High-frequency circuit

Abstract

To provide a high-frequency circuit in which fluctuations in transmission characteristics due to load fluctuations are suppressed.SOLUTION: A high-frequency circuit 1 includes a power amplifier 11 to which a first signal is input, a power amplifier 12 to which a second signal of +90° relative to the first signal is input, a combining circuit that in-phase combines a third signal input from a fourth input terminal and a fourth signal input from a fifth input terminal, a phase shift circuit 21 connected to a third output terminal of the power amplifier 11, a phase shift circuit 22 connected to a fourth output terminal of the power amplifier 12 and in which the passing phase of a fundamental wave is -90° relative to the phase shift circuit 21, a harmonic phase shift circuit 31 connected to the third output terminal, and a harmonic phase shift circuit 32 connected to the fourth output terminal. The difference between a first reflection phase of the fundamental wave at the third output terminal and a second reflection phase of the fundamental wave at the fourth output terminal is 180°, and the difference between a third reflection phase of the harmonic at the third output terminal and a fourth reflection phase of the harmonic at the fourth output terminal is 180°.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a high-frequency circuit. [Background technology]

[0002] Patent Document 1 discloses a semiconductor device (high-frequency circuit) including a first amplifier and a second amplifier constituting a balanced amplifier, a first phase-shift circuit disposed in a first output path connecting the output end and output terminal of the first amplifier, a second phase-shift circuit disposed in a second output path connecting the output end and output terminal of the second amplifier, a resistor connected to the output end of the first phase-shift circuit and the output end of the second phase-shift circuit, a first inductor connected between the output end and output terminal of the first phase-shift circuit, and a second inductor connected between the output end and output terminal of the second phase-shift circuit. This is said to reduce power combining loss in a power combiner composed of the resistor, the first inductor, and the second inductor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-147352 Summary of the Invention [Problem to be solved by the invention]

[0004] With the demand for higher output power in mobile phones, there is a demand for high-frequency circuits that suppress fluctuations in transmission characteristics due to load fluctuations.

[0005] The present invention has been made to solve the above-mentioned problems, and has an object to provide a high-frequency circuit in which fluctuations in transmission characteristics due to load fluctuations are suppressed. [Means for solving the problem]

[0006] In order to achieve the above object, a high-frequency circuit according to one aspect of the present invention includes a duplexer having a first antenna terminal, a first input terminal, a first output terminal, and a second output terminal, and configured to demultiplex a fundamental wave signal of a first transmission band input to the first input terminal, output a first demultiplexed signal from the first output terminal, and output a second demultiplexed signal from the second output terminal, the second demultiplexed signal having a phase difference of +90° relative to the first demultiplexed signal; a first power amplifier having a second input terminal and a third output terminal, the second input terminal being connected to the first output terminal; a second power amplifier having a third input terminal and a fourth output terminal, the third input terminal being connected to the second output terminal; a combining circuit having a fourth input terminal, a fifth input terminal and a fifth output terminal, the combining circuit configured to in-phase combine the third demultiplexed signal input from the fourth input terminal and the fourth demultiplexed signal input from the fifth input terminal and output from the fifth output terminal an output signal generated by combining the third demultiplexed signal input from the fourth input terminal and the fourth demultiplexed signal input from the fifth input terminal; a first phase shift circuit connected between the third output terminal and the fourth input terminal; a second phase shift circuit connected between the fourth output terminal and the fifth input terminal; a first harmonic phase shift circuit connected between the fourth output port and the fifth input port, and / or a second harmonic phase shift circuit connected between the fourth output port and the fifth input port, and a first filter connected between the fifth output port and the first antenna terminal and having a pass band including the transmission band, wherein the first phase shift circuit and the second phase shift circuit are configured so that the passing phase of the fundamental wave of the transmission band of the second phase shift circuit in the direction from the fourth output port to the fifth input port is −90° relative to the passing phase of the fundamental wave of the first phase shift circuit in the direction from the third output port to the fourth input port; The first phase shift circuit, the second phase shift circuit, the first harmonic phase shift circuit and the second harmonic phase shift circuit are configured so that the difference between the first reflection phase of the fundamental wave when viewed from the third output terminal to the fifth output terminal and the second reflection phase of the fundamental wave when viewed from the fourth output terminal to the fifth output terminal is 180°, and so that the difference between the third reflection phase of at least one of the harmonics in the transmission band when viewed from the third output terminal to the fifth output terminal and the fourth reflection phase of the at least one of the harmonics when viewed from the fourth output terminal to the fifth output terminal is 180°.

[0007] Also, a high-frequency circuit according to one aspect of the present invention includes a first antenna terminal, a first input terminal, a first output terminal, and a second output terminal, and is configured to branch a fundamental wave signal of a first transmission band input to the first input terminal, output a first branched signal from the first output terminal, and output a second branched signal from the second output terminal, the second branched signal having a phase of +90° relative to the first branched signal; a first power amplifier having the second input terminal and a third output terminal, the second input terminal being connected to the first output terminal; a second power amplifier having a third input terminal connected to the second output terminal; a combining circuit having a fourth input terminal, a fifth input terminal, and a fifth output terminal, configured to output from the fifth output terminal an output signal generated by combining in anti-phase the third demultiplexed signal input from the fourth input terminal and the fourth demultiplexed signal input from the fifth input terminal; a first phase shift circuit connected between the third output terminal and the fourth input terminal; a second phase shift circuit connected between the fourth output terminal and the fifth input terminal; a second harmonic phase shift circuit and / or a second harmonic phase shift circuit connected between the fourth output terminal and the fifth input terminal, and a first transmission filter connected between the fifth output terminal and the first antenna terminal and having a pass band including the transmission band, wherein the first phase shift circuit and the second phase shift circuit are configured so that the passing phase of the fundamental wave of the transmission band of the second phase shift circuit in the direction from the fourth output terminal to the fifth input terminal is −90° relative to the passing phase of the fundamental wave of the first phase shift circuit in the direction from the third output terminal to the fourth input terminal, The phase shift circuit, the second phase shift circuit, the first harmonic phase shift circuit and the second harmonic phase shift circuit are configured so that the difference between the first reflection phase of the fundamental wave when viewed from the third output terminal to the fifth output terminal and the second reflection phase of the fundamental wave when viewed from the fourth output terminal to the fifth output terminal is 180°, and so that the difference between the third reflection phase of at least one of the harmonics in the transmission band when viewed from the third output terminal to the fifth output terminal and the fourth reflection phase of the at least one of the harmonics when viewed from the fourth output terminal to the fifth output terminal is 180°. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a high-frequency circuit in which fluctuations in transmission characteristics due to load fluctuations are suppressed. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a circuit configuration diagram of an amplifier circuit, a high-frequency circuit, and a communication device according to an embodiment; [Figure 2A] 1 is a circuit state diagram of a high-frequency circuit according to an embodiment in a band A transmission mode. [Figure 2B] 1 is a circuit state diagram of a high-frequency circuit according to an embodiment in a band B transmission mode. [Figure 3A] FIG. 2 is a diagram illustrating a fundamental impedance of a power amplifier according to an embodiment. [Figure 3B] FIG. 2 is a diagram illustrating second harmonic impedance of a power amplifier according to an embodiment. [Figure 4A] 4 is a graph showing the gain, EVM, and ACLR of the amplifier circuit according to the embodiment. [Figure 4B] 4 is a graph showing the output characteristics of second harmonics of the amplifier circuit according to the embodiment. [Figure 5A] FIG. 10 is a circuit configuration diagram of a first phase shift circuit according to a first modified example of the embodiment. [Figure 5B] FIG. 10 is a circuit configuration diagram of a second phase shift circuit according to a first modified example of the embodiment. [Figure 5C] FIG. 10 is a circuit configuration diagram of a first harmonic phase shift circuit according to a first modified example of the embodiment. [Figure 5D] FIG. 10 is a circuit configuration diagram of a second harmonic phase shift circuit according to a first modified example of the embodiment. [Figure 6] FIG. 10 is a circuit configuration diagram of an amplifier circuit according to a second modification of the embodiment. [Figure 7A] FIG. 10 is a diagram illustrating a fundamental wave impedance of a power amplifier according to a second modification of the embodiment. [Figure 7B] FIG. 10 is a diagram illustrating a third harmonic impedance of a power amplifier according to a second modification of the embodiment. [Figure 8] 10 is a graph showing the output characteristics of a third harmonic of an amplifier circuit according to a second modification of the embodiment. [Figure 9] FIG. 10 is a circuit configuration diagram of an amplifier circuit and a high-frequency circuit according to a third modification of the embodiment. [Figure 10] FIG. 10 is a circuit configuration diagram of an amplifier circuit, a high-frequency circuit, and a communication device according to a fourth modified example of the embodiment. [Figure 11] FIG. 1 is a plan view of an amplifier circuit according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, arrangements and connection forms of the components shown in the following embodiments are merely examples and are not intended to limit the present invention.

[0011] It should be noted that the drawings are schematic diagrams in which emphasis, omission, or adjustment of proportions has been appropriately made to illustrate the present invention, and are not necessarily strictly illustrated, and may differ from the actual shapes, positional relationships, and proportions. In the drawings, the same reference numerals are used to denote substantially the same components, and redundant explanations may be omitted or simplified.

[0012] In the following figures, the x-axis and y-axis are axes that are perpendicular to each other on a plane parallel to the main surface of the mounting board. Specifically, if the mounting board has a rectangular shape in a plan view, the x-axis is parallel to a first side of the mounting board, and the y-axis is parallel to a second side that is perpendicular to the first side of the mounting board. The z-axis is an axis perpendicular to the main surface of the mounting board, with its positive direction indicating the upward direction and its negative direction indicating the downward direction.

[0013] In the component placement of the present disclosure, "a component is placed on a substrate" includes a component being placed on the main surface of the substrate and a component being placed within the substrate. "A component is placed on the main surface of the substrate" includes a component being placed in contact with the main surface of the substrate, as well as a component being placed above the main surface without contacting the main surface (for example, a component being stacked on another component placed in contact with the main surface). "A component is placed on the main surface of the substrate" may also include a component being placed in a recess formed in the main surface. "A component is placed within the substrate" includes a component being encapsulated within a module substrate, as well as a component being entirely placed between the two main surfaces of the substrate but partially not covered by the substrate, and a component being only partially placed within the substrate.

[0014] In the component layout of the present invention, "planar view of the main surface" means viewing an object by orthogonally projecting it onto the xy plane from the positive side of the z axis. "A overlaps with B in planar view" means that at least a portion of the area of ​​A orthogonally projected onto the xy plane overlaps with at least a portion of the area of ​​B orthogonally projected onto the xy plane. "A is located between B and C" means that at least one of multiple line segments connecting any point in B and any point in C passes through A.

[0015] Furthermore, in the present disclosure, terms indicating the relationship between elements, such as parallel and perpendicular, terms indicating the shape of elements, such as rectangular, and numerical ranges do not only represent the strict meaning, but also include a substantially equivalent range, for example, a difference of a few percent.

[0016] In the circuit configuration of the present disclosure, "connected" includes not only direct connection by connection terminals and / or wiring conductors, but also electrical connection via other circuit elements. "Connected between A and B" means connected to both A and B between A and B.

[0017] In addition, in this disclosure, a "path" means a transmission line composed of a wiring through which a high-frequency signal propagates, an electrode directly connected to the wiring, and a terminal directly connected to the wiring or the electrode.

[0018] In addition, in this disclosure, "component A is arranged in series with path B" means that both the signal input terminal and the signal output terminal of component A are connected to the wiring, electrode, or terminal that constitutes path B.

[0019] In the present invention, the terms "terminal," "input end," and "output end" refer to the points at which conductors within elements terminate. However, if the impedance of the conductor between elements is sufficiently low, a terminal is interpreted as any point on the conductor between elements or the entire conductor, not just a single point.

[0020] Furthermore, terms indicating the relationship between elements, such as "parallel" and "perpendicular," terms indicating the shape of elements, such as "rectangle," and numerical ranges do not only represent the strict meaning, but also include a substantially equivalent range, for example, an error of a few percent.

[0021] The "passband of a filter" is defined as the portion of the frequency spectrum transmitted by the filter over which the output power is not attenuated by more than 3 dB below the maximum output power. The upper and lower ends of a bandpass filter's passband are therefore identified as the higher and lower frequencies of the two points where the output power is attenuated by 3 dB below the maximum output power.

[0022] A "transmission band" refers to a frequency band used for transmission in a communication device. A "reception band" refers to a frequency band used for reception in a communication device. For example, in frequency division duplex (FDD), different frequency bands are used as the transmission band and the reception band, while in time division duplex (TDD), the same frequency band is used as the transmission band and the reception band. In particular, in FDD, when a communication device is implemented in a user equipment (UE) of a cellular network, the uplink operation band is used as the transmission band, and the downlink operation band is used as the reception band. Conversely, when a communication device is implemented as a base station (BS) of a cellular network, the downlink band is used as the transmission band, and the uplink band is used as the reception band.

[0023] The "pass phase" of a high-frequency signal between two terminals can be obtained by applying a measurement RF probe to the two terminals and measuring the pass characteristic (S21) with a network analyzer. The "reflection phase" of a high-frequency signal at one terminal can be obtained by applying a measurement RF probe to the one terminal and measuring the pass characteristic (S11) with a network analyzer.

[0024] (Embodiment) [1 Circuit configuration of amplifier circuits, high frequency circuits and communication devices] The circuit configurations of an amplifier circuit 10, a high-frequency circuit 1, and a communication device 4 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a circuit configuration diagram of an amplifier circuit 10, a high-frequency circuit 1, and a communication device 4 according to this embodiment.

[0025] [1.1 Circuit configuration of communication device 4] First, a description will be given of the circuit configuration of the communication device 4. As shown in Fig. 1, the communication device 4 according to this embodiment includes a high-frequency circuit 1, an antenna 2, and an RF signal processing circuit (RFIC: Radio Frequency Integrated Circuit) 3.

[0026] The high-frequency circuit 1 transmits high-frequency signals between the antenna 2 and the RFIC 3. The detailed circuit configuration of the high-frequency circuit 1 will be described later.

[0027] The antenna 2 is connected to the antenna connection terminal 100 (first antenna terminal) of the high-frequency circuit 1, and transmits the high-frequency signal output from the high-frequency circuit 1. The antenna 2 may also receive a high-frequency signal from an external source and output it to the high-frequency circuit 1.

[0028] The RFIC 3 is an example of a signal processing circuit that processes radio frequency signals. Specifically, the RFIC 3 performs signal processing such as up-conversion on a transmission signal input from a baseband signal processing circuit (BBIC, not shown), and outputs the transmission signal generated by the signal processing to the transmission path of the radio frequency circuit 1. The RFIC 3 also performs signal processing such as down-conversion on a reception signal input via the reception path of the radio frequency circuit 1, and outputs the reception signal generated by the signal processing to the BBIC. The RFIC 3 also has a control unit that controls the radio frequency circuit 1. Note that part or all of the functions of the RFIC 3 as a control unit may be implemented outside the RFIC 3, for example, in the BBIC or the radio frequency circuit 1.

[0029] The RFIC 3 also functions as a control unit that controls the power supply voltage Vcc and bias current supplied to each amplifier in the amplifier circuit 10. Specifically, the RFIC 3 outputs control signals to a power supply circuit (not shown) and a bias circuit (not shown). The power supply circuit and bias circuit may be disposed in the high-frequency circuit 1 or the amplifier circuit 10. Each amplifier in the amplifier circuit 10 is supplied with the power supply voltage Vcc controlled by the control signal from the power supply circuit, and with the bias current controlled by the control signal from the bias circuit.

[0030] The RFIC 3 also functions as a control unit that controls the connection of the switch circuits 41 and 42 included in the high frequency circuit 1 based on the frequency band to be used, etc.

