High-frequency circuit

Abstract

To provide a high-frequency circuit that achieves improved isolation between transmission and reception.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 of a band A input from a fourth input terminal and a fourth signal of the band A 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 the signal of the band A is -90° relative to the phase shift circuit 21, a filter 61 whose passband includes a transmission band of the band A, and a filter 64 whose passband includes a reception band of a band B, which can be transmitted simultaneously with the band A. The difference between a first reflection phase of the reception band of the band B at the third output terminal and a second reflection phase of the reception band of the band B 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] In high-frequency circuits that simultaneously transmit transmit and receive signals, there is a demand for highly efficient power combining in response to load fluctuations, as well as improved isolation between the transmitter and receiver.

[0005] The present invention has been made to solve the above-mentioned problems, and has an object to provide a high-frequency circuit that realizes highly efficient power combining and improved isolation between transmission and reception. [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 demultiplexer having a first antenna terminal, a first input terminal, a first output terminal, and a second output terminal, configured to demultiplex a signal of a transmission band of a first 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 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; and a fourth input terminal, a fifth input terminal, and a fifth output terminal, configured to output a first-band output signal from the fifth output terminal, the first-band output signal being generated by in-phase combining the third demultiplexed signal of the first band input from the fourth input terminal and the fourth demultiplexed signal of the first band input from the fifth input terminal. a combining circuit configured as 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 and configured so that the passing phase of signals in the transmission band of the first band is −90° relative to the first phase-shift circuit; a first filter connected between the fifth output terminal and the first antenna terminal or between the first phase-shift circuit and the fourth input terminal and having a pass band that includes the transmission band of the first band; and a second filter connected to a path connecting the first antenna terminal and the first filter and having a pass band that includes a reception band of a second band that can transmit simultaneously with the first band, wherein the first phase-shift circuit and the second phase-shift circuit are configured so that the difference between a first reflection phase of the reception band of the second band when viewed from the third output terminal to the fifth output terminal and a second reflection phase of the reception band of the second band when viewed from the fourth output terminal to the fifth output terminal is 180°.

[0007] Furthermore, a high-frequency circuit according to one aspect of the present invention includes a first antenna terminal, a combiner having a first output terminal, a first input terminal, and a second input terminal, configured to combine a first signal in a reception band of a first band input to the first input terminal and a second signal in which the signal in the reception band of the first band input to the second input terminal has a phase difference of +90° relative to the first signal, and output the resultant signal from the first output terminal; a first low-noise amplifier having a second output terminal and a third input terminal, the second output terminal being connected to the first input terminal; a second low-noise amplifier having a third output terminal and a fourth input terminal, the third output terminal being connected to the second input terminal; a branching circuit having a fourth output terminal, a fifth output terminal, and the fifth input terminal, configured to power-divide the reception signal in the first band input to the fifth input terminal to the fourth output terminal and the fifth output terminal; the first phase-shift circuit is connected between the fourth input terminal and the fifth output terminal; a second phase-shift circuit is connected between the fourth input terminal and the fifth output terminal and configured so that the pass phase of the receive band of the first band is −90° relative to the first phase-shift circuit; a first filter is connected between the fifth input terminal and the first antenna terminal or between the first phase-shift circuit and the fourth output terminal and has a pass band that includes the receive band of the first band; and a second filter is connected to a path connecting the first antenna terminal and the first filter and has a pass band that includes a transmit band of a second band that can transmit simultaneously with the first band, the first phase-shift circuit and the second phase-shift circuit are configured so that the difference between a first reflected phase of the transmit band of the second band when viewed from the third input terminal to the fifth input terminal and a second reflected phase of the transmit band of the second band when viewed from the fourth input terminal to the fifth input terminal is 180°. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a high-frequency circuit that realizes highly efficient power combining and improved isolation between transmission and reception. [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 2] 3 is a circuit state diagram of the high-frequency circuit according to the embodiment in a first mode. FIG. [Figure 3] 4 is a Smith chart showing the transmission pass characteristics and the impedance in the reception band of the high-frequency circuits according to Example 1 and the comparative example. [Figure 4] FIG. 4 is a circuit state diagram of the high-frequency circuit according to the embodiment in a second mode. [Figure 5] FIG. 4 is a circuit state diagram of the high-frequency circuit according to the embodiment in a third mode. [Figure 6] 10 is a circuit configuration diagram of an amplifier circuit, a high-frequency circuit, and a communication device according to a first modified example of the embodiment. FIG. [Figure 7A] FIG. 10 is a circuit state diagram of a high-frequency circuit according to a second modification of the embodiment in a first mode. [Figure 7B] FIG. 10 is a circuit state diagram of a high-frequency circuit according to a second modification of the embodiment in a second mode. [Figure 8] 10A and 10B are a plan view and a cross-sectional view of a high-frequency circuit according to a second modification of the 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] In the present invention, the numerical values ​​of the transmission phase, reflection phase, and reflection phase difference do not only indicate the strict meaning, but also include a substantially equivalent range, for example, including a difference of about 30%.

[0025] (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.

[0026] [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.

[0027] 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.

[0028] The antenna 2 is connected to the antenna connection terminal 100 (first antenna terminal) of the high frequency circuit 1, and transmits high frequency signals output from the high frequency circuit 1, and also receives high frequency signals from the outside and outputs them to the high frequency circuit 1.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] In the communication device 4 according to this embodiment, the antenna 2 is not an essential component.

[0033] [1.2 Circuit configuration of high frequency circuit 1] Next, a description will be given of 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, 62, 63, 64, 65, and 66, a switch circuit 42, inductors 71 to 78, and an antenna connection terminal 100.

[0034] The amplifier circuit 10 amplifies the transmission signals of band A and band B input from the high frequency input terminal 110 and also amplifies the reception signals of band A and band B input from the antenna connection terminal 100.

[0035] 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.

[0036] 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 71 and 77 and the switch circuit 42.

[0037] The filter 62 is an example of a fifth filter, is connected between the phase-shift circuit 22 and the switch circuit 42, and has a pass band that includes the transmission band of band A (first 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 terminal 42c of the switch circuit 42 via the inductor 72.

[0038] The filter 63 is an example of a third 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 63 is connected to the terminal 41c of the switch circuit 41, and the other end of the filter 63 is connected to the antenna connection terminal 100 via the inductors 73 and 77 and the switch circuit 42.

[0039] The filter 64 is an example of a second filter, and has a passband that includes the reception band of band B (second band). One end of the filter 64 is connected to a path that connects the antenna connection terminal 100 and the filter 61, and the other end is connected to the input terminal of the low-noise amplifier 14.

[0040] The filter 65 is an example of a fourth filter, and has a passband that includes the reception band of band A (first band). One end of the filter 65 is connected to a path that connects the antenna connection terminal 100 and the filter 63, and the other end is connected to the input terminal of the low-noise amplifier 15.

[0041] The filter 66 has a pass band that includes the reception band of band C. One end of the filter 66 is connected to the terminal 42 e of the switch circuit 42 , and the other end is connected to the input terminal of the low-noise amplifier 16 .

[0042] The low noise amplifiers connected to the filters 64 to 66 may be included in the amplifier circuit 10.

[0043] Band A (first band) and band B (second band) are a band combination that allows simultaneous transmission. Note that each of band A (first band) and band B (second band) may be a band that uses time division duplex. In this case, the passbands of filters 61 to 65 may be the same.

[0044] Band A is, for example, band B41 for 4G-LTE or band n41 for 5G-NR, and band B is, for example, band B40 for 4G-LTE or band n40 for 5G-NR.

[0045] Switch circuit 42 is an example of an antenna switch and has terminals 42a, 42b, 42c, 42d, and 42e. Terminal 42a is connected to antenna connection terminal 100 via inductor 77, terminal 42b is connected to filters 61 and 64 via inductor 71, terminal 42c is connected to filter 62 via inductor 72, terminal 42d is connected to filters 63 and 65 via inductor 73, and terminal 42e is connected to filter 66.

[0046] When the high-frequency circuit 1 operates in a third mode (see FIG. 5), which will be described later, the switch circuit 42 corresponds to a combining circuit. In the third mode, the terminal 42b corresponds to a fourth input terminal, the terminal 42c corresponds to a fifth input terminal, and the terminal 42a corresponds to a fifth output terminal.

[0047] With the above configuration, the switch circuit 42 switches between connection and disconnection between the antenna connection terminal 100 and filters 61 and 64, between connection and disconnection between the antenna connection terminal 100 and filter 62, between connection and disconnection between the antenna connection terminal 100 and filters 63 and 65, and between connection and disconnection between the antenna connection terminal 100 and filter 66.

[0048] Inductor 71 is connected in series to a path connecting terminal 42b and filters 61 and 64. Inductor 74 is connected between this path and ground. Inductors 71 and 74 match the impedance between switch circuit 42 and filters 61 and 64. Inductor 72 is connected in series to a path connecting terminal 42c and filter 62. Inductor 75 is connected between this path and ground. Inductors 72 and 75 match the impedance between switch circuit 42 and filter 62. Inductor 73 is connected in series to a path connecting terminal 42d and filters 63 and 65. Inductor 76 is connected between this path and ground. Inductors 73 and 76 match the impedance between switch circuit 42 and filters 63 and 65. Inductor 77 is connected in series to a path connecting terminal 42a and antenna connection terminal 100. Inductor 78 is connected between this path and ground. Inductors 77 and 78 match the impedance between switch circuit 42 and antenna 2. At least one of the inductors 71 to 78 may be omitted.

[0049] According to the above circuit configuration, the high frequency circuit 1 can simultaneously transmit a transmission signal in band A and a reception signal in band B, and simultaneously transmit a transmission signal in band B and a reception signal in band A.

