High-frequency circuit and communication device

Abstract

A high-frequency circuit (1) comprises: a switch circuit (51) including a filter (31) having a passband including the reception band of a band A, a filter (32) having a passband including the transmission band of a band B, common terminals (511 and 512) respectively connected to antenna connection terminals (101 and 102), a selection terminal (513) connected to the filter (31), and a selection terminal (514) connected to the filter (32); a coupler (41) including a main line (411) that is connected to the path connecting the antenna connection terminal (101) and the common terminal (511), and a sub-line (412) that can be coupled to the main line (411); and a switch circuit (52) including input terminals (521 and 522) that are respectively connected to both ends of the sub-line (412), an input terminal (523) connected to the signal path connecting the antenna connection terminal (101) and the filter (31), an output terminal (524), and a phase adjustment circuit (520).

Description

High frequency circuits and communication devices

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

[0002] In order to improve the data rate of wireless links, mobile communication devices such as mobile phones are increasingly supporting carrier aggregation (CA) and dual connectivity (DC), which simultaneously use multiple frequency bands or multiple channels within the same frequency band. Patent Document 1 discloses a high-frequency circuit having multiple filters for multiple frequency bands.

[0003] International Publication No. 2023 / 276871

[0004] However, in the above-mentioned conventional technology, when signals of multiple frequency bands are simultaneously communicated, when an SRS (Sounding Reference Signal) for measuring the reception quality or adjusting the timing of a specific frequency band is transmitted, the reception throughput of other frequency bands may decrease.

[0005] Therefore, the present invention provides a high-frequency circuit and a communication device that can suppress the decrease in reception throughput that accompanies SRS transmission.

[0006] a first common terminal connected to the first antenna connection terminal, a second common terminal connected to the second antenna connection terminal, a first selection terminal connected to the first filter, and a second selection terminal connected to the second filter; a first coupler including a first main line connected to a path connecting the first antenna connection terminal and the first common terminal, and a first sub-line coupleable with the first main line; a first input terminal connected to one end of the first sub-line, a second input terminal connected to the other end of the first sub-line, a third input terminal connected to a signal path connecting the first antenna connection terminal and the first filter; an output terminal; and a first phase adjustment circuit switchably connected to the first input terminal, the second input terminal, and the third input terminal.

[0007] A high-frequency circuit according to one aspect of the present invention includes a first antenna connection terminal for transmitting and receiving high-frequency signals, a second antenna connection terminal for transmitting SRS, a third antenna connection terminal for transmitting and receiving high-frequency signals, a first filter having a pass band including a reception band of a first band, a second filter having a pass band including a transmission band of a second band, a first common terminal connected to the first antenna connection terminal, a second common terminal connected to the second antenna connection terminal, a third common terminal connected to the third antenna connection terminal, a first selection terminal connected to the first filter, and a second selection terminal connected to the second filter, a first coupler including a first main line connected to a path connecting the first antenna connection terminal and the first common terminal, and a first sub-line coupleable with the first main line, and a third antenna connection circuit. a second coupler including a second main line connected to a path connecting the antenna connecting terminal and the third common terminal and a second sub-line that can be coupled to the second main line; a first input terminal connected to one end of the first sub-line; a second input terminal connected to the other end of the first sub-line; a third input terminal connected to a signal path connecting the first antenna connecting terminal and the first filter; a fourth input terminal connected to one end of the second sub-line; a fifth input terminal connected to the other end of the second sub-line; a sixth input terminal connected to the signal path connecting the third antenna connecting terminal and the first filter; an output terminal; a second switch circuit including a first phase adjustment circuit switchably connected to the first input terminal, the second input terminal, and the sixth input terminal; and a second phase adjustment circuit switchably connected to the third input terminal, the fourth input terminal, and the fifth input terminal.

[0008] A communication device according to one aspect of the present invention comprises a signal processing circuit configured to process a high-frequency signal, and the high-frequency circuit configured to transmit the high-frequency signal between the signal processing circuit and an antenna.

[0009] According to the present invention, it is possible to suppress a decrease in reception throughput due to SRS transmission.

