High-frequency circuits

Abstract

The present invention provides a high-frequency circuit that can reduce the transmission loss of high-frequency signals in a matching circuit (including a harmonic attenuation circuit) connected to the output terminal of a power amplifier circuit. [Solution] The high-frequency circuit 1 comprises a power amplifier circuit 10, a harmonic attenuation circuit 30 having an attenuation band that includes at least a portion of the harmonic band of the transmission band of band A, a matching circuit 20 connected between the harmonic attenuation circuit 30 and the power amplifier circuit 10, a filter 51 having a passband that includes the transmission band of band A, a switch 41 connected between the harmonic attenuation circuit 30 and the filter 51, a switch 61 connected between the filter 51 and the antenna connection terminal 100, and a switch 63 connected between the matching circuit 20 and the antenna connection terminal 100 without going through the harmonic attenuation circuit 30.

Description

Technical Field

[0005]

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

Background Art

[0002] Patent Document 1 discloses a high-frequency module (high-frequency circuit) including an output matching circuit connected between an output terminal of a power amplifier and a switch.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Generally, a matching circuit connected to the output terminal of a power amplification circuit has a function of harmonic attenuation in addition to impedance conversion. Therefore, when the requirement for harmonic attenuation is strict, an increase in the passing loss of a high-frequency signal in the matching circuit (including a harmonic attenuation circuit) may become a problem.

[0005] Therefore, the present invention provides a high-frequency circuit capable of reducing the passing loss of a high-frequency signal in a matching circuit (including a harmonic attenuation circuit) connected to the output terminal of a power amplification circuit.

Means for Solving the Problems

[0006] A high-frequency circuit according to one aspect of the present invention comprises a power amplifier circuit, a harmonic attenuation circuit having an attenuation band that includes at least a portion of the harmonic band of the first band's transmission bandwidth, a matching circuit connected between the harmonic attenuation circuit and the power amplifier circuit, a first filter having a passband that includes the first band's transmission bandwidth, a first switch connected between the harmonic attenuation circuit and the first filter, a second switch connected between the first filter and an antenna connection terminal, and a third switch connected between the matching circuit and the antenna connection terminal without going through the harmonic attenuation circuit. [Effects of the Invention]

[0007] According to the present invention, the transmission loss of high-frequency signals in a matching circuit (including a harmonic attenuation circuit) connected to the output terminal of a power amplifier circuit can be reduced. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a circuit diagram of a communication device according to Embodiment 1. [Figure 2] Figure 2 shows the first mode of the communication device according to Embodiment 1. [Figure 3] Figure 3 shows the second mode of the communication device according to Embodiment 1. [Figure 4] Figure 4 shows the third mode of the communication device according to Embodiment 1. [Figure 5A] Figure 5A is a circuit diagram of a harmonic attenuation circuit according to a modified example 1 of Embodiment 1. [Figure 5B] Figure 5B is a circuit diagram of a harmonic attenuation circuit according to a modified example 2 of Embodiment 1. [Figure 5C] Figure 5C is a circuit diagram of a harmonic attenuation circuit according to a modified example 3 of Embodiment 1. [Figure 6] Figure 6 is a circuit diagram of the communication device according to Embodiment 2. [Figure 7] Figure 7 shows the first mode of the communication device according to Embodiment 2. [Figure 8]Figure 8 shows the second mode of the communication device according to Embodiment 2. [Figure 9] Figure 9 shows the third mode of the communication device according to Embodiment 2. [Figure 10] Figure 10 shows the fourth mode of the communication device according to Embodiment 2. [Modes for carrying out the invention]

[0009] The embodiments of the present invention will be described in detail below with reference to the drawings. Note that the embodiments described below are all general or specific examples. The numerical values, shapes, materials, components, arrangement of components, and connection configurations shown in the following embodiments are examples only and are not intended to limit the present invention.

[0010] The figures are schematic diagrams that have been appropriately emphasized, omitted, or had their proportions adjusted to illustrate the present invention, and are not necessarily strictly accurate representations. Actual shapes, positional relationships, and proportions may differ. In each figure, substantially identical components are denoted by the same reference numerals, and redundant explanations may be omitted or simplified.

[0011] In the following descriptions, “connected” includes not only direct connections via terminals and / or wiring conductors, but also electrical connections via other circuit elements. “Connected between A and B” means connected to both A and B, and means placed in series in the path connecting A and B. “C is connected between A and B” means one end of C is connected to A and the other end of C is connected to B, and means that C is placed in series in the path connecting A and B. “Path connecting A and B” means a path consisting of conductors that electrically connect A to B.

[0012] The "passband of a filter" is the portion of the frequency spectrum transmitted by the filter, and is defined as the frequency band between two frequencies that are 3 dB greater than the minimum power insertion loss.

[0013] The "attenuation band of the harmonic attenuation circuit" refers to the portion of the frequency spectrum attenuated by the harmonic attenuation circuit, and is defined as the frequency band in which the power insertion loss is 5 dB or more greater than its minimum value.

[0014] The "transmission band" means the frequency band used for transmission in a communication device, and the "reception band" means the frequency band used for reception in a communication device. For example, in a frequency division duplex (FDD) band, different frequency bands (uplink band and downlink band) are used as the transmission band and the reception band. Also, for example, in a time division duplex (TDD) band, the same frequency band is used for the transmission band and the reception band.

[0015] The "harmonic band of a predetermined band" means the band from n times the lower frequency end of the predetermined band to n times the higher frequency end of the predetermined band. Here, n is a natural number of 2 or more. For example, the second harmonic band of a predetermined band is the band from 2 times the lower frequency end of the predetermined band to 2 times the higher frequency end of the predetermined band, and the third harmonic band of a predetermined band is the band from 3 times the lower frequency end of the predetermined band to 3 times the higher frequency end of the predetermined band. When no order is added, the "harmonic band" means the harmonic bands of all orders.

[0016] A "terminal" means a point where a conductor in a circuit element ends. When the impedance of the conductor between circuit elements is sufficiently low, the terminal is interpreted not only as a single point but also as any point on the conductor between circuit elements or the entire conductor.

[0017] A "node" means a point on a conductor between circuit elements. When the impedance of the conductor between circuit elements is sufficiently low, the node is interpreted not only as a single point but also as any point on the conductor between circuit elements or the entire conductor.

[0018] "Power class" is a classification of the output power of user equipment (UE) defined by its maximum output power. A lower power class value indicates a higher maximum output power that is permitted. For example, 3GPP (3rd Generation Partnership Project) defines power classes 1, 1.5, 2, and 3. Specifically, power class 1 specifies a maximum output power of 31 dBm. Power class 1.5 specifies a maximum output power of 29 dBm. Power class 2 specifies a maximum output power of 26 dBm. Power class 3 specifies a maximum output power of 23 dBm.

[0019] The maximum output power of a UE is defined as the maximum output power at the antenna terminal. The maximum output power of a UE is measured using methods defined by 3GPP, etc. For example, the maximum output power can be measured by measuring the radiated power at the antenna. Alternatively, instead of measuring the radiated power, the maximum output power of the antenna can be measured by installing a terminal near the antenna and connecting a measuring instrument (such as a spectrum analyzer) to that terminal.

[0020] "Bands corresponding to a specified power class" refers to frequency bands where that power class can be used, and is defined in standards and specifications. For example, in 3GPP Release 17, n1, n3, n34, n39, n40, n41, n77, n78, n79, n95, n97, n98, and n104 are defined as bands corresponding to power class 2 for 5GNR, and n41, n77, n78, and n79 are defined as bands corresponding to power class 1.5 for 5GNR.

[0021] (Embodiment 1) Embodiment 1 will be described below.

[0022] [1.1. Circuit Configuration of Communication Devices] First, the circuit configuration of the communication device 5 according to this embodiment will be explained with reference to Figure 1. Figure 1 is a circuit diagram of the communication device 5 according to this embodiment.

[0023] Figure 1 shows an exemplary circuit configuration, and the communication device 5 can be implemented using a wide variety of circuit implementations and circuit technologies. Therefore, the description of the communication device 5 provided below should not be interpreted restrictively.

[0024] The communication device 5 can be used to provide wireless connectivity. For example, the communication device 5 can be implemented in a UE (Unmanned Environment) on a cellular network (also called a mobile network) such as a mobile phone, smartphone, tablet computer, or wearable device. In another example, by implementing the communication device 5, wireless connectivity can be provided to IoT (Internet of Things) sensor devices, medical / healthcare devices, cars, unmanned aerial vehicles (UAVs) (so-called drones), and automated guided vehicles (AGVs). In yet another example, by implementing the communication device 5, wireless connectivity can also be provided in a wireless access point or wireless hotspot.

[0025] The communication device 5 comprises a high-frequency circuit 1, an antenna 2, an RFIC (Radio Frequency Integrated Circuit) 3, and a BBIC (Baseband Integrated Circuit) 4.

[0026] The high-frequency circuit 1 is connected between the antenna 2 and the RFIC 3. The high-frequency circuit 1 can transmit high-frequency signals between the antenna 2 and the RFIC 3. Details of the circuit configuration of the high-frequency circuit 1 will be described later.

[0027] Antenna 2 is connected to the high-frequency circuit 1. Antenna 2 can receive high-frequency signals from the high-frequency circuit 1 and transmit them to the outside of the communication device 5. Furthermore, antenna 2 may receive high-frequency signals from outside the communication device 5 and supply them to the high-frequency circuit 1. Note that antenna 2 does not have to be included in the communication device 5. In addition, the communication device 5 may have one or more antennas in addition to antenna 2.

