Abstract: An electronic component includes a single-layer glass plate, an outer-surface conductor that is disposed above an outer surface of the single-layer glass plate and that is at least a part of an electrical element, and a terminal electrode that is a terminal of the electrical element. The terminal electrode is disposed above the outer surface of the single-layer glass plate and being electrically connected to the outer-surface conductor.

Abstract: An electronic component includes a single-layer glass plate, an outer-surface conductor that is disposed above an outer surface of the single-layer glass plate and that is at least a part of an electrical element, and a terminal electrode that is a terminal of the electrical element. The terminal electrode is disposed above the outer surface of the single-layer glass plate and being electrically connected to the outer-surface conductor.

Abstract: A filter includes a series-arm resonator located on a path that connects an input/output terminal (11m) with an input/output terminal (11n), and a first parallel-arm resonant circuit connected between a node, which is located on the path, and ground. The first parallel-arm resonant circuit includes a parallel-arm resonator, and a pair of a capacitor and a switch connected in parallel with each other and in series with the parallel-arm resonator between the parallel-arm resonator and ground. An interconnect line (a1) is connected to the input/output terminal (11m), and an interconnect line (a2) is connected to the input/output terminal. The parallel-arm resonator and the switch are connected by an interconnect line (a3). The interconnect line (a3) has a characteristic impedance lower than a characteristic impedance of the interconnect line (a1) or a characteristic impedance of the interconnect line (a2).

Abstract: A tunable filter includes a series-arm resonant circuit, and a parallel-arm resonant circuit. The series-arm resonant circuit includes a group of acoustic wave resonant circuits that have different resonant frequencies, a variable capacitor, and switching circuits. The parallel-arm resonant circuit includes another group of acoustic wave resonant circuits that have different resonant frequencies, a variable capacitor, and switching circuits. For example, the difference in pass-band frequency caused by the difference in resonant frequency between the acoustic wave resonant circuit in the group and the acoustic wave resonant circuit in the other group is greater than the maximum difference in pass-band frequency resulting from the variable range of capacitance of the variable capacitor.

Abstract: A radio frequency filter circuit (22A) includes a series-arm resonator (22s), a parallel-arm resonator (22p1), a parallel-arm resonator (22p2) that is connected between a node x1 and a ground terminal, a switch (22SW) that is arranged between the node x1 and the ground terminal and switches between electrical connection and electrical non-connection of a path connecting the node x1, the parallel-arm resonator (22p2), and the ground terminal. The parallel-arm resonator (22p1) and a series circuit in which the parallel-arm resonator (22p2) and the switch (22SW) are connected in series are connected in parallel between the node x1 and the ground terminal. A resonant frequency (frp) of the parallel-arm resonator (22p1) is lower than a resonant frequency (frs) of the series-arm resonator (22s). A resonant frequency (frp2) of the parallel-arm resonator (22p2) is higher than the resonant frequency (frp) of the parallel-arm resonator (22p1).

Abstract: A filter includes a series-arm resonator located on a path that connects an input/output terminal (11m) with an input/output terminal (11n), and a first parallel-arm resonant circuit connected between a node, which is located on the path, and ground. The first parallel-arm resonant circuit includes a parallel-arm resonator, and a pair of a capacitor and a switch connected in parallel with each other and in series with the parallel-arm resonator between the parallel-arm resonator and ground. An interconnect line (a1) is connected to the input/output terminal (11m), and an interconnect line (a2) is connected to the input/output terminal. The parallel-arm resonator and the switch are connected by an interconnect line (a3). The interconnect line (a3) has a characteristic impedance lower than a characteristic impedance of the interconnect line (a1) or a characteristic impedance of the interconnect line (a2).

Abstract: A radio frequency filter circuit (22A) includes a series-arm resonator (22s), a parallel-arm resonator (22p1), a parallel-arm resonator (22p2) that is connected between a node x1 and a ground terminal, a switch (22SW) that is arranged between the node x1 and the ground terminal and switches between electrical connection and electrical non-connection of a path connecting the node x1, the parallel-arm resonator (22p2), and the ground terminal. The parallel-arm resonator (22p1) and a series circuit in which the parallel-arm resonator (22p2) and the switch (22SW) are connected in series are connected in parallel between the node x1 and the ground terminal. A resonant frequency (frp) of the parallel-arm resonator (22p1) is lower than a resonant frequency (frs) of the series-arm resonator (22s). A resonant frequency (frp2) of the parallel-arm resonator (22p2) is higher than the resonant frequency (frp) of the parallel-arm resonator (22p1).