[0010] FIG. 1 is a circuit configuration diagram of a communication device according to a first embodiment. FIG. 2 is a circuit configuration diagram of a phase adjustment circuit according to the first embodiment. FIG. 3 is a diagram illustrating a transmission path and a reception path in a first mode and forward operation in a high-frequency circuit according to the first embodiment. FIG. 4 is a diagram illustrating a first mode and reverse operation in a high-frequency circuit according to the first embodiment. FIG. 5 is a diagram illustrating a second mode in a high-frequency circuit according to the first embodiment. FIG. 6 is a circuit configuration diagram of a communication device according to a second embodiment. FIG. 7 is a diagram illustrating a first mode and forward operation in a high-frequency circuit according to the second embodiment. FIG. 8 is a diagram illustrating a first mode and reverse operation in a high-frequency circuit according to the second embodiment. FIG. 9 is a diagram illustrating a second mode and forward operation in a high-frequency circuit according to the second embodiment. FIG. 10 is a diagram illustrating a second mode and reverse operation in a high-frequency circuit according to the second embodiment. FIG. 11 is a diagram illustrating a third mode and forward operation in a high-frequency circuit according to the second embodiment. FIG. 12 is a diagram illustrating a third mode and reverse operation in a high-frequency circuit according to the second embodiment. FIG. 13 is a diagram illustrating a fourth mode and forward operation in a high-frequency circuit according to the second embodiment. FIG. 14 is a diagram showing the fourth mode and reverse operation in the high-frequency circuit according to the second embodiment.

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, arrangements and connection forms of the components shown in the following embodiments are merely examples and are not intended to limit the present invention.

[0012] It should be noted that the drawings are schematic diagrams in which emphasis, omission, or adjustment of proportions has been appropriately made to illustrate the present invention, and are not necessarily strictly illustrated, and may differ from the actual shapes, positional relationships, and proportions. In the drawings, the same reference numerals are used to denote substantially the same components, and redundant explanations may be omitted or simplified.

[0013] In the following description of the circuit configuration, "connected" includes not only direct connection by connection terminals and / or wiring conductors, but also electrical connection via other circuit elements. "A is switchably connected to B" means that the connection and disconnection between A and B can be switched, and A is connected to B via a switch. "A is connected to B" includes "A is switchably connected to B." "C is connected between A and B" means that one end of C is connected to A and the other end of C is connected to B, and C is arranged in series in the path connecting A and B. "Path connecting A and B" means a path made up of a conductor electrically connecting A to B.

[0014] "Terminal" means a point where a conductor within an element terminates. Note that terminal is understood to mean any point on the conductor between elements or the entire conductor, not just a single point, provided the impedance of the conductor between elements is sufficiently low.

[0015] The "filter passband" is the portion of the frequency spectrum transmitted by the filter, defined as the frequency band between two frequencies 3 dB above the minimum power insertion loss.

[0016] The term "transmission band" refers to a frequency band used for transmission in a communication device, and the term "reception band" refers to a frequency band used for reception in a communication device. For example, in a frequency division duplex (FDD) band, different frequency bands (e.g., an uplink band and a downlink band) are used as the transmission band and the reception band. For example, in a time division duplex (TDD) band, the same frequency band is used as the transmission band and the reception band.

[0017] A "band combination that allows simultaneous communication" refers to a combination of multiple frequency bands that can be used for simultaneous transmission, simultaneous reception, or simultaneous transmission and reception. "Band combinations that allow simultaneous communication" are defined in advance by standardization organizations (e.g., 3GPP (registered trademark) (3rd Generation Partnership Project) and IEEE (Institute of Electrical and Electronics Engineers)). Examples of "simultaneous communication" include CA, EN-DC (E-UTRAN New Radio - Dual Connectivity), NR-DC (New Radio - Dual Connectivity), and NE-DC (New Radio E-UTRAN - Dual Connectivity).

[0018] Terms indicating the relationship between elements, such as "parallel" and "perpendicular," terms indicating the shape of elements, such as "rectangle," and numerical ranges do not only indicate the strict meaning, but also include a substantially equivalent range, for example, an error of a few percent.

[0019] (First Embodiment) A first embodiment will be described. A communication device 5 according to this embodiment can be used to provide wireless connectivity. For example, the communication device 5 can be implemented in UEs in a cellular network (also referred to as a mobile network), such as mobile phones, smartphones, tablet computers, and wearable devices. In another example, the communication device 5 can be implemented to provide wireless connectivity to Internet of Things (IoT) sensor devices, medical / healthcare devices, cars, unmanned aerial vehicles (UAVs) (so-called drones), and automated guided vehicles (AGVs). In yet another example, the communication device 5 can be implemented to provide wireless connectivity in a wireless access point or a wireless hotspot.

[0020] The circuit configuration of a communication device 5 and a high-frequency circuit 1 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a circuit configuration diagram of a communication device 5 according to this embodiment.