[0028] RFIC3 is an example of a signal processing circuit that processes high-frequency signals. Specifically, RFIC3 processes the transmission signal input from BBIC4 by upconversion or the like, and outputs the high-frequency transmission signal generated by this signal processing to high-frequency circuit 1. Furthermore, RFIC3 may process the high-frequency received signal input via the receiving path of high-frequency circuit 1 by downconversion or the like, and output the received signal generated by this signal processing to BBIC4. RFIC3 may also have a control unit that controls the switch circuit and power amplifier circuit of high-frequency circuit 1. Note that some or all of the control unit functions of RFIC3 may be included outside of RFIC3, for example, in BBIC4 or high-frequency circuit 1.

[0029] BBIC4 is a baseband signal processing circuit that processes signals using a frequency band lower than the high-frequency signal transmitted by the high-frequency circuit 1. Examples of signals processed by BBIC4 include image signals for image display and / or voice signals for communication via a speaker. Note that part or all of BBIC4 may not be included in the communication device 5.

[0030] [1.2. Circuit Configuration of High-Frequency Circuit 1] Next, the circuit configuration of the high-frequency circuit 1 according to this embodiment will be described with reference to Figure 1. Note that Figure 1 shows an exemplary circuit configuration, and the high-frequency circuit 1 can be implemented using a wide variety of circuit implementations and circuit technologies. Therefore, the description of the high-frequency circuit 1 provided below should not be interpreted as restrictive.

[0031] The high-frequency circuit 1 includes a power amplifier circuit 10, a matching circuit 20, a harmonic attenuation circuit 30, switch circuits 40 and 60, filters 51 and 52, an antenna connection terminal 100, and a high-frequency input terminal 110.

[0032] The antenna connection terminal 100 is an external connection terminal of the high-frequency circuit 1 and is a terminal for supplying high-frequency signals to the antenna 2. The antenna connection terminal 100 is connected to the antenna 2 outside the high-frequency circuit 1 and to the switch circuit 60 inside the high-frequency circuit 1.

[0033] The high-frequency input terminal 110 is an external connection terminal of the high-frequency circuit 1 and is a terminal for receiving high-frequency signals from the RFIC 3. The high-frequency input terminal 110 is connected to the RFIC 3 outside the high-frequency circuit 1 and to the power amplification circuit 10 inside the high-frequency circuit 1.

[0034] [1.2.1. Power Amplifier Circuit 10] The power amplifier circuit 10 is connected between the high-frequency input terminal 110 and the matching circuit 20. Specifically, the input terminal of the power amplifier circuit 10 is connected to the high-frequency input terminal 110, and the output terminal of the power amplifier circuit 10 is connected to the matching circuit 20. The power amplifier circuit 10 can amplify high-frequency signals using power supplied from a power source (not shown).

[0035] In this embodiment, the power amplification circuit 10 is an amplification circuit comprising two power amplifiers connected in parallel, and is, for example, a differential amplification type, a balanced type, or a Doherty type amplification circuit. The power amplification circuit 10 includes power amplifiers 11 and 12, a combiner 13, and a distributor 14.

[0036] The power amplifier 11 is an example of a first power amplifier and is connected between the distributor 14 and the combiner 13. Specifically, the input terminal of the power amplifier 11 is connected to the output terminal 142 of the distributor 14, and the output terminal of the power amplifier 11 is connected to the input terminal 131 of the combiner 13.

[0037] The power amplifier 12 is an example of a second power amplifier and is connected between the distributor 14 and the combiner 13. Specifically, the input terminal of the power amplifier 12 is connected to the output terminal 143 of the distributor 14, and the output terminal of the power amplifier 12 is connected to the input terminal 132 of the combiner 13.

[0038] The combiner 13 is connected between the power amplifiers 11 and 12 and the matching circuit 20. Specifically, the combiner 13 includes input terminals 131 and 132 and an output terminal 133. Input terminal 131 is an example of a first input terminal and is connected to the output terminal of the power amplifier 11. Input terminal 132 is an example of a second input terminal and is connected to the output terminal of the power amplifier 12. Output terminal 133 is connected to the matching circuit 20. The combiner 13 can be, for example, a transformer, a 90-degree hybrid coupler, a 180-degree hybrid coupler, a Wilkinson coupler, etc., and is not particularly limited.

[0039] The distributor 14 is connected between the high-frequency input terminal 110 and the power amplifiers 11 and 12. Specifically, the distributor 14 includes an input terminal 141 connected to the high-frequency input terminal 110, an output terminal 142 connected to the input terminal of the power amplifier 11, and an output terminal 143 connected to the input terminal of the power amplifier 12. The distributor 14 can be, for example, a transformer, a 90-degree hybrid coupler, a 180-degree hybrid coupler, a Wilkinson coupler, etc., and is not particularly limited. Note that the distributor 14 does not have to be included in the power amplification circuit 10, nor does it have to be included in the high-frequency circuit 1.

[0040] Some or all of such power amplifier circuits 10 can be implemented in a semiconductor integrated circuit. For example, silicon germanium (SiGe) or gallium arsenide (GaAs) can be used as the semiconductor material for the semiconductor integrated circuit. In this case, some or all of the power amplifiers 11 and 12 can be composed of heterojunction bipolar transistors (HBTs). Alternatively, gallium nitride (GaN) or silicon carbide (SiC) can be used as the semiconductor material for the power amplifier circuit 10. In this case, some or all of the power amplifiers 11 and 12 can be composed of HEMTs (High Electron Mobility Transistors) or MESFETs (Metal-Semiconductor Field Effect Transistors). Alternatively, silicon single crystal (Si) can be used as the semiconductor material for the power amplifier circuit 10. In this case, some or all of the power amplifiers 11 and 12 may be composed of CMOS (Complementary Metal Oxide Semiconductors) and may be manufactured by an SOI (Silicon on Insulator) process. The power amplifier circuit 10 may be divided and implemented on multiple semiconductor integrated circuits.

[0041] The power amplification circuit 10 may also be a multi-stage amplification circuit. In this case, the power amplification circuit 10 may further include a power amplifier connected between the high-frequency input terminal 110 and the distributor 14. Furthermore, the power amplification circuit 10 does not have to include two power amplifiers connected in parallel. In this case, the power amplification circuit 10 does not have to include the power amplifier 12, the combiner 13, and the distributor 14.

[0042] [1.2.2. Matching circuit 20] The matching circuit 20 is connected between the power amplifier circuit 10 and the antenna connection terminal 100. Specifically, the input terminal of the matching circuit 20 is connected to the power amplifier circuit 10, and the output terminal of the matching circuit 20 is connected to the harmonic attenuation circuit 30 and the switch circuit 60. The matching circuit 20 can achieve impedance matching between the power amplifier circuit 10 and the harmonic attenuation circuit 30 and the switch circuit 60. In this embodiment, the matching circuit 20 includes a capacitor 21 and an LC series circuit 22.

[0043] Capacitor 21 is a so-called DC (Direct Current) cut-off capacitor and coupling capacitor, and is connected between the power amplifier circuit 10 and the harmonic attenuation circuit 30. Specifically, one of the two electrodes of capacitor 21 is connected to the output terminal of the power amplifier circuit 10, and the other of the two electrodes of capacitor 21 is connected to the input terminal of the harmonic attenuation circuit 30.

[0044] The LC series circuit 22 is connected between the path connecting the power amplifier circuit 10 and the harmonic attenuation circuit 30 and ground. The LC series circuit 22 includes a capacitor 221 and an inductor 222 connected in series.

[0045] Note that the circuit configuration of the matching circuit 20 is not limited to the configuration shown in Figure 1. For example, the LC series circuit 22 may be connected between the path connecting the capacitor 21 and the harmonic attenuation circuit 30 and ground.

[0046] [1.2.3. Harmonic Attenuation Circuit 30] The harmonic attenuation circuit 30 has an attenuation band that includes at least a portion of the harmonic bands of the transmission bands A and C. The harmonic attenuation circuit 30 is connected between the matching circuit 20 and the switch circuit 40. Specifically, the input terminal of the harmonic attenuation circuit 30 is connected to the output terminal of the matching circuit 20, and the output terminal of the harmonic attenuation circuit 30 is connected to the common terminal 400 of the switch circuit 40. The harmonic attenuation circuit 30 can attenuate the harmonics of the signals in bands A and C.

[0047] In this embodiment, the harmonic attenuation circuit 30 includes an LC parallel circuit 31 connected between the matching circuit 20 and the switch circuit 40. The harmonic attenuation circuit 30 does not include a ground connection. In other words, the harmonic attenuation circuit 30 does not include active or passive elements connected between the path between the matching circuit 20 and the switch circuit 40 and ground.

[0048] The LC parallel circuit 31 includes an inductor 311 and a capacitor 312 connected in parallel between the matching circuit 20 and the switching circuit 40. The capacitor 312 is a variable capacitor whose capacitance can be changed.

[0049] Note that the circuit configuration of the harmonic attenuation circuit 30 is not limited to the configuration shown in Figure 1. For example, the capacitor 312 does not have to be a variable capacitor; it may be a fixed capacitor.

[0050] [1.2.4. Switch Circuit 40] The switch circuit 40 is connected between the harmonic attenuation circuit 30 and filters 51 and 52. Specifically, the switch circuit 40 includes a common terminal 400, selection terminals 401 and 402, and switches 41 and 42. The common terminal 400 is connected to the output terminal of the harmonic attenuation circuit 30. Selection terminal 401 is connected to filter 51. Selection terminal 402 is connected to filter 52. Note that if filter 52 is not included in the high-frequency circuit 1, selection terminal 402 does not need to be included in the switch circuit 40.

[0051] Switch 41 is an example of a first switch and is connected between the common terminal 400 and the selection terminal 401. In other words, switch 41 is connected between the harmonic attenuation circuit 30 and the filter 51.

[0052] Switch 42 is an example of a fourth switch and is connected between the common terminal 400 and the selection terminal 402. In other words, switch 42 is connected between the harmonic attenuation circuit 30 and the filter 52. Note that if the filter 52 is not included in the high-frequency circuit 1, switch 42 does not need to be included in the switch circuit 40.