[0031] In the communication device 4 according to this embodiment, the antenna 2 is not an essential component.

[0032] [1.2 Circuit configuration of high frequency circuit 1] Next, we will explain the circuit configuration of the high-frequency circuit 1. As shown in Fig. 1, the high-frequency circuit 1 includes an amplifier circuit 10, filters 61 and 62, a switch circuit 42, inductors 54 to 59, and an antenna connection terminal 100.

[0033] The amplifier circuit 10 is a circuit that amplifies the transmission signals of band A and band B input from the radio frequency input terminal 110. Note that the radio frequency circuit 1 may include, instead of the amplifier circuit 10, a first amplifier circuit that amplifies the transmission signal of band A and a second amplifier circuit that amplifies the transmission signal of band B.

[0034] In the present embodiment, each of band A and band B refers to a frequency band defined in advance by a standardization organization (e.g., 3GPP (registered trademark) (3rd Generation Partnership Project), IEEE (Institute of Electrical and Electronics Engineers), etc.) for a communication system constructed using radio access technology (RAT). In the present embodiment, the communication system may be, for example, a 4G (4th Generation)-LTE (Long Term Evolution) system, a 5G (5th Generation)-NR (New Radio) system, a WLAN (Wireless Local Area Network) system, etc., but is not limited to these.

[0035] The filter 61 is an example of a first filter, is connected between the switch circuit 41 and the antenna connection terminal 100, and has a pass band that includes the transmission band of band A (first band). Specifically, one end of the filter 61 is connected to the terminal 41a of the switch circuit 41, and the other end of the filter 61 is connected to the antenna connection terminal 100 via the inductors 54 and 58 and the switch circuit 42.

[0036] The filter 62 is an example of a second filter, is connected between the switch circuit 41 and the antenna connection terminal 100, and has a pass band that includes the transmission band of band B (second band). Specifically, one end of the filter 62 is connected to the terminal 41b of the switch circuit 41, and the other end of the filter 62 is connected to the antenna connection terminal 100 via the inductors 56 and 58 and the switch circuit 42.

[0037] Switch circuit 42 is an example of an antenna switch and has terminals 42a, 42b, and 42c, with terminal 42a connected to antenna connection terminal 100 via inductor 58, terminal 42b connected to filter 61 via inductor 54, and terminal 42c connected to filter 62 via inductor 56. With the above configuration, switch circuit 42 switches between connection and disconnection between antenna connection terminal 100 and filter 61, and also switches between connection and disconnection between antenna connection terminal 100 and filter 62.

[0038] Inductor 54 is arranged in series in a path connecting terminal 42b of switch circuit 42 and filter 61. Inductor 55 is connected between this path and ground. Inductors 54 and 55 match the impedance between switch circuit 42 and filter 61. Inductor 56 is arranged in series in a path connecting terminal 42c of switch circuit 42 and filter 62. Inductor 57 is connected between this path and ground. Inductors 56 and 57 match the impedance between switch circuit 42 and filter 62. Inductor 58 is arranged in series in a path connecting terminal 42a of switch circuit 42 and antenna connection terminal 100. Inductor 59 is connected between this path and ground. Inductors 58 and 59 match the impedance between switch circuit 42 and antenna 2. Note that at least one of inductors 54 to 59 may be omitted.

[0039] According to the above circuit configuration, the high frequency circuit 1 is capable of transmitting high frequency signals of band A and band B.

[0040] The high-frequency circuit 1 according to the present invention may include at least the amplifier circuit 10 and the filter 61 from the circuit configuration shown in FIG.

[0041] [1.3 Circuit configuration of amplifier circuit 10] Next, the circuit configuration of the amplifier circuit 10 will be described in detail.

[0042] As shown in FIG. 1, the amplifier circuit 10 includes power amplifiers 11 and 12, phase shift circuits 21 and 22, harmonic phase shift circuits 31 and 32, a switch circuit 41, a 90° hybrid 50, phase shift lines 51 and 52, a capacitor 53, and a high-frequency input terminal 110.

[0043] The radio frequency input terminal 110 is connected to the RFIC 3. Each of the radio frequency input terminal 110 and the antenna connection terminal 100 may be a metal conductor such as a metal electrode or a metal bump, or may be a point (node) on a metal wiring.

[0044] The 90° hybrid 50 is an example of a demultiplexer and has a first input terminal, a first output terminal, and a second output terminal, with the first input terminal connected to the radio frequency input terminal 110, the first output terminal connected to the second input terminal of the power amplifier 11, and the second output terminal connected to the third input terminal of the power amplifier 12. The 90° hybrid 50 is configured to demultiplex a fundamental signal of the transmission band of Band A or Band B input to the first input terminal, output a first demultiplexed signal RF1 from the first output terminal, and output a second demultiplexed signal RF2 whose phase is +90° relative to the first demultiplexed signal RF1 from the second output terminal.

[0045] Instead of the 90° hybrid 50, a phase shift circuit having another circuit configuration may be arranged.

[0046] Power amplifier 11 is an example of a first power amplifier and has a second input terminal and a third output terminal, with the second input terminal connected to the first output terminal of 90° hybrid 50. Power amplifier 12 is an example of a second power amplifier and has a third input terminal and a fourth output terminal, with the third input terminal connected to the second output terminal of 90° hybrid 50. Power amplifiers 11 and 12 are capable of amplifying the high-frequency signal of band A or band B output from 90° hybrid 50.

[0047] Each of the power amplifiers 11 and 12 has an amplifying transistor. The amplifying transistor is, for example, a bipolar transistor such as a heterojunction bipolar transistor (HBT) or a field-effect transistor such as a metal-oxide-semiconductor field-effect transistor (MOSFET). If the amplifying transistor is a bipolar transistor, the input terminals of the power amplifiers 11 and 12 are, for example, the base terminals of the bipolar transistors, and the output terminals of the power amplifiers 11 and 12 are, for example, the collector terminals of the bipolar transistors. If the amplifying transistors are field-effect transistors, the input terminals of the power amplifiers 11 and 12 are, for example, the gate terminals of the field-effect transistors, and the output terminals of the power amplifiers 11 and 12 are, for example, the drain terminals of the field-effect transistors.

[0048] The phase-shift circuit 21 is an example of a first phase-shift circuit and is connected between the third output terminal of the power amplifier 11 and the terminal 41c of the switch circuit 41. The phase-shift circuit 21 includes, for example, capacitors 211 and 212 and an inductor 213. The capacitor 211 is an example of a first capacitor and is connected between the third output terminal and the terminal 41c. The inductor 213 is an example of a first inductor and is connected between the path connecting the capacitor 211 and the terminal 41c and ground. The capacitor 212 is arranged in series in the path connecting the capacitor 211 and the terminal 41c. The phase-shift circuit 21 has a so-called high-pass filter configuration and shifts the passing phase of the fundamental waves of band A and band B by, for example, +45° (advancing them by 45°). Note that the capacitor 212 is a DC-blocking capacitor and does not contribute to phase shifting, and may not be included in the phase-shift circuit 21.

[0049] The phase-shift circuit 22 is an example of a second phase-shift circuit and is connected between the fourth output terminal of the power amplifier 12 and the terminal 41d of the switch circuit 41. The phase-shift circuit 22 is configured so that the phase of the fundamental waves of bands A and B passing through the phase-shift circuit 21 in the direction from the fourth output terminal to the terminal 41d is relatively −90° (delayed by 90°) relative to the phase of the fundamental waves of bands A and B passing through the phase-shift circuit 21 in the direction from the third output terminal to the terminal 41c. The phase-shift circuit 22 includes, for example, an inductor 221 and capacitors 222 and 223. The inductor 221 is an example of a second inductor and is connected between the fourth output terminal and the terminal 41d. The capacitor 223 is an example of a second capacitor and is connected between the path connecting the inductor 221 and the terminal 41d and ground. The capacitor 222 is arranged in series in the path connecting the inductor 221 and the terminal 41d. Phase shift circuit 22 has a so-called low-pass filter configuration, and sets the passing phase of the fundamental wave signals of bands A and B to, for example, −45° (delays by 45°). Note that capacitor 222 is a DC blocking capacitor and does not contribute to phase shifting, so it does not necessarily need to be included in phase shift circuit 22.

[0050] Harmonic phase shift circuit 31 is an example of a first harmonic phase shift circuit, and is connected between the third output port of power amplifier 11 and terminal 41c of switch circuit 41. Harmonic phase shift circuit 31 includes, for example, capacitor 311 (third capacitor) connected between ground and a path connecting the third output port and capacitor 211. Harmonic phase shift circuit 31 serves as a low-pass filter whose passband is the fundamental wave bands of band A and band B, and the passing phase of the fundamental wave is, for example, 0°.

[0051] Harmonic phase shift circuit 32 is an example of a second harmonic phase shift circuit, and is connected between the fourth output port of power amplifier 12 and terminal 41d of switch circuit 41. Harmonic phase shift circuit 32 includes, for example, inductor 321 and capacitor 322. Inductor 321 (third inductor) and capacitor 322 (fourth capacitor) are connected in series to form an LC circuit, and this LC circuit is connected between a path connecting the fourth output port and inductor 221 and ground. Harmonic phase shift circuit 32 serves as a notch filter whose passbands are the fundamental wave bands of band A and band B, and the passing phase of the fundamental wave is, for example, 0°.

[0052] Phase shift circuit 21 and harmonic phase shift circuit 31 are configured so that the phase of the second harmonics of band A and band B passing through the combined circuit of phase shift circuit 21 and harmonic phase shift circuit 31 is +45° (45° lead). Phase shift circuit 22 and harmonic phase shift circuit 32 are configured so that the phase of the second harmonics passing through the combined circuit of phase shift circuit 22 and harmonic phase shift circuit 32 is -45° (45° lag).

[0053] The switch circuit 41 is an example of a combining circuit and has terminals 41a (fifth output terminal), 41b (sixth output terminal), 41c (fourth input terminal), 41d (fifth input terminal), and 41e (monitor terminal). The switch circuit 41 switches between a connection between the terminal 41c and the terminal 41a and a connection between the terminal 41d and the terminal 41a, and a connection between the terminal 41c and the terminal 41b and a connection between the terminal 41d and the terminal 41b. The switch circuit 41 outputs from the terminal 41a an output signal generated by in-phase combining at the terminal 41a the third demultiplexed signal of Band A input from the terminal 41c and the fourth demultiplexed signal of Band A input from the terminal 41d. The switch circuit 41 also outputs from the terminal 41b an output signal generated by in-phase combining at the terminal 41b the third demultiplexed signal of Band B input from the terminal 41c and the fourth demultiplexed signal of Band B input from the terminal 41d. Terminal 41a is a signal combining point where the third demultiplexed signal of band A and the fourth demultiplexed signal of band A are combined in phase, and terminal 41b is a signal combining point where the third demultiplexed signal of band B and the fourth demultiplexed signal of band B are combined in phase.

[0054] Terminal 41e (monitor terminal) is a terminal for measuring the reflection phase when viewing switch circuit 41 from the collector terminal (third output terminal) of power amplifier 11 or the collector terminal (third output terminal) of power amplifier 12. Specifically, by connecting terminal 41e to terminal 41c while terminal 41c is disconnected from terminals 41a and 41b, the reflection phase of the fundamental wave and second harmonic of band A or band B can be measured at terminal 41e. The reflection phase measured by connecting terminal 41e to terminal 41c is equivalent to the reflection phase of the fundamental wave and second harmonic of band A or band B measured from the collector terminal of power amplifier 11. Furthermore, by connecting terminal 41e to terminal 41d while terminal 41d is disconnected from terminals 41a and 41b, the reflection phase of the fundamental wave and second harmonic of band A or band B can be measured at terminal 41e. The reflection phase measured by connecting terminal 41e and terminal 41d is equivalent to the reflection phase of the fundamental wave and second harmonic of band A or band B measured from the collector end of power amplifier 12.

[0055] Phase shift line 51 is connected in series between the third output terminal of power amplifier 11 and the power supply voltage (Vcc) terminal, and prevents the first high-frequency signal output from power amplifier 11 from leaking to the Vcc terminal. Phase shift line 52 is connected in series between the fourth output terminal of power amplifier 12 and the power supply voltage (Vcc) terminal, and prevents the second high-frequency signal output from power amplifier 12 from leaking to the Vcc terminal. Capacitor 53 is connected between the Vcc terminal and ground, and prevents leakage components of the first and second high-frequency signals from entering the Vcc terminal and also prevents the power supply voltage from dropping to ground.

[0056] In the amplifier circuit 10 having the above configuration, the phase-shift circuits 21 and 22 and the harmonic phase-shift circuits 31 and 32 are configured so that the difference between the first reflection phase of the fundamental wave in the transmission band of band A when viewing terminal 41a from the third output end and the second reflection phase of the fundamental wave in the transmission band of band A when viewing terminal 41a from the fourth output end is 180°, and so that the difference between the third reflection phase of the second harmonic in the transmission band of band A when viewing terminal 41a from the third output end and the fourth reflection phase of the second harmonic in the transmission band of band A when viewing terminal 41a from the fourth output end is 180°.

[0057] The first reflection phase of the fundamental wave of the transmission band of band A when viewed from terminal 41a to the third output terminal is defined as the amount of phase change of the fundamental wave of the reflected signal reflected by terminal 41a and returning to the third output terminal, relative to the phase of the fundamental wave of the transmission signal of the transmission band of band A output from the third output terminal, when terminal 41c is connected to terminal 41a and terminal 41a is disconnected from filter 61. Furthermore, the second reflection phase of the fundamental wave of the transmission band of band A when viewed from terminal 41a to the fourth output terminal is defined as the amount of phase change of the fundamental wave of the reflected signal reflected by terminal 41a and returning to the fourth output terminal, relative to the phase of the fundamental wave of the transmission signal of the transmission band of band A output from the fourth output terminal, when terminal 41d is connected to terminal 41a and terminal 41a is disconnected from filter 61. Furthermore, the third reflection phase of the second harmonic of the transmission band of Band A when viewed from the third output end to terminal 41a is defined as the amount of phase change of the second harmonic of the reflected signal that is reflected by terminal 41a and returned to the third output end, relative to the phase of the second harmonic of the transmission signal of the transmission band of Band A that is output from the third output end, when terminal 41c is connected to terminal 41a and terminal 41a is disconnected from filter 61. Furthermore, the fourth reflection phase of the second harmonic of the transmission band of Band A when viewed from terminal 41a to the fourth output end is defined as the amount of phase change of the second harmonic of the reflected signal that is reflected by terminal 41a and returned to the fourth output end, relative to the phase of the second harmonic of the transmission signal of the transmission band of Band A that is output from the fourth output end, when terminal 41d is connected to terminal 41a and terminal 41a is disconnected from filter 61.

[0058] The first reflection phase of the fundamental wave in the transmission band of band A is obtained by measuring the reflection phase of the fundamental wave in band A at terminal 41a with terminal 41c and terminal 41a connected, terminal 41d and terminal 41a disconnected, and terminal 41a disconnected from filter 61. The first reflection phase of the fundamental wave in the transmission band of band B is obtained by measuring the reflection phase of the fundamental wave in band B at terminal 41b with terminal 41c and terminal 41b connected, terminal 41d and terminal 41b disconnected, and terminal 41b disconnected from filter 62.

[0059] The second reflection phase of the fundamental wave in the transmission band of band A is obtained by measuring the reflection phase of the fundamental wave in band A at terminal 41a with terminal 41d and terminal 41a connected, terminal 41c and terminal 41a disconnected, and terminal 41a disconnected from filter 61. The second reflection phase of the fundamental wave in the transmission band of band B is obtained by measuring the reflection phase of the fundamental wave in band B at terminal 41b with terminal 41d and terminal 41b connected, terminal 41c and terminal 41b disconnected, and terminal 41b disconnected from filter 62.