[0021] 1 is an exemplary circuit configuration, and communication device 5 may be implemented using any of a wide variety of circuit implementations and circuit technologies, and therefore the description of communication device 5 provided below should not be construed as limiting.

[0022] [1.1 Circuit Configuration of Communication Device 5] First, the circuit configuration of the communication device 5 according to this embodiment will be described with reference to Fig. 1. The communication device 5 includes a high-frequency circuit 1, antennas 2a and 2b, an RFIC (Radio Frequency Integrated Circuit) 3, and a BBIC (Baseband Integrated Circuit) 4.

[0023] The high-frequency circuit 1 can transmit high-frequency signals between the antennas 2a and 2b and the RFIC 3. The circuit configuration of the high-frequency circuit 1 will be described later.

[0024] The antennas 2a and 2b are connected to antenna connection terminals 101 and 102, respectively, of the high-frequency circuit 1. The antennas 2a and 2b can receive high-frequency signals from the high-frequency circuit 1 and transmit them to the outside of the communication device 5. The antennas 2a and 2b can also receive high-frequency signals from the outside of the communication device 5 and output them to the high-frequency circuit 1. The antennas 2a and 2b do not necessarily have to be included in the communication device 5. The communication device 5 may also include one or more antennas in addition to the antennas 2a and 2b.

[0025] The RFIC 3 is an example of a signal processing circuit that processes high-frequency signals. Specifically, the RFIC 3 can perform signal processing on a transmission signal input from the BBIC 4 by up-conversion or the like, and output the high-frequency transmission signal generated by the signal processing to the high-frequency circuit 1. Furthermore, the RFIC 3 can perform signal processing on a high-frequency reception signal input via the reception path of the high-frequency circuit 1 by down-conversion or the like, and output the reception signal generated by the signal processing to the BBIC 4. The RFIC 3 may also have a control unit that controls switches, power amplifiers, and the like included in the high-frequency circuit 1. Note that some or all of the functions of the RFIC 3 as a control unit may be included outside the RFIC 3, and may be included in, for example, the BBIC 4 or the high-frequency circuit 1.

[0026] The BBIC 4 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. The signals processed by the BBIC 4 include, for example, image signals for image display and / or audio signals for calls via a speaker. The BBIC 4 does not necessarily have to be included in the communication device 5.

[0027] [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 Fig. 1. The high-frequency circuit 1 includes power amplifiers 11 and 12, low-noise amplifiers 21 and 22, filters 31, 32, and 33, a coupler 41, switch circuits 51, 52, and 53, antenna connection terminals 101 and 102, high-frequency input terminals 111 and 112, high-frequency output terminals 121 and 122, and a feedback terminal 131. Note that in the following figures, dashed lines in the switch circuits represent paths between terminals that can be switched between connected and disconnected.

[0028] The antenna connection terminal 101 is an example of a first antenna connection terminal and is a terminal for transmitting and receiving high-frequency signals. The antenna connection terminal 101 is connected to an antenna 2a outside the high-frequency circuit 1 and is connected to a switch circuit 51 inside the high-frequency circuit 1 via a coupler 41. The antenna connection terminal 102 is an example of a second antenna connection terminal and is a terminal for transmitting a sounding reference signal (SRS). The antenna connection terminal 102 is connected to an antenna 2b outside the high-frequency circuit 1 and is connected to a switch circuit 51 inside the high-frequency circuit 1.

[0029] The radio frequency input terminals 111 and 112 are external connection terminals of the radio frequency circuit 1 and are connected to the RFIC 3 outside the radio frequency circuit 1. The radio frequency input terminals 111 and 112 are also connected to the power amplifiers 11 and 12, respectively, inside the radio frequency circuit 1. This allows the radio frequency circuit 1 to supply transmission signals (including SRS) received from the RFIC 3 via the radio frequency input terminals 111 and 112 to the power amplifiers 11 and 12, respectively.

[0030] The radio frequency output terminals 121 and 122 are external connection terminals of the radio frequency circuit 1 and are connected to the RFIC 3 outside the radio frequency circuit 1. The radio frequency output terminals 121 and 122 are also connected to the low noise amplifiers 21 and 22, respectively, inside the radio frequency circuit 1. This allows the radio frequency circuit 1 to supply the received signals amplified by the low noise amplifiers 21 and 22 to the RFIC 3 via the radio frequency output terminals 121 and 122, respectively.