[0053] In this connection configuration, the switch circuit 40 can selectively connect the common terminal 400 to the select terminals 401 and 402 by controlling switches 41 and 42 based on control signals from, for example, the RFIC 3. In other words, the switch circuit 40 can switch the connection of the harmonic attenuation circuit 30 between filters 51 and 52. Such a switch circuit 40 is composed of, for example, an SPDT (Single-Pole Double-Throw) type switch circuit.

[0054] The switch circuit 40 can be mounted on a semiconductor integrated circuit. As the semiconductor material for the semiconductor integrated circuit, for example, silicon single crystal (Si), gallium nitride (GaN), or silicon carbide (SiC) can be used. In this case, some or all of the switches 41 and 42 can be composed of field-effect transistors (FETs). Bipolar transistors may be used instead of FETs. Furthermore, the switch circuit 40 may be divided and mounted on multiple semiconductor integrated circuits.

[0055] Note that the circuit configuration of the switch circuit 40 is not limited to the configuration shown in Figure 1. The switch circuit 40 may further include one or more additional common terminals and / or one or more additional selection terminals. In this case, the switch circuit 40 may further include one or more additional switches. For example, the switch circuit 40 may further include a switch connected between the matching circuit 20 and the switch circuit 60 without going through the harmonic attenuation circuit 30.

[0056] [1.2.5. Filters 51 and 52] Filter 51 is an example of a first filter and is a bandpass filter having a passband that includes the transmission band of band A. Filter 51 is connected between switch circuits 40 and 60. Specifically, one end of filter 51 is connected to the select terminal 401 of switch circuit 40, and the other end of filter 51 is connected to the select terminal 601 of switch circuit 60.

[0057] Filter 52 is an example of a second filter and is a bandpass filter having a passband that includes the transmission bandwidth of band C. Filter 52 is connected between switch circuits 40 and 60. Specifically, one end of filter 52 is connected to the select terminal 402 of switch circuit 40, and the other end of filter 52 is connected to the select terminal 602 of switch circuit 60. Note that filter 52 does not necessarily have to be included in the high-frequency circuit 1.

[0058] Filters 51 and 52 may be, and are not limited to, surface acoustic wave (SAW) filters, bulk acoustic wave (BAW) filters, LC filters, or dielectric filters, or any combination thereof.

[0059] Filters 51 and 52 are not limited to bandpass filters. Some or all of filters 51 and 52 may be band-elimination filters, high-pass filters, or low-pass filters.

[0060] Furthermore, the high-frequency circuit 1 may include additional filters. For example, the high-frequency circuit 1 may include additional filters connected between the matching circuit 20 and the switch 63.

[0061] [1.2.6. Switch Circuit 60] The switch circuit 60 is connected between filters 51 and 52, the matching circuit 20, and the antenna connection terminal 100. Specifically, the switch circuit 60 includes a common terminal 600, selection terminals 601, 602, and 603, and switches 61, 62, and 63. The common terminal 600 is connected to the antenna connection terminal 100. Selection terminal 601 is connected to filter 51. Selection terminal 602 is connected to filter 52. Note that if filter 52 is not included in the high-frequency circuit 1, selection terminal 602 does not need to be included in the switch circuit 60. Selection terminal 603 is connected to the matching circuit 20 without going through the harmonic attenuation circuit 30. Specifically, selection terminal 603 is connected to node N23 on the path between the matching circuit 20 and the harmonic attenuation circuit 30.

[0062] Switch 61 is an example of a second switch and is connected between the common terminal 600 and the selection terminal 601. In other words, switch 61 is connected between the antenna connection terminal 100 and the filter 51.

[0063] Switch 62 is an example of a fifth switch and is connected between the common terminal 600 and the selection terminal 602. In other words, switch 62 is connected between the antenna connection terminal 100 and the filter 52. Note that if the filter 52 is not included in the high-frequency circuit 1, switch 62 does not need to be included in the switch circuit 60.

[0064] Switch 63 is an example of a third switch and is connected between the common terminal 600 and the selection terminal 603. In other words, switch 63 is connected between the antenna connection terminal 100 and the matching circuit 20 without going through the harmonic attenuation circuit 30. Note that switch 63 does not have to be included in the switch circuit 60. For example, switch 63 may be included in the switch circuit 40.

[0065] In this connection configuration, the switch circuit 60 can selectively connect the common terminal 600 to the select terminals 601 to 603 by controlling switches 61 to 63 based on, for example, a control signal from the RFIC 3. In other words, the switch circuit 60 can switch the connection of the antenna connection terminal 100 between filters 51 and 52 and the matching circuit 20. Such a switch circuit 60 is composed of, for example, an SP3T (Single-Pole Triple-Throw) type switch circuit.

[0066] The switch circuit 60 can be mounted on a semiconductor integrated circuit. As the semiconductor material for the semiconductor integrated circuit, for example, silicon single crystal (Si), gallium nitride (GaN), or silicon carbide (SiC) can be used. In this case, some or all of the switches 61-63 can be composed of FETs. Bipolar transistors may be used instead of FETs. Furthermore, the switch circuit 60 may be mounted on multiple semiconductor integrated circuits, or it may be included in the same semiconductor integrated circuit as the switch circuit 40.

[0067] Note that the circuit configuration of the switch circuit 60 is not limited to the configuration shown in Figure 1. The switch circuit 60 may further include one or more additional common terminals and / or one or more additional selection terminals. In this case, the switch circuit 60 may further include one or more additional switches.

[0068] [1.3. Frequency Bands] Here, we will explain the bands A, B, and C that the communication device 5 supports.

[0069] Bands A through C are frequency bands for communication systems built using Radio Access Technology (RAT). Bands A through C are predefined by standardization bodies (e.g., 3GPP and IEEE (Institute of Electrical and Electronics Engineers)). Examples of communication systems include 5GNR (5th Generation New Radio) systems, 4GLTE (4th Generation Long Term Evolution) systems, and 2GGSM (2nd Generation Global System for Mobile communications) systems.

[0070] In this embodiment, bands A and C are examples of the first and third bands, respectively, and are 5G NR bands. Bands A and / or C may also be 4G LTE bands.

[0071] In this embodiment, Band B is an example of a second band and is a 2G SM band. Band B may also be a 5G NR band or a 4G LTE band. In this case, the maximum output power of the transmitted signal in Band B may be lower than the maximum output power of the transmitted signals in Bands A and C. That is, Band B may be a band operating in low power mode (LPM).

[0072] [1.4. Multiple communication modes of communication device 5] Next, we will describe the multiple communication modes of the communication device 5.

[0073] [1.4.1. First Mode] First, the first mode, which is included in multiple communication modes, will be explained with reference to Figure 2. The first mode is a communication mode for transmitting high-frequency signals in the transmission bandwidth of Band A (an example of a first high-frequency signal).

[0074] In the first mode, the switch circuit 40 connects the common terminal 400 to the selection terminal 401, but not to the selection terminal 402. That is, switch 41 is closed and switch 42 is open. Furthermore, the switch circuit 60 connects the common terminal 600 to the selection terminal 601, but not to the selection terminals 602 and 603. That is, switch 61 is closed and switches 62 and 63 are open.

[0075] As a result, the transmission signal for band A is transmitted from RFIC3 to antenna 2 via the high-frequency input terminal 110, power amplifier circuit 10, matching circuit 20, harmonic attenuation circuit 30, switch circuit 40, filter 51, switch circuit 60, and antenna connection terminal 100.

[0076] At this time, the capacitor 312 of the harmonic attenuation circuit 30 is controlled to the first capacitance. As a result, the resonant frequency of the LC parallel circuit 31 is included in the harmonic band of the transmission bandwidth of band A. Consequently, the harmonic attenuation circuit 30 can effectively attenuate signals in the harmonic band of the transmission bandwidth of band A.

[0077] [1.4.2. Second Mode] Next, the second mode, which is included in the multiple communication modes, will be explained with reference to Figure 3. The second mode is a communication mode for transmitting high-frequency signals in the transmission bandwidth of Band B (an example of a second high-frequency signal).

[0078] In the second mode, the switch circuit 40 does not connect the common terminal 400 to the selection terminals 401 and 402. That is, switches 41 and 42 are open. Furthermore, the switch circuit 60 connects the common terminal 600 to the selection terminal 603, but does not connect it to the selection terminals 601 and 602. That is, switch 63 is closed, and switches 61 and 62 are open.

[0079] As a result, the transmission signal for band B is transmitted from RFIC3 to antenna 2 via the high-frequency input terminal 110, power amplifier circuit 10, matching circuit 20, switch circuit 60, and antenna connection terminal 100. In other words, the transmission signal for band B is transmitted to antenna 2 without passing through the harmonic attenuation circuit 30.

[0080] At this time, the capacitor 312 of the harmonic attenuation circuit 30 is controlled to a second capacitance that is larger than the first capacitance. As a result, the resonant frequency of the LC parallel circuit 31 is included in the transmission band of band B. Consequently, the impedance of the harmonic attenuation circuit 30 in the transmission band of band B increases, and the voltage applied to the common terminal 400 of the switch circuit 40 can be reduced.

[0081] [1.4.3. Third Mode] Next, the third mode, which is included in the multiple communication modes, will be explained with reference to Figure 4. The third mode is a communication mode for transmitting high-frequency signals in the transmission bandwidth of Band C (an example of a third high-frequency signal).

[0082] In the third mode, the switch circuit 40 connects the common terminal 400 to the selection terminal 402, but not to the selection terminal 401. That is, switch 42 is closed and switch 41 is open. Furthermore, the switch circuit 60 connects the common terminal 600 to the selection terminal 602, but not to the selection terminals 601 and 603. That is, switch 62 is closed and switches 61 and 63 are open.

[0083] As a result, the transmission signal for band C is transmitted from RFIC3 to antenna 2 via the high-frequency input terminal 110, power amplifier circuit 10, matching circuit 20, harmonic attenuation circuit 30, switch circuit 40, filter 52, switch circuit 60, and antenna connection terminal 100.