Abstract: A front-end circuit includes an antenna terminal, front-end terminals (Pfe1, Pfe2), a circulator, and frequency-variable filters. The circulator sends transmission signals of communication bands of a frequency division duplex system and a time division duplex system from the front-end terminal (Pfe1) to the antenna terminal. The circulator sends a reception signal from the antenna terminal to the front-end terminal (Pfe2). The frequency-variable filter is connected between the front-end terminal (Pfe1) and the circulator, passes transmission signals of the frequency division duplex system and the time division duplex system, and attenuates signals other than the above transmission signals. The frequency-variable filter is connected between the circulator and the front-end terminal (Pfe2), passes a reception signal of the frequency division duplex system, and attenuates signals other than the above 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 tunable filter includes a series-arm resonant circuit, and a parallel-arm resonant circuit. The series-arm resonant circuit includes a group of acoustic wave resonant circuits that have different resonant frequencies, a variable capacitor, and switching circuits. The parallel-arm resonant circuit includes another group of acoustic wave resonant circuits that have different resonant frequencies, a variable capacitor, and switching circuits. For example, the difference in pass-band frequency caused by the difference in resonant frequency between the acoustic wave resonant circuit in the group and the acoustic wave resonant circuit in the other group is greater than the maximum difference in pass-band frequency resulting from the variable range of capacitance of the variable capacitor.

Abstract: An irreversible circuit element includes first and second high pass isolators each including first and second center electrodes intersecting with and being insulated from each other on a ferrite to which a direct-current magnetic field is applied with a permanent magnet. One end of the first center electrode is an output port and the other end thereof is an input port, and one end of the second center electrode is another output port and the other end thereof is a ground port. A pass frequency band of the first isolator is higher than a pass frequency band of the second isolator. Respective output portions of the first and second isolators are electrically connected and defined as one output terminal, and a low pass filter LPF is inserted between the output terminal and the output port of the second isolator.

Abstract: The present disclosure provides a high-frequency circuit including a matching circuit capable of adjusting the input/output impedance of a high-frequency device to an optimal value, even if the high-frequency device includes a circuit element whose input/output impedance varies upon the variation in the operating frequency, and provides a transmission and reception circuit including the high-frequency circuit. The high-frequency circuit includes a first high-frequency device, a second high-frequency device electrically connected to the first high-frequency device, and a matching circuit connected between the first high-frequency device 1 and the second high-frequency device. At least one of the first high-frequency device 1 and the second high-frequency device includes a variable device and has a changeable operating frequency.

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 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 an antenna terminal, front-end terminals (Pfe1, Pfe2), a circulator, and frequency-variable filters. The circulator sends transmission signals of communication bands of a frequency division duplex system and a time division duplex system from the front-end terminal (Pfe1) to the antenna terminal. The circulator sends a reception signal from the antenna terminal to the front-end terminal (Pfe2). The frequency-variable filter is connected between the front-end terminal (Pfe1) and the circulator, passes transmission signals of the frequency division duplex system and the time division duplex system, and attenuates signals other than the above transmission signals. The frequency-variable filter is connected between the circulator and the front-end terminal (Pfe2), passes a reception signal of the frequency division duplex system, and attenuates signals other than the above reception signal.

Abstract: A high frequency power amplifier includes a first high frequency amplifier, a final high frequency amplifier, and a tunable filter. The tunable filter is connected between the first high frequency amplifier and the final high frequency amplifier. The first high frequency amplifier and the final high frequency amplifier are each a multimode/multiband power amplifier. The tunable filter is regulated such that its pass band includes the frequency band of a transmission signal and its attenuation band includes the frequency band of a reception signal in a communication band used in transmission and reception. The pass band and the attenuation band are switched by the tunable filter in accordance with the communication band used in transmission and reception.

Abstract: An irreversible circuit element includes first and second high pass isolators each including first and second center electrodes intersecting with and being insulated from each other on a ferrite to which a direct-current magnetic field is applied with a permanent magnet. One end of the first center electrode is an output port and the other end thereof is an input port, and one end of the second center electrode is another output port and the other end thereof is a ground port. A pass frequency band of the first isolator is higher than a pass frequency band of the second isolator. Respective output portions of the first and second isolators are electrically connected and defined as one output terminal, and a low pass filter LPF is inserted between the output terminal and the output port of the second isolator.

Abstract: A non-reciprocal circuit element includes a ferrite, a first central electrode and a second central electrode that are arranged on the ferrite so as to cross each other in an insulated state, and a permanent magnet configured to apply 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 between the input port and the output port. A switching capacitance unit configured to switch a capacitance is connected in parallel with the resistance element between the input port and the output port.

Abstract: An irreversible circuit element includes first and second high pass isolators each including first and second center electrodes intersecting with and being insulated from each other on a ferrite to which a direct-current magnetic field is applied with a permanent magnet. One end of the first center electrode is an output port and the other end thereof is an input port, and one end of the second center electrode is another output port and the other end thereof is a ground port. A pass frequency band of the first isolator is higher than a pass frequency band of the second isolator. Respective output portions of the first and second isolators are electrically connected and defined as one output terminal, and a low pass filter LPF is inserted between the output terminal and the output port of the second isolator.

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.