[0050] The high-frequency circuit 1 according to the present invention may include at least the amplifier circuit 10 and the filters 61 and 64 from the circuit configuration shown in FIG.

[0051] [1.3 Circuit configuration of amplifier circuit 10] Next, the circuit configuration of the amplifier circuit 10 will be described in detail.

[0052] As shown in FIG. 1, the amplifier circuit 10 includes power amplifiers 11 and 12, phase-shift circuits 21 and 22, a switch circuit 41, a 90° hybrid 50, phase-shift lines 51 and 52, a capacitor 53, a high-frequency input terminal 110, and low-noise amplifiers 14, 15, and 16.

[0053] 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.

[0054] 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.

[0055] Instead of the 90° hybrid 50, a phase shift circuit having another circuit configuration may be arranged.

[0056] 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.

[0057] 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.

[0058] 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 41d 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 41d. The inductor 213 is an example of a first inductor and is connected between the path connecting the capacitor 211 and the terminal 41d and ground. The capacitor 212 is arranged in series in the path connecting the capacitor 211 and the terminal 41d. The phase-shift circuit 21 has a so-called high-pass filter configuration and shifts the passing phase of the transmission signals 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.

[0059] 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 41e of the switch circuit 41. The phase shift circuit 22 is configured so that the transmission phase of the band A and band B transmission signals is −90° (delayed by 90°) relative to the phase shift circuit 21. 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 41e. The capacitor 223 is an example of a second capacitor and is connected between the path connecting the inductor 221 and the terminal 41e and ground. The capacitor 222 is arranged in series with the path connecting the inductor 221 and the terminal 41e. The phase shift circuit 22 has a so-called low-pass filter configuration and causes the transmission phase of the band A and band B transmission signals to be, for example, −45° (delayed by 45°). The capacitor 222 is a DC blocking capacitor, does not contribute to the phase shift, and does not need to be included in the phase shift circuit 22.

[0060] Switch circuit 41 is an example of a composite circuit, and has terminals 41a, 41b, 41c, 41d, and 41e, and switches between (1) a connection between terminal 41d and terminal 41a and a connection between terminal 41e and terminal 41a (first mode), (2) a connection between terminal 41d and terminal 41c and a connection between terminal 41e and terminal 41c (second mode), and (3) a connection between terminal 41d and terminal 41a and a connection between terminal 41e and terminal 41b (third mode).

[0061] As a result, the switch circuit 41 (1) outputs from the terminal 41a an output signal generated by in-phase combining at the terminal 41a the band A transmission signal input from the terminal 41d and the band A transmission signal input from the terminal 41e (first mode).The switch circuit 41 also (2) outputs from the terminal 41c an output signal generated by in-phase combining at the terminal 41c the band B transmission signal input from the terminal 41d and the band B transmission signal input from the terminal 41e (second mode).The switch circuit 41 also (3) outputs from the terminal 41a the band A transmission signal input from the terminal 41d, and outputs from the terminal 41b the band B transmission signal input from the terminal 41e (third mode).

[0062] The first mode is a mode in which the transmit signal of band A and the receive signal of band B that are in-phase combined at terminal 41a are simultaneously transmitted. The second mode is a mode in which the transmit signal of band B and the receive signal of band A that are in-phase combined at terminal 41c are simultaneously transmitted. The third mode is a mode in which the transmit signal of band A and the receive signal of band B that are in-phase combined at terminal 42a of switch circuit 42 are simultaneously transmitted.

[0063] When the high-frequency circuit 1 operates in the first mode (see FIG. 2) or the second mode (see FIG. 4), the switch circuit 41 corresponds to a combining circuit. In the first mode or the second mode, the terminal 41d corresponds to the fourth input terminal, the terminal 41e corresponds to the fifth input terminal, the terminal 41a corresponds to the fifth output terminal, and the terminal 41c corresponds to the sixth output terminal. In the first mode or the second mode, the 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 the terminal 41c 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.

[0064] 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.

[0065] In the amplifier circuit 10 having the above configuration, the phase-shift circuits 21 and 22 are configured so that the difference between the first reflection phase of the receiving band of band B when viewed from the third output terminal to the fifth output terminal and the second reflection phase of the receiving band of band B when viewed from the fourth output terminal to the fifth output terminal is 180°.

[0066] The first reflection phase of the reception band of band B when viewed from the third output terminal to the fifth output terminal is defined as the amount of phase change of the reflection signal reflected at terminal 41a and returning to the third output terminal, relative to the phase of the signal in the reception band of band B output from the third output terminal when terminal 41d and terminal 41a are connected in the first mode. Also, the second reflection phase of the reception band of band B when viewed from the fourth output terminal to the fifth output terminal is defined as the amount of phase change of the reflection signal reflected at terminal 41a and returning to the fourth output terminal, relative to the phase of the signal in the reception band of band B output from the fourth output terminal when terminal 41e and terminal 41a are connected in the first mode.

[0067] Furthermore, the first reflection phase of the reception band of Band B when viewed from the third output terminal to the fifth output terminal is defined as the amount of phase change of the reflection signal reflected at terminal 42a and returning to the third output terminal, relative to the phase of the signal in the reception band of Band B output from the third output terminal, when terminals 41d and 41a are connected and terminals 42b and 42a are connected in the third mode. Furthermore, the second reflection phase of the reception band of Band B when viewed from the fourth output terminal to the fifth output terminal is defined as the amount of phase change of the reflection signal reflected at terminal 42a and returning to the fourth output terminal, relative to the phase of the signal in the reception band of Band B output from the fourth output terminal, when terminals 41e and 41b are connected and terminals 42c and 42a are connected in the third mode.

[0068] According to this, when a transmit signal of band A and a receive signal of band B are transmitted simultaneously, the reflection phase difference in the receive band of band B as seen from the output ends of the two balanced power amplifiers 11 and 12 is 180°, which makes it possible to increase the reflection coefficient (Γ) of band B (attenuation band) of filter 61, which has the transmit band of band A as its pass band. This makes it possible to prevent the receive signal of band B from leaking to the two power amplifiers 11 and 12 via filter 61, thereby improving the isolation between the simultaneously transmitted transmit signal of band A and receive signal of band B. Therefore, it is possible to provide a high-frequency circuit 1 that is equipped with balanced power amplifiers 11 and 12 and achieves highly efficient power combining and improved isolation between transmitter and receiver.

[0069] The first reflection phase of the reception band of band B when viewed from the third output terminal to the fifth output terminal can be obtained in the first mode by connecting terminal 41a and terminal 41d, disconnecting terminal 41a and terminal 41e, and disconnecting terminal 41a and filter 61, and measuring the reflection phase of the reception band of band B at terminal 41a.

[0070] Furthermore, the second reflection phase of the reception band of band B when viewed from the fourth output terminal to the fifth output terminal can be obtained in the first mode by connecting terminal 41a and terminal 41e, disconnecting terminal 41a and terminal 41d, and disconnecting terminal 41a and filter 61, and measuring the reflection phase of the reception band of band B at terminal 41a.

[0071] Furthermore, the first reflection phase of the reception band of band B when viewed from the third output terminal to the fifth output terminal can be obtained in the third mode by measuring the reflection phase of the reception band of band B at terminal 42a while connecting terminal 41a and terminal 41d, disconnecting terminal 41a and terminal 41e, connecting terminal 42b and terminal 42a, disconnecting terminals 42c, 42d, and 42e from terminal 42a, and disconnecting antenna connection terminal 100 from antenna 2.

[0072] In addition, the second reflection phase of the reception band of band B when viewed from the fourth output terminal to the fifth output terminal can be obtained in the third mode by connecting terminal 41b and terminal 41e, disconnecting terminal 41b and terminal 41d, connecting terminal 42c and terminal 42a, disconnecting terminals 42b, 42d, and 42e from terminal 42a, and disconnecting antenna connection terminal 100 from antenna 2, and measuring the reflection phase of the reception band of band B at terminal 42a.

[0073] Furthermore, in the amplifier circuit 10 having the above configuration, the phase-shift circuits 21 and 22 may be configured so that the difference between the third reflection phase of the receiving band of band A when viewed from the third output terminal to the sixth output terminal and the fourth reflection phase of the receiving band of band A when viewed from the fourth output terminal to the sixth output terminal is 180°.

[0074] The third reflection phase of the reception band of Band A when viewed from the third output terminal to the sixth output terminal is defined as the amount of phase change of the reflection signal reflected by terminal 41c and returning to the third output terminal, relative to the phase of the signal in the reception band of Band A output from the third output terminal when terminals 41d and 41c are connected in the second mode. Also, the fourth reflection phase of the reception band of Band A when viewed from the fourth output terminal to the sixth output terminal is defined as the amount of phase change of the reflection signal reflected by terminal 41c and returning to the fourth output terminal, relative to the phase of the signal in the reception band of Band A output from the fourth output terminal when terminals 41e and 41c are connected in the second mode.

[0075] According to this, when a transmit signal of band B and a receive signal of band A are transmitted simultaneously, the reflection phase difference in the receive band of band A as seen from the output ends of the two balanced power amplifiers 11 and 12 is 180°, which makes it possible to increase the reflection coefficient (Γ) of band A (attenuation band) of filter 63, which has the transmit band of band B as its pass band. This makes it possible to prevent the receive signal of band A from leaking to the two power amplifiers 11 and 12 via filter 63, thereby improving the isolation between the simultaneously transmitted transmit signal of band B and receive signal of band A. Therefore, it is possible to provide a high-frequency circuit 1 that is equipped with balanced power amplifiers 11 and 12 and achieves highly efficient power combining and improved isolation between transmitter and receiver.