[0084] At this time, the capacitor 312 of the harmonic attenuation circuit 30 is controlled to the third capacitance. As a result, the resonant frequency of the LC parallel circuit 31 is included in the harmonic band of the transmission bandwidth of band C. Consequently, the harmonic attenuation circuit 30 can effectively attenuate signals in the harmonic band of the transmission bandwidth of band C.

[0085] [1.5. Summary] As described above, the high-frequency circuit 1 according to this embodiment comprises a power amplifier circuit 10, a harmonic attenuation circuit 30 having an attenuation band that includes at least a portion of the harmonic band of the transmission band of band A, a matching circuit 20 connected between the harmonic attenuation circuit 30 and the power amplifier circuit 10, a filter 51 having a passband that includes the transmission band of band A, a switch 41 connected between the harmonic attenuation circuit 30 and the filter 51, a switch 61 connected between the filter 51 and the antenna connection terminal 100, and a switch 63 connected between the matching circuit 20 and the antenna connection terminal 100 without going through the harmonic attenuation circuit 30.

[0086] According to this, the matching circuit connected to the output terminal of the power amplifier circuit 10 is divided into a matching circuit 20 and a harmonic attenuation circuit 30, and a transmission path is realized that connects the matching circuit 20 to the antenna connection terminal 100 without going through the harmonic attenuation circuit 30. Furthermore, the transmission path that connects the matching circuit 20 to the antenna connection terminal 100 via the harmonic attenuation circuit 30 and the transmission path that connects the matching circuit 20 to the antenna connection terminal 100 without going through the harmonic attenuation circuit 30 can be switched using switches 41, 61, and 63.Therefore, for the transmission of high-frequency signals with strict harmonic attenuation requirements, the harmonic attenuation requirements can be met by using the transmission path that connects the matching circuit 20 to the antenna connection terminal 100 via the harmonic attenuation circuit 30.On the other hand, for the transmission of high-frequency signals with less strict harmonic attenuation requirements, the transmission path that connects the matching circuit 20 to the antenna connection terminal 100 without going through the harmonic attenuation circuit 30 can reduce the transmission loss of high-frequency signals in the harmonic attenuation circuit 30. In other words, the high-frequency circuit 1 can reduce the transmission loss of high-frequency signals in the harmonic attenuation circuit 30 while satisfying the harmonic attenuation requirement.

[0087] For example, in the high-frequency circuit 1 according to this embodiment, the harmonic attenuation circuit 30 may include an inductor 311 connected between the matching circuit 20 and the switch 41, and may not include a ground connection.

[0088] According to this, since the harmonic attenuation circuit 30 does not include a ground connection, when switch 41 is opened and switch 63 is closed, the influence of the harmonic attenuation circuit 30 on the signal path of band B can be suppressed even if the harmonic attenuation circuit 30 does not include a switch. Also, since the inductor 311 is connected between the matching circuit 20 and switch 41, the pass-through loss of the inductor 311 is large, and the effect of reducing the pass-through loss of high-frequency signals in the harmonic attenuation circuit 30 is large.

[0089] For example, in the high-frequency circuit 1 according to this embodiment, in the first mode for transmitting a first high-frequency signal in the transmission band of band A, switches 41 and 61 may be closed and switch 63 may be open, and in the second mode for transmitting a second high-frequency signal in the transmission band of band B, switch 63 may be closed and switches 41 and 61 may be open.

[0090] According to this, when the harmonic attenuation requirement is strict, the first high-frequency signal can be transmitted via the harmonic attenuation circuit 30 by using the first mode. On the other hand, when the harmonic attenuation requirement is not strict, the second high-frequency signal can be transmitted without going through the harmonic attenuation circuit 30 by using the second mode. Therefore, it is possible to satisfy the harmonic attenuation requirement for transmitting the first high-frequency signal, which has a strict harmonic attenuation requirement, while reducing the transmission loss of the second high-frequency signal in the harmonic attenuation circuit 30 when transmitting the second high-frequency signal, which does not have a strict harmonic attenuation requirement.

[0091] For example, in the high-frequency circuit 1 according to this embodiment, band A may be a 5G NR band or a 4G LTE band, and band B may be a 2G SM band.

[0092] According to this, the first mode can be used for transmitting the first high-frequency signal in the 5G NR band or 4G LTE band, where harmonic attenuation requirements are strict, and the second mode can be used for transmitting the second high-frequency signal in the 2G GSM band, where harmonic attenuation requirements are not strict.

[0093] Furthermore, for example, in the high-frequency circuit 1 according to this embodiment, bands A and B are 5GNR bands or 4GLTE bands, and the maximum output power of the first high-frequency signal may be higher than the maximum output power of the second high-frequency signal.

[0094] According to this, in the low-power mode (LPM), where a lower maximum output power is applied, the harmonic attenuation requirements are not as stringent, so signal loss can be reduced by using the second mode.

[0095] For example, the high-frequency circuit 1 according to this embodiment may further include a filter 52 having a passband that includes the transmission band of band C, a switch 42 connected between the harmonic attenuation circuit 30 and the filter 52, and a switch 62 connected between the filter 52 and the antenna connection terminal 100.

[0096] According to this, high-frequency signals in band C can be transmitted via the harmonic attenuation circuit 30, satisfying the harmonic attenuation requirement for both band A and band C signals, while reducing the signal transmission loss for band B in the harmonic attenuation circuit 30 when transmitting band B signals.

[0097] For example, in the high-frequency circuit 1 according to this embodiment, in the third mode for transmitting the third high-frequency signal in the transmission band of band C, switches 42 and 62 may be closed, and switches 41, 61 and 63 may be open.

[0098] According to this, when the requirement for harmonic attenuation is strict, the third high-frequency signal can be transmitted via the harmonic attenuation circuit 30 by using the third mode.

[0099] Furthermore, for example, in the high-frequency circuit 1 according to this embodiment, the harmonic attenuation circuit 30 may include an LC parallel circuit 31 connected between the matching circuit 20 and the switch 41.

[0100] According to this, harmonics can be attenuated using the LC parallel circuit 31.

[0101] Furthermore, for example, in the high-frequency circuit 1 according to this embodiment, the capacitor 312 of the LC parallel circuit 31 may be a variable capacitor.

[0102] According to this, the capacitance of the capacitor 312 in the LC parallel circuit 31 can be changed.

[0103] For example, in the high-frequency circuit 1 according to this embodiment, in the first mode for transmitting a first high-frequency signal in the transmission band of band A, the capacitor 312 may be controlled to a first capacitance, and in the second mode for transmitting a second high-frequency signal in the transmission band of band B, the capacitor 312 may be controlled to a second capacitance that is larger than the first capacitance.

[0104] According to this, the attenuation bandwidth of the harmonic attenuation circuit 30 can be changed by changing the capacitance of the capacitor 312.

[0105] For example, in the high-frequency circuit 1 according to this embodiment, in the first mode for transmitting a first high-frequency signal in the transmission band of band A, the capacitor 312 may be controlled to a first capacitance such that the resonant frequency of the LC parallel circuit 31 is included in the harmonic band of the transmission band of band A, and in the second mode for transmitting a second high-frequency signal in the transmission band of band B, the capacitor 312 may be controlled to a second capacitance such that the resonant frequency of the LC parallel circuit 31 is included in the transmission band of band B.

[0106] According to this, in the first mode, the resonant frequency of the LC parallel circuit 31 is included in the harmonic band of the transmission band of band A, so the high-frequency distortion of the first high-frequency signal can be effectively attenuated. On the other hand, in the second mode, the resonant frequency of the LC parallel circuit 31 is included in the transmission band of band B, so the impedance of the LC parallel circuit 31 in the transmission band of band B can be increased, and the voltage applied to switches 41 and 42 can be reduced. As a result, the voltage withstand performance required of switches 41 and 42 can be reduced, which can contribute to miniaturization of switches 41 and 42.

[0107] Furthermore, for example, in the high-frequency circuit 1 according to this embodiment, the matching circuit 20 may include a capacitor 21 connected between the power amplification circuit 10 and the harmonic attenuation circuit 30.

[0108] According to this, the DC component can be cut off by the matching circuit 20.

[0109] Furthermore, for example, in the high-frequency circuit 1 according to this embodiment, the matching circuit 20 may include an LC series circuit 22 connected between the path connecting the power amplifier circuit 10 and the harmonic attenuation circuit 30 and ground.

[0110] According to this, high-frequency distortion can also be attenuated in the matching circuit 20.

[0111] For example, in the high-frequency circuit 1 according to this embodiment, the power amplification circuit 10 may also include power amplifiers 11 and 12, and a combiner 13 that includes an input terminal 131 connected to the output terminal of the power amplifier 11, an input terminal 132 connected to the output terminal of the power amplifier 12, and an output terminal 133 connected to the matching circuit 20.

[0112] According to this, high-frequency signals can be amplified using power amplifiers 11 and 12 connected in parallel, enabling support for higher output power.

[0113] (Modification 1 of Embodiment 1) Next, a modification 1 of the above embodiment 1 will be described. In this modification, the circuit configuration of the harmonic attenuation circuit differs mainly from that of the above embodiment 1. Below, this modification will be described with reference to Figure 5A, focusing on the differences from the above embodiment 1.

[0114] Figure 5A is a circuit diagram of the harmonic attenuation circuit 30A according to this modified example. Note that Figure 5A represents an exemplary circuit configuration, and the harmonic attenuation circuit 30A can be implemented using a wide variety of circuit implementations and circuit technologies. Therefore, the description of the harmonic attenuation circuit 30A provided below should not be interpreted restrictively.