[0060] The third reflection phase of the second harmonic in the transmission band of band A is obtained by measuring the reflection phase of the second harmonic in band A at terminal 41a with terminal 41c and terminal 41a connected, terminal 41d and terminal 41a disconnected, and terminal 41a disconnected from filter 61. The third reflection phase of the second harmonic in the transmission band of band B is obtained by measuring the reflection phase of the second harmonic in band B at terminal 41b with terminal 41c and terminal 41b connected, terminal 41d and terminal 41b disconnected, and terminal 41b disconnected from filter 62.

[0061] The fourth reflection phase of the second harmonic in the transmission band of band A is obtained by measuring the reflection phase of the second harmonic in band A at terminal 41a with terminal 41d and terminal 41a connected, terminal 41c and terminal 41a disconnected, and terminal 41a disconnected from filter 61. The fourth reflection phase of the second harmonic in the transmission band of band B is obtained by measuring the reflection phase of the second harmonic in band B at terminal 41b with terminal 41d and terminal 41b connected, terminal 41c and terminal 41b disconnected, and terminal 41b disconnected from filter 62.

[0062] With this, even if unwanted signals having the fundamental frequency and second harmonic frequency of the transmission band of Band A leak from an external circuit into the high-frequency circuit 1 via the antenna connection terminal 100, the reflection phase difference of the fundamental wave as seen from the output ends of the two balanced power amplifiers 11 and 12 is 180°, and the reflection phase difference of the second harmonic is also 180°, so that fluctuations in the transmission characteristics of the high-frequency circuit 1 in the fundamental band and harmonic bands can be suppressed even if there is a load fluctuation. Thus, it is possible to provide an amplifier circuit 10 and a high-frequency circuit 1 in which fluctuations in the output characteristics of the fundamental band and harmonic band of the transmission signal are suppressed.

[0063] In the amplifier circuit 10 and the high-frequency circuit 1 according to this embodiment, the phase shift circuits 21 and 22 and the harmonic phase shift circuits 31 and 32 are circuits that adjust the phase of the fundamental wave and the phase of the second harmonic, but may also be circuits that adjust the phase of the fundamental wave and the phase of at least one of the nth harmonic (n is an integer of 3 or more).

[0064] In other words, even if an unwanted signal having the fundamental frequency and n-th harmonic (n is an integer greater than or equal to 3) frequencies of the transmission band of Band A leaks from an external circuit into the high-frequency circuit via antenna connection terminal 100, it is sufficient that the reflection phase difference of the fundamental wave as viewed from the output ends of two balanced power amplifiers 11 and 12 is 180° and the reflection phase difference of the n-th harmonic is also 180°. This makes it possible to suppress fluctuations in the transmission characteristics of the high-frequency circuit in the fundamental wave band and n-th harmonic band even if there is load fluctuation. Therefore, it is possible to provide an amplifier circuit and a high-frequency circuit in which fluctuations in the output characteristics of the fundamental wave band and n-th harmonic band of the transmission signal are suppressed.

[0065] [1.4 Transmission characteristics of high frequency circuit 1] 2A is a circuit state diagram of the high-frequency circuit 1 according to the embodiment in the Band A transmission mode. As shown in the figure, in the Band A transmission mode, in the switch circuit 41, the terminals 41a and 41c are connected, and the terminals 41a and 41d are connected. In addition, in the switch circuit 42, the terminals 42a and 42b are connected.

[0066] The transmit signal of band A is demultiplexed by 90° hybrid 50 into a first demultiplexed signal RF1 and a second demultiplexed signal RF2, which are input to power amplifiers 11 and 12 and amplified to become a first signal and a second signal. At the third output terminal of power amplifier 11, the phase of the fundamental wave of the first signal is 0°, and at the fourth output terminal of power amplifier 12, the phase of the fundamental wave of the second signal is 90°.

[0067] The phase of the fundamental wave of the first signal at terminal 41a after passing through harmonic phase shift circuit 31 (fundamental wave passing phase 0°) and phase shift circuit 21 (fundamental wave passing phase +45°) is +45°, and the phase of the fundamental wave of the second signal at terminal 41a after passing through harmonic phase shift circuit 32 (fundamental wave passing phase 0°) and phase shift circuit 22 (fundamental wave passing phase -45°) is +45°. As a result, the first and second signals of Band A are combined in phase at terminal 41a, enabling highly efficient power combining of fundamental waves despite load fluctuations.

[0068] Furthermore, the difference between the first reflection phase (+45°×2=90°) of the fundamental wave of the first signal when viewing terminal 41a from the third output end and the second reflection phase (-45°×2=-90°) of the fundamental wave of the second signal when viewing terminal 41a from the fourth output end is 180°.

[0069] Furthermore, the passing phase of the second harmonic of the first signal in the combined circuit of harmonic phase shift circuit 31 and phase shift circuit 21 is +45°, and the passing phase of the second harmonic of the second signal in the combined circuit of harmonic phase shift circuit 32 and phase shift circuit 22 is -45°. In other words, the difference between the third reflected phase (+45° × 2 = 90°) of the second harmonic of the first signal when looking at terminal 41a from the third output end and the fourth reflected phase (-45° × 2 = -90°) of the second harmonic of the second signal when looking at terminal 41a from the fourth output end is 180°.

[0070] 2B is a circuit state diagram of the high-frequency circuit 1 according to the embodiment in the Band B transmission mode. As shown in the figure, in the Band B transmission mode, in the switch circuit 41, the terminals 41b and 41c are connected, and the terminals 41b and 41d are connected. In addition, in the switch circuit 42, the terminals 42a and 42c are connected.

[0071] The transmit signal of band B is demultiplexed by 90° hybrid 50 into a first demultiplexed signal RF1 and a second demultiplexed signal RF2, which are input to power amplifiers 11 and 12 and amplified to become a first signal and a second signal. At the third output terminal of power amplifier 11, the phase of the fundamental wave of the first signal is 0°, and at the fourth output terminal of power amplifier 12, the phase of the fundamental wave of the second signal is 90°.

[0072] The phase of the fundamental wave of the first signal at terminal 41b after passing through harmonic phase shift circuit 31 (fundamental wave passing phase 0°) and phase shift circuit 21 (fundamental wave passing phase +45°) is +45°, and the phase of the fundamental wave of the second signal at terminal 41b after passing through harmonic phase shift circuit 32 (fundamental wave passing phase 0°) and phase shift circuit 22 (fundamental wave passing phase -45°) is +45°. As a result, the first and second signals of Band B are combined in phase at terminal 41b, enabling highly efficient power combining of fundamental waves despite load fluctuations.

[0073] Furthermore, the difference between the first reflection phase (+45°×2=90°) of the fundamental wave of the first signal when viewing terminal 41b from the third output end and the second reflection phase (-45°×2=-90°) of the fundamental wave of the second signal when viewing terminal 41b from the fourth output end is 180°.

[0074] Furthermore, the passing phase of the second harmonic of the first signal in the combined circuit of harmonic phase shift circuit 31 and phase shift circuit 21 is +45°, and the passing phase of the second harmonic of the second signal in the combined circuit of harmonic phase shift circuit 32 and phase shift circuit 22 is -45°. In other words, the difference between the third reflected phase (+45° × 2 = 90°) of the second harmonic of the first signal when terminal 41b is viewed from the third output end and the fourth reflected phase (-45° × 2 = -90°) of the second harmonic of the second signal when terminal 41b is viewed from the fourth output end is 180°.

[0075] 3A is a diagram showing the fundamental wave impedance of the power amplifiers 11 and 12 according to the embodiment. FIG. 3B is a diagram showing the second harmonic impedance of the power amplifiers 11 and 12 according to the embodiment. FIG. 3A shows the fundamental wave (frequency f L1 ~f H1 ) impedance of the power amplifier 12 (PA12) and the fundamental impedance of band A at the fourth output terminal of the power amplifier 12 (PA12) are shown in polar coordinates. Also, FIG. 3B shows the second harmonic (frequency f L2 ~f H2) impedance and the second harmonic impedance of Band A at the fourth output terminal of the power amplifier 12 (PA12) are displayed in polar coordinates.

[0076] As shown in FIG. 3A, the difference between the first reflection phase of the fundamental wave and the second reflection phase of the fundamental wave is 180°. Therefore, the fundamental wave impedance of the power amplifier 11 and the fundamental wave impedance of the power amplifier 12 are different from each other in the fundamental wave band of band A (frequency f L1 ~f H1 ), a phase difference of 180° is always ensured. Therefore, the high-frequency circuit 1 can offset load fluctuations in the fundamental wave band of band A and obtain stable transmission output characteristics in the fundamental wave band.

[0077] Furthermore, as shown in FIG. 3B, the difference between the third reflection phase of the second harmonic and the fourth reflection phase of the second harmonic is 180°, so the second harmonic impedance of the power amplifier 11 and the second harmonic impedance of the power amplifier 12 are different from each other in the second harmonic band of band A (frequency f L2 ~f H2 ), a phase difference of 180° is always ensured. Therefore, the high-frequency circuit 1 can cancel out load fluctuations in the second harmonic band of Band A and obtain stable transmission output characteristics in the second harmonic band.

[0078] FIG. 4A is a graph showing the gain, EVM (Error Vector Magnitude), and ACLR (Adjacent Channel Leakage Ratio) of the amplifier circuit 10 according to the embodiment. FIG. 4B is a graph showing the second harmonic output characteristics of the amplifier circuit 10 according to the embodiment. The upper part of FIG. 4A shows a fundamental impedance having a load impedance of Γ=0.2 on a Smith chart that is a contour plot of (a) gain, (b) EVM, and (c) ACLR obtained by load pull measurement. The lower part of FIG. 4A shows the result of mapping the contour plot with the fundamental impedance.

[0079] 4A, the gain, EVM, and ACLR of power amplifiers 11 and 12 fluctuate due to load fluctuations (phase fluctuations), but because the difference between the first reflection phase of the fundamental wave and the second reflection phase of the fundamental wave is 180°, fluctuations are suppressed in the gain, EVM, and ACLR of the combined fundamental waves of power amplifiers 11 and 12. In other words, amplifier circuit 10 can obtain stable fundamental wave transmission output characteristics even when load fluctuations occur.

[0080] 4B, the second harmonic output of power amplifiers 11 and 12 fluctuates due to load fluctuations (phase fluctuations), but because the difference between the third reflection phase of the second harmonic and the fourth reflection phase of the second harmonic is 180°, fluctuations are suppressed in the second harmonic output obtained by combining the second harmonics of power amplifiers 11 and 12. In other words, amplifier circuit 10 can obtain stable second harmonic transmission output characteristics even when load fluctuations occur.

[0081] In a conventional balanced amplifier circuit having a first power amplifier and a second power amplifier, the fundamental wave phase difference between the output terminal of the first power amplifier and the output terminal of the second power amplifier is set to 90°, and in-phase synthesis is performed at the synthesis point, while harmonics are suppressed.

[0082] However, in situations where higher output is required, it is important to make the fundamental wave and harmonics coexist and output both stably regardless of load fluctuations. In order to solve the above problem, it is very effective and important to make the reflection phase difference at the output ends of power amplifiers 11 and 12 180° in the two bands of the fundamental wave and the harmonics, as in amplifier circuit 10 and high-frequency circuit 1 according to this embodiment.

[0083] It should be noted that amplifier circuit 10 according to the present embodiment does not necessarily need to include either harmonic phase shift circuits 31 or 32. The amplifier circuit according to the present invention may have a circuit configuration in which the difference between the reflected phase of the second harmonic of the first signal in the path connecting the third output terminal of power amplifier 11 and terminal 41a (combining point) and the reflected phase of the second harmonic of the second signal in the path connecting the fourth output terminal of power amplifier 12 and terminal 41a is 180°.

[0084] In this embodiment, the numerical values ​​of the transmission phase, reflection phase, and reflection phase difference do not only represent the strict meaning, but also include a substantially equivalent range, for example, including a difference of about 30%.

[0085] [2. Circuit configuration of amplifier circuit according to modification example 1] An amplifier circuit according to Modification 1 will be described. Although not shown, the amplifier circuit according to this modification includes power amplifiers 11 and 12, phase shift circuits 21A and 22A, harmonic phase shift circuits 31A and 32A, switch circuit 41, 90° hybrid 50, phase shift lines 51 and 52, capacitor 53, and high-frequency input terminal 110. The amplifier circuit according to this modification differs from amplifier circuit 10 according to the embodiment in the circuit configurations of the phase shift circuits and harmonic phase shift circuits. Hereinafter, a description of the same configurations as amplifier circuit 10 according to the embodiment will be omitted, and only the phase shift circuits 21A and 22A and harmonic phase shift circuits 31A and 32A, which have different configurations, will be described.

[0086] 5A is a circuit configuration diagram of a phase-shift circuit 21A according to a first modification of the embodiment. The phase-shift circuit 21A is an example of a first phase-shift circuit and is connected between the third output terminal of the power amplifier 11 and the terminal 41c of the switch circuit 41. The phase-shift circuit 21A includes capacitors 211, 212, and 214, an inductor 213, and a switch 215. The capacitor 211 is an example of a first capacitor and is connected between the terminal 201 and the terminal 202. The inductor 213 is an example of a first inductor and is connected between the path connecting the capacitor 211 and the terminal 202 and ground. The capacitor 212 is arranged in series in the path connecting the capacitor 211 and the terminal 202. The switch 215 (a fifth switch) and the capacitor 214 are connected in series to each other and form a first variable circuit. The first variable circuit is connected between the terminals 201 and 202. The phase-shift circuit 21A has a so-called high-pass filter configuration and shifts the passing phase of the fundamental wave of band A and band B by, for example, +45° (advances it by 45°). Note that the capacitor 212 is a DC-blocking capacitor and does not contribute to phase shifting, so it may not be included in the phase-shift circuit 21A. The passing phase of the fundamental wave changes by switching the conduction and non-conduction of the switch 215. For example, the amplifier circuit of this modification switches the conduction and non-conduction of the switch 215 depending on whether a transmission signal of band A or band B is to be transmitted. In other words, the phase-shift circuit 21A is configured to change the passing phase depending on the connection between the terminal 41c and the terminal 41d and the terminal 41a, and the connection between the terminal 41c and the terminal 41d and the terminal 41b. This allows the amount of reflected phase shift of the fundamental wave to be adjusted with high precision depending on the band being transmitted.

[0087] FIG. 5B is a circuit diagram of a phase-shift circuit 22A according to a first modification of the embodiment. The phase-shift circuit 22A is an example of a second phase-shift circuit and is connected between the terminal 203 and the terminal 204. The phase-shift circuit 22A is configured so that the passing phase of the fundamental waves of bands A and B is relatively −90° (delayed by 90°) with respect to the phase-shift circuit 21A. The phase-shift circuit 22A includes an inductor 221, capacitors 222, 223, and 224, and a switch 225. The inductor 221 is an example of a second inductor and is connected between the terminals 203 and 204. The capacitor 223 is an example of a second capacitor and is connected between the path connecting the inductor 221 and the terminal 204 and ground. The capacitor 222 is arranged in series with the path connecting the inductor 221 and the terminal 204. The switch 225 (a sixth switch) and the capacitor 224 are connected in series with each other to form a second variable circuit. The second variable circuit is connected between the terminal 204 and ground. The phase-shift circuit 22A has a so-called low-pass filter configuration and shifts the passing phase of the fundamental wave signals of bands A and B, for example, by −45° (delaying them by 45°). Note that the capacitor 222 is a DC-blocking capacitor that does not contribute to phase shifting and may not be included in the phase-shift circuit 22A. The passing phase of the fundamental wave changes by switching the conduction and non-conduction of the switch 225. For example, the amplifier circuit of this modification switches the conduction and non-conduction of the switch 225 depending on whether a transmission signal of band A or band B is being transmitted. In other words, the phase-shift circuit 22A is configured to change the passing phase depending on the connection between the terminal 41c and the terminal 41d and the terminal 41a, and the connection between the terminal 41c and the terminal 41d and the terminal 41b. This allows the amount of reflected phase shift of the fundamental wave to be adjusted with high precision depending on the band being transmitted.