[0076] The third reflection phase of the reception band of band A when viewed from the third output terminal to the sixth output terminal can be obtained in the second mode by connecting terminal 41c and terminal 41d, disconnecting terminal 41c and terminal 41e, and disconnecting terminal 41c and filter 63, and measuring the reflection phase of the reception band of band A at terminal 41c.

[0077] Furthermore, the fourth reflection phase of the reception band of band A when viewed from the fourth output terminal to the sixth output terminal can be obtained in the second mode by connecting terminal 41c and terminal 41e, disconnecting terminal 41c and terminal 41d, and disconnecting terminal 41c and filter 63, and measuring the reflection phase of the reception band of band A at terminal 41c.

[0078] [1.4 Transmission and reception characteristics of high-frequency circuit 1] 2 is a circuit state diagram of the high-frequency circuit 1 according to the embodiment in the first mode. As shown in the figure, in the first mode in which a transmission signal of band A and a reception signal of band B are simultaneously transmitted, in the switch circuit 41, the terminals 41a and 41d are connected, and the terminals 41a and 41e are connected. In addition, in the switch circuit 42, the terminals 42a and 42b are connected.

[0079] 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. The phase of the first signal at the third output terminal of power amplifier 11 is 0°, and the phase of the second signal at the fourth output terminal of power amplifier 12 is 90°.

[0080] The phase of the first signal at terminal 41a after passing through phase shift circuit 21 (the transmission signal of band A has a passing phase of +45°) is +45°, and the phase of the second signal at terminal 41a after passing through phase shift circuit 22 (the transmission signal of band A has a passing phase of -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 in response to load fluctuations.

[0081] Furthermore, due to the phase shift circuits 21 and 22, the difference between the first reflection phase (+45°×2=90°) of the receiving band of band B when looking at terminal 41a from the third output end and the second reflection phase (-45°×2=-90°) of the receiving band of band B when looking at terminal 41a from the fourth output end is 180°.

[0082] 3 is a Smith chart showing the transmission pass characteristics and impedance in the reception band of the high-frequency circuits according to Example 1 and the comparative example. The high-frequency circuit according to Example 1 has the same configuration and characteristics as the high-frequency circuit 1 according to the embodiment, with band A being band B41 (TDD: 2496-2690 MHz) for 4G-LTE and band B being band B40 (TDD: 2300-2400 MHz) for 4G-LTE. The high-frequency circuit according to the comparative example has the same circuit configuration as the high-frequency circuit 1 according to the embodiment, but does not have the characteristic that "phase shift circuits 21 and 22 are configured so that the difference between the first reflection phase of the reception band of band B when viewed from the third output terminal to the fifth output terminal and the second reflection phase of the reception band of band B when viewed from the fourth output terminal to the fifth output terminal is 180°."

[0083] Since the difference between the first reflection phase of the band B40 at the third output terminal of the power amplifier 11 (PA11) and the second reflection phase of the band B40 at the fourth output terminal of the power amplifier 12 (PA12) is 180°, the reflection coefficient (Γ) of the band B40 (2300-2400 MHz) becomes large, as shown in Figure 3 (b), and the output impedance of the power amplifier 11 (PA11) and the output impedance of the power amplifier 12 (PA12) become phase inverted and move away from the gain match point, thereby enabling low gain across the entire band B40.

[0084] 3(a), the attenuation of band B40 (receive band Rx) is significantly improved in the pass characteristics of the combined circuit including power amplifiers 11, 12 and filter 61. This prevents the receive signal of band B from leaking to the two power amplifiers 11 and 12 via filter 61, improving the isolation between the transmit signal of band A and the receive signal of band B that are transmitted simultaneously. This makes it possible to provide a high-frequency circuit 1 that is equipped with balanced power amplifiers 11 and 12 and achieves highly efficient power combining and improved isolation between the transmitter and receiver.

[0085] 4 is a circuit state diagram of the high-frequency circuit 1 according to the embodiment in the second mode. As shown in the figure, in the second mode in which a transmission signal of band B and a reception signal of band A are simultaneously transmitted, in switch circuit 41, terminals 41c and 41d are connected, and terminals 41c and 41e are connected. In switch circuit 42, terminals 42a and 42d are connected.

[0086] 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, respectively. The phase of the first signal at the third output terminal of power amplifier 11 is 0°, and the phase of the second signal at the fourth output terminal of power amplifier 12 is 90°.

[0087] The phase of the first signal at terminal 41c after passing through phase shift circuit 21 (the transmission signal of band B has a passing phase of +45°) is +45°, and the phase of the second signal at terminal 41c after passing through phase shift circuit 22 (the transmission signal of band B has a passing phase of -45°) is +45°. As a result, the first and second signals of band B are combined in phase at terminal 41c, enabling highly efficient power combining in response to load fluctuations.

[0088] Furthermore, due to the phase shift circuits 21 and 22, the difference between the third reflection phase (+45°×2=90°) of the receiving band of band A when looking at terminal 41c from the third output terminal and the fourth reflection phase (-45°×2=-90°) of the receiving band of band A when looking at terminal 41c from the fourth output terminal is 180°.

[0089] This increases the reflection coefficient (Γ) in the reception band of band A, causing the output impedance of power amplifier 11 and the output impedance of power amplifier 12 to be out of phase with each other and moving away from the gain match point, thereby enabling low gain across the entire reception band of band A.

[0090] This significantly improves the attenuation in the reception band of band A in the pass characteristics of the combined circuit including power amplifiers 11, 12 and filter 63. This prevents the reception signal of band A from leaking to the two power amplifiers 11 and 12 via filter 63, improving the isolation between the transmission signal of band B and the reception signal of band A that are transmitted simultaneously. This makes it possible to provide a high-frequency circuit 1 that is equipped with balanced power amplifiers 11 and 12 and achieves highly efficient power combining and improved isolation between transmission and reception.

[0091] 5 is a circuit state diagram of the high-frequency circuit 1 according to the embodiment in the third mode. As shown in the figure, in the third mode in which a transmission signal of band A and a reception signal of band B are simultaneously transmitted, in switch circuit 41, terminals 41a and 41d are connected, and terminals 41b and 41e are connected. In switch circuit 42, terminals 42a and 42b are connected, and terminals 42a and 42c are connected.

[0092] 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. The phase of the first signal at the third output terminal of power amplifier 11 is 0°, and the phase of the second signal at the fourth output terminal of power amplifier 12 is 90°.

[0093] The phase of the first signal at terminal 41a, which has passed through phase shift circuit 21 (the transmission signal of band A has a passing phase of +45°), is +45°, and the phase of the second signal at terminal 41b, which has passed through phase shift circuit 22 (the transmission signal of band A has a passing phase of -45°), is +45°. Furthermore, filter 61, through which the first signal passes, and filter 62, through which the second signal passes, have the same passband and characteristics, so the passing phases of filter 61 and filter 62 are the same. As a result, the first and second signals of band A are combined in phase at terminal 42a, enabling highly efficient power combining despite load fluctuations.

[0094] Furthermore, due to the phase shift circuits 21 and 22, the difference between the first reflection phase (+45°×2=90°) of the receiving band of band B when looking at terminal 42a from the third output terminal and the second reflection phase (-45°×2=-90°) of the receiving band of band B when looking at terminal 42a from the fourth output terminal is 180°.

[0095] As a result, the reflection coefficient (Γ) of the reception band of band B becomes large, the output impedance of power amplifier 11 and the output impedance of power amplifier 12 become out of phase with each other, and the reception band of band B moves away from the gain match point, thereby enabling a low gain across the entire reception band of band B.

[0096] This significantly improves the attenuation in the reception band of Band B in the pass characteristics of the combined circuit including power amplifiers 11, 12 and filters 61 and 62. This prevents the reception signal of Band B from leaking to the two power amplifiers 11 and 12 via filter 61 or 62, improving the isolation between the transmission signal of Band A and the reception signal of Band B that are transmitted simultaneously. This makes it possible to provide a high-frequency circuit 1 that is equipped with balanced power amplifiers 11 and 12 and achieves highly efficient power combining and improved isolation between transmission and reception.

[0097] In the first mode, the transmission signal of band A passes through filter 61, whereas in the third mode, the transmission signal of band A passes through filters 61 and 62. According to this, when transmitting band A and receiving band B simultaneously, the first mode allows fewer filters to be used, whereas the third mode allows the power resistance of the filters to be relaxed, allowing each filter to be made smaller.

[0098] In the third mode, the switch circuit 42 serves both as a combining circuit that combines balanced signals and as an antenna switch circuit, so that the high-frequency circuit 1 can be made smaller.

[0099] [2. Configurations of the Amplifier Circuit, High-Frequency Circuit, and Communication Device According to Modification 1] While the amplifier circuit 10 according to the embodiment has a function of adjusting the reflection phase of the transmission path, the amplifier circuit 10A according to the first modification has a function of adjusting the reflection phase of the reception path. FIG. 6 is a circuit configuration diagram of the amplifier circuit 10A, a high-frequency circuit 1A, and a communication device 4A according to the first modification of the embodiment. As shown in the figure, the communication device 4A according to this modification includes the high-frequency circuit 1A, an antenna 2, and an RFIC 3. The communication device 4A according to this modification has a different configuration of the high-frequency circuit 1A from the communication device 4 according to the embodiment. Therefore, the configuration of the high-frequency circuit 1A according to this modification will be described below.

[0100] The high-frequency circuit 1A includes an amplifier circuit 10A, filters 61 to 66, a switch circuit 42, inductors 71 to 78, and an antenna connection terminal 100. The high-frequency circuit 1A according to this modification differs from the high-frequency circuit 1 according to the embodiment mainly in the configuration of the amplifier circuit 10A. Hereinafter, the high-frequency circuit 1A according to this modification will be described mainly with respect to the different configuration, and a description of the same configuration as the high-frequency circuit 1 according to the embodiment will be omitted.