[0115] The harmonic attenuation circuit 30A is connected between the matching circuit 20 and the switch circuit 40. Specifically, the input terminal of the harmonic attenuation circuit 30A is connected to the output terminal of the matching circuit 20, and the output terminal of the harmonic attenuation circuit 30A is connected to the common terminal 400 of the switch circuit 40. The harmonic attenuation circuit 30A can attenuate the harmonics of signals in bands A and C.

[0116] In this modified example, the harmonic attenuation circuit 30A includes an inductor 311 but does not include a capacitor 312 connected in parallel with the inductor 311. The inductor 311 is connected between the matching circuit 20 and the switching circuit 40.

[0117] As described above, the harmonic attenuation circuit 30A according to this modified example may include an inductor 311, but may not include a capacitor 312. Even in such a case, the harmonic attenuation circuit 30A can attenuate harmonics.

[0118] (Modification 2 of Embodiment 1) Next, a modified example 2 of Embodiment 1 will be described. In this modified example, the circuit configuration of the harmonic attenuation circuit differs mainly from that of Embodiment 1. Below, this modified example will be described with reference to Figure 5B, focusing on the differences from Embodiment 1.

[0119] Figure 5B is a circuit diagram of the harmonic attenuation circuit 30B according to this modified example. Note that Figure 5B represents an exemplary circuit configuration, and the harmonic attenuation circuit 30B can be implemented using a wide variety of circuit implementations and circuit technologies. Therefore, the description of the harmonic attenuation circuit 30B provided below should not be interpreted restrictively.

[0120] The harmonic attenuation circuit 30B is connected between the matching circuit 20 and the switch circuit 40. Specifically, the input terminal of the harmonic attenuation circuit 30B is connected to the output terminal of the matching circuit 20, and the output terminal of the harmonic attenuation circuit 30B is connected to the common terminal 400 of the switch circuit 40. The harmonic attenuation circuit 30B can attenuate the harmonics of signals in bands A and C.

[0121] In this modified example, the harmonic attenuation circuit 30B includes a switch 32 in addition to the LC parallel circuit 31. The switch 32 is connected between the matching circuit 20 and the LC parallel circuit 31.

[0122] As described above, the harmonic attenuation circuit 30B according to this modified example may include a switch 32 connected between the matching circuit 20 and the LC parallel circuit 31. With this, in the second mode, the influence of the LC parallel circuit 31 on the signal path of band B can be further reduced by opening the switch 32.

[0123] (Modification 3 of Embodiment 1) Next, a modification 3 of Embodiment 1 described above will be explained. In this modification, the circuit configuration of the harmonic attenuation circuit differs mainly from that of Embodiment 1. Below, this modification will be explained with reference to Figure 5C, focusing on the differences from Embodiment 1.

[0124] Figure 5C is a circuit diagram of the harmonic attenuation circuit 30C according to this modified example. Note that Figure 5C represents an exemplary circuit configuration, and the harmonic attenuation circuit 30C can be implemented using a wide variety of circuit implementations and circuit technologies. Therefore, the description of the harmonic attenuation circuit 30C provided below should not be interpreted restrictively.

[0125] The harmonic attenuation circuit 30C is connected between the matching circuit 20 and the switch circuit 40. Specifically, the input terminal of the harmonic attenuation circuit 30C is connected to the output terminal of the matching circuit 20, and the output terminal of the harmonic attenuation circuit 30C is connected to the common terminal 400 of the switch circuit 40. The harmonic attenuation circuit 30C can attenuate the harmonics of signals in bands A and C.

[0126] In this modified example, the harmonic attenuation circuit 30C includes an inductor 311C and a switch 32. The inductor 311C is connected between the path connecting the matching circuit 20 and the switch circuit 40 and ground. The switch 32 is an example of a ninth switch and is connected between the matching circuit 20 and the inductor 311C.

[0127] In Figure 5C, the switch 32 is connected between the matching circuit 20 and the switch circuit 40, but it may also be connected between the path connecting the matching circuit 20 and the switch circuit 40 and the inductor 311C. Furthermore, the harmonic attenuation circuit 30C may include a capacitor connected in series with the inductor 311C between the path connecting the matching circuit 20 and the switch circuit 40 and ground. Alternatively, the harmonic attenuation circuit 30C may include a capacitor connected between the path connecting the matching circuit 20 and the switch circuit 40 and ground instead of the inductor 311C.

[0128] As described above, the harmonic attenuation circuit 30C according to this modified example may include an inductor 311C connected between the path between the matching circuit 20 and the switch 41 and the ground, and a switch 32 connected between the matching circuit 20 and the inductor 311C.

[0129] According to this, in the second mode, opening switch 32 reduces the influence of the ground-connected inductor 311C on the signal path of band B. Furthermore, inductor 311C, which is shunt-connected to the signal paths of bands A and C, can reduce the signal transmission loss in bands A and C more effectively than inductor 311, which is series-connected to the signal paths of bands A and C.

[0130] (Embodiment 2) Next, Embodiment 2 will be described. This embodiment differs from Embodiment 1 in that it includes two additional filters in the high-frequency circuit. Below, this embodiment will be described with reference to Figure 6, focusing on the differences from Embodiment 1.

[0131] The communication device 5A according to this embodiment is the same as the communication device 5 according to Embodiment 1, except that it is equipped with a high-frequency circuit 1A instead of the high-frequency circuit 1, so its description will be omitted.

[0132] [2.1. Circuit configuration of high-frequency circuit 1A] The circuit configuration of the high-frequency circuit 1A according to this embodiment will be described with reference to Figure 6. Note that Figure 6 shows an exemplary circuit configuration, and the high-frequency circuit 1A can be implemented using a wide variety of circuit implementations and circuit technologies. Therefore, the description of the high-frequency circuit 1A provided below should not be interpreted as limiting.

[0133] The high-frequency circuit 1A includes a power amplifier circuit 10, a matching circuit 20, a harmonic attenuation circuit 30, switch circuits 40A and 60A, filters 51, 52, 53 and 54, an antenna connection terminal 100, and a high-frequency input terminal 110.

[0134] [2.1.1. Switch Circuit 40A] The switch circuit 40A is connected between the harmonic attenuation circuit 30 and filters 51-54. Specifically, the switch circuit 40A includes common terminals 400 and 403, select terminals 401, 402, 404 and 405, and switches 41, 42, 43 and 44. Common terminal 400 is connected to the output terminal of the harmonic attenuation circuit 30. Common terminal 403 is connected to the output terminal of the matching circuit 20 without going through the harmonic attenuation circuit 30. Select terminal 401 is connected to filter 51. Select terminal 402 is connected to filter 52. Select terminal 404 is connected to filter 53. Select terminal 405 is connected to filter 54.

[0135] Switch 41 is an example of a first switch and is connected between the common terminal 400 and the selection terminal 401. In other words, switch 41 is connected between the harmonic attenuation circuit 30 and the filter 51.

[0136] Switch 42 is an example of a fourth switch and is connected between the common terminal 400 and the selection terminal 402. In other words, switch 42 is connected between the harmonic attenuation circuit 30 and the filter 52. Note that if the filter 52 is not included in the high-frequency circuit 1A, switch 42 does not need to be included in the switch circuit 40A.

[0137] Switch 43 is an example of a sixth switch and is connected between the common terminal 403 and the selection terminal 404. In other words, switch 43 is connected between the matching circuit 20 and the filter 53 without going through the harmonic attenuation circuit 30.

[0138] Switch 44 is an example of a seventh switch and is connected between the common terminal 403 and the selection terminal 405. In other words, switch 44 is connected between the matching circuit 20 and the filter 54 without going through the harmonic attenuation circuit 30.

[0139] In this connection configuration, the switch circuit 40A can selectively connect the common terminal 400 to the select terminals 401 and 402, and the common terminal 403 to the select terminals 404 and 405, by controlling switches 41 to 44 based on a control signal from the RFIC 3, for example. In other words, the switch circuit 40A can switch the connection of the harmonic attenuation circuit 30 between filters 51 and 52, and switch the connection of the matching circuit 20 between filters 53 and 54. Such a switch circuit 40A is composed of, for example, a DPDT (Double-Pole Double-Throw) type switch circuit.

[0140] The switch circuit 40A, like the switch circuit 40, can be implemented in a semiconductor integrated circuit.

[0141] Note that the circuit configuration of switch circuit 40A is not limited to the configuration shown in Figure 6. Switch circuit 40A may further include one or more additional common terminals and / or one or more additional selection terminals. In this case, switch circuit 40A may further include one or more additional switches.

[0142] [2.1.2. Filters 53 and 54] Filter 53 is an example of a third filter and is a bandpass filter having a passband that includes the transmission bandwidth of band B. Filter 53 is connected between switch circuits 40A and 60A. Specifically, one end of filter 53 is connected to the select terminal 404 of switch circuit 40A, and the other end of filter 53 is connected to the select terminal 603 of switch circuit 60A.

[0143] Filter 54 is an example of a fourth filter and is a bandpass filter having a passband that includes the transmission bandwidth of band D. Filter 54 is connected between switch circuits 40A and 60A. Specifically, one end of filter 54 is connected to the select terminal 405 of switch circuit 40A, and the other end of filter 54 is connected to the select terminal 604 of switch circuit 60A. Note that filter 54 does not necessarily have to be included in the high-frequency circuit 1A.

[0144] Filters 53 and 54 may be, and are not limited to, SAW filters, BAW filters, LC filters, or dielectric filters, or any combination thereof.

[0145] Filters 53 and 54 are not limited to bandpass filters. Some or all of filters 53 and 54 may be band-elimination filters, high-pass filters, or low-pass filters.

[0146] [2.1.3. Switch Circuit 60A] The switch circuit 60A is connected between filters 51-54 and the antenna connection terminal 100. Specifically, the switch circuit 60A includes a common terminal 600, selection terminals 601, 602, 603 and 604, and switches 61, 62, 63 and 64. The common terminal 600 is connected to the antenna connection terminal 100. Selection terminal 601 is connected to filter 51. Selection terminal 602 is connected to filter 52. Selection terminal 603 is connected to filter 53. Selection terminal 604 is connected to filter 54.