[0031] The feedback terminal 131 is an external connection terminal of the high-frequency circuit 1, and is connected to the RFIC 3 outside the high-frequency circuit 1. The feedback terminal 131 is also connected to the output terminal 524 of the switch circuit 52 inside the high-frequency circuit 1. This allows the high-frequency circuit 1 to feed back a portion of the high-frequency signal transmitted between the antenna connection terminal 101 and the switch circuit 51 to the RFIC 3 via the feedback terminal 131.

[0032] Power amplifier 11 uses power supplied from a power supply (not shown) to amplify a band A transmission signal received via radio frequency input terminal 111. The input terminal of power amplifier 11 is connected to radio frequency input terminal 111, and the output terminal of power amplifier 11 is connected to filter 33.

[0033] Power amplifier 12 uses power supplied from a power supply (not shown) to amplify a band B transmission signal received via radio frequency input terminal 112. The input terminal of power amplifier 12 is connected to radio frequency input terminal 112, and the output terminal of power amplifier 12 is switchably connected to filter 32.

[0034] The power amplifiers 11 and 12 may be configured with heterojunction bipolar transistors (HBTs) and may be manufactured using semiconductor materials. Examples of the semiconductor materials that may be used include silicon germanium (SiGe) and gallium arsenide (GaAs). The amplifying transistors of the power amplifiers 11 and 12 are not limited to HBTs. For example, the power amplifiers 11 and / or 12 may be configured with high electron mobility transistors (HEMTs) or metal-semiconductor field effect transistors (MESFETs). In this case, gallium nitride (GaN) or silicon carbide (SiC) may be used as the semiconductor material.

[0035] Note that part or all of the power amplifiers 11 and 12 may not be included in the high-frequency circuit 1. In this case, part or all of the power amplifier 11 may be connected between the RFIC 3 and the high-frequency input terminal 111, or may be included in the RFIC 3. Similarly, part or all of the power amplifier 12 may be connected between the RFIC 3 and the high-frequency input terminal 112, or may be included in the RFIC 3.

[0036] The low-noise amplifier 21 uses power supplied from a power supply (not shown) to amplify the received signal of band A that has passed through the filter 31. The input terminal of the low-noise amplifier 21 is connected to the filter 31, and the output terminal of the low-noise amplifier 21 is connected to the high-frequency output terminal 121.

[0037] The low-noise amplifier 22 uses power supplied from a power supply (not shown) to amplify the received signal of band B that has passed through the filter 32. The input terminal of the low-noise amplifier 22 is switchably connected to the filter 32, and the output terminal of the low-noise amplifier 22 is connected to the high-frequency output terminal 122.

[0038] The low-noise amplifiers 21 and 22 may be configured with field-effect transistors (FETs) and may be manufactured using semiconductor materials. Examples of the semiconductor materials that may be used include single crystal silicon, GaN, and SiC. The amplifying transistors of the low-noise amplifiers 21 and 22 are not limited to FETs. For example, some or all of the low-noise amplifiers 21 and 22 may be configured with bipolar transistors.

[0039] Note that part or all of the low-noise amplifiers 21 and 22 may not be included in the high-frequency circuit 1. In this case, part or all of the low-noise amplifier 21 may be connected between the high-frequency output terminal 121 and the RFIC 3, or may be included in the RFIC 3. Similarly, part or all of the low-noise amplifier 22 may be connected between the high-frequency output terminal 122 and the RFIC 3, or may be included in the RFIC 3.

[0040] The filter 31 (A-Rx) is an example of a first filter, and is a band-pass filter having a pass band that includes the reception band of band A. One end of the filter 31 is connected to the switch circuit 51, and the other end of the filter 31 is connected to the low-noise amplifier 21. Note that the filter 31 is not limited to a band-pass filter.

[0041] The filter 32 (B-TRx) is an example of a second filter, and is a band-pass filter having a pass band that includes the transmission band and reception band of band B. One end of the filter 32 is connected to the switch circuit 51, and the other end of the filter 32 is switchably connected to the power amplifier 12 and the low-noise amplifier 22. Note that the filter 32 is not limited to a band-pass filter.

[0042] The filter 33 (A-Tx) is an example of a third filter, and is a band-pass filter having a pass band that includes the transmission band of band A. One end of the filter 33 is connected to the switch circuit 51, and the other end of the filter 33 is connected to the power amplifier 11. Note that the filter 33 is not limited to a band-pass filter, and does not necessarily have to be included in the high-frequency circuit 1.

[0043] Bands A and B are frequency bands for communication systems built using radio access technologies (RATs), and are defined in advance by standardization organizations (e.g., 3GPP and IEEE). Examples of communication systems include 5GNR (5th Generation New Radio) systems, LTE (Long Term Evolution) systems, and WLAN (Wireless Local Area Network) systems.