[0088] FIG. 5C is a circuit diagram of a harmonic phase-shift circuit 31A according to a first modification of the embodiment. The harmonic phase-shift circuit 31A is an example of a first harmonic phase-shift circuit and is connected between the third output terminal and terminal 41c. The harmonic phase-shift circuit 31A includes capacitors 311 and 312 and a switch 313. The capacitor 311 is connected between a path connecting the third output terminal and capacitor 211 and ground. The switch 313 (seventh switch) and capacitor 312 are connected in series to form a third variable circuit. The third variable circuit is connected between the path and ground. The harmonic phase-shift circuit 31A functions as a low-pass filter that has the fundamental wave bands of band A and band B as its passband, and the passing phase of the fundamental wave is, for example, 0°. The passing phase of the second harmonic changes by switching the switch 313 between conductive and non-conductive states. For example, the amplifier circuit according to this modification switches the conduction and non-conduction of switch 313 depending on whether a transmission signal of Band A or Band B is to be transmitted. In other words, harmonic phase-shift circuit 31A is configured to vary the passing phase depending on the switching between the connection between terminal 41c and terminal 41d and terminal 41a, and the connection between terminal 41c and terminal 41d and terminal 41b. This allows the amount of reflected phase shift of the second harmonic to be adjusted with high precision depending on the transmission band.

[0089] FIG. 5D is a circuit diagram of a harmonic phase-shift circuit 32A according to a first modification of the embodiment. The harmonic phase-shift circuit 32A is an example of a second harmonic phase-shift circuit and is connected between the fourth output port and terminal 41d. The harmonic phase-shift circuit 32A includes an inductor 321, capacitors 322 and 323, and a switch 324. The inductor 321 and capacitor 322 are connected in series to form an LC circuit, and the LC circuit is connected between a path connecting the fourth output port and inductor 221 and ground. The switch 324 (the eighth switch) and capacitor 323 are connected in series to form a fourth variable circuit. The fourth variable circuit is connected in parallel to the capacitor 322. The harmonic phase-shift circuit 32A functions as a notch filter that has the fundamental wave bands of band A and band B as its passband, and the passing phase of the fundamental wave is, for example, 0°. The passing phase of the second harmonic changes by switching the switch 324 between conductive and non-conductive states. For example, the amplifier circuit according to this modification switches the conduction and non-conduction of the switch 324 depending on whether a transmit signal of Band A or Band B is to be transmitted. In other words, the harmonic phase-shift circuit 32A is configured to vary the passing phase depending on the switching between the connection between the terminal 41c and the terminal 41d and the terminal 41a, and the connection between the terminal 41c and the terminal 41d and the terminal 41b. This allows the amount of reflected phase shift of the second harmonic to be adjusted with high precision depending on the band being transmitted.

[0090] In this modified example, the numerical values ​​of the transmission phase, reflection phase, and reflection phase difference do not only represent the strict meaning, but also include a substantially equivalent range, and include a difference of, for example, about 30%.

[0091] [3. Configuration of Amplifier Circuit 10B According to Modification 2] An amplifier circuit 10B according to Modification 2 will be described. FIG. 6 is a circuit configuration diagram of the amplifier circuit 10B according to Modification 2 of the embodiment. As shown in the figure, the amplifier circuit 10B includes power amplifiers 11 and 12, phase shift circuits 21 and 22, harmonic phase shift circuits 31B and 32B, a switch circuit 41, a 90° hybrid 50, phase shift lines 51 and 52, a capacitor 53, and a high-frequency input terminal 110. The amplifier circuit 10B according to this modification has a different circuit configuration for the harmonic phase shift circuit compared to the amplifier circuit 10 according to the embodiment. The following description of the amplifier circuit 10B according to this modification will focus on the harmonic phase shift circuits 31B and 32B, which have different configurations, and will omit a description of the same configuration as the amplifier circuit 10 according to the embodiment.

[0092] The harmonic phase shift circuit 31B is an example of a first harmonic phase shift circuit and is connected between the third output terminal of the power amplifier 11 and the terminal 41c of the switch circuit 41. In this modification, one end of the harmonic phase shift circuit 31B is connected between the third output terminal of the power amplifier 11 and the connection point between the phase shift line 51 and the phase shift circuit 21. Since the reflection phase of the third harmonic, which is in a higher frequency band, at the third output terminal must be adjusted with high precision, the harmonic phase shift circuit 31B is connected near the third output terminal to suppress parasitic inductance and parasitic capacitance. The harmonic phase shift circuit 31B includes, for example, a third capacitor connected between the path connecting the third output terminal and the capacitor 211 and ground. The harmonic phase shift circuit 31B functions as a low-pass filter whose passbands are the fundamental wave bands of bands A and B, and the pass phase of the fundamental wave is, for example, 0°.

[0093] The harmonic phase shift circuit 32B is an example of a second harmonic phase shift circuit and is connected between the fourth output terminal of the power amplifier 12 and the terminal 41d of the switch circuit 41. In this modification, one end of the harmonic phase shift circuit 32B is connected between the fourth output terminal of the power amplifier 12 and the connection point between the phase shift line 52 and the phase shift circuit 22. Because the reflection phase of the third harmonic, which is in a higher frequency band, at the fourth output terminal must be adjusted with high precision, the harmonic phase shift circuit 32B is connected near the fourth output terminal to suppress parasitic inductance and parasitic capacitance. The harmonic phase shift circuit 32B includes, for example, a third inductor and a fourth capacitor. The third inductor and the fourth capacitor are connected in series to form an LC circuit, and the LC circuit is connected between a path connecting the fourth output terminal and the third inductor and ground. The harmonic phase shift circuit 32B is a notch filter that has the fundamental wave bands of band A and band B as its passband, and the passing phase of the fundamental wave is, for example, 0°.

[0094] Phase shift circuit 21 and harmonic phase shift circuit 31B are configured so that the phase of the third harmonics of bands A and B passing through the combined circuit of phase shift circuit 21 and harmonic phase shift circuit 31B is +45° (45° lead). Phase shift circuit 22 and harmonic phase shift circuit 32B are configured so that the phase of the third harmonics passing through the combined circuit of phase shift circuit 22 and harmonic phase shift circuit 32B is -45° (45° lag).

[0095] In the amplifier circuit 10B having the above configuration, the phase-shift circuits 21 and 22 and the harmonic phase-shift circuits 31B and 32B are configured so that the difference between the first reflection phase of the fundamental wave in the transmission band of band A when viewing terminal 41a from the third output end and the second reflection phase of the fundamental wave in the transmission band of band A when viewing terminal 41a from the fourth output end is 180°, and so that the difference between the third reflection phase of the third harmonic in the transmission band of band A when viewing terminal 41a from the third output end and the fourth reflection phase of the third harmonic in the transmission band of band A when viewing terminal 41a from the fourth output end is 180°.

[0096] The third reflection phase of the third harmonic of the transmission band of Band A when viewed from the third output end to terminal 41a is defined as the amount of phase change of the third harmonic of the reflected signal reflected by terminal 41a and returning to the third output end, relative to the phase of the third harmonic of the transmission signal of the transmission band of Band A output from the third output end, when terminal 41c is connected to terminal 41a and terminal 41a is disconnected from filter 61. Furthermore, the fourth reflection phase of the third harmonic of the transmission band of Band A when viewed from terminal 41a to the fourth output end is defined as the amount of phase change of the third harmonic of the reflected signal reflected by terminal 41a and returning to the fourth output end, relative to the phase of the third harmonic of the transmission signal of the transmission band of Band A output from the fourth output end, when terminal 41d is connected to terminal 41a and terminal 41a is disconnected from filter 61.

[0097] The third reflection phase of the third harmonic in the transmission band of band A is obtained by measuring the reflection phase of the third harmonic in band A at terminal 41a with terminal 41c and terminal 41a connected, terminal 41d and terminal 41a disconnected, and terminal 41a disconnected from filter 61. The third reflection phase of the third harmonic in the transmission band of band B is obtained by measuring the reflection phase of the third harmonic in band B at terminal 41b with terminal 41c and terminal 41b connected, terminal 41d and terminal 41b disconnected, and terminal 41b disconnected from filter 62.

[0098] The fourth reflection phase of the third harmonic in the transmission band of band A is obtained by measuring the reflection phase of the third harmonic in band A at terminal 41a with terminal 41d and terminal 41a connected, terminal 41c and terminal 41a disconnected, and terminal 41a disconnected from filter 61. The fourth reflection phase of the third harmonic in the transmission band of band B is obtained by measuring the reflection phase of the third harmonic in band B at terminal 41b with terminal 41d and terminal 41b connected, terminal 41c and terminal 41b disconnected, and terminal 41b disconnected from filter 62.

[0099] FIG. 7A is a diagram illustrating the fundamental wave impedance of the power amplifiers 11 and 12 according to the second modification of the embodiment. FIG. 7B is a diagram illustrating the third harmonic impedance of the power amplifiers 11 and 12 according to the second modification of the embodiment. FIG. 7A shows the fundamental wave (frequency f L1 ~f H1 ) impedance of the third harmonic (frequency f) of band A at the third output terminal of the power amplifier 11 (PA11) is shown in polar coordinates. L3 ~f H3 ) impedance and the third harmonic impedance of Band A at the fourth output terminal of the power amplifier 12 (PA12) are displayed in polar coordinates.

[0100] As shown in FIG. 7A, the difference between the first reflection phase of the fundamental wave and the second reflection phase of the fundamental wave is 180°. Therefore, the fundamental wave impedance of the power amplifier 11 and the fundamental wave impedance of the power amplifier 12 are different from each other in the fundamental wave band of band A (frequency f L1 ~f H1 ), a phase difference of 180° is always ensured. Therefore, the high-frequency circuit according to this modification can cancel out load fluctuations in the fundamental wave band of Band A and obtain stable transmission output characteristics in the fundamental wave band.

[0101] Furthermore, as shown in FIG. 7B, the difference between the third reflection phase of the third harmonic and the fourth reflection phase of the third harmonic is 180°, so the third harmonic impedance of the power amplifier 11 and the third harmonic impedance of the power amplifier 12 are different from each other in the third harmonic band of band A (frequency f L3 ~f H3 ), a phase difference of 180° is always ensured. Therefore, the high-frequency circuit according to this modification can cancel out load fluctuations in the third harmonic band of Band A and obtain stable transmission output characteristics in the third harmonic band.

[0102] 8 is a graph showing the third harmonic output characteristics of amplifier circuit 10B according to the second modification of the embodiment. As shown in the figure, the third harmonic output of power amplifiers 11 and 12 fluctuates due to load fluctuations (phase fluctuations). However, because the difference between the third reflection phase of the third harmonic and the fourth reflection phase of the third harmonic is 180°, fluctuations in the third harmonic output resulting from the combination of the third harmonics of power amplifiers 11 and 12 are suppressed. In other words, amplifier circuit 10B can obtain stable third harmonic transmission output characteristics even when load fluctuations occur.

[0103] As described above, with amplifier circuit 10B and the high-frequency circuit according to this modification, even if unwanted signals of the fundamental frequency and third harmonic frequency of the transmission band of Band A leak from an external circuit into the high-frequency circuit via antenna connection terminal 100, the reflection phase difference of the fundamental wave as seen from the output ends of two balanced power amplifiers 11 and 12 is 180°, and the reflection phase difference of the third harmonic is also 180°, so that fluctuations in the transmission characteristics of the fundamental wave band and harmonic band of the high-frequency circuit can be suppressed even if there is a load fluctuation. Therefore, it is possible to provide amplifier circuit 10B and a high-frequency circuit in which fluctuations in the output characteristics of the fundamental wave band and harmonic band of the transmission signal are suppressed.

[0104] Note that amplifier circuit 10B according to this modification does not necessarily need to include either harmonic phase shift circuits 31B or 32B. The amplifier circuit according to the present invention may have a circuit configuration in which the difference in phase between the reflected third harmonic of the first signal in the path connecting the third output terminal of power amplifier 11 and terminal 41a (combining point) and the reflected third harmonic of the second signal in the path connecting the fourth output terminal of power amplifier 12 and terminal 41a is 180°.

[0105] In the amplifier circuit 10B according to this modification, at least one of the phase-shift circuits 21 and 22 and the harmonic phase-shift circuits 31B and 32B may include a variable circuit that varies the passing phase. Specific circuit configurations including the variable circuit include those shown in FIGS. 5A to 5D. For example, the amplifier circuit 10B according to this modification switches the circuit state of the variable circuit depending on whether a transmission signal of Band A or Band B is being transmitted. In other words, the passing phases of the fundamental wave and the third harmonic are varied depending on whether the connection between the terminals 41c and 41d and the terminal 41a is switched, or whether the connection between the terminals 41c and 41d and the terminal 41b is switched. This allows the amount of reflected phase shift of the third harmonic to be adjusted with high precision depending on the transmission band.

[0106] In this modified example, the numerical values ​​of the transmission phase, reflection phase, and reflection phase difference do not only represent the strict meaning, but also include a substantially equivalent range, and include a difference of, for example, about 30%.

[0107] [4. Configuration of Amplifier Circuit 10C According to Modification 3] An amplifier circuit 10C according to Modification 3 will be described. FIG. 9 is a circuit configuration diagram of the amplifier circuit 10C and a high-frequency circuit according to Modification 3 of the embodiment. As shown in the figure, the amplifier circuit 10C includes power amplifiers 11 and 12, phase-shift circuits 21C and 22C, harmonic phase-shift circuits 31C and 32C, a transformer 45, a switch circuit 46, a 90° hybrid 50, phase-shift lines 51 and 52, a capacitor 53, and a high-frequency input terminal 110. The amplifier circuit 10C according to this modification differs from the amplifier circuit 10 according to the embodiment mainly in the inclusion of a transformer 45. Hereinafter, the amplifier circuit 10C according to this modification will be described focusing on the different configurations, and a description of the same configurations as those of the amplifier circuit 10 according to the embodiment will be omitted. Note that the high-frequency circuit according to this modification differs from the high-frequency circuit 1 according to the embodiment only in the configuration of the amplifier circuit.

[0108] The phase-shift circuit 21C is an example of a first phase-shift circuit and is connected between the third output terminal of the power amplifier 11 and terminal 45b of the transformer 45. The phase-shift circuit 21C includes, for example, an inductor 221 and capacitors 222 and 223. The inductor 221 is an example of a first inductor and is connected between the fourth output terminal and terminal 45b. The capacitor 223 is an example of a first capacitor and is connected between a path connecting the inductor 221 and terminal 45b and ground. The capacitor 222 is arranged in series in the path connecting the inductor 221 and terminal 45b. The phase-shift circuit 21C has a so-called low-pass filter configuration and shifts the passing phase of the fundamental signals of band A and band B by, for example, −45° (delaying them by 45°). Note that the capacitor 222 is a DC-blocking capacitor and does not contribute to phase shifting, so it may not be included in the phase-shift circuit 21C.