[0147] Switch 61 is an example of a second switch and is connected between the common terminal 600 and the selection terminal 601. In other words, switch 61 is connected between the antenna connection terminal 100 and the filter 51.

[0148] Switch 62 is an example of a fifth switch and is connected between the common terminal 600 and the selection terminal 602. In other words, switch 62 is connected between the antenna connection terminal 100 and the filter 52. Note that if the filter 52 is not included in the high-frequency circuit 1A, then switch 62 does not need to be included in the switch circuit 60A.

[0149] Switch 63 is an example of a third switch and is connected between the common terminal 600 and the selection terminal 603. In other words, switch 63 is connected between the antenna connection terminal 100 and the filter 53.

[0150] Switch 64 is an example of an eighth switch and is connected between the common terminal 600 and the selection terminal 604. In other words, switch 64 is connected between the antenna connection terminal 100 and the filter 54.

[0151] In this connection configuration, the switch circuit 60A can selectively connect the common terminal 600 to the select terminals 601 to 604 by controlling switches 61 to 64 based on a control signal from, for example, the RFIC 3. In other words, the switch circuit 60A can switch the connection of the antenna connection terminal 100 between filters 51 to 54. Such a switch circuit 60A is composed of, for example, an SP4T (Single-Pole Quadruple-Throw) type switch circuit.

[0152] The switch circuit 60A, like the switch circuit 60, can be implemented in a semiconductor integrated circuit.

[0153] Note that the circuit configuration of switch circuit 60A is not limited to the configuration shown in Figure 6. Switch circuit 60A may further include one or more additional common terminals and / or one or more additional selection terminals. In this case, switch circuit 60A may further include one or more additional switches.

[0154] [2.2. Frequency Bands] Next, we will describe the bands A, B, C, and D that the communication device 5A supports.

[0155] Bands A through D are frequency bands for communication systems built using RAT (Radio Frequency Transit). Bands A through D are predefined by standardization bodies (e.g., 3GPP and IEEE). Examples of communication systems include 5G NR systems, 4G LTE systems, and 2G GSM systems.

[0156] In this embodiment, bands A and C are examples of the first and third bands, respectively, and are 5G NR bands corresponding to the first and second power classes. Bands B and D are examples of the second and fourth bands, respectively, and are 5G NR bands corresponding to the second power class but not to the first power class. Note that some or all of bands A to D may be 4G LTE bands.

[0157] The first power class is defined by a first maximum output power higher than the second maximum output power, and in this embodiment, it is called the high power class (HPC). The second power class is defined by a second maximum output power lower than the first maximum output power, and in this embodiment, it is called the low power class (LPC). For example, power class 2 or 1.5 may be used as the first power class, and power class 3 may be used as the second power class.

[0158] [2.3. Multiple communication modes of communication device 5A] Next, we will describe the multiple communication modes of the communication device 5A.

[0159] [2.3.1. First Mode] First, the first mode, which is included in multiple communication modes, will be explained with reference to Figure 7. The first mode is a communication mode for transmitting high-frequency signals (an example of the first high-frequency signal) in the transmission bandwidth of Band A using HPC or LPC.

[0160] In the first mode, switch circuit 40A connects the common terminal 400 to the selection terminal 401 but not to the selection terminal 402, and does not connect the common terminal 403 to the selection terminals 404 and 405. In other words, switch 41 is closed and switches 42 to 44 are open. Furthermore, switch circuit 60A connects the common terminal 600 to the selection terminal 601 but not to the selection terminals 602 to 604. In other words, switch 61 is closed and switches 62 to 64 are open.

[0161] As a result, the transmission signal for band A is transmitted from RFIC3 to antenna 2 via the high-frequency input terminal 110, power amplifier circuit 10, matching circuit 20, harmonic attenuation circuit 30, switch circuit 40A, filter 51, switch circuit 60A, and antenna connection terminal 100.

[0162] At this time, the capacitor 312 of the harmonic attenuation circuit 30 is controlled to the first capacitance. As a result, the resonant frequency of the LC parallel circuit 31 is included in the harmonic band of the transmission bandwidth of band A. Consequently, the harmonic attenuation circuit 30 can effectively attenuate signals in the harmonic band of the transmission bandwidth of band A.

[0163] [2.3.2. Second Mode] Next, the second mode, which is included in the multiple communication modes, will be explained with reference to Figure 8. The second mode is a communication mode for transmitting high-frequency signals in the transmission bandwidth of Band B (an example of a second high-frequency signal) using LPC.

[0164] In the second mode, switch circuit 40A connects the common terminal 403 to the selection terminal 404 but not to the selection terminal 405, and does not connect the common terminal 400 to the selection terminals 401 and 402. In other words, switch 43 is closed and switches 41, 42 and 44 are open. Furthermore, switch circuit 60A connects the common terminal 600 to the selection terminal 603 but not to the selection terminals 601, 602 and 604. In other words, switch 63 is closed and switches 61, 62 and 64 are open.

[0165] As a result, the transmission signal for band B is transmitted from RFIC3 to antenna 2 via the high-frequency input terminal 110, power amplifier circuit 10, matching circuit 20, switch circuit 40A, filter 53, switch circuit 60A, and antenna connection terminal 100. In other words, the transmission signal for band B is transmitted to antenna 2 without passing through the harmonic attenuation circuit 30.

[0166] [2.3.3. Third Mode] Next, the third mode, which is included in the multiple communication modes, will be explained with reference to Figure 9. The third mode is a communication mode for transmitting high-frequency signals in the transmission bandwidth of Band C (an example of a third high-frequency signal) using HPC or LPC.

[0167] In the third mode, switch circuit 40A connects the common terminal 400 to the selection terminal 402 but not to the selection terminal 401, and does not connect the common terminal 403 to the selection terminals 404 and 405. In other words, switch 42 is closed and switches 41, 43 and 44 are open. Furthermore, switch circuit 60A connects the common terminal 600 to the selection terminal 602 but not to the selection terminals 601, 603 and 604. In other words, switch 62 is closed and switches 61, 63 and 64 are open.

[0168] As a result, the transmission signal for band C is transmitted from RFIC3 to antenna 2 via the high-frequency input terminal 110, power amplifier circuit 10, matching circuit 20, harmonic attenuation circuit 30, switch circuit 40A, filter 52, switch circuit 60A, and antenna connection terminal 100.

[0169] At this time, the capacitor 312 of the harmonic attenuation circuit 30 is controlled to the third capacitance. As a result, the resonant frequency of the LC parallel circuit 31 is included in the harmonic band of the transmission bandwidth of band C. Consequently, the harmonic attenuation circuit 30 can effectively attenuate signals in the harmonic band of the transmission bandwidth of band C.

[0170] [2.3.4. Fourth Mode] Next, the fourth mode, which is included in the multiple communication modes, will be explained with reference to Figure 10. The fourth mode is a communication mode for transmitting high-frequency signals in the transmission bandwidth of band D (an example of a fourth high-frequency signal) using LPC.

[0171] In the fourth mode, switch circuit 40A connects the common terminal 403 to the selection terminal 405 but not to the selection terminal 404, and does not connect the common terminal 400 to the selection terminals 401 and 402. In other words, switch 44 is closed and switches 41, 42 and 43 are open. Furthermore, switch circuit 60A connects the common terminal 600 to the selection terminal 604 but not to the selection terminals 601, 602 and 603. In other words, switch 64 is closed and switches 61, 62 and 63 are open.

[0172] As a result, the transmission signal for band D is transmitted from RFIC3 to antenna 2 via the high-frequency input terminal 110, power amplifier circuit 10, matching circuit 20, switch circuit 40A, filter 54, switch circuit 60A, and antenna connection terminal 100. In other words, the transmission signal for band D is transmitted to antenna 2 without passing through the harmonic attenuation circuit 30.

[0173] [2.4. Summary] As described above, the high-frequency circuit 1A according to this embodiment comprises a power amplifier circuit 10, a harmonic attenuation circuit 30 having an attenuation band that includes at least a portion of the harmonic band of the transmission band of band A, a matching circuit 20 connected between the harmonic attenuation circuit 30 and the power amplifier circuit 10, a filter 51 having a passband that includes the transmission band of band A, a switch 41 connected between the harmonic attenuation circuit 30 and the filter 51, a switch 61 connected between the filter 51 and the antenna connection terminal 100, and a switch 63 connected between the matching circuit 20 and the antenna connection terminal 100 without going through the harmonic attenuation circuit 30.

[0174] According to this, the matching circuit connected to the output terminal of the power amplifier circuit 10 is divided into a matching circuit 20 and a harmonic attenuation circuit 30, and a transmission path is realized that connects the matching circuit 20 to the antenna connection terminal 100 without going through the harmonic attenuation circuit 30. Furthermore, the transmission path that connects the matching circuit 20 to the antenna connection terminal 100 via the harmonic attenuation circuit 30 and the transmission path that connects the matching circuit 20 to the antenna connection terminal 100 without going through the harmonic attenuation circuit 30 can be switched using switches 41, 61, and 63.Therefore, for the transmission of high-frequency signals with strict harmonic attenuation requirements, the harmonic attenuation requirements can be met by using the transmission path that connects the matching circuit 20 to the antenna connection terminal 100 via the harmonic attenuation circuit 30.On the other hand, for the transmission of high-frequency signals with less strict harmonic attenuation requirements, the transmission path that connects the matching circuit 20 to the antenna connection terminal 100 without going through the harmonic attenuation circuit 30 can reduce the transmission loss of high-frequency signals in the harmonic attenuation circuit 30. In other words, the high-frequency circuit 1A can reduce the transmission loss of high-frequency signals in the harmonic attenuation circuit 30 while satisfying the harmonic attenuation requirement.