[0101] The amplifier circuit 10A amplifies the transmit signals of bands A and B input from the high-frequency input terminal 110, and also amplifies the receive signals of bands A and B input from the antenna connection terminal 100 and outputs them from the high-frequency output terminal 120.

[0102] The filter 61 is an example of a second filter, and 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 (second band). One end of the filter 61 is connected to a path that connects the antenna connection terminal 100 and the filter 64, and the other end is connected to the switch circuit 41.

[0103] The filter 62 is connected between the phase shift circuit 22 and the switch circuit 42, and has a pass band that includes the transmission band of band A (second band).

[0104] The filter 63 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 (first band). One end of the filter 63 is connected to a path that connects the antenna connection terminal 100 and the filter 65, and the other end is connected to the switch circuit 41.

[0105] The filter 64 is an example of a first filter, is connected between the switch circuit 43 and the antenna connection terminal 100, and has a pass band that includes the reception band of band B (first band). Specifically, one end of the filter 64 is connected to the terminal 43a of the switch circuit 43, and the other end of the filter 64 is connected to the antenna connection terminal 100 via the inductors 71 and 77 and the switch circuit 42.

[0106] The filter 65 is an example of a third filter, is connected between the switch circuit 43 and the antenna connection terminal 100, and has a pass band that includes the reception band of band A (second band). Specifically, one end of the filter 65 is connected to the terminal 43b of the switch circuit 43, and the other end of the filter 65 is connected to the antenna connection terminal 100 via the inductors 73 and 77 and the switch circuit 42.

[0107] The filter 66 has a pass band that includes the reception band of band C. One end of the filter 66 is connected to the terminal 42e of the switch circuit 42, and the other end is connected to the terminal 43c of the switch circuit 43.

[0108] Band A (second band) and band B (first band) are a band combination that allows simultaneous transmission. Note that each of band A (second band) and band B (first band) may be a band that uses time division duplex. In this case, the passbands of filters 61 to 65 may be the same.

[0109] Band A is, for example, band B41 for 4G-LTE or band n41 for 5G-NR, and band B is, for example, band B40 for 4G-LTE or band n40 for 5G-NR.

[0110] Switch circuit 42 is an example of an antenna switch and has terminals 42a, 42b, 42c, 42d, and 42e. Terminal 42a is connected to antenna connection terminal 100 via inductor 77, terminal 42b is connected to filters 61 and 64 via inductor 71, terminal 42c is connected to filter 62 via inductor 72, terminal 42d is connected to filters 63 and 65 via inductor 73, and terminal 42e is connected to filter 66.

[0111] According to the above circuit configuration, the high frequency circuit 1A can simultaneously transmit a transmission signal of band A and a reception signal of band B, and simultaneously transmit a transmission signal of band B and a reception signal of band A.

[0112] The high-frequency circuit 1A according to this modification only needs to include at least the amplifier circuit 10A and the filters 61 and 64 from the circuit configuration shown in FIG.

[0113] Next, the circuit configuration of the amplifier circuit 10A will be described in detail.

[0114] 6, amplifier circuit 10A includes power amplifiers 11 and 12, low-noise amplifiers 14 and 15, phase-shift circuits 21, 22, 23, and 24, switch circuits 41 and 43, 90° hybrids 50 and 54, phase-shift lines 51 and 52, a capacitor 53, a high-frequency input terminal 110, and a high-frequency output terminal 120. Amplifier circuit 10A according to this modification differs from amplifier circuit 10 according to the embodiment in the configuration of the receiver circuit. The following description of amplifier circuit 10A according to this modification will focus on the receiver circuit, which has a different configuration, and will omit a description of the transmitter circuit, which has the same configuration as amplifier circuit 10 according to the embodiment.

[0115] The radio frequency output terminal 120 is connected to the RFIC 3. The radio frequency output terminal 120 may be a metal conductor such as a metal electrode or a metal bump, or may be a point (node) on a metal wiring.

[0116] The 90° hybrid 54 is an example of a combiner and has a first output terminal, a first input terminal, and a second input terminal, the first output terminal being connected to the high-frequency output terminal 120, the first input terminal being connected to the second output terminal of the low-noise amplifier 14, and the second input terminal being connected to the third output terminal of the low-noise amplifier 15. The 90° hybrid 54 is configured to combine a first signal in the reception band of Band A or Band B input to the first input terminal with a second signal obtained by inputting a signal in the reception band of Band A or Band B to the second input terminal and setting it at +90° relative to the first signal, and output the combined signal from the first output terminal.

[0117] Instead of the 90° hybrid 54, a phase shift circuit having another circuit configuration may be arranged.

[0118] The low-noise amplifier 14 is an example of a first low-noise amplifier and has a second output terminal and a third input terminal, the second output terminal being connected to the first input terminal of the 90° hybrid 54. The low-noise amplifier 15 is an example of a second low-noise amplifier and has a third output terminal and a fourth input terminal, the third output terminal being connected to the second input terminal of the 90° hybrid 54.

[0119] Each of the low-noise amplifiers 14 and 15 has an amplifying transistor. The amplifying transistor is, for example, a bipolar transistor such as an HBT, or a field-effect transistor such as a MOSFET. If the amplifying transistor is a bipolar transistor, the input terminals of the low-noise amplifiers 14 and 15 are, for example, the base terminals of the bipolar transistors, and the output terminals of the low-noise amplifiers 14 and 15 are, for example, the collector terminals of the bipolar transistors. If the amplifying transistors are field-effect transistors, the input terminals of the low-noise amplifiers 14 and 15 are, for example, the gate terminals of the field-effect transistors, and the output terminals of the low-noise amplifiers 14 and 15 are, for example, the drain terminals of the field-effect transistors.

[0120] The phase-shift circuit 23 is an example of a first phase-shift circuit and is connected between the third input terminal of the low-noise amplifier 14 and the terminal 43d of the switch circuit 43. The phase-shift circuit 23 includes, for example, capacitors 231 and 232 and an inductor 233. The capacitor 231 is connected between the third input terminal and the terminal 43d. The inductor 233 is connected between the ground and a path connecting the capacitor 231 and the terminal 43d. The capacitor 232 is arranged in series in the path connecting the capacitor 231 and the terminal 43d. The phase-shift circuit 23 has a so-called high-pass filter configuration and shifts the passing phase of the received signals of Band A and Band B by, for example, +45° (advancing them by 45°). Note that the capacitor 232 is a DC-blocking capacitor and does not contribute to phase shifting, and may not be included in the phase-shift circuit 23.

[0121] The phase-shift circuit 24 is an example of a second phase-shift circuit and is connected between the fourth input terminal of the low-noise amplifier 15 and the terminal 43e of the switch circuit 43. The phase-shift circuit 24 is configured so that the phase of the received signals for Band A and Band B is −90° (delayed by 90°) relative to the phase-shift circuit 23. The phase-shift circuit 24 includes, for example, an inductor 241 and capacitors 242 and 243. The inductor 241 is connected between the fourth input terminal and the terminal 43e. The capacitor 243 is connected between the path connecting the inductor 241 and the terminal 43e and ground. The capacitor 242 is connected in series with the path connecting the inductor 241 and the terminal 43e. The phase-shift circuit 24 has a so-called low-pass filter configuration and causes the phase of the received signals for Band A and Band B to be, for example, −45° (delayed by 45°). Note that the capacitor 242 is a DC-blocking capacitor and does not contribute to phase shifting, so it may not be included in the phase-shift circuit 24.

[0122] Switch circuit 43 is an example of a diplexer circuit, and has terminals 43a, 43b, 43c, 43d, and 43e, and switches between (1) a connection between terminal 43d and terminal 43a and a connection between terminal 43e and terminal 43a (first mode), and (2) a connection between terminal 43d and terminal 43b and a connection between terminal 43e and terminal 43b (second mode).

[0123] As a result, switch circuit 43 (1) distributes the power of the band B reception signal input to terminal 43a to terminals 43d and 43e (first mode), and (2) distributes the power of the band A reception signal input to terminal 43b to terminals 43d and 43e (second mode).

[0124] The first mode is a mode in which a band A transmission signal combined in phase at terminal 41a and a band B reception signal power-split at terminal 43a are simultaneously transmitted. The second mode is a mode in which a band B transmission signal combined in phase at terminal 41c and a band A reception signal power-split at terminal 43b are simultaneously transmitted.

[0125] When the high-frequency circuit 1A operates in the first mode or the second mode, the switch circuit 41 corresponds to a combining circuit, and the switch circuit 43 corresponds to a branching circuit. In the first mode or the second mode, the terminal 43d corresponds to the fourth output terminal, the terminal 43e corresponds to the fifth output terminal, the terminal 43a corresponds to the fifth input terminal, and the terminal 43b corresponds to the sixth input terminal. In the first mode or the second mode, the terminal 43a is a signal distribution point that power-divides the received signal of band B into a first signal of band B and a second signal of band B, and the terminal 43b is a signal distribution point that power-divides the received signal of band A into a first signal of band A and a second signal of band A.

[0126] In the amplifier circuit 10A having the above configuration, the phase-shift circuits 23 and 24 are configured so that the difference between the first reflection phase of the transmission band of band A when viewed from the third input terminal to the fifth input terminal and the second reflection phase of the transmission band of band A when viewed from the fourth input terminal to the fifth input terminal is 180°.

