, and is joined to the emitter electrodes. The ground terminal electrodes are formed on the back surface of the insulating substrate. The thickness-direction coupling electrodes couple the common ground electrode to the ground terminal electrodes.

Abstract: A radio-frequency signal amplifier circuit that is used in a front-end circuit configured to propagate a radio-frequency transmission signal and a radio-frequency reception signal, includes an amplifier transistor configured to amplify the radio-frequency transmission signal, a bias circuit configured to supply a bias to a signal input terminal of the amplifier transistor, a resistor having one end connected to the bias circuit and the other end connected to the signal input terminal, and an LC series resonance circuit that has one end connected to a node n1 between the resistor and the signal input terminal and the other end connected to a grounding terminal. A resonant frequency fr of the LC series resonance circuit is included in a difference frequency band between the radio-frequency transmission signal and the radio-frequency reception signal.

Abstract: A radio frequency filter includes communication bandpass filters disposed corresponding respectively to a plurality of communication bands, a switch, and a matching circuit. The switch includes a common terminal and a plurality of optionally selectable terminals, the plurality of optionally selectable terminals being individually connected to the plurality of bandpass filters in a one-to-one relation. The matching circuit is connected to the common terminal and is a common matching circuit to the plurality of communication bandpass filters. The plurality of communication bandpass filters are set such that filter characteristics of a serial circuit in combination of one of the plurality of communication bandpass filters, the one being selected by the switch, and the common matching circuit are improved in comparison with filter characteristics of the selected communication bandpass filter with respect to the communication band corresponding to the selected communication bandpass filter.

Abstract: A front end circuit includes a circulator having a first port into which a transmission signal is input, a second port into/from which a transmission/reception signal is input/output, and a third port from which a reception signal is output. The impedance of the second port of the circulator is set to a value different from the impedance value of the first port and the third port. With his configuration, the narrowing of a frequency band and the increase in loss, which occur when an impedance matching circuit is additionally provided, are prevented.

Abstract: A PA module (10A) includes a previous stage amplification element (12) to amplify a high-frequency signal, a posterior stage amplification element (13) to amplify the high-frequency signal amplified by the previous stage amplification element (12), and a variable filter circuit arranged between the previous stage amplification element (12) and the posterior stage amplification element (13) to vary a pass band and an attenuation band in accordance with a frequency band of the high-frequency signal, in which the variable filter circuit includes a filter portion (16) and switches (14 and 15) to vary the pass band and the attenuation band of the variable filter circuit, and the previous stage amplification element (12) and at least a part of the switches (14 and 15) are formed in one chip using a chip A, the posterior stage amplification element (13) are included in a second chip which is different from the chip A.

Abstract: A PA module includes a previous stage amplification element to amplify a high-frequency signal, a posterior stage amplification element to amplify the high-frequency signal amplified by the previous stage amplification element, and a variable filter circuit arranged between the previous stage amplification element and the posterior stage amplification element and to vary a pass band and an attenuation band in accordance with a frequency band of the high-frequency signal, in which the variable filter circuit includes a filter portion and switches, the previous stage amplification element, the switches, and the posterior stage amplification element are arranged on a mounting surface of a substrate, the filter portion is stacked and arranged so as to overlap with at least one of the previous stage amplification element, the switches, and the posterior stage amplification element when the substrate is viewed in a plan view.

Abstract: A radio frequency front-end circuit includes an antenna, a circulator, a signal transmission circuit, and first and second variable matching circuits. The first variable matching circuit is connected between the antenna and the signal transmission circuit and variably performs matching of impedance between the antenna and the signal transmission circuit. The second variable matching circuit is connected between the circulator and the signal transmission circuit, variably performs matching of impedance between the signal transmission circuit and the circulator, and further performs, if there is impedance for which matching has not been achieved by the first variable matching circuit, matching of the impedance for which matching has not been achieved.

Abstract: A high-frequency module (1) includes a first substrate (101), a second substrate (102) that faces the first substrate (101), a support (103) that supports the first substrate (101) and the second substrate (102), and a plurality of high-frequency circuit components arranged in internal space formed by the first substrate (101), the second substrate (102), and the support and on both of facing principal faces of the first substrate (101) and the second substrate (102), and the plurality of high-frequency circuit components include a power amplifier element that constitutes a power amplifier circuit (16).