[0044] Band A is an example of a first band and is an FDD band. Band A can be, for example, Band 1, Band 3, Band 25, Band 66, Band 34, Band 39, or Band 7 for LTE, or n1, n3, n25, n66, n34, n39, or n7 for 5G NR. Note that Band A is not limited to the FDD band.

[0045] Band B is an example of a second band and is a TDD band. A combination of Bands A and B is a band combination that allows simultaneous communication. Band B can be Band 40 or Band 41 for LTE, or n40 or n41 for 5G NR. Note that Band B is not limited to a TDD band.

[0046] The coupler 41 is an example of a first coupler and a bidirectional coupler. The coupler 41 includes a main line 411 connected to a path connecting the antenna connection terminal 101 and the common terminal 511, and a sub-line 412 that can be coupled to the main line 411. The main line 411 is an example of a first main line, one end of which is connected to the common terminal 511 of the switch circuit 51, and the other end of which is connected to the antenna connection terminal 101. The sub-line 412 is an example of a first sub-line, one end of which is connected to an input terminal 521 of the switch circuit 52, and the other end of which is connected to an input terminal 522 of the switch circuit 52. In this embodiment, the coupler 41 terminates one end of the sub-line 412 and can extract a signal from the other end of the sub-line 412. Note that the coupler 41 is not limited to a bidirectional coupler.

[0047] The switch circuit 51 is an example of a first switch circuit and includes common terminals 511 and 512 and selection terminals 513 and 514. The common terminal 511 is an example of a first common terminal and is connected to the antenna connection terminal 101. The common terminal 512 is an example of a second common terminal and is connected to the antenna connection terminal 102. The selection terminal 513 is an example of a first selection terminal and is connected to the filters 31 and 33. The selection terminal 514 is an example of a second selection terminal and is connected to the filter 32. Within the switch circuit 51, the common terminals 511 and 512 can be connected to the selection terminals 513 and 514, respectively.

[0048] In such a connection configuration, the switch circuit 51 can connect the common terminals 511 and 512 to the selection terminals 513 and 514 based on, for example, a control signal from the RFIC 3. The switch circuit 51 is configured as, for example, a multi-connection type switch circuit.

[0049] The switch circuit 52 is an example of a second switch circuit, and includes a phase adjustment circuit 520 , input terminals 521 , 522 and 523 , and an output terminal 524 .

[0050] The phase adjustment circuit 520 is an example of a first phase adjustment circuit, and is switchably connected to the input terminals 521, 522, and 523. The phase adjustment circuit 520 can function as a termination circuit for the coupler 41, and can also adjust the phase of the path connecting the antenna connection terminal 101 and the filters 31 and 33.

[0051] 2 is a circuit diagram of the phase adjustment circuit 520 according to the present embodiment. Note that FIG. 2 is an exemplary circuit configuration, and the phase adjustment circuit 520 can be implemented using any of a wide variety of circuit implementations and circuit technologies. Therefore, the description of the phase adjustment circuit 520 provided below should not be construed as limiting.

[0052] 2, the phase adjustment circuit 520 includes a variable capacitance 5201 and a variable resistance 5202. One end of the variable capacitance 5201 and one end of the variable resistance 5202 can be connected to input terminals 521 to 523, and the other end of the variable capacitance 5201 and one end of the variable resistance 5202 are connected to ground.

[0053] The input terminal 521 is an example of a first input terminal and is connected to one end of the sub-line 412. The input terminal 522 is an example of a second input terminal and is connected to the other end of the sub-line 412. The input terminal 523 is an example of a third input terminal and is connected to a signal path connecting the antenna connection terminal 101 and the coupler 41. The input terminal 523 may also be connected to a signal path connecting the coupler 41 and the filters 31 and 33. In the switch circuit 52, the input terminals 521 and 522 are each connectable to an output terminal 524 and a phase adjustment circuit 520, and the input terminal 523 is connectable to the phase adjustment circuit 520.

[0054] In such a connection configuration, the switch circuit 52 can connect the input terminals 521 to 523 to the phase adjustment circuit 520 and the output terminal 524 based on, for example, a control signal from the RFIC 3. The switch circuit 52 is configured as, for example, a multi-connection type switch circuit.

[0055] The switch circuit 53 includes a common terminal 531 and selection terminals 532 and 533. The common terminal 531 is connected to the filter 32. The selection terminal 532 is