[0175] Furthermore, for example, in the high-frequency circuit 1A according to this embodiment, the harmonic attenuation circuit 30 may include an inductor connected between the matching circuit 20 and the switch 41, but may not include a ground connection.

[0176] According to this, since the harmonic attenuation circuit 30 does not include a ground connection, when switch 41 is opened and switch 63 is closed, the influence of the harmonic attenuation circuit 30 on the signal path of band B can be suppressed even if the harmonic attenuation circuit 30 does not include a switch. Also, since the inductor 311 is connected between the matching circuit 20 and switch 41, the pass-through loss of the inductor 311 is large, and the effect of reducing the pass-through loss of high-frequency signals in the harmonic attenuation circuit 30 is large.

[0177] For example, the high-frequency circuit 1A according to this embodiment may further include a filter 52 having a passband that includes the transmission band of band C, a switch 42 connected between the harmonic attenuation circuit 30 and the filter 52, and a switch 62 connected between the filter 52 and the antenna connection terminal 100.

[0178] According to this, high-frequency signals in band C can be transmitted via the harmonic attenuation circuit 30, satisfying the harmonic attenuation requirement for both band A and band C signals, while reducing the signal transmission loss for band B in the harmonic attenuation circuit 30 when transmitting band B signals.

[0179] For example, the high-frequency circuit 1A according to this embodiment may further include a switch 43 connected between the matching circuit 20 and the switch 63 without going through the harmonic attenuation circuit 30, and a filter 53 connected between the switch 63 and the switch 43, having a passband that includes the transmission bandwidth of band B.

[0180] According to this, since the signal for band B can be transmitted via filter 53, spurious emissions in the transmission of the band B signal can be reduced.

[0181] For example, the high-frequency circuit 1A according to this embodiment may further include a filter 54 having a passband that includes the transmission band of band D, a switch 44 connected between the matching circuit 20 and the filter 54 without going through the harmonic attenuation circuit 30, and a switch 64 connected between the filter 54 and the antenna connection terminal 100.

[0182] According to this, high-frequency signals in band D can be transmitted without going through the harmonic attenuation circuit 30, and the signal transmission loss in band D in the harmonic attenuation circuit 30 can be reduced not only when transmitting signals in band B but also when transmitting signals in band D.

[0183] For example, in the high-frequency circuit 1A according to this embodiment, in the first mode for transmitting a first high-frequency signal in the transmission band of band A, switches 41 and 61 may be closed and switches 63, 42, 62, 43, 44 and 64 may be open; in the second mode for transmitting a second high-frequency signal in the transmission band of band B, switches 63 and 43 may be closed and switches 41, 61, 42, 62, 44 and 64 may be open; in the third mode for transmitting a third high-frequency signal in the transmission band of band C, switches 42 and 62 may be closed and switches 41, 61, 63, 43, 44 and 64 may be open; and in the fourth mode for transmitting a fourth high-frequency signal in the transmission band of band D, switches 44 and 64 may be closed and switches 41, 61, 63, 42, 62 and 43 may be open.

[0184] According to this, when the harmonic attenuation requirement is strict, the first and third modes can be used to transmit high-frequency signals through the harmonic attenuation circuit 30. On the other hand, when the harmonic attenuation requirement is not strict, the second and fourth modes can be used to transmit high-frequency signals without going through the harmonic attenuation circuit 30. Therefore, it is possible to satisfy the harmonic attenuation requirement for the transmission of the first and third high-frequency signals, which have a strict harmonic attenuation requirement, while reducing the transmission loss of high-frequency signals in the harmonic attenuation circuit 30 when transmitting the second and fourth high-frequency signals, which do not have a strict harmonic attenuation requirement.

[0185] For example, in the high-frequency circuit 1A according to this embodiment, bands A and C may be 5GNR bands or 4GLTE bands corresponding to a first power class defined by a first maximum output power and a second power class defined by a second maximum output power lower than the first maximum output power, and bands B and D may be 5GNR bands or 4GLTE bands corresponding to the second power class but not to the first power class.

[0186] According to this, the harmonic attenuation requirements can be met in the first power class, where the harmonic attenuation requirements are stricter, and the transmission loss of high-frequency signals can be reduced in the second power class, where the harmonic attenuation requirements are less stringent.

[0187] Furthermore, for example, in the high-frequency circuit 1A according to this embodiment, the harmonic attenuation circuit 30 may include an LC parallel circuit 31 connected between the matching circuit 20 and the switch 41.

[0188] According to this, harmonics can be attenuated using the LC parallel circuit 31.

[0189] For example, in the high-frequency circuit 1A according to this embodiment, the matching circuit 20 may also include a capacitor 21 connected between the power amplifier circuit 10 and the harmonic attenuation circuit 30.

[0190] According to this, the DC component can be cut off by the matching circuit 20.

[0191] Furthermore, for example, in the high-frequency circuit 1A according to this embodiment, the matching circuit 20 may include an LC series circuit 22 connected between the path between the power amplifier circuit 10 and the harmonic attenuation circuit 30 and ground.

[0192] According to this, high-frequency distortion can also be attenuated in the matching circuit 20.

[0193] For example, in the high-frequency circuit 1A according to this embodiment, the power amplification circuit 10 may also include power amplifiers 11 and 12, and a combiner 13 that includes an input terminal 131 connected to the output terminal of the power amplifier 11, an input terminal 132 connected to the output terminal of the power amplifier 12, and an output terminal 133 connected to the matching circuit 20.

[0194] According to this, high-frequency signals can be amplified using power amplifiers 11 and 12 connected in parallel, enabling support for higher output power.

[0195] (Other embodiments) The high-frequency circuit according to the present invention has been described above based on embodiments, but the high-frequency circuit according to the present invention is not limited to the above embodiments. Other embodiments realized by combining any of the components in the above embodiments, modified versions obtained by applying various modifications to the above embodiments that a person skilled in the art can conceive of without departing from the spirit of the present invention, and various devices incorporating the above high-frequency circuit are also included in the present invention.

[0196] For example, in the circuit configuration of the high-frequency circuit according to each of the above embodiments, other circuit elements and wiring may be inserted between the paths connecting each circuit element and signal path disclosed in the drawings. For example, an impedance matching circuit may be connected between filters 51 and 52 and the switch circuit 60. Also, for example, a coupler may be connected between the switch circuit 60 and the antenna connection terminal 100.

[0197] Furthermore, for example, variations 1 to 3 of Embodiment 1 may be applied to Embodiment 2. In other words, the high-frequency circuit 1A may include harmonic attenuation circuits 30A, 30B, or 30C instead of the harmonic attenuation circuit 30.

[0198] The characteristics of the high-frequency circuits described based on the above embodiments are shown below.

[0199] <1> Power amplifier circuit, A harmonic attenuation circuit having an attenuation band that includes at least a portion of the harmonic band of the first band's transmission bandwidth, A matching circuit connected between the harmonic attenuation circuit and the power amplification circuit, A first filter having a passband that includes the transmission bandwidth of the first band, A first switch connected between the harmonic attenuation circuit and the first filter, A second switch connected between the first filter and the antenna connection terminal, The system includes a third switch that is connected between the matching circuit and the antenna connection terminal without going through the harmonic attenuation circuit. High-frequency circuits.

[0200] <2> The harmonic attenuation circuit includes an inductor connected between the matching circuit and the first switch, and does not include a ground connection. <1> The high-frequency circuit described above.

[0201] <3> In a first mode for transmitting a first high-frequency signal in the transmission bandwidth of the first band, the first and second switches are closed, and the third switch is open. In a second mode for transmitting a second high-frequency signal in the second band's transmission bandwidth, the third switch is closed, and the first and second switches are opened. <1> or <2> The high-frequency circuit described above.

[0202] <4> The first band is either a 5G NR band or a 4G LTE band. The second band is the 2GGSM band. <3> The high-frequency circuit described above.

[0203] <5> The first band and the second band are 5G NR bands or 4G LTE bands. The maximum output power of the first high-frequency signal is higher than the maximum output power of the second high-frequency signal. <3> The high-frequency circuit described above.

[0204] <6> The aforementioned high-frequency circuit further, A second filter having a passband that includes the transmission bandwidth of the third band, A fourth switch connected between the harmonic attenuation circuit and the second filter, The system comprises a fifth switch connected between the second filter and the antenna connection terminal, <4> or <5> The high-frequency circuit described above.

[0205] <7> In a third mode for transmitting a third high-frequency signal in the transmission bandwidth of the third band, the fourth and fifth switches are closed, and the first, second, and third switches are open. <6> The high-frequency circuit described above.

[0206] <8> The aforementioned high-frequency circuit further, A second filter having a passband that includes the transmission bandwidth of the third band, A fourth switch connected between the harmonic attenuation circuit and the second filter, The system comprises a fifth switch connected between the second filter and the antenna connection terminal, <1> or <2> The high-frequency circuit described above.

[0207] <9> The aforementioned high-frequency circuit further, A sixth switch connected between the matching circuit and the third switch without going through the aforementioned harmonic attenuation circuit, A third filter connected between the third switch and the sixth switch, having a passband that includes the transmission bandwidth of the second band, <8> The high-frequency circuit described above.

[0208] <10> The aforementioned high-frequency circuit further, A fourth filter having a passband that includes the transmission bandwidth of the fourth band, A seventh switch connected between the matching circuit and the fourth filter without going through the aforementioned harmonic attenuation circuit, The system comprises an eighth switch connected between the fourth filter and the antenna connection terminal, <9> The high-frequency circuit described above.