[0127] According to this, when a reception signal of band B and a transmission signal of band A are transmitted simultaneously, the reflection phase difference of the transmission band of band A as seen from the input ends of the two balanced low-noise amplifiers 14 and 15 is 180°, so that the reflection coefficient (Γ) of band A (attenuation band) of filter 64, which has the reception band of band B as its passband, can be increased. This prevents the transmission signal of band A from leaking to the two low-noise amplifiers 14 and 15 via filter 64, improving isolation between the transmission signal of band A and the reception signal of band B, which are transmitted simultaneously, and suppressing deterioration of the reception sensitivity of band B. Therefore, it is possible to provide a high-frequency circuit 1A that is equipped with balanced low-noise amplifiers 14 and 15 and achieves highly efficient power combining and improved isolation between transmission and reception.

[0128] The first reflection phase of the transmission band of band A when viewed from the third input terminal to the fifth input terminal can be obtained in the first mode by connecting terminal 43a and terminal 43d, disconnecting terminal 43a and terminal 43e, and disconnecting terminal 43a and filter 64, and measuring the reflection phase of the transmission band of band A at terminal 43a.

[0129] Furthermore, the second reflection phase of the transmission band of band A when viewed from the fourth input terminal to the fifth input terminal can be obtained in the first mode by connecting terminal 43a and terminal 43e, disconnecting terminal 43a and terminal 43d, and disconnecting terminal 43a and filter 64, and then measuring the reflection phase of the transmission band of band A at terminal 43a.

[0130] Furthermore, in the amplifier circuit 10A having the above configuration, the phase-shift circuits 23 and 24 may be configured so that the difference between the third reflection phase of the transmission band of band B when viewed from the third input terminal to the sixth input terminal and the fourth reflection phase of the transmission band of band B when viewed from the fourth input terminal to the sixth input terminal is 180°.

[0131] According to this, when a reception signal of band A and a transmission signal of band B are transmitted simultaneously, the reflection phase difference of the transmission band of band B as seen from the input ends of the two balanced low-noise amplifiers 14 and 15 is 180°, so that the reflection coefficient (Γ) of band B (attenuation band) of filter 65, which has the reception band of band A as its passband, can be increased. Therefore, leakage of the transmission signal of band B to the two low-noise amplifiers 14 and 15 via filter 65 can be suppressed, improving isolation between the reception signal of band A and the transmission signal of band B, which are transmitted simultaneously, and suppressing deterioration of the reception sensitivity of band A. Therefore, it is possible to provide a high-frequency circuit 1A that is equipped with balanced low-noise amplifiers 14 and 15 and that achieves highly efficient power combining and improved isolation between transmission and reception.

[0132] The third reflection phase of the transmission band of band B when viewed from the third input terminal to the sixth input terminal can be obtained in the second mode by connecting terminal 43b and terminal 43d, disconnecting terminal 43b and terminal 43e, and disconnecting terminal 43b and filter 65, and measuring the reflection phase of the transmission band of band B at terminal 43b.

[0133] Furthermore, the fourth reflection phase of the transmission band of band B when viewed from the fourth input terminal to the sixth input terminal can be obtained in the second mode by connecting terminal 43b and terminal 43e, disconnecting terminal 43b and terminal 43d, and disconnecting terminal 43b and filter 65, and measuring the reflection phase of the transmission band of band B at terminal 43b.

[0134] [3. Configuration of Amplifier Circuit and High-Frequency Circuit According to Modification 2] This modification has a configuration in which the number of filters is reduced compared to the high-frequency circuit 1A according to modification 1. Fig. 7A is a circuit state diagram of a high-frequency circuit 1B according to modification 2 of the embodiment in a first mode. Fig. 7B is a circuit state diagram of a high-frequency circuit 1B according to modification 2 of the embodiment in a second mode.

[0135] 7A and 7B, the high-frequency circuit 1B according to this modification includes an amplifier circuit 10B, filters 61 to 63 and 66, a switch circuit 42, inductors 71 to 78, and an antenna connection terminal 100. The high-frequency circuit 1B according to this modification differs from the high-frequency circuit 1A according to Modification 1 mainly in that the filters 61 and 63 are used for both transmission and reception. Below, a description of the same components of the high-frequency circuit 1B according to Modification 1 will be omitted, and the description will focus on the different components.

[0136] Band A (second band) and Band B (first band) are a band combination that allows simultaneous transmission. Band A (second band) and Band B (first band) each use time division duplex. Therefore, the transmission band and reception band of Band A are the same, and the transmission band and reception band of Band B are the same.

[0137] The filter 61 is an example of a second filter, and is connected between the terminal 44a of the switch circuit 44 and the antenna connection terminal 100, and has a pass band that includes band A (second band).

[0138] The filter 62 is connected between the phase shift circuit 22 and the switch circuit 42, and has a pass band that includes band A (second band).

[0139] The filter 63 is an example of a first filter, and is connected between the terminal 44c of the switch circuit 44 and the antenna connection terminal 100, and has a pass band that includes band B (first band).

[0140] The filter 66 has a pass band that includes the reception band of band C. One end of the filter 66 is connected to the terminal 42e of the switch circuit 42, and the other end is connected to the terminal 44h of the switch circuit 44.

[0141] The switch circuit 42 is an example of an antenna switch and has terminals 42a, 42b, 42c, 42d, and 42e. The terminal 42a is connected to the antenna connection terminal 100 via an inductor 77, the terminal 42b is connected to the filter 61 via an inductor 71, the terminal 42c is connected to the filter 62 via an inductor 72, the terminal 42d is connected to the filter 63 via an inductor 73, and the terminal 42e is connected to the filter 66.

[0142] 7A and 7B, amplifier circuit 10B includes power amplifiers 11 and 12, low-noise amplifiers 14 and 15, phase-shift circuits 21, 22, 23, and 24, switch circuit 44, 90° hybrids 50 and 54, phase-shift lines 51 and 52, a capacitor 53, a high-frequency input terminal 110, and a high-frequency output terminal 120. Amplifier circuit 10B according to this modification differs from amplifier circuit 10A according to modification 1 in the configuration of switch circuit 44. Hereinafter, amplifier circuit 10B according to this modification will be described mainly with reference to the different configuration, and a description of the same configuration as amplifier circuit 10A according to modification 1 will be omitted.

[0143] The switch circuit 44 is an example of a combining circuit and a demultiplexing circuit, and has terminals 44a, 44b, 44c, 44d, 44e, 44f, 44g, and 44h, and switches between (1) a connection between terminal 44a and terminal 44d, a connection between terminal 44a and terminal 44e, a connection between terminal 44c and terminal 44f, and a connection between terminal 44c and terminal 44g (first mode), and (2) a connection between terminal 44c and terminal 44d, a connection between terminal 44c and terminal 44e, a connection between terminal 44a and terminal 44f, and a connection between terminal 44a and terminal 44g (second mode).

[0144] Terminal 44a is connected to filter 61, terminal 44b is connected to filter 62, terminal 44c is connected to filter 63, terminal 44d is connected to phase shift circuit 21, terminal 44e is connected to phase shift circuit 22, terminal 44f is connected to phase shift circuit 23, terminal 44g is connected to phase shift circuit 24, and terminal 44h is connected to filter 66.

[0145] 7A, the switch circuit 44 (1) outputs from the terminal 44a an output signal generated by in-phase combining at the terminal 44a the band A transmission signal input from the terminal 44d and the band A transmission signal input from the terminal 44e, and simultaneously distributes the power of the band B reception signal input from the terminal 44c and outputs it from the terminals 44f and 44g. Also, as shown in FIG. 7B, the switch circuit 44 (2) outputs from the terminal 44c an output signal generated by in-phase combining at the terminal 44c the band A transmission signal input from the terminal 44d and the band B transmission signal input from the terminal 44e, and simultaneously distributes the power of the band A reception signal input from the terminal 44a and outputs it from the terminals 44f and 44g.

[0146] According to this, when a transmit signal of band A and a receive signal of band B are transmitted simultaneously, the reflection phase difference of band B as viewed from the output ends of the two balanced power amplifiers 11 and 12 is 180°, which makes it possible to increase the reflection coefficient (Γ) of band B (attenuation band) of filter 61, which has band A as its passband. This makes it possible to prevent the receive signal of band B from leaking to the two power amplifiers 11 and 12 via filter 61. Furthermore, since the reflection phase difference of band A as viewed from the input ends of two balanced low-noise amplifiers 14 and 15 is 180°, it is possible to increase the reflection coefficient (Γ) of band A (attenuation band) of filter 63, which has band B as its passband. This makes it possible to prevent the transmit signal of band A from leaking to the two low-noise amplifiers 14 and 15 via filter 63. This improves isolation between the transmit signal of band A and the receive signal of band B, which are transmitted simultaneously.

[0147] Furthermore, when a transmit signal of band B and a receive signal of band A are transmitted simultaneously, the reflection phase difference of band A as viewed from the output ends of the two balanced power amplifiers 11 and 12 is 180°, which increases the reflection coefficient (Γ) of band A (attenuation band) of filter 63, which has band B as its passband. This reduces the possibility of the receive signal of band A leaking to the two power amplifiers 11 and 12 via filter 63. Furthermore, the reflection phase difference of band B as viewed from the input ends of two balanced low-noise amplifiers 14 and 15 is 180°, which increases the reflection coefficient (Γ) of band B (attenuation band) of filter 61, which has band A as its passband. This reduces the possibility of the transmit signal of band B leaking to the two low-noise amplifiers 14 and 15 via filter 61. This improves isolation between the simultaneously transmitted transmit signal of band B and the receive signal of band A. Therefore, it is possible to realize highly efficient power combining and distribution using the balanced power amplifiers 11 and 12 and the balanced low noise amplifiers 14 and 15, as well as improved isolation between the transmitter and receiver.