[0109] The phase-shift circuit 22C is an example of a second phase-shift circuit and is connected between the fourth output terminal of the power amplifier 12 and the terminal 45c of the transformer 45. The phase-shift circuit 22C is configured so that the passing phase of the fundamental waves of bands A and B is +90° (advanced by 90°) relative to the phase-shift circuit 21C. The phase-shift circuit 22C includes, for example, capacitors 211 and 212 and an inductor 213. The capacitor 211 is an example of a second capacitor and is connected between the third output terminal and the terminal 45c. The inductor 213 is an example of a second inductor and is connected between the path connecting the capacitor 211 and the terminal 45c and ground. The capacitor 212 is arranged in series with the path connecting the capacitor 211 and the terminal 45c. The phase-shift circuit 22C has a so-called high-pass filter configuration and changes the passing phase of the fundamental waves of bands A and B, for example, to +45° (advanced by 45°). It should be noted that capacitor 212 is a DC blocking capacitor and does not contribute to phase shifting, and may not be included in phase shift circuit 22C.

[0110] Harmonic phase shift circuit 31C is an example of a first harmonic phase shift circuit, and is connected between the third output port of power amplifier 11 and terminal 45b of transformer 45. Harmonic phase shift circuit 31C includes, for example, inductor 321 and capacitor 322. Inductor 321 (third inductor) and capacitor 322 (third capacitor) are connected in series to form an LC circuit, and this LC circuit is connected between a path connecting the third output port and inductor 221 and ground. Harmonic phase shift circuit 31C serves as a notch filter whose passbands are the fundamental wave bands of band A and band B, and the passing phase of the fundamental wave is, for example, 0°.

[0111] Harmonic phase shift circuit 32C is an example of a second harmonic phase shift circuit, and is connected between the fourth output port of power amplifier 12 and terminal 45c of transformer 45. Harmonic phase shift circuit 32C includes, for example, capacitor 311 (fourth capacitor) connected between ground and a path connecting the fourth output port and capacitor 211. Harmonic phase shift circuit 32C serves as a low-pass filter whose passband is the fundamental wave bands of band A and band B, and the passing phase of the fundamental wave is, for example, 0°.

[0112] Phase shift circuit 21C and harmonic phase shift circuit 31C are configured so that the second harmonics of band A and band B passing through the combined circuit of phase shift circuit 21C and harmonic phase shift circuit 31C are phase shifted by −45° (45° delayed). Phase shift circuit 22C and harmonic phase shift circuit 32C are configured so that the second harmonics passing through the combined circuit of phase shift circuit 22C and harmonic phase shift circuit 32C are phase shifted by +45° (45° advanced).

[0113] Transformer 45 is an example of a combining circuit and has a primary coil, a secondary coil, terminal 45a (fifth output terminal) which is one end of the primary coil, terminal 45b (fourth input terminal) which is the other end of the primary coil, and terminal 45c (fifth input terminal) which is one end of the secondary coil, and outputs an output signal from terminal 45a which is generated by combining, in anti-phase, the third demultiplexed signal input from terminal 45b and the fourth demultiplexed signal input from terminal 45c. Transformer 45 is a signal combining point which combines, in anti-phase, the third demultiplexed signal of band A with the fourth demultiplexed signal of band A, and which combines, in anti-phase, the third demultiplexed signal of band B with the fourth demultiplexed signal of band B.

[0114] The switch circuit 46 is a band changeover switch, has terminals 46a, 46b and 46c, and switches between the connection between the terminal 46a and the terminal 46b and the connection between the terminal 46a and the terminal 46c.

[0115] In the above configuration, the transmit signal of band A is demultiplexed by 90° hybrid 50 into a first demultiplexed signal RF1 and a second demultiplexed signal RF2, which are input to power amplifiers 11 and 12 and amplified to become a first signal and a second signal, respectively. At the third output terminal of power amplifier 11, the phase of the fundamental wave of the first signal is 0°, and at the fourth output terminal of power amplifier 12, the phase of the fundamental wave of the second signal is 90°.

[0116] The phase of the fundamental wave of the first signal at terminal 45b after passing through harmonic phase shift circuit 31C (fundamental wave passing phase 0°) and phase shift circuit 21C (fundamental wave passing phase -45°) is -45°, and the phase of the fundamental wave of the second signal at terminal 45c after passing through harmonic phase shift circuit 32C (fundamental wave passing phase 0°) and phase shift circuit 22C (fundamental wave passing phase +45°) is +135°. As a result, the first and second signals of Band A are combined in opposite phases by transformer 45, enabling highly efficient power combining of the fundamental wave despite load fluctuations.

[0117] Furthermore, the difference between the first reflection phase (-45° x 2 = -90°) of the fundamental wave of the first signal when viewed from the third output terminal to terminal 45b and the second reflection phase (45° x 2 = +90°) of the fundamental wave of the second signal when viewed from the fourth output terminal to terminal 45c is 180°.

[0118] Furthermore, the passing phase of the second harmonic of the first signal in the combined circuit of harmonic phase shift circuit 31C and phase shift circuit 21C is −45°, and the passing phase of the second harmonic of the second signal in the combined circuit of harmonic phase shift circuit 32C and phase shift circuit 22C is +45°. In other words, the difference between the third reflected phase (−45° × 2 = −90°) of the second harmonic of the first signal when viewed from the third output end to terminal 45b and the fourth reflected phase (45° × 2 = +90°) of the second harmonic of the second signal when viewed from the fourth output end to terminal 45c is 180°.

[0119] In the amplifier circuit 10C having the above configuration, the phase-shift circuits 21C and 22C and the harmonic phase-shift circuits 31C and 32C are configured so that the difference between the first reflection phase of the fundamental wave in the transmission band of band A when viewed from the third output end to terminal 45b and the second reflection phase of the fundamental wave in the transmission band of band A when viewed from the fourth output end to terminal 45c is 180°, and so that the difference between the third reflection phase of the second harmonic in the transmission band of band A when viewed from the third output end to terminal 45b and the fourth reflection phase of the second harmonic in the transmission band of band A when viewed from the fourth output end to terminal 45c is 180°.

[0120] With this, even if unwanted signals of the fundamental frequency and second harmonic frequency of the transmission band of Band A leak from an external circuit and are input to the high-frequency circuit via antenna connection terminal 100, the reflection phase difference of the fundamental wave as seen from the output ends of two balanced power amplifiers 11 and 12 is 180°, and the reflection phase difference of the second harmonic is also 180°, so fluctuations in the transmission characteristics of the high-frequency circuit in the fundamental and harmonic bands can be suppressed even if there is a load fluctuation. Thus, it is possible to provide amplifier circuit 10C and a high-frequency circuit in which fluctuations in the output characteristics of the transmission signal in the fundamental and harmonic bands are suppressed.

[0121] Note that amplifier circuit 10C according to this modification may not include either harmonic phase shift circuits 31C or 32C. The amplifier circuit according to the present invention may have a circuit configuration in which the difference in phase between the reflected phase of the second harmonic of the first signal in the path connecting the third output port of power amplifier 11 and terminal 45b and the reflected phase of the second harmonic of the second signal in the path connecting the fourth output port of power amplifier 12 and terminal 45c is 180°.

[0122] Furthermore, in the amplifier circuit 10C of this modified example, the phase-shift circuits 21C and 22C and the harmonic phase-shift circuits 31C and 32C may be configured so that the difference between the first reflection phase of the fundamental wave in the transmission band of band A when viewed from the third output end to terminal 45b and the second reflection phase of the fundamental wave in the transmission band of band A when viewed from the fourth output end to terminal 45c is 180°, and so that the difference between the third reflection phase of the third harmonic in the transmission band of band A when viewed from the third output end to terminal 45b and the fourth reflection phase of the third harmonic in the transmission band of band A when viewed from the fourth output end to terminal 45c is 180°.

[0123] With this, even if unwanted signals of the fundamental frequency and third harmonic frequency of the transmission band of Band A leak from an external circuit and are input to the high-frequency circuit via antenna connection terminal 100, the reflection phase difference of the fundamental wave as seen from the output ends of two balanced power amplifiers 11 and 12 is 180°, and the reflection phase difference of the third harmonic is also 180°, so that fluctuations in the transmission characteristics of the fundamental band and harmonic band of the high-frequency circuit can be suppressed even if there are load fluctuations.

[0124] In this modified example, the numerical values ​​of the transmission phase, reflection phase, and reflection phase difference do not only represent the strict meaning, but also include a substantially equivalent range, and include a difference of, for example, about 30%.

[0125] [5. Configurations of Amplifier Circuit, High-Frequency Circuit, and Communication Device According to Modification 4] The following describes amplifier circuits 10Da and 10Db, a high-frequency circuit 1D, and a communication device 4D according to Modification 4. Fig. 10 is a circuit configuration diagram of amplifier circuits 10Da and 10Db, a high-frequency circuit 1D, and a communication device 4D according to Modification 4 of the embodiment. As shown in the figure, the communication device 4D according to this modification includes the high-frequency circuit 1D, antennas 2a and 2b, and an RFIC 3.

[0126] The antenna 2a is connected to the antenna connection terminal 100a (first antenna terminal) of the high frequency circuit 1D, transmits high frequency signals output from the high frequency circuit 1D, and receives high frequency signals from the outside and outputs them to the high frequency circuit 1D.

[0127] The antenna 2b is connected to the antenna connection terminal 100b (second antenna terminal) of the high frequency circuit 1D, transmits high frequency signals output from the high frequency circuit 1D, and receives high frequency signals from the outside and outputs them to the high frequency circuit 1D.

[0128] The high-frequency circuit 1D includes amplifier circuits 10Da and 10Db, filters 61a, 61b, 62a and 62b, a switch circuit 43, and antenna connection terminals 100a and 100b. The high-frequency circuit 1D according to this modification differs from the high-frequency circuit 1 according to the embodiment mainly in that a receiver circuit is added and two amplifier circuits are provided. Hereinafter, the high-frequency circuit 1D according to this modification will be described mainly focusing on the different configurations, and a description of the same configurations as the high-frequency circuit 1 according to the embodiment will be omitted.

[0129] The amplifier circuit 10Da includes power amplifiers 11a and 12a, phase-shift circuits 21Da and 22Da, harmonic phase-shift circuits 31Da and 32Da, a switch circuit 44a, a 90° hybrid 50a, and a high-frequency input terminal 110a. The amplifier circuit 10Da has the same circuit configuration as the amplifier circuit 10 according to the embodiment. The phase shift circuits 21Da and 22Da and the harmonic phase shift circuits 31Da and 32Da are configured so that the difference between the first reflection phase of the fundamental wave in the transmission band of band A when viewing the switch circuit 44a from the output end of the power amplifier 11a and the second reflection phase of the fundamental wave in the transmission band of band A when viewing the switch circuit 44a from the output end of the power amplifier 12a is 180°, and so that the difference between the third reflection phase of the second harmonic in the transmission band of band A when viewing the switch circuit 44a from the output end of the power amplifier 11a and the fourth reflection phase of the second harmonic in the transmission band of band A when viewing the switch circuit 44a from the output end of the power amplifier 12a is 180°.

[0130] The amplifier circuit 10Db includes power amplifiers 11b and 12b, phase-shift circuits 21Db and 22Db, harmonic phase-shift circuits 31Db and 32Db, a switch circuit 44b, a 90° hybrid 50b, and a high-frequency input terminal 110b. The power amplifiers 11b and 12b are an example of a third power amplifier. The amplifier circuit 10Db has the same circuit configuration as the amplifier circuit 10 according to the embodiment. The phase shift circuits 21Db and 22Db and the harmonic phase shift circuits 31Db and 32Db are configured so that the difference between the first reflection phase of the fundamental wave in the transmission band of band A when viewing the switch circuit 44b from the output end of the power amplifier 11b and the second reflection phase of the fundamental wave in the transmission band of band A when viewing the switch circuit 44b from the output end of the power amplifier 12b is 180°, and so that the difference between the third reflection phase of the second harmonic in the transmission band of band A when viewing the switch circuit 44b from the output end of the power amplifier 11b and the fourth reflection phase of the second harmonic in the transmission band of band A when viewing the switch circuit 44b from the output end of the power amplifier 12b is 180°.

[0131] The filter 61a is an example of a first filter, is connected between the switch circuit 44a and the antenna connection terminal 100a, and has a passband that includes band A. Specifically, one end of the filter 61a is connected to the switch circuit 44a, and the other end of the filter 61a is connected to the antenna connection terminal 100a via the switch circuit 43. Note that, as shown in FIG. 10 , a receiving filter and a low-noise amplifier that have a passband that includes band A may be connected to a node of the path connecting the filter 61a and the switch circuit 43.

[0132] The filter 62a is an example of a second filter, is connected between the switch circuit 44a and the antenna connection terminal 100a, and has a passband that includes band B. Specifically, one end of the filter 62a is connected to the switch circuit 44a, and the other end of the filter 62a is connected to the antenna connection terminal 100a via the switch circuit 43. Note that, as shown in FIG. 10 , a receiving filter and a low-noise amplifier that have a passband that includes band B may be connected to a node of the path connecting the filter 62a and the switch circuit 43.

[0133] The filter 61b is an example of a third filter, is connected between the switch circuit 44b and the antenna connection terminal 100b, and has a passband that includes band A. Specifically, one end of the filter 61b is connected to the switch circuit 44b, and the other end of the filter 61b is connected to the antenna connection terminal 100b via the switch circuit 43. Note that, as shown in FIG. 10 , a receiving filter and a low-noise amplifier that have a passband that includes band A may be connected to a node of the path connecting the filter 61b and the switch circuit 43.

[0134] The filter 62b is an example of a second filter, is connected between the switch circuit 44b and the antenna connection terminal 100b, and has a passband that includes band B. Specifically, one end of the filter 62b is connected to the switch circuit 44b, and the other end of the filter 62b is connected to the antenna connection terminal 100b via the switch circuit 43. Note that, as shown in FIG. 10 , a receiving filter and a low-noise amplifier that have a passband that includes band B may be connected to a node of the path connecting the filter 62b and the switch circuit 43.

[0135] The switch circuit 43 is an example of an antenna switch and has terminals 43a, 43b, 43c, 43d, 43e, 43f, 43g, and 43h, with the terminal 43a connected to the antenna connection terminal 100a, the terminal 43b connected to the antenna connection terminal 100b, the terminal 43c connected to the filter 61a, the terminal 43d connected to the filter 62a, the terminal 43f connected to the filter 61b, and the terminal 43g connected to the filter 62b. With the above configuration, the switch circuit 43 switches between connection and disconnection between the antenna connection terminal 100a and the filter 61a, between connection and disconnection between the antenna connection terminal 100a and the filter 62a, between connection and disconnection between the antenna connection terminal 100b and the filter 61b, and between connection and disconnection between the antenna connection terminal 100b and the filter 62b. Furthermore, the switch circuit 43 can simultaneously connect the antenna connection terminal 100a to the filter 61a and the antenna connection terminal 100b to the filter 61b, and can simultaneously connect the antenna connection terminal 100a to the filter 62a and the antenna connection terminal 100b to the filter 62b. That is, the communication device 4D can output the band A transmission signal output from the amplifier circuit 10Da from the antenna 2a and simultaneously output the band A transmission signal output from the amplifier circuit 10Db from the antenna 2b. The communication device 4D can also output the band B transmission signal output from the amplifier circuit 10Da from the antenna 2a and simultaneously output the band B transmission signal output from the amplifier circuit 10Db from the antenna 2b.

[0136] This may cause the band A transmission signal output from amplifier circuit 10Db to leak to amplifier circuit 10Da via antenna connection terminal 100b (antenna 2b) and antenna connection terminal 100a (antenna 2a). Even in this case, the reflection phase difference between the fundamental wave and harmonics of band A as seen from the output ends of balanced power amplifiers 11a and 11b is 180°, so load fluctuations in the fundamental wave band and harmonic bands can be suppressed. This makes it possible to provide a high-frequency circuit 1D in which fluctuations in the output characteristics of the transmission signal in the fundamental wave band and harmonic bands are suppressed.

[0137] In this modified example, the numerical values ​​of the transmission phase, reflection phase, and reflection phase difference do not only represent the strict meaning, but also include a substantially equivalent range, and include a difference of, for example, about 30%.