[0209] <11> In a first mode for transmitting a first high-frequency signal in the transmission bandwidth of the first band, the first and second switches are closed, and the third, fourth, fifth, sixth, seventh, and eighth switches are open. In a second mode for transmitting a second high-frequency signal in the transmission bandwidth of the second band, the third switch and the sixth switch are closed, and the first switch, the second switch, the fourth switch, the fifth switch, the seventh switch, and the eighth switch are open. In the third mode for transmitting a third high-frequency signal in the transmission bandwidth of the third band, the fourth and fifth switches are closed, and the first, second, third, sixth, seventh, and eighth switches are open. In the fourth mode for transmitting the fourth high-frequency signal in the transmission bandwidth of the fourth band, the seventh and eighth switches are closed, and the first, second, third, fourth, fifth, and sixth switches are open. <10> The high-frequency circuit described above.

[0210] <12> The first band and the third band are 5G NR bands or 4G LTE bands corresponding to a first power class defined by a first maximum power and a second power class defined by a second maximum power lower than the first maximum power. The second and fourth bands are 5G NR bands or 4G LTE bands that correspond to the second power class and do not correspond to the first power class. <11> The high-frequency circuit described above.

[0211] <13> The harmonic attenuation circuit includes an LC parallel circuit connected between the matching circuit and the first switch. <1> ~ <12> A high-frequency circuit as described in any one of the following.

[0212] <14> The capacitor in the aforementioned LC parallel circuit is a variable capacitor. <13> The high-frequency circuit described above.

[0213] <15> In a first mode for transmitting a first high-frequency signal in the transmission bandwidth of the first band, the variable capacitor is controlled to a first capacitance, In a second mode for transmitting a second high-frequency signal in the transmission bandwidth of the second band, the variable capacitor is controlled to a second capacitance that is larger than the first capacitance. <14> The high-frequency circuit described above.

[0214] <16> In a first mode for transmitting a first high-frequency signal in the transmission bandwidth of the first band, the variable capacitor is controlled to the first capacitance such that the resonant frequency of the LC parallel circuit falls within the harmonic band of the transmission bandwidth of the first band. In a second mode for transmitting a second high-frequency signal in the transmission bandwidth of the second band, the variable capacitor is controlled to the second capacitance such that the resonant frequency of the LC parallel circuit falls within the transmission bandwidth of the second band. <15> The high-frequency circuit described above.

[0215] <17> The aforementioned harmonic attenuation circuit is At least one of an inductor and a capacitor is connected between the path between the matching circuit and the first switch and ground, A ninth switch connected between the matching circuit and at least one of the inductor and the capacitor, <1> The high-frequency circuit described above.

[0216] <18> The matching circuit includes a capacitor connected between the power amplifier circuit and the harmonic attenuation circuit. <1> ~ <17> A high-frequency circuit as described in any one of the following.

[0217] <19> The matching circuit includes an LC series circuit connected between the path between the power amplifier circuit and the harmonic attenuation circuit and ground. <1> ~ <18> A high-frequency circuit as described in any one of the following.

[0218] <20> The aforementioned power amplification circuit is First power amplifier and second power amplifier, A combiner including a first input terminal connected to the output terminal of the first power amplifier, a second input terminal connected to the output terminal of the second power amplifier, and an output terminal connected to the matching circuit, <1> ~ <19> A high-frequency circuit as described in any one of the following. [Industrial applicability]

[0219] This invention can be widely used in communication devices such as mobile phones as a high-frequency circuit placed in the front end. [Explanation of Symbols]

[0220] 1. 1A High-Frequency Circuit 2 antennas 3RFIC 4 BBIC 5, 5A communication device 10 Power Amplifier Circuit 11, 12 Power amplifier 13 Synthesizer 14 Distributor 20 Matching circuit 21,221 Capacitors 22 LC series circuit 30, 30A, 30B, 30C harmonic attenuation circuits 31 LC parallel circuit 32, 41, 42, 43, 44, 61, 62, 63, 64 switches 40, 40A, 60, 60A switch circuit 51, 52, 53, 54 filters 100 Antenna connection terminal 110 High-frequency input terminal Input terminals 131, 132, 141 Output terminals 133, 142, 143 222, 311, 311C inductors 312 Capacitors 400, 403, 600 Common terminal 401, 402, 404, 405, 601, 602, 603, 604 Selectable terminals N23 node

Claims

1. Power amplifier circuit, A harmonic attenuation circuit having an attenuation band that includes at least a portion of the harmonic band of the first band's transmission bandwidth, A matching circuit connected between the harmonic attenuation circuit and the power amplification circuit, A first filter having a passband that includes the transmission bandwidth of the first band, A first switch connected between the harmonic attenuation circuit and the first filter, A second switch is connected between the first filter and the antenna connection terminal, The system includes a third switch that is connected between the matching circuit and the antenna connection terminal without going through the harmonic attenuation circuit. High-frequency circuits.

2. The harmonic attenuation circuit includes an inductor connected between the matching circuit and the first switch, and does not include a ground connection. The high-frequency circuit according to claim 1.

3. In a first mode for transmitting a first high-frequency signal in the transmission bandwidth of the first band, the first switch and the second switch are closed, and the third switch is open. In a second mode for transmitting a second high-frequency signal in the transmission bandwidth of the second band, the third switch is closed, and the first and second switches are opened. The high-frequency circuit according to claim 1 or 2.

4. The first band is a 5GNR band or a 4GLTE band. The second band is the 2GGSM band. The high-frequency circuit according to claim 3.

5. The first band and the second band are the 5GNR band or the 4GLTE band. The maximum output power of the first high-frequency signal is higher than the maximum output power of the second high-frequency signal. The high-frequency circuit according to claim 3.

6. The aforementioned high-frequency circuit further, A second filter having a passband that includes the transmission bandwidth of the third band, A fourth switch connected between the harmonic attenuation circuit and the second filter, The system comprises a fifth switch connected between the second filter and the antenna connection terminal, The high-frequency circuit according to claim 4.

7. In a third mode for transmitting a third high-frequency signal in the transmission bandwidth of the third band, the fourth and fifth switches are closed, and the first, second, and third switches are open. The high-frequency circuit according to claim 6.

8. The aforementioned high-frequency circuit further, A second filter having a passband that includes the transmission bandwidth of the third band, A fourth switch connected between the harmonic attenuation circuit and the second filter, The system comprises a fifth switch connected between the second filter and the antenna connection terminal, The high-frequency circuit according to claim 1 or 2.

9. The aforementioned high-frequency circuit further, A sixth switch connected between the matching circuit and the third switch without going through the aforementioned harmonic attenuation circuit, A third filter connected between the third switch and the sixth switch, having a passband that includes the transmission bandwidth of the second band, The high-frequency circuit according to claim 8.

10. The aforementioned high-frequency circuit further, A fourth filter having a passband that includes the transmission bandwidth of the fourth band, A seventh switch connected between the matching circuit and the fourth filter without going through the aforementioned harmonic attenuation circuit, The system comprises an eighth switch connected between the fourth filter and the antenna connection terminal, The high-frequency circuit according to claim 9.

11. In a first mode for transmitting a first high-frequency signal in the transmission bandwidth of the first band, the first and second switches are closed, and the third, fourth, fifth, sixth, seventh, and eighth switches are open. In a second mode for transmitting a second high-frequency signal in the transmission bandwidth of the second band, the third switch and the sixth switch are closed, and the first switch, the second switch, the fourth switch, the fifth switch, the seventh switch, and the eighth switch are open. In the third mode for transmitting a third high-frequency signal in the transmission bandwidth of the third band, the fourth and fifth switches are closed, and the first, second, third, sixth, seventh, and eighth switches are open. In the fourth mode for transmitting the fourth high-frequency signal in the transmission bandwidth of the fourth band, the seventh and eighth switches are closed, and the first, second, third, fourth, fifth, and sixth switches are open. The high-frequency circuit according to claim 10.

12. The first band and the third band are 5GNR bands or 4GLTE bands corresponding to a first power class defined by a first maximum power output and a second power class defined by a second maximum power output lower than the first maximum power output. The second and fourth bands are 5GNR bands or 4GLTE bands that correspond to the second power class and do not correspond to the first power class. The high-frequency circuit according to claim 11.

13. The harmonic attenuation circuit includes an LC parallel circuit connected between the matching circuit and the first switch. The high-frequency circuit according to claim 1 or 2.

14. The capacitor in the aforementioned LC parallel circuit is a variable capacitor. The high-frequency circuit according to claim 13.

15. In a first mode for transmitting a first high-frequency signal in the transmission bandwidth of the first band, the variable capacitor is controlled to a first capacitance, In a second mode for transmitting a second high-frequency signal in the transmission bandwidth of the second band, the variable capacitor is controlled to a second capacitance that is larger than the first capacitance. The high-frequency circuit according to claim 14.

16. In a first mode for transmitting a first high-frequency signal in the transmission bandwidth of the first band, the variable capacitor is controlled to the first capacitance such that the resonant frequency of the LC parallel circuit falls within the harmonic band of the transmission bandwidth of the first band. In a second mode for transmitting a second high-frequency signal in the transmission bandwidth of the second band, the variable capacitor is controlled to the second capacitance such that the resonant frequency of the LC parallel circuit falls within the transmission bandwidth of the second band. The high-frequency circuit according to claim 15.

17. The aforementioned harmonic attenuation circuit is At least one of an inductor and a capacitor is connected between the path connecting the matching circuit and the first switch and ground, A ninth switch connected between the matching circuit and at least one of the inductor and the capacitor, The high-frequency circuit according to claim 1.

18. The matching circuit includes a capacitor connected between the power amplifier circuit and the harmonic attenuation circuit. The high-frequency circuit according to claim 1 or 2.

19. The matching circuit includes an LC series circuit connected between the path between the power amplifier circuit and the harmonic attenuation circuit and ground. The high-frequency circuit according to claim 1 or 2.

20. The aforementioned power amplification circuit is A first power amplifier and a second power amplifier, A combiner including a first input terminal connected to the output terminal of the first power amplifier, a second input terminal connected to the output terminal of the second power amplifier, and an output terminal connected to the matching circuit, The high-frequency circuit according to claim 1 or 2.

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