[0148] Furthermore, the transmission signal and reception signal of band A pass through the same filter 61, and the transmission signal and reception signal of band B pass through the same filter 63. This allows the high-frequency circuit 1B to be miniaturized.

[0149] [4. Component Arrangement of High-Frequency Circuit According to Modification 2] Next, the component arrangement of a high-frequency circuit 1B according to Modification 2 will be described. FIG. 8 is a plan view and a cross-sectional view of a high-frequency circuit 1B according to Modification 2 of the embodiment. FIG. 8(a) shows the arrangement of circuit components (shown by solid lines) when the main surface 90a of the mounting board 90 is viewed from the positive side of the z-axis, and the arrangement of circuit components (shown by dashed lines) when the main surface 90b of the mounting board 90 is viewed from the positive side of the z-axis. FIG. 8(b) shows a cross-sectional view taken along line VIII-VIII in FIG. 8(a). Note that the wiring connecting the mounting board 90 and the circuit components is partially omitted in FIG.

[0150] The high-frequency circuit 1B shown in FIG. 8 further includes a mounting substrate 90, a resin member 91, and a shield electrode layer 95 compared to the high-frequency circuit 1B shown in FIGS. 7A and 7B.

[0151] The mounting substrate 90 has main surfaces 90a and 90b facing each other, and is a substrate on which circuit components constituting the high-frequency circuit 1B 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, etc.

[0152] The resin member 91 is disposed on the main surface 90a, covers some of the plurality of circuit components and the main surface 90a, and has the function of ensuring reliability such as mechanical strength and moisture resistance of the plurality of circuit components.

[0153] The shield electrode layer 95 covers the surface and side surfaces of the resin member 91 and is set to the ground potential, thereby improving the electromagnetic field shielding function from external circuits.

[0154] The resin member 91 and the shield electrode layer 95 are not essential components of the high-frequency circuit 1B.

[0155] 8, the main surface 90a is arranged with the power amplifiers 11 and 12, the phase shift circuits 21 and 22, the 90° hybrid 50, the filters 61 to 63 and 66, the high-frequency input terminal 110, and the antenna connection terminal 100. The main surface 90b is arranged with the low-noise amplifiers 14 and 15, the phase shift circuits 23 and 24, the switch circuits 42 and 44, and the 90° hybrid 54.

[0156] According to this, the circuit components that make up the high-frequency circuit 1B are distributed and arranged on the main surfaces 90a and 90b of the mounting substrate 90, so that the high-frequency circuit 1B can be made smaller.

[0157] The power amplifiers 11, 12 and the 90° hybrid 50 are included in a semiconductor IC 81. The low-noise amplifiers 14, 15, the 90° hybrid 54, and the phase shift circuits 23 and 24 are included in a semiconductor IC 83. The switch circuit 44 is included in a semiconductor IC 82. The switch circuit 42 is included in a semiconductor IC 84. The semiconductor IC 81 is arranged on the main surface 90a, and the semiconductor ICs 82 to 84 are arranged on the main surface 90b. The semiconductor IC 83 may be formed within the semiconductor IC 82.

[0158] The semiconductor ICs 81 to 84 may be configured using, for example, a CMOS (Complementary Metal Oxide Semiconductor), and specifically may be manufactured using an SOI (Silicon on Insulator) process. The semiconductor ICs 81 to 84 may also be configured using at least one of GaAs, SiGe, and GaN. The semiconductor materials of the semiconductor ICs 81 to 84 are not limited to the above-mentioned materials.

[0159] This allows the high-frequency circuit 1B to be miniaturized.

[0160] When mounting substrate 90 is viewed from above, filters 61 to 63 each overlap semiconductor IC 84. This allows the wiring connecting filters 61 to 63 and switch circuit 42 to be shortened, thereby reducing signal transmission loss in band A and band B.

[0161] At least one of the phase shift circuit 21 (capacitors 211 and 212, inductor 213) and the phase shift circuit 22 (inductor 221, capacitors 222 and 223) may be included in the semiconductor IC 82. This allows parts of the phase shift circuits 21 and 22 to be included in the semiconductor IC 82 in which the switch circuit 44 is formed, thereby enabling the high-frequency circuit 1B to be miniaturized.

[0162] The component layout of the high-frequency circuit 1B according to this modification can also be applied to the component layout of the high-frequency circuit 1 according to the embodiment. That is, the high-frequency circuit 1 has a mounting substrate 90, and on a main surface 90a, power amplifiers 11 and 12, phase-shift circuits 21 and 22, a 90° hybrid 50, filters 61 to 66, a high-frequency input terminal 110, and an antenna connection terminal 100 are arranged. On a main surface 90b, low-noise amplifiers 14 to 16 and switch circuits 41 and 42 are arranged.

[0163] Power amplifiers 11 and 12 and 90-degree hybrid 50 are included in semiconductor IC 81, low-noise amplifiers 14 to 16 are included in semiconductor IC 83, switch circuit 41 is included in semiconductor IC 82, and switch circuit 42 is included in semiconductor IC 84. At least one of phase shift circuit 21 (capacitors 211 and 212, inductor 213) and phase shift circuit 22 (inductor 221, capacitors 222 and 223) may be included in semiconductor IC 82. This allows parts of phase shift circuits 21 and 22 to be included in semiconductor IC 82 in which switch circuit 41 is formed, thereby enabling the high-frequency circuit 1 to be miniaturized.

[0164] [5 Effects etc.] As described above, the high-frequency circuit 1 according to this embodiment includes the antenna connection terminal 100, a 90° hybrid 50 having a first input terminal, a first output terminal, and a second output terminal, and configured to demultiplex a signal in the transmission band of band A 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 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, a power amplifier 12 having a third input terminal and a fourth output terminal, the third input terminal being connected to the second output terminal, and a fourth input terminal, a fifth input terminal, and a fifth output terminal, and outputting a band A output signal from the fifth output terminal, the band A output signal being generated by in-phase combining the third demultiplexed signal of band A input from the fourth input terminal and the fourth demultiplexed signal of band A input from the fifth input terminal. a phase-shift circuit 22 connected between the fourth output terminal and the fifth input terminal and configured so that the passing phase of a signal in the transmission band of band A is −90° relative to the phase-shift circuit 21; a filter 61 connected between the fifth output terminal and the antenna connection terminal 100 or between the phase-shift circuit 21 and the fourth input terminal and having a pass band that includes the transmission band of band A; and a filter 64 connected to a path connecting the antenna connection terminal 100 and the filter 61 and having a pass band that includes the reception band of band B, which can be transmitted simultaneously with band A. The phase-shift circuits 21 and 22 are configured so that the difference between a first reflection phase of the reception band of band B when viewed from the third output terminal to the fifth output terminal and a second reflection phase of the reception band of band B when viewed from the fourth output terminal to the fifth output terminal is 180°.

[0165] According to this, when a transmit signal of band A and a receive signal of band B are transmitted simultaneously, the reflection phase difference in the receive band of band B as seen from the output ends of the two balanced power amplifiers 11 and 12 is 180°, which makes it possible to increase the reflection coefficient (Γ) of band B (attenuation band) of filter 61, which has the transmit band of band A as its pass band. This makes it possible to prevent the receive signal of band B from leaking to the two power amplifiers 11 and 12 via filter 61, thereby improving the isolation between the simultaneously transmitted transmit signal of band A and receive signal of band B. Therefore, it is possible to provide a high-frequency circuit 1 that is equipped with balanced power amplifiers 11 and 12 and achieves highly efficient power combining and improved isolation between transmitter and receiver.

[0166] Also, for example, in the high-frequency circuit 1, the phase shift circuit 21 is configured so that the pass phase of the transmission band of band A is +45°, and the phase shift circuit 22 is configured so that the pass phase of the transmission band of band A is −45°.

[0167] According to this, the first signal and the second signal, which are two high frequency signals of band A, are combined in phase at the fifth output terminal, and it becomes possible to combine the power of the fundamental wave with high efficiency against load fluctuations.

[0168] 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.

[0169] According to this, the phase shift circuit 21 has a high-pass filter configuration and can set the pass phase of the transmission band of band A to +45°, and the phase shift circuit 22 has a low-pass filter configuration and can set the pass phase of the transmission band of band A to -45°.

[0170] For example, the high-frequency circuit 1 further includes a filter 63, and the filter 61 is connected between the fifth output terminal and the antenna connection terminal 100, and the combining circuit has a terminal 41d (fourth input terminal), a terminal 41e (fifth input terminal), a terminal 41a (fifth output terminal), and a terminal 41c (sixth output terminal), and includes a switch circuit 41 that switches between the connection between terminal 41d and terminal 41a and the connection between terminal 41e and terminal 41a, and the connection between terminal 41d and terminal 41c and the connection between terminal 41e and terminal 41c, and the filter 63 is connected to terminal 41c.

[0171] According to this, the band A transmission signal output from power amplifier 11 and the band A transmission signal output from power amplifier 12 are combined in phase at terminal 41a of switch circuit 41, which switches between filter 61 and filter 63. Therefore, switch circuit 41 serves both as a combining circuit that combines balanced signals and as a switch circuit that switches filter connections, allowing high-frequency circuit 1 to be made smaller.

[0172] Furthermore, for example, in the high-frequency circuit 1, the switch circuit 41 is included in the semiconductor IC 82, and at least a part of the phase shift circuits 21 and 22 is included in the semiconductor IC 82.

[0173] This allows a part of the phase shift circuit to be included in the semiconductor IC 82 in which the switch circuit 41 is formed, thereby making it possible to reduce the size of the high frequency circuit 1.