[0138] [6. Component layout of amplifier circuit 10] Next, the arrangement of components in the amplifier circuit 10 according to the embodiment will be described. Fig. 11 is a plan view of the amplifier circuit 10 according to the embodiment. Fig. 11(a) shows the arrangement of circuit components when the main surface 90a of the mounting board 90 is viewed from the positive side of the z-axis. Fig. 11(b) shows the arrangement of circuit components when the main surface 90b of the mounting board 90 is viewed from the positive side of the z-axis. Note that in Fig. 11, the mounting board 90 and the wiring connecting the circuit components are partially omitted.

[0139] The amplifier circuit 10 shown in FIG. 11 further includes a mounting substrate 90 in addition to the amplifier circuit 10 shown in FIG.

[0140] The mounting substrate 90 has main surfaces 90a and 90b facing each other, and is a substrate on which circuit components constituting the amplifier circuit 10 are mounted. Examples of the mounting substrate 90 that can be used include a low temperature co-fired ceramics (LTCC) substrate having a laminated structure of multiple dielectric layers, a high temperature co-fired ceramics (HTCC) substrate, a component-embedded substrate, a substrate having a redistribution layer (RDL), a printed circuit board, and the like.

[0141] 11, the 90° hybrid 50, power amplifiers 11 and 12, inductors 213, 221 and 321, and capacitors 211, 212, 222, 223, 311, 322 and 53 are arranged on the main surface 90a. On the other hand, the switch circuit 41 is arranged on the main surface 90b.

[0142] According to this, the circuit components are distributed and arranged on the main surfaces 90a and 90b of the mounting substrate 90, so that the amplifier circuit 10 can be made smaller.

[0143] The 90° hybrid 50 and the power amplifiers 11 and 12 are included in a semiconductor IC 71. The switch circuit 41 is included in a semiconductor IC 72.

[0144] According to this, the 90° hybrid 50, the power amplifiers 11 and 12, and the switch circuit 41 are integrated into a single chip, so that the amplifier circuit 10 can be made smaller.

[0145] The semiconductor ICs 71 and 72 may be configured using, for example, a complementary metal oxide semiconductor (CMOS), and more specifically, may be manufactured using an SOI (silicon on insulator) process. The semiconductor ICs 71 and 72 may also be configured using at least one of GaAs, SiGe, and GaN. The semiconductor materials of the semiconductor ICs 71 and 72 are not limited to the above-mentioned materials.

[0146] The switch circuit 41 includes terminals 41 a , 41 b , 41 c , 41 d and 41 e and switches 411 , 412 , 413 , 414 , 415 and 416 .

[0147] Switch 411 is an example of a first switch and is connected between terminal 41c and terminal 41a. Switch 413 is an example of a second switch and is connected between terminal 41c and terminal 41b. Switch 412 is an example of a third switch and is connected between terminal 41d and terminal 41a. Switch 414 is an example of a fourth switch and is connected between terminal 41d and terminal 41b. Switch 415 is connected between terminal 41e and terminal 41c. Switch 416 is connected between terminal 41e and terminal 41d.

[0148] When the main surface of semiconductor IC 72 is viewed from above, switches 411 and 412 are arranged between terminals 41c and 41d, and terminal 41a is arranged between switches 411 and 412. Switches 413 and 414 are arranged between terminals 41c and 41d, and terminal 41b is arranged between switches 413 and 414.

[0149] This makes it possible to make the line length from terminal 41c to terminal 41a for transmitting a band A signal equal to the line length from terminal 41d to terminal 41a, and to make the line length from terminal 41c to terminal 41b for transmitting a band B signal equal to the line length from terminal 41d to terminal 41b. Therefore, it is possible to set with high precision the difference in the reflection phase from the third output terminal of power amplifier 11 to terminal 41a and the reflection phase from the fourth output terminal of power amplifier 12 to terminal 41a, and it is possible to set with high precision the difference in the reflection phase from the third output terminal of power amplifier 11 to terminal 41b and the reflection phase from the fourth output terminal of power amplifier 12 to terminal 41b.

[0150] The amplifier circuit according to the first modification has a component layout similar to that shown in Fig. 11. However, the first variable circuit of the phase shift circuit 21A is included in the semiconductor IC 72 and is connected to the terminal 41c. The second variable circuit of the phase shift circuit 22A is included in the semiconductor IC 72 and is connected to the terminal 41d.

[0151] This allows the variable circuits of the phase shift circuits 21A and 22A to be included in the semiconductor IC 72 in which the switch circuit 41 is formed, thereby enabling the amplifier circuit and the high frequency circuit to be made smaller.

[0152] The third variable circuit of the harmonic phase shift circuit 31A is included in the semiconductor IC 72. The fourth variable circuit of the harmonic phase shift circuit 32A is included in the semiconductor IC72.

[0153] This allows the variable circuits of the harmonic phase shift circuits 31A and 32A to be included in the semiconductor IC 72 in which the switch circuit 41 is formed, thereby enabling the amplifier circuit and the high frequency circuit to be made smaller.

[0154] [7 Effects etc.] As described above, the high-frequency circuit 1 according to this embodiment includes the antenna connection terminal 100, the 90° hybrid 50 configured to demultiplex a fundamental signal in the transmission band of band A input to a first input terminal, output a first demultiplexed signal from a first output terminal, and output a second demultiplexed signal from a second output terminal, the second demultiplexed signal having a phase of +90° relative to the first demultiplexed signal, the power amplifier 11 having a second input terminal and a third output terminal, the second input terminal being connected to the first output terminal, and the power amplifier 11 having a third input terminal and a fourth output terminal, the third input terminal being connected to the a power amplifier 12 connected to the second output terminal; a combining circuit having a fourth input terminal, a fifth input terminal, and a fifth output terminal, configured to output from the fifth output terminal an output signal generated by in-phase combining the third demultiplexed signal input from the fourth input terminal and the fourth demultiplexed signal input from the fifth input terminal; a phase shift circuit 21 connected between the third output terminal and the fourth input terminal; a phase shift circuit 22 connected between the fourth output terminal and the fifth input terminal; a harmonic phase shift circuit 31 connected between the third output terminal and the fourth input terminal; and / or a harmonic phase shift circuit 32 connected between the fourth output terminal and the fifth input terminal, and a filter 61 connected between the fifth output terminal and the antenna connection terminal 100 and having a pass band including the above-mentioned transmission band, wherein the phase shift circuits 21 and 22 are configured so that the passing phase of the fundamental wave of the above-mentioned transmission band through the phase shift circuit 22 in the direction from the fourth output terminal to the fifth input terminal is −90° relative to the passing phase of the above-mentioned fundamental wave through the phase shift circuit 21 in the direction from the third output terminal to the fourth input terminal, and 22 and harmonic phase shift circuits 31 and 32 are configured so that the difference between the first reflection phase of the fundamental wave when viewed from the third output terminal to the fifth output terminal and the second reflection phase of the fundamental wave when viewed from the fourth output terminal to the fifth output terminal is 180°, and so that the difference between the third reflection phase of at least one of the harmonics in the transmission band when viewed from the third output terminal to the fifth output terminal and the fourth reflection phase of the at least one of the harmonics when viewed from the fourth output terminal to the fifth output terminal is 180°.

[0155] With this, even if unwanted signals of the fundamental frequency and second harmonic frequency of the transmission band of Band A leak from an external circuit to the high-frequency circuit 1 via the antenna connection terminal 100, the reflection phase difference of the fundamental wave as seen from the output ends of the two balanced power amplifiers 11 and 12 is 180°, and the reflection phase difference of the second harmonic is also 180°, so fluctuations in the transmission characteristics of the fundamental wave band and harmonic band of the high-frequency circuit 1 can be suppressed even if there is a load fluctuation. Therefore, it is possible to provide an amplifier circuit 10 and a high-frequency circuit 1 in which fluctuations in transmission characteristics due to load fluctuations are suppressed.

[0156] Furthermore, for example, in the high frequency circuit 1, the above-mentioned harmonic is a second harmonic having a frequency twice that of the fundamental wave.

[0157] This makes it possible to provide a high-frequency circuit 1 in which fluctuations in the output characteristics of the fundamental wave band and second harmonic band of the transmission signal are suppressed.

[0158] Furthermore, for example, in the high-frequency circuit according to the second modification, the harmonic is a third harmonic having a frequency three times that of the fundamental wave.

[0159] This makes it possible to provide a high-frequency circuit in which fluctuations in the output characteristics of the fundamental wave band and the third harmonic band of the transmission signal are suppressed.

[0160] For example, in the high-frequency circuit 1, the phase shift circuit 21 is configured so that the fundamental wave passes through it at a phase of +45°, the phase shift circuit 22 is configured so that the fundamental wave passes through it at a phase of -45°, the phase shift circuit 21 and the harmonic phase shift circuit 31 are configured so that the harmonics of the combined circuit formed by the phase shift circuit 21 and the harmonic phase shift circuit 31 pass through it at a phase of +45°, and the phase shift circuit 22 and the harmonic phase shift circuit 32 are configured so that the harmonics of the combined circuit formed by the phase shift circuit 22 and the harmonic phase shift circuit 32 pass through it at a phase of -45°.

[0161] This allows the first and second signals, two high-frequency signals in Band A, to be in-phase combined at the fifth output port, enabling highly efficient power combining of fundamental waves despite load fluctuations. Furthermore, the difference between the first reflected phase (+45° × 2 = 90°) of the fundamental wave of the first signal when viewed from the third output port to the fifth output port and the second reflected phase (-45° × 2 = -90°) of the fundamental wave of the second signal when viewed from the fourth output port to the fifth output port can be set to 180°. Furthermore, the difference between the third reflected phase (+45° × 2 = 90°) of the second harmonic of the first signal when viewed from the third output port to the fifth output port and the fourth reflected phase (-45° × 2 = -90°) of the second harmonic of the second signal when viewed from the fourth output port to the fifth output port can be set to 180°.

[0162] For example, in the high-frequency circuit 1, the phase-shift circuit 21 includes a capacitor 211 connected between the third output terminal and the fourth input terminal, and an inductor 213 connected between the path connecting the capacitor 211 and the fourth input terminal and ground, and the phase-shift circuit 22 includes an inductor 221 connected between the fourth output terminal and the fifth input terminal, and a capacitor 223 connected between the path connecting the inductor 221 and the fifth input terminal and ground.

[0163] According to this, the phase shift circuit 21 has a high-pass filter configuration and can set the passing phase of the fundamental wave of band A to +45°, and the phase shift circuit 22 has a low-pass filter configuration and can set the passing phase of the fundamental wave of band A to -45°.

[0164] For example, in the high-frequency circuit 1, the harmonic phase shift circuit 31 includes a capacitor 311 connected between the path connecting the third output terminal and the capacitor 211 and ground, and the harmonic phase shift circuit 32 has an LC circuit including an inductor 321 and a capacitor 322 connected in series with each other, and the LC circuit is connected between the path connecting the fourth output terminal and the inductor 221 and ground.

[0165] As a result, the harmonic phase shift circuit 31 becomes a low-pass filter whose passband is the fundamental wave band of band A, and the passing phase of the fundamental wave of band A can be set to 0°, and the harmonic phase shift circuit 32 becomes a notch filter whose passband is the above-mentioned fundamental wave band, and the passing phase of the above-mentioned fundamental wave can be set to 0°.

[0166] For example, the high-frequency circuit 1 further includes a filter 62 having a passband that includes the transmission band of band B, and the combining circuit has a terminal 41c (fourth input terminal), a terminal 41d (fifth input terminal), a terminal 41a (fifth output terminal), and a terminal 41b (sixth output terminal), and includes a switch circuit 41 that switches between the connection between terminal 41c and terminal 41a and the connection between terminal 41d and terminal 41a, and the connection between terminal 41c and terminal 41b and the connection between terminal 41d and terminal 41b, and the filter 62 is connected to terminal 41b.

[0167] This makes it possible to provide a multi-band compatible high-frequency circuit 1 that can output a transmission signal for band A and a transmission signal for band B. Furthermore, terminals 41a and 41b of switch circuit 41 serve as a signal combining point, and the switch circuit can also be used as a combining circuit, allowing the high-frequency circuit 1 to be made smaller.

[0168] For example, in the high-frequency circuit 1, the switch circuit 41 is included in the semiconductor IC 72, and includes a switch 411 connected to the terminals 41c and 41a, a switch 413 connected to the terminals 41c and 41b, a switch 412 connected to the terminals 41d and 41a, and a switch 414 connected to the terminals 41d and 41b, and when the main surface of the semiconductor IC 72 is viewed in plan, the switches 411 and 412 are arranged between the terminals 41c and 41d, the terminal 41a is arranged between the switches 411 and 412, the switches 413 and 414 are arranged between the terminals 41c and 41d, and the terminal 41b is arranged between the switches 413 and 414.

[0169] This makes it possible to make the line length from terminal 41c to terminal 41a for transmitting a band A signal equal to the line length from terminal 41d to terminal 41a, and to make the line length from terminal 41c to terminal 41b for transmitting a band B signal equal to the line length from terminal 41d to terminal 41b. Therefore, it is possible to set with high precision the difference in the reflection phase from the third output terminal of power amplifier 11 to terminal 41a and the reflection phase from the fourth output terminal of power amplifier 12 to terminal 41a, and it is possible to set with high precision the difference in the reflection phase from the third output terminal of power amplifier 11 to terminal 41b and the reflection phase from the fourth output terminal of power amplifier 12 to terminal 41b.

[0170] For example, in the high-frequency circuit 1, the switch circuit 41 further has a terminal 41e, which is connected to the terminal 41c in a state in which the terminal 41c is not connected to the terminals 41a and 41b, or is connected to the terminal 41d in a state in which the terminal 41d is not connected to the terminals 41a and 41b.

[0171] This allows the reflected phase of the fundamental wave and second harmonic of band A or band B to be measured at terminal 41e.

[0172] For example, in the high-frequency circuit according to variant example 2, at least one of the phase shift circuits 21A and 22A is configured so that the passing phase is variable depending on the switching between the connection between terminals 41c and 41d and terminal 41a, and the connection between terminals 41c and 41d and terminal 41b.

[0173] This allows the amount of reflected phase shift of the fundamental wave to be adjusted with high precision according to the band being transmitted.

[0174] For example, in the high-frequency circuit according to variant example 2, the switch circuit 41 is included in the semiconductor IC 72, the phase shift circuit 21A has a switch 215 and a first variable circuit having at least one of an inductor and a capacitor connected to the switch 215, the phase shift circuit 22A has a switch 225 and a second variable circuit having at least one of an inductor and a capacitor connected to the switch 225, the first variable circuit is connected to the terminal 41c and is included in the semiconductor IC 72, and the second variable circuit is connected to the terminal 41d and is included in the semiconductor IC 72.

[0175] This allows the variable circuits of the phase shift circuits 21A and 22A to be included in the semiconductor IC 72 in which the switch circuit 41 is formed, thereby enabling the amplifier circuit and the high frequency circuit to be made smaller.

[0176] For example, in the high-frequency circuit according to variant example 2, at least one of the harmonic phase shift circuits 31A and 32A is configured so that the passing phase is variable depending on the switching between the connection between terminals 41c and 41d and terminal 41a, and the connection between terminals 41c and 41d and terminal 41b.

[0177] This allows the amount of reflected phase shift of the second harmonic to be adjusted with high precision according to the band being transmitted.

[0178] For example, in the high-frequency circuit of variant example 2, switch circuit 41 is included in semiconductor IC 72, harmonic phase shift circuit 31A has a switch 313 and a third variable circuit having at least one of an inductor and a capacitor connected to switch 313, harmonic phase shift circuit 32A has a switch 324 and a fourth variable circuit having at least one of an inductor and a capacitor connected to switch 324, and the third variable circuit and the fourth variable circuit are included in semiconductor IC 72.