Abstract: A semiconductor substrate includes emitter electrodes for multiple high-frequency amplifying transistors. An insulating substrate includes multiple land electrodes, ground electrodes, and multiple inductor electrodes. The land electrodes are formed on the front surface or near the front surface of the insulating substrate, and are joined to the respective emitter electrodes. The ground electrodes are formed inside the insulating substrate. Each of the inductor electrodes couples a corresponding one of the land electrodes to any of the ground electrodes in such a manner that the lengths of the coupling to the ground electrodes are individually determined.

Abstract: A high-frequency amplifier module includes a semiconductor substrate and an insulating substrate. The semiconductor substrate includes multiple emitter electrodes, each of which is coupled to the emitter of a corresponding one of high-frequency amplifying transistors. The insulating substrate includes a common ground electrode, ground terminal electrodes, and thickness-direction coupling electrodes. The common ground electrode is formed on or near the front surface of the insulating substrate, and is joined to the emitter electrodes. The ground terminal electrodes are formed on the back surface of the insulating substrate. The thickness-direction coupling electrodes couple the common ground electrode to the ground terminal electrodes.

Abstract: An isolator includes a core isolator, a main substrate and a circuit-defining section. The main substrate includes a first wiring portion, a second wiring portion and a third wiring portion and has the core isolator and the circuit-defining section mounted thereon. An input port of the core isolator is connected to the first wiring portion. An output port of the core isolator is connected to the second wiring portion. A ground port of the core isolator is connected to the third wiring portion. In the circuit-defining section, a conductor pattern includes a capacitor that is connected in parallel with the core isolator via the first wiring portion and the second wiring portion, and an impedance element that is connected to at least either of the first wiring portion and the second wiring portion.

Abstract: A circulator includes: a ferrite plate; a permanent magnet that applies a direct current (DC) magnetic field to the ferrite plate; a first coil, a second coil, and a third coil arranged on the ferrite plate while being insulated from one another, the first coil, the second coil, and the third coil having coil axes intersecting one another; a first port that is electrically continuous with the first coil; a second port that is electrically continuous with the second coil; and a third port that is electrically continuous with the third coil. An inductance of the first coil or the second coil is different from an inductance of the third coil, and an impedance of the first port or the second port is not 50?.

Abstract: A radio frequency filter includes communication bandpass filters disposed corresponding respectively to a plurality of communication bands, a switch, and a matching circuit. The switch includes a common terminal and a plurality of optionally selectable terminals, the plurality of optionally selectable terminals being individually connected to the plurality of bandpass filters in a one-to-one relation. The matching circuit is connected to the common terminal and is a common matching circuit to the plurality of communication bandpass filters. The plurality of communication bandpass filters are set such that filter characteristics of a serial circuit in combination of one of the plurality of communication bandpass filters, the one being selected by the switch, and the common matching circuit are improved in comparison with filter characteristics of the selected communication bandpass filter with respect to the communication band corresponding to the selected communication bandpass filter.

Abstract: A high-frequency signal amplifier circuit is used in a front-end circuit configured to propagate a high-frequency transmission signal and a high-frequency reception signal, and includes an amplifier transistor configured to amplify the high-frequency transmission signal; a bias circuit configured to supply a bias to a signal input end of the amplifier transistor; and a ferrite bead, one end of which is connected to a bias output end of the bias circuit and the other end of which is connected to the signal input end of the amplifier transistor, having characteristics in which impedance in a difference frequency band between the high-frequency transmission signal and the high-frequency reception signal is higher than impedance in DC.

Abstract: A high-frequency signal amplifier circuit is used in a front-end circuit configured to propagate a high-frequency transmission signal and a high-frequency reception signal, and includes an amplifier transistor configured to amplify the high-frequency transmission signal; a bias circuit configured to supply a bias to a signal input end of the amplifier transistor; and a ferrite bead, one end of which is connected to a bias output end of the bias circuit and the other end of which is connected to the signal input end of the amplifier transistor, having characteristics in which impedance in a difference frequency band between the high-frequency transmission signal and the high-frequency reception signal is higher than impedance in DC.

Abstract: A non-reciprocal circuit element includes a ferrite, a first central electrode and a second central electrode arranged on the ferrite so as to cross each other in an insulated state, and a permanent magnet that applies a DC magnetic field to a portion where the first and second central electrodes cross each other. One end of the first central electrode defines an input port, and the other end thereof defines an output port. One end of the second central electrode defines the input port, and the other end thereof defines a ground port. A resistance element and a capacitance element, which are connected in parallel with each other, are connected in series with and between the input port and the output port. Input impedance is lowered by making inductance of the second central electrode relatively large.