[0174] Also, for example, in the high-frequency circuit 1, the filter 63 has a pass band that includes the transmission band of band B.

[0175] According to this, the band A transmission signal output from power amplifier 11 and the band A transmission signal output from power amplifier 12 are combined in phase at terminal 41a of switch circuit 41, which switches between the band A transmission signal and the band B transmission signal. Therefore, switch circuit 41 serves both as a combining circuit that combines balanced signals and as a switch circuit that switches between band A and band B, allowing high-frequency circuit 1 to be made smaller.

[0176] For example, the high-frequency circuit 1 further includes a filter 65 connected to a path connecting the antenna connection terminal 100 and the filter 63, the filter 65 having a passband that includes the reception band of band A, and each of band A and band B is a band that uses a time division duplex method.

[0177] This makes it possible to simultaneously transmit a transmission signal in band A and a reception signal in band B, and simultaneously transmit a transmission signal in band B and a reception signal in band A.

[0178] Also, for example, in the high-frequency circuit 1, the phase-shift circuits 21 and 22 are configured so that the difference between the first reflection phase of the receiving band of band B when viewed from the third output terminal to the fifth output terminal and the second reflection phase of the receiving band of the second band 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 receiving band of band A when viewed from the third output terminal to the sixth output terminal and the fourth reflection phase of the receiving band of band A when viewed from the fourth output terminal to the sixth output terminal is 180°.

[0179] This improves the isolation between the transmit signal and the receive signal in both cases where a transmit signal in band A and a receive signal in band B are transmitted and received simultaneously, and where a transmit signal in band B and a receive signal in band A are transmitted and received simultaneously.

[0180] Also, for example, in the high-frequency circuit 1, band A is band B41 for 4G-LTE or band n41 for 5G-NR, and band B is band B40 for 4G-LTE or band n40 for 5G-NR.

[0181] For example, the high-frequency circuit 1 further includes a low-noise amplifier 14 connected to the filter 64 .

[0182] This makes it possible to prevent the band B reception signal from leaking to the two power amplifiers 11 and 12 via the filter 61, thereby improving the isolation between the simultaneously transmitted band A transmission signal and band B reception signal. As a result, it is possible to prevent deterioration in the reception sensitivity of the band B reception signal output from the low-noise amplifier 14.

[0183] For example, the high-frequency circuit 1 further includes a filter 62 whose passband includes the transmission band of band A, and the filter 61 is connected between the phase-shift circuit 21 and terminal 42b of the switch circuit 42, the combining circuit has terminal 42b (fourth input terminal), terminal 42c (fifth input terminal), and terminal 42a (fifth output terminal), and includes a switch circuit 42 that can connect terminal 42b and terminal 42a and connect terminal 42c and terminal 42a, and terminal 42a is connected to the antenna connection terminal 100, and the filter 62 is connected between the phase-shift circuit 22 and terminal 42c.

[0184] According to this, the band A transmission signal output from power amplifier 11 and the band A transmission signal output from power amplifier 12 are combined in phase at terminal 42a of switch circuit 42 connected to antenna connection terminal 100 (third mode). Therefore, switch circuit 42 serves both as a combining circuit that combines balanced signals and as an antenna switch circuit, allowing high-frequency circuit 1 to be made smaller.

[0185] Furthermore, for example, a high-frequency circuit 1A according to Modification 1 and a high-frequency circuit 1B according to Modification 2 each include an antenna connection terminal 100, a 90° hybrid 54 having a first output terminal, a first input terminal, and a second input terminal, and configured to combine a first signal in the reception band of Band B input to the first input terminal with a second signal obtained by relatively adjusting the angle of the signal in the reception band of Band B input to the second input terminal to +90° relative to the first signal, and output the combined signal from the first output terminal, a low-noise amplifier 14 having a second output terminal and a third input terminal, the second output terminal being connected to the first input terminal, a low-noise amplifier 15 having a third output terminal and a fourth input terminal, the third output terminal being connected to the second input terminal, and a fourth output terminal, a fifth output terminal, and the fifth input terminal, and configured to power-distribute a reception signal of Band B input to the fifth input terminal to the fourth output terminal and the fifth output terminal. the phase shift circuit 24 is connected between the fourth input terminal and the fifth output terminal and is configured so that the pass phase of the receive band of band B is −90° relative to the phase shift circuit 23; a filter 64 is connected between the fifth input terminal and the antenna connection terminal 100 or between the phase shift circuit 23 and the fourth output terminal and has a pass band that includes the receive band of band B; and a filter 61 is connected to a path connecting the antenna connection terminal 100 and the filter 64 and has a pass band that includes the transmit band of band A, which can transmit simultaneously with band B. The phase shift circuits 23 and 24 are configured so that the difference between the first reflection phase of the transmit band of band A when viewed from the third input terminal to the fifth input terminal and the second reflection phase of the transmit band of band A when viewed from the fourth input terminal to the fifth input terminal is 180°.

[0186] According to this, when a reception signal of band B and a transmission signal of band A are transmitted simultaneously, the reflection phase difference of the transmission band of band A as seen from the input ends of the two balanced low-noise amplifiers 14 and 15 is 180°, so that the reflection coefficient (Γ) of band A (attenuation band) of filter 64, which has the reception band of band B as its passband, can be increased. Therefore, leakage of the transmission signal of band A via filter 64 to the two low-noise amplifiers 14 and 15 can be suppressed, improving isolation between the transmission signal of band A and the reception signal of band B that are transmitted simultaneously, and suppressing deterioration of the reception sensitivity of band B. Therefore, it is possible to provide high-frequency circuits 1A and 1B that are equipped with balanced low-noise amplifiers 14 and 15 and that achieve highly efficient power combining and improved isolation between transmission and reception.

[0187] For example, the high-frequency circuit 1A further includes a filter 65, and the filter 64 is connected between the terminal 43a and the antenna connection terminal 100. The diplexer circuit has a terminal 43d (fourth output terminal), a terminal 43e (fifth output terminal), a terminal 43a (fifth input terminal), and a terminal 43b (sixth input terminal), and includes a switch circuit 43 that switches between the connection between the terminal 43d and the terminal 43a and the connection between the terminal 43e and the terminal 43a, and the connection between the terminal 43d and the terminal 43b and the connection between the terminal 43e and the terminal 43b, and the filter 65 is connected to the terminal 43b.

[0188] According to this, the power of the received signal of band B input to low-noise amplifier 14 and the received signal of band B input to low-noise amplifier 15 is divided by terminal 43a of switch circuit 43, which switches between filter 64 and filter 65. Therefore, switch circuit 43 serves both as a branching circuit that branches the balanced signal and as a switch circuit that switches the filter connection, allowing the high-frequency circuit 1A to be made smaller.

[0189] For example, the high-frequency circuits 1A and 1B further include a power amplifier 11 connected to a filter 61.

[0190] This prevents the transmission signal of band A output from power amplifier 11 from leaking to the two low-noise amplifiers 14 and 15 via filter 64, thereby improving the isolation between the transmission signal of band A and the reception signal of band B that are transmitted simultaneously.

[0191] (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.

[0192] 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.

[0193] The features of the high-frequency circuits described based on the above embodiments will be described below.

[0194] <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 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 that is +90° relative to the first demultiplexed signal; 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 the first band output signal generated by in-phase combining the third demultiplexed signal of the first band inputted from the fourth input terminal and the fourth demultiplexed signal of the first band inputted 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 and configured so that a passing phase of a signal in the transmission band of the first band is −90° relative to the first phase shift circuit; a first filter connected between the fifth output port and the first antenna terminal or between the first phase shift circuit and the fourth input port, the first filter having a passband that includes a transmission band of the first band; a second filter connected to a path connecting the first antenna terminal and the first filter, the second filter having a passband that includes a reception band of a second band that can transmit simultaneously with the first band; The first phase shift circuit and the second phase shift circuit are a high-frequency circuit configured so that a difference between a first reflection phase of the receiving band of the second band when viewed from the third output end to the fifth output end and a second reflection phase of the receiving band of the second band when viewed from the fourth output end to the fifth output end is 180°.

[0195] <2> the first phase shift circuit is configured so that a pass phase of the transmission band of the first band is +45°; the second phase shift circuit is configured so that the pass phase of the transmission band of the first band is −45°; <1> The high-frequency circuit according to claim 1.

[0196] <3> 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; <2> The high-frequency circuit according to claim 1.

[0197] <4> Further, a third filter is provided, the first filter is connected between the fifth output port and the first antenna terminal; 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 third filter is connected to the sixth output terminal; <1> ~ <3> 10. The high-frequency circuit according to claim 9,

[0198] <5> the switch circuit is included in a semiconductor IC, At least a portion of the first phase shift circuit and the second phase shift circuit is included in the semiconductor IC. <4> The high-frequency circuit according to claim 1.

[0199] <6> the third filter has a passband that includes the transmission band of the second band; <4> or <5> The high-frequency circuit according to claim 1.

[0200] <7> further comprising a fourth filter connected to a path connecting the first antenna terminal and the third filter, the fourth filter having a passband that includes a reception band of the first band; Each of the first band and the second band is a band using a time division duplex method. <6> The high-frequency circuit according to claim 1.

[0201] <8> The first phase shift circuit and the second phase shift circuit are a difference between the first reflection phase of the receiving band of the second band when the fifth output terminal is viewed from the third output terminal and the second reflection phase of the receiving band of the second band when the fifth output terminal is viewed from the fourth output terminal is 180°; and a difference between the third reflection phase of the receiving band of the first band when the sixth output terminal is viewed from the third output terminal and the fourth reflection phase of the receiving band of the first band when the sixth output terminal is viewed from the fourth output terminal is 180°. <7> The high-frequency circuit according to claim 1.