[0179] This allows the variable circuits of the harmonic phase shift circuits 31A and 32A to be included in the semiconductor IC 72 in which the switch circuit 41 is formed, thereby enabling the amplifier circuit and the high frequency circuit to be made smaller.

[0180] For example, a high-frequency circuit 1D according to variant example 4 includes antenna connection terminals 100a and 100b, an amplifier circuit 10Da connected to the antenna connection terminal 100a and including power amplifiers 11a and 12a, an amplifier circuit 10Db connected to the antenna connection terminal 100b and including power amplifiers 11b and 12b, a filter 61a connected between the antenna connection terminal 100a and the amplifier circuit 10Da, and a filter 61b connected between the antenna connection terminal 100b and the amplifier circuit 10Db.

[0181] With this configuration, even if the band A transmission signal output from amplifier circuit 10Db leaks to amplifier circuit 10Da via antenna connection terminals 100b and 100a, the reflection phase difference between the fundamental wave and harmonics of band A as seen from the output ends of balanced power amplifiers 11a and 11b is 180°, thereby suppressing load fluctuations in the fundamental and harmonic bands.This makes it possible to provide a high-frequency circuit 1D in which fluctuations in the output characteristics of the transmission signal in the fundamental and harmonic bands are suppressed.

[0182] The high-frequency circuit according to the third modification includes an antenna connection terminal 100, a 90° hybrid 50 configured to demultiplex a fundamental signal in the transmission band of band A input to a first input terminal, output a first demultiplexed signal from a first output terminal, and output a second demultiplexed signal from a second output terminal, the second demultiplexed signal having a phase of +90° relative to the first demultiplexed signal, a power amplifier 11 having a second input terminal and a third output terminal, the second input terminal being connected to the first output terminal, and a third input terminal and a fourth output terminal, the third input terminal being connected to a power amplifier 12 connected to the second output terminal; a combining circuit having a fourth input terminal, a fifth input terminal, and a fifth output terminal, configured to output from the fifth output terminal an output signal generated by combining in antiphase the third demultiplexed signal input from the fourth input terminal and the fourth demultiplexed signal input from the fifth input terminal; a phase shift circuit 21C connected between the third output terminal and the fourth input terminal; a phase shift circuit 22C connected between the fourth output terminal and the fifth input terminal; and a harmonic phase shift circuit 3C connected between the third output terminal and the fourth input terminal. and a harmonic phase shift circuit 32C connected between the fourth output terminal and the fifth input terminal, and a filter 61 connected between the fifth output terminal and the antenna connection terminal 100 and having a pass band including the above-mentioned transmission band, and the phase shift circuits 21C and 22C are arranged such that the passing phase of the fundamental wave of the above-mentioned transmission band of the phase shift circuit 22C in the direction from the fourth output terminal to the fifth input terminal is −90° relative to the passing phase of the above-mentioned fundamental wave of the phase shift circuit 21C in the direction from the third output terminal to the fourth input terminal. The phase-shift circuits 21C and 22C and the harmonic phase-shift circuits 31C and 32C are configured so that the difference between the first reflection phase of the fundamental wave when viewed from the third output terminal to the fifth output terminal and the second reflection phase of the fundamental wave when viewed from the fourth output terminal to the fifth output terminal is 180°, and so that the difference between the third reflection phase of the harmonic of the transmission band when viewed from the third output terminal to the fifth output terminal and the fourth reflection phase of the harmonic when viewed from the fourth output terminal to the fifth output terminal is 180°.

[0183] With this, even if unwanted signals of the fundamental frequency and second harmonic frequency of the transmission band of Band A leak from an external circuit to the high-frequency circuit via antenna connection terminal 100, the reflection phase difference of the fundamental wave as seen from the output ends of two balanced power amplifiers 11 and 12 is 180°, and the reflection phase difference of the second harmonic is also 180°, so fluctuations in the transmission characteristics of the high-frequency circuit in the fundamental band and harmonic band can be suppressed even if there is a load fluctuation. Thus, it is possible to provide amplifier circuit 10C and a high-frequency circuit in which fluctuations in transmission characteristics due to load fluctuations are suppressed.

[0184] Furthermore, for example, in the high-frequency circuit according to the third modification, the harmonic is a second harmonic having a frequency twice that of the fundamental wave.

[0185] This makes it possible to provide a high-frequency circuit in which fluctuations in the output characteristics of the fundamental wave band and second harmonic band of the transmission signal are suppressed.

[0186] Furthermore, for example, in the high-frequency circuit according to the third modification, the harmonic is a third harmonic having a frequency three times that of the fundamental wave.

[0187] This makes it possible to provide a high-frequency circuit in which fluctuations in the output characteristics of the fundamental wave band and the third harmonic band of the transmission signal are suppressed.

[0188] For example, in the high-frequency circuit of variant example 3, the phase shift circuit 21C is configured so that the passing phase of the fundamental wave is -45°, the phase shift circuit 22C is configured so that the passing phase of the fundamental wave is +45°, the phase shift circuit 21C and the harmonic phase shift circuit 31C are configured so that the passing phase of the harmonics of the circuit combined with the phase shift circuit 21C and the harmonic phase shift circuit 31C is -45°, and the phase shift circuit 22C and the harmonic phase shift circuit 32C are configured so that the passing phase of the harmonics of the circuit combined with the phase shift circuit 22C and the harmonic phase shift circuit 32C is +45°.

[0189] This allows the first and second signals, which are two high-frequency signals in Band A, to be combined in antiphase at the fifth output port, enabling highly efficient power combining of fundamental waves despite load fluctuations. Furthermore, the difference between the first reflected phase (-90°) of the fundamental wave of the first signal when viewed from the third output port to the fifth output port and the second reflected phase (+90°) of the fundamental wave of the second signal when viewed from the fourth output port to the fifth output port can be set to 180°. Furthermore, the difference between the third reflected phase of the second harmonic of the first signal when viewed from the third output port to the fifth output port and the fourth reflected phase of the second harmonic of the second signal when viewed from the fourth output port to the fifth output port can be set to 180°.

[0190] Also, for example, in the high-frequency circuit according to variant example 3, the phase-shift circuit 21C includes an inductor 221 connected between the third output terminal and the fourth input terminal, and a capacitor 223 connected between the path connecting the inductor 221 and the fourth input terminal and ground, and the phase-shift circuit 22C includes a capacitor 211 connected between the fourth output terminal and the fifth input terminal, and an inductor 213 connected between the path connecting the capacitor 211 and the fifth input terminal and ground.

[0191] According to this, phase shift circuit 21C has a low-pass filter configuration and can set the passing phase of the fundamental wave of band A to -45°, and phase shift circuit 22C has a high-pass filter configuration and can set the passing phase of the fundamental wave of band A to +45°.

[0192] For example, in the high-frequency circuit according to variant example 3, the harmonic phase shift circuit 31C has an LC circuit including an inductor 321 and a capacitor 322 connected in series with each other, and the LC circuit is connected between the path connecting the third output terminal and the inductor 221 and ground, and the harmonic phase shift circuit 32C includes a capacitor 311 connected between the path connecting the fourth output terminal and the capacitor 211 and ground.

[0193] As a result, the harmonic phase shift circuit 31C becomes a notch filter whose passband is the fundamental wave band of band A, and the passing phase of the fundamental wave of band A can be set to 0°, and the harmonic phase shift circuit 32C becomes a low-pass filter whose passband is the above-mentioned fundamental wave band, and the passing phase of the above-mentioned fundamental wave can be set to 0°.

[0194] (Other embodiments, etc.) Although the high-frequency circuits according to the embodiments of the present invention have been described above by way of examples and modifications, the high-frequency circuits according to the present invention are not limited to the above-described embodiments and modifications. The present invention also includes other embodiments realized by combining any of the components in the above-described embodiments and modifications, modifications obtained by applying various modifications to the above-described embodiments and modifications that would occur to those skilled in the art without departing from the spirit of the present invention, and various devices incorporating the above-described high-frequency circuits.

[0195] For example, in the amplifier circuits, high-frequency circuits, and communication devices according to the above-described embodiments and modifications, other circuit elements, wiring, etc. may be inserted between the paths connecting the circuit elements and signal paths disclosed in the drawings.

[0196] The features of the high-frequency circuits described based on the above embodiments will be described below.

[0197] <1> a first antenna terminal; a demultiplexer having a first input terminal, a first output terminal, and a second output terminal, configured to demultiplex a fundamental wave signal of a first transmission band input to the first input terminal, output a first demultiplexed signal from the first output terminal, and output a second demultiplexed signal having a phase that is +90° relative to the first demultiplexed signal from the second output terminal; a first power amplifier having a second input and a third output, the second input connected to the first output; a second power amplifier having a third input and a fourth output, the third input connected to the second output; a combining circuit having a fourth input terminal, a fifth input terminal, and a fifth output terminal, configured to output from the fifth output terminal an output signal generated by in-phase combining the third demultiplexed signal input from the fourth input terminal and the fourth demultiplexed signal input from the fifth input terminal; a first phase shift circuit connected between the third output terminal and the fourth input terminal; a second phase shift circuit connected between the fourth output terminal and the fifth input terminal; a first harmonic phase shift circuit connected between the third output terminal and the fourth input terminal, and / or a second harmonic phase shift circuit connected between the fourth output terminal and the fifth input terminal; a first filter connected between the fifth output port and the first antenna terminal and having a passband including the transmission band; The first phase shift circuit and the second phase shift circuit are a phase of the fundamental wave of the transmission band passing through the second phase shift circuit in a direction from the fourth output port to the fifth input port is configured to be −90° relative to a phase of the fundamental wave passing through the first phase shift circuit in a direction from the third output port to the fourth input port, The first phase shift circuit, the second phase shift circuit, the first harmonic phase shift circuit, and the second harmonic phase shift circuit are a difference between a first reflection phase of the fundamental wave when viewed from the third output end to the fifth output end and a second reflection phase of the fundamental wave when viewed from the fourth output end to the fifth output end is 180°; and a high-frequency circuit configured so that a difference between a third reflection phase of at least one of the harmonics in the transmission band when viewed from the third output end to the fifth output end and a fourth reflection phase of the at least one of the harmonics when viewed from the fourth output end to the fifth output end is 180°.

[0198] <2> The harmonic is a second harmonic having twice the frequency of the fundamental wave. <1> The high-frequency circuit according to claim 1.

[0199] <3> The harmonic is a third harmonic having a frequency three times that of the fundamental wave. <1> The high-frequency circuit according to claim 1.

[0200] <4> the first phase shift circuit is configured so that the passing phase of the fundamental wave is +45°; the second phase shift circuit is configured so that the passing phase of the fundamental wave is −45°; the first phase shift circuit and the first harmonic phase shift circuit are configured so that the phase of the harmonic passing through a circuit including the first phase shift circuit and the first harmonic phase shift circuit is +45°; the second phase shift circuit and the second harmonic phase shift circuit are configured so that the phase of the harmonic passing through a circuit including the second phase shift circuit and the second harmonic phase shift circuit is −45°; <1> ~ <3> 10. The high-frequency circuit according to claim 9,

[0201] <5> The first phase shift circuit comprises: a first capacitor connected between the third output terminal and the fourth input terminal; a first inductor connected between a path connecting the first capacitor and the fourth input terminal and ground; The second phase shift circuit comprises: a second inductor connected between the fourth output terminal and the fifth input terminal; a second capacitor connected between a path connecting the second inductor and the fifth input terminal and ground; <4> The high-frequency circuit according to claim 1.

[0202] <6> the high-frequency circuit comprises the first harmonic phase shift circuit and the second harmonic phase shift circuit; The first harmonic phase shift circuit comprises: a third capacitor connected between a path connecting the third output terminal and the first capacitor and ground; The second harmonic phase shift circuit comprises: an LC circuit including a third inductor and a fourth capacitor connected in series with each other; the LC circuit is connected between a path connecting the fourth output terminal and the second inductor and ground. <5> The high-frequency circuit according to claim 1.

[0203] <7> further comprising a second filter having a passband including a transmission band of the second band; The synthesis circuit a switch circuit having the fourth input terminal, the fifth input terminal, the fifth output terminal, and a sixth output terminal, which switches between a connection between the fourth input terminal and the fifth output terminal and a connection between the fifth input terminal and the fifth output terminal, and a connection between the fourth input terminal and the sixth output terminal and a connection between the fifth input terminal and the sixth output terminal; the second filter is connected to the sixth output terminal; <1> ~ <6> 10. The high-frequency circuit according to claim 9,

[0204] <8> the switch circuit is included in a semiconductor IC, a first switch connected to the fourth input terminal and the fifth output terminal; a second switch connected to the fourth input terminal and the sixth output terminal; a third switch connected to the fifth input terminal and the fifth output terminal; a fourth switch connected to the fifth input terminal and the sixth output terminal; When the main surface of the semiconductor IC is viewed in plan, the first switch and the third switch are disposed between the fourth input terminal and the fifth input terminal; the fifth output terminal is disposed between the first switch and the third switch; the second switch and the fourth switch are disposed between the fourth input terminal and the fifth input terminal; the sixth output terminal is disposed between the second switch and the fourth switch; <7> The high-frequency circuit according to claim 1.

[0205] <9> The switch circuit further has a monitor terminal, the monitor terminal is connected to the fourth input terminal in a state in which the fourth input terminal is not connected to the fifth output terminal and the sixth output terminal, or is connected to the fifth input terminal in a state in which the fifth input terminal is not connected to the fifth output terminal and the sixth output terminal, <7> or <8> The high-frequency circuit according to claim 1.

[0206] <10> At least one of the first phase shift circuit and the second phase shift circuit is configured to vary a passing phase in response to switching of connections between the fourth input terminal and the fifth input terminal and the fifth output terminal, and between the fourth input terminal and the fifth input terminal and the sixth output terminal. <7> ~ <9> 10. The high-frequency circuit according to claim 9,

[0207] <11> the switch circuit is included in a semiconductor IC, the first phase-shift circuit includes a fifth switch and a first variable circuit having at least one of an inductor and a capacitor connected to the fifth switch; the second phase-shift circuit includes a sixth switch and a second variable circuit having at least one of an inductor and a capacitor connected to the sixth switch; the first variable circuit is connected to the fourth input terminal and is included in the semiconductor IC; the second variable circuit is connected to the fifth input terminal and is included in the semiconductor IC; <10> The high-frequency circuit according to claim 1.

[0208] <12> the high-frequency circuit comprises the first harmonic phase shift circuit and the second harmonic phase shift circuit; At least one of the first harmonic phase shift circuit and the second harmonic phase shift circuit is configured to vary a passing phase in response to switching of connections between the fourth input terminal and the fifth input terminal and the fifth output terminal, and between the fourth input terminal and the fifth input terminal and the sixth output terminal. <7> ~ <11> 10. The high-frequency circuit according to claim 9,

[0209] <13> the switch circuit is included in a semiconductor IC, the first harmonic phase shift circuit includes a seventh switch and a third variable circuit having at least one of an inductor and a capacitor connected to the seventh switch; the second harmonic phase shift circuit includes an eighth switch and a fourth variable circuit having at least one of an inductor and a capacitor connected to the eighth switch; the third variable circuit and the fourth variable circuit are included in the semiconductor IC; <12> The high-frequency circuit according to claim 1.