[0202] <9> The first band is band B41 for 4G-LTE or band n41 for 5G-NR, The second band is band B40 for 4G-LTE or band n40 for 5G-NR. <1> ~ <8> 10. The high-frequency circuit according to claim 9,

[0203] <10> further comprising a low noise amplifier connected to the second filter. <1> ~ <9> 10. The high-frequency circuit according to claim 9,

[0204] <11> further comprising a fifth filter having a passband that includes the transmission band of the first band, the first filter is connected between the first phase shift circuit and the fourth input terminal; The synthesis circuit a switch circuit having the fourth input terminal, the fifth input terminal, and the fifth output terminal, and capable of connecting the fourth input terminal and the fifth output terminal, and also connecting the fifth input terminal and the fifth output terminal; the fifth output terminal is connected to the first antenna terminal; the fifth filter is connected between the second phase shift circuit and the fifth input terminal; <1> ~ <3> 10. The high-frequency circuit according to claim 9,

[0205] <12> a first antenna terminal; a combiner having a first output terminal, a first input terminal, and a second input terminal, configured to combine a first signal in a receiving band of a first band input to the first input terminal and a second signal in which the signal in the receiving band of the first band input to the second input terminal has a phase of +90° relative to the first signal, and output the combined signal from the first output terminal; a first low noise amplifier having a second output terminal and a third input terminal, the second output terminal being connected to the first input terminal; a second low noise amplifier having a third output terminal and a fourth input terminal, the third output terminal being connected to the second input terminal; a branching circuit having a fourth output terminal, a fifth output terminal, and a fifth input terminal, and configured to power-divide the received signal of the first band input to the fifth input terminal to the fourth output terminal and the fifth output terminal; a first phase shift circuit connected between the third input terminal and the fourth output terminal; a second phase shift circuit connected between the fourth input terminal and the fifth output terminal and configured so that the pass phase of the reception band of the first band is −90° relative to the first phase shift circuit; a first filter connected between the fifth input port and the first antenna terminal or between the first phase shift circuit and the fourth output port, the first filter having a passband that includes a reception band of the first band; a second filter connected to a path connecting the first antenna terminal and the first filter, the second filter having a passband that includes a transmission band of a second band that can transmit simultaneously with the first band; The first phase shift circuit and the second phase shift circuit are a high-frequency circuit configured so that a difference between a first reflection phase of the transmission band of the second band when viewed from the third input terminal to the fifth input terminal and a second reflection phase of the transmission band of the second band when viewed from the fourth input terminal to the fifth input terminal is 180°.

[0206] <13> Further, a third filter is provided, the first filter is connected between the fifth input port and the first antenna terminal; The branching circuit comprises: a switch circuit having the fourth output terminal, the fifth output terminal, the fifth input terminal, and a sixth input terminal, which switches between a connection between the fourth output terminal and the fifth input terminal and a connection between the fifth output terminal and the fifth input terminal, and a connection between the fourth output terminal and the sixth input terminal and a connection between the fifth output terminal and the sixth input terminal; the third filter is connected to the sixth input terminal; <12> The high-frequency circuit according to claim 1.

[0207] <14> further comprising a power amplifier connected to the second filter. <12> or <13> The high-frequency circuit according to claim 1. [Industrial Applicability]

[0208] 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]

[0209] 1, 1A, 1B High frequency circuit 2 antennas 3 RF signal processing circuit (RFIC) 4, 4A Communication Equipment 10, 10A, 10B amplifier circuit 11, 12 Power amplifier 14, 15, 16 Low noise amplifier 21, 22, 23, 24 phase shift circuit 41, 42, 43, 44 Switch circuit 41a, 41b, 41c, 41d, 41e, 42a, 42b, 42c, 42d, 42e, 43a, 43b, 43c, 43d, 43e, 44a, 44b, 44c, 44d, 44e, 44f, 44g, 44h terminals 50, 54 90° Hybrid 51, 52 phase shift line 53, 211, 212, 222, 223, 231, 232, 242, 243 capacitors 61, 62, 63, 64, 65, 66 Filters 71, 72, 73, 74, 75, 76, 77, 78, 213, 221, 233, 241 Inductors 81, 82, 83, 84 Semiconductor ICs 90 Mounting board 90a, 90b main surface 91 Resin parts 95 Shield electrode layer 100 Antenna connection terminal 110 High frequency input terminal 120 High frequency output terminal

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 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 that is +90° relative to the first demultiplexed signal; 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 the first band output signal generated by in-phase combining the third demultiplexed signal of the first band inputted from the fourth input terminal and the fourth demultiplexed signal of the first band inputted 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 and configured so that a passing phase of a signal in the transmission band of the first band is −90° relative to the first phase shift circuit; a first filter connected between the fifth output port and the first antenna terminal or between the first phase shift circuit and the fourth input port, the first filter having a passband that includes a transmission band of the first band; a second filter connected to a path connecting the first antenna terminal and the first filter, the second filter having a passband that includes a reception band of a second band that can be transmitted simultaneously with the first band; The first phase shift circuit and the second phase shift circuit are a difference between a first reflection phase of the receiving band of the second band when the fifth output end is viewed from the third output end and a second reflection phase of the receiving band of the second band when the fifth output end is viewed from the fourth output end is 180°; High frequency circuits.

2. the first phase shift circuit is configured so that a passing phase of a transmission band of the first band is +45°; the second phase shift circuit is configured so that a passing phase of the transmission band of the first band is −45°; The high frequency circuit according to claim 1 .

3. 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 2.

4. Further, a third filter is provided, the first filter is connected between the fifth output port and the first antenna terminal; 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 third filter is connected to the sixth output terminal; The high-frequency circuit according to any one of claims 1 to 3.

5. the switch circuit is included in a semiconductor IC, at least a portion of the first phase shift circuit and the second phase shift circuit is included in the semiconductor IC; The high frequency circuit according to claim 4.

6. the third filter has a passband that includes a transmission band of the second band; The high frequency circuit according to claim 4.

7. a fourth filter connected to a path connecting the first antenna terminal and the third filter, the fourth filter having a passband that includes a reception band of the first band; Each of the first band and the second band is a band using a time division duplex method. The high frequency circuit according to claim 6.

8. The first phase shift circuit and the second phase shift circuit are a difference between the first reflection phase of the receiving band of the second band when the fifth output end is viewed from the third output end and the second reflection phase of the receiving band of the second band when the fifth output end is viewed from the fourth output end is 180°; and a difference between the third reflection phase of the receiving band of the first band when the sixth output end is viewed from the third output end and the fourth reflection phase of the receiving band of the first band when the sixth output end is viewed from the fourth output end is 180°. The high frequency circuit according to claim 7.

9. The first band is band B41 for 4G-LTE or band n41 for 5G-NR, The second band is band B40 for 4G-LTE or band n40 for 5G-NR. The high-frequency circuit according to any one of claims 1 to 3.

10. further comprising a low noise amplifier connected to the second filter. The high-frequency circuit according to any one of claims 1 to 3.

11. further comprising a fifth filter having a passband that includes a transmission band of the first band, the first filter is connected between the first phase shift circuit and the fourth input terminal; The synthesis circuit a switch circuit having the fourth input terminal, the fifth input terminal, and the fifth output terminal, and capable of connecting the fourth input terminal and the fifth output terminal, and also connecting the fifth input terminal and the fifth output terminal; the fifth output terminal is connected to the first antenna terminal; the fifth filter is connected between the second phase shift circuit and the fifth input terminal; The high-frequency circuit according to any one of claims 1 to 3.

12. a first antenna terminal; a combiner having a first output terminal, a first input terminal, and a second input terminal, configured to combine a first signal in a receiving band of a first band input to the first input terminal and a second signal in which the signal in the receiving band of the first band input to the second input terminal has a phase of +90° relative to the first signal, and output the combined signal from the first output terminal; a first low noise amplifier having a second output and a third input, the second output connected to the first input; a second low noise amplifier having a third output and a fourth input, the third output connected to the second input; a branching circuit having a fourth output terminal, a fifth output terminal, and a fifth input terminal, configured to power-divide the received signal of the first band input to the fifth input terminal to the fourth output terminal and the fifth output terminal; a first phase shift circuit connected between the third input terminal and the fourth output terminal; a second phase shift circuit connected between the fourth input terminal and the fifth output terminal and configured so that a passing phase of the reception band of the first band is −90° relative to the first phase shift circuit; a first filter connected between the fifth input terminal and the first antenna terminal or between the first phase shift circuit and the fourth output terminal, the first filter having a passband that includes a reception band of the first band; a second filter connected to a path connecting the first antenna terminal and the first filter, the second filter having a passband that includes a transmission band of a second band that can transmit simultaneously with the first band; The first phase shift circuit and the second phase shift circuit are a difference between a first reflection phase of the transmission band of the second band when the fifth input end is viewed from the third input end and a second reflection phase of the transmission band of the second band when the fifth input end is viewed from the fourth input end is configured to be 180°; High frequency circuits.

13. Further, a third filter is provided, the first filter is connected between the fifth input terminal and the first antenna terminal; The branching circuit comprises: a switch circuit having the fourth output terminal, the fifth output terminal, the fifth input terminal, and a sixth input terminal, which switches between a connection between the fourth output terminal and the fifth input terminal and a connection between the fifth output terminal and the fifth input terminal, and a connection between the fourth output terminal and the sixth input terminal and a connection between the fifth output terminal and the sixth input terminal; the third filter is connected to the sixth input terminal; The high frequency circuit according to claim 12.

14. further comprising a power amplifier connected to the second filter. The high-frequency circuit according to claim 12 or 13.

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