[0210] <14> moreover, a second antenna terminal; a third power amplifier; a third filter connected between the second antenna terminal and the output end of the third power amplifier and having a passband including a transmission band of the first band; <1> ~ <13> 10. The high-frequency circuit according to claim 9,

[0211] <15> a first antenna terminal; a demultiplexer having a first input terminal, a first output terminal, and a second output terminal, configured to demultiplex a fundamental wave signal of a first transmission band input to the first input terminal, output a first demultiplexed signal from the first output terminal, and output a second demultiplexed signal having a phase that is +90° relative to the first demultiplexed signal from the second output terminal; a first power amplifier having a second input and a third output, the second input connected to the first output; a second power amplifier having a third input and a fourth output, the third input connected to the second output; a combining circuit having a fourth input terminal, a fifth input terminal, and a fifth output terminal, configured to output from the fifth output terminal an output signal generated by combining, in antiphase, the third demultiplexed signal input from the fourth input terminal and the fourth demultiplexed signal input from the fifth input terminal; a first phase shift circuit connected between the third output terminal and the fourth input terminal; a second phase shift circuit connected between the fourth output terminal and the fifth input terminal; a first harmonic phase shift circuit connected between the third output terminal and the fourth input terminal, and / or a second harmonic phase shift circuit connected between the fourth output terminal and the fifth input terminal; a first transmission filter connected between the fifth output port and the first antenna terminal and having a passband including the transmission band; The first phase shift circuit and the second phase shift circuit are a phase of the fundamental wave of the transmission band passing through the second phase shift circuit in a direction from the fourth output port to the fifth input port is configured to be −90° relative to a phase of the fundamental wave passing through the first phase shift circuit in a direction from the third output port to the fourth input port, The first phase shift circuit, the second phase shift circuit, the first harmonic phase shift circuit, and the second harmonic phase shift circuit are a difference between a first reflection phase of the fundamental wave when viewed from the third output end to the fifth output end and a second reflection phase of the fundamental wave when viewed from the fourth output end to the fifth output end is 180°; and a high-frequency circuit configured so that a difference between a third reflection phase of at least one of the harmonics in the transmission band when viewed from the third output end to the fifth output end and a fourth reflection phase of the at least one of the harmonics when viewed from the fourth output end to the fifth output end is 180°.

[0212] <16> The harmonic is a second harmonic having twice the frequency of the fundamental wave. <15> The high-frequency circuit according to claim 1.

[0213] <17> The harmonic is a third harmonic having a frequency three times that of the fundamental wave. <15> The high-frequency circuit according to claim 1.

[0214] <18> the first phase shift circuit is configured so that the passing phase of the fundamental wave is −45°; the second phase shift circuit is configured so that the passing phase of the fundamental wave is +45°; the first phase shift circuit and the first harmonic phase shift circuit are configured so that the phase of the harmonic passing through a circuit including the first phase shift circuit and the first harmonic phase shift circuit is −45°; the second phase shift circuit and the second harmonic phase shift circuit are configured so that the phase of the harmonic passing through a circuit including the second phase shift circuit and the second harmonic phase shift circuit is +45°; <15> ~ <17> 10. The high-frequency circuit according to claim 9,

[0215] <19> The first phase shift circuit comprises: a first inductor connected between the third output terminal and the fourth input terminal; a first capacitor connected between a path connecting the first inductor and the fourth input terminal and ground; The second phase shift circuit comprises: a second capacitor connected between the fourth output terminal and the fifth input terminal; a second inductor connected between a path connecting the second capacitor and the fifth input terminal and ground; <18> The high-frequency circuit according to claim 1.

[0216] <20> the high-frequency circuit comprises the first harmonic phase shift circuit and the second harmonic phase shift circuit; The first harmonic phase shift circuit comprises: an LC circuit including a third inductor and a third capacitor connected in series with each other; the LC circuit is connected between a path connecting the third output terminal and the first inductor and ground; The second harmonic phase shift circuit comprises: a fourth capacitor connected between a path connecting the fourth output terminal and the second capacitor and ground; <19> The high-frequency circuit according to claim 1. [Industrial Applicability]

[0217] The present invention can be widely used in communication devices such as mobile phones as an amplifier circuit, a high frequency circuit or a communication device arranged in a front end portion. [Explanation of symbols]

[0218] 1. 1D high frequency circuit 2, 2a, 2b antennas 3 RF signal processing circuit (RFIC) 4, 4D communication device 10, 10B, 10C, 10Da, 10Db amplifier circuits 11, 11a, 11b, 12, 12a, 12b Power amplifiers 21, 21A, 21C, 21Da, 21Db, 22, 22A, 22C, 22Da, 22Db phase shift circuit 31, 31A, 31B, 31C, 31Da, 31Db, 32, 32A, 32B, 32C, 32Da, 32Db harmonic phase shift circuit 41, 42, 43, 44a, 44b, 46 Switch circuit 41a, 41b, 41c, 41d, 41e, 42a, 42b, 42c, 43a, 43b, 43c, 43d, 43e, 43f, 43g, 43h, 45a, 45b, 45c, 46a, 46b, 46c, 201, 202, 203, 204 terminal 45 Trans 50, 50a, 50b 90° hybrid 51, 52 phase shift line 53, 211, 212, 214, 222, 223, 224, 311, 312, 322, 323 capacitors 54, 55, 56, 57, 58, 59, 213, 221, 321 Inductors 61, 61a, 61b, 62, 62a, 62b filters 71, 72 Semiconductor IC 90 Mounting board 90a, 90b main surface 100, 100a, 100b Antenna connection terminal 110, 110a, 110b High frequency input terminals 215, 225, 313, 324, 411, 412, 413, 414, 415, 416 switches

Claims

1. a first antenna terminal; a demultiplexer having a first input terminal, a first output terminal, and a second output terminal, configured to demultiplex a fundamental wave signal of a first transmission band input to the first input terminal, output a first demultiplexed signal from the first output terminal, and output a second demultiplexed signal having a phase that is +90° relative to the first demultiplexed signal from the second output terminal; a first power amplifier having a second input and a third output, the second input connected to the first output; a second power amplifier having a third input and a fourth output, the third input connected to the second output; a combining circuit having a fourth input terminal, a fifth input terminal, and a fifth output terminal, configured to output from the fifth output terminal an output signal generated by in-phase combining the third demultiplexed signal input from the fourth input terminal and the fourth demultiplexed signal input from the fifth input terminal; a first phase shift circuit connected between the third output terminal and the fourth input terminal; a second phase shift circuit connected between the fourth output terminal and the fifth input terminal; a first harmonic phase shift circuit connected between the third output terminal and the fourth input terminal, and / or a second harmonic phase shift circuit connected between the fourth output terminal and the fifth input terminal; a first filter connected between the fifth output port and the first antenna terminal and having a pass band including the transmission band; The first phase shift circuit and the second phase shift circuit are a phase of the fundamental wave of the transmission band passing through the second phase shift circuit in a direction from the fourth output terminal to the fifth input terminal is configured to be −90° relative to a phase of the fundamental wave passing through the first phase shift circuit in a direction from the third output terminal to the fourth input terminal, The first phase shift circuit, the second phase shift circuit, the first harmonic phase shift circuit, and the second harmonic phase shift circuit are a difference between a first reflection phase of the fundamental wave when viewed from the third output end to the fifth output end and a second reflection phase of the fundamental wave when viewed from the fourth output end to the fifth output end is 180°; and a difference between a third reflection phase of at least one of the harmonics in the transmission band when viewed from the third output end to the fifth output end and a fourth reflection phase of the at least one of the harmonics when viewed from the fourth output end to the fifth output end is 180°; High frequency circuits.

2. The harmonic is a second harmonic having twice the frequency of the fundamental wave. The high frequency circuit according to claim 1 .

3. The harmonic is a third harmonic having a frequency three times that of the fundamental wave. The high frequency circuit according to claim 1 .

4. the first phase shift circuit is configured so that the passing phase of the fundamental wave is +45°; the second phase shift circuit is configured so that the passing phase of the fundamental wave is −45°; the first phase shift circuit and the first harmonic phase shift circuit are configured so that the phase of the harmonic passing through a circuit including the first phase shift circuit and the first harmonic phase shift circuit is +45°; the second phase shift circuit and the second harmonic phase shift circuit are configured so that the phase of the harmonic passing through a circuit including the second phase shift circuit and the second harmonic phase shift circuit is −45°; The high frequency circuit according to claim 1 .

5. The first phase shift circuit comprises: a first capacitor connected between the third output terminal and the fourth input terminal; a first inductor connected between a path connecting the first capacitor and the fourth input terminal and ground; The second phase shift circuit comprises: a second inductor connected between the fourth output terminal and the fifth input terminal; a second capacitor connected between a path connecting the second inductor and the fifth input terminal and ground; The high frequency circuit according to claim 4.

6. the high-frequency circuit includes the first harmonic phase shift circuit and the second harmonic phase shift circuit; The first harmonic phase shift circuit comprises: a third capacitor connected between a path connecting the third output terminal and the first capacitor and ground; The second harmonic phase shift circuit comprises: an LC circuit including a third inductor and a fourth capacitor connected in series with each other; the LC circuit is connected between a path connecting the fourth output terminal and the second inductor and ground. The high frequency circuit according to claim 5.

7. further comprising a second filter having a passband including a transmission band of the second band; The synthesis circuit a switch circuit having the fourth input terminal, the fifth input terminal, the fifth output terminal, and a sixth output terminal, and switching between a connection between the fourth input terminal and the fifth output terminal and a connection between the fifth input terminal and the fifth output terminal, and a connection between the fourth input terminal and the sixth output terminal and a connection between the fifth input terminal and the sixth output terminal; the second filter is connected to the sixth output terminal; The high-frequency circuit according to any one of claims 1 to 6.

8. the switch circuit is included in a semiconductor IC, a first switch connected to the fourth input terminal and the fifth output terminal; a second switch connected to the fourth input terminal and the sixth output terminal; a third switch connected to the fifth input terminal and the fifth output terminal; a fourth switch connected to the fifth input terminal and the sixth output terminal; When the main surface of the semiconductor IC is viewed in plan, the first switch and the third switch are disposed between the fourth input terminal and the fifth input terminal; the fifth output terminal is disposed between the first switch and the third switch; the second switch and the fourth switch are disposed between the fourth input terminal and the fifth input terminal; the sixth output terminal is disposed between the second switch and the fourth switch; The high frequency circuit according to claim 7.

9. The switch circuit further has a monitor terminal, the monitor terminal is connected to the fourth input terminal in a state in which the fourth input terminal is not connected to the fifth output terminal and the sixth output terminal, or is connected to the fifth input terminal in a state in which the fifth input terminal is not connected to the fifth output terminal and the sixth output terminal, The high frequency circuit according to claim 7.

10. at least one of the first phase shift circuit and the second phase shift circuit is configured to vary a passing phase in response to switching of connections between the fourth input terminal and the fifth input terminal and the fifth output terminal, and between the fourth input terminal and the fifth input terminal and the sixth output terminal; The high frequency circuit according to claim 7.

11. the switch circuit is included in a semiconductor IC, the first phase-shift circuit includes a fifth switch and a first variable circuit having at least one of an inductor and a capacitor connected to the fifth switch; the second phase-shift circuit includes a sixth switch and a second variable circuit having at least one of an inductor and a capacitor connected to the sixth switch; the first variable circuit is connected to the fourth input terminal and is included in the semiconductor IC; the second variable circuit is connected to the fifth input terminal and is included in the semiconductor IC; The high frequency circuit according to claim 10.

12. the high-frequency circuit includes the first harmonic phase shift circuit and the second harmonic phase shift circuit; at least one of the first harmonic phase shift circuit and the second harmonic phase shift circuit is configured to vary a passing phase in response to switching of connections between the fourth input terminal and the fifth input terminal and the fifth output terminal, and between the fourth input terminal and the fifth input terminal and the sixth output terminal; The high frequency circuit according to claim 7.

13. the switch circuit is included in a semiconductor IC, the first harmonic phase shift circuit includes a seventh switch and a third variable circuit having at least one of an inductor and a capacitor connected to the seventh switch; the second harmonic phase shift circuit includes an eighth switch and a fourth variable circuit having at least one of an inductor and a capacitor connected to the eighth switch; the third variable circuit and the fourth variable circuit are included in the semiconductor IC. The high frequency circuit according to claim 12.

14. moreover, a second antenna terminal; a third power amplifier; a third filter connected between the second antenna terminal and an output end of the third power amplifier and having a passband including a transmission band of the first band; The high-frequency circuit according to any one of claims 1 to 6.

15. a first antenna terminal; a demultiplexer having a first input terminal, a first output terminal, and a second output terminal, configured to demultiplex a fundamental wave signal of a first transmission band input to the first input terminal, output a first demultiplexed signal from the first output terminal, and output a second demultiplexed signal having a phase that is +90° relative to the first demultiplexed signal from the second output terminal; a first power amplifier having a second input and a third output, the second input connected to the first output; a second power amplifier having a third input and a fourth output, the third input connected to the second output; a combining circuit having a fourth input terminal, a fifth input terminal, and a fifth output terminal, configured to output from the fifth output terminal an output signal generated by combining, in antiphase, the third demultiplexed signal input from the fourth input terminal and the fourth demultiplexed signal input from the fifth input terminal; a first phase shift circuit connected between the third output terminal and the fourth input terminal; a second phase shift circuit connected between the fourth output terminal and the fifth input terminal; a first harmonic phase shift circuit connected between the third output terminal and the fourth input terminal, and / or a second harmonic phase shift circuit connected between the fourth output terminal and the fifth input terminal; a first transmission filter connected between the fifth output port and the first antenna terminal and having a passband including the transmission band; The first phase shift circuit and the second phase shift circuit are a phase of the fundamental wave of the transmission band passing through the second phase shift circuit in a direction from the fourth output terminal to the fifth input terminal is configured to be −90° relative to a phase of the fundamental wave passing through the first phase shift circuit in a direction from the third output terminal to the fourth input terminal, The first phase shift circuit, the second phase shift circuit, the first harmonic phase shift circuit, and the second harmonic phase shift circuit are a difference between a first reflection phase of the fundamental wave when viewed from the third output end to the fifth output end and a second reflection phase of the fundamental wave when viewed from the fourth output end to the fifth output end is 180°; and a difference between a third reflection phase of at least one of the harmonics in the transmission band when viewed from the third output end to the fifth output end and a fourth reflection phase of the at least one of the harmonics when viewed from the fourth output end to the fifth output end is 180°; High frequency circuits.

16. The harmonic is a second harmonic having twice the frequency of the fundamental wave. The high frequency circuit according to claim 15.

17. The harmonic is a third harmonic having a frequency three times that of the fundamental wave. The high frequency circuit according to claim 15.

18. the first phase shift circuit is configured so that the passing phase of the fundamental wave is −45°; the second phase shift circuit is configured so that the passing phase of the fundamental wave is +45°; the first phase shift circuit and the first harmonic phase shift circuit are configured so that a phase of the harmonic passing through a circuit including the first phase shift circuit and the first harmonic phase shift circuit is −45°; the second phase shift circuit and the second harmonic phase shift circuit are configured so that the phase of the harmonic passing through a circuit including the second phase shift circuit and the second harmonic phase shift circuit is +45°; The high-frequency circuit according to any one of claims 15 to 17.

19. The first phase shift circuit comprises: a first inductor connected between the third output terminal and the fourth input terminal; a first capacitor connected between a path connecting the first inductor and the fourth input terminal and ground; The second phase shift circuit comprises: a second capacitor connected between the fourth output terminal and the fifth input terminal; a second inductor connected between a path connecting the second capacitor and the fifth input terminal and ground; The high frequency circuit according to claim 18.

20. the high-frequency circuit includes the first harmonic phase shift circuit and the second harmonic phase shift circuit; The first harmonic phase shift circuit comprises: an LC circuit including a third inductor and a third capacitor connected in series with each other; the LC circuit is connected between a path connecting the third output terminal and the first inductor and ground; The second harmonic phase shift circuit comprises: a fourth capacitor connected between a path connecting the fourth output terminal and the second capacitor and ground; 20. The high frequency circuit according to claim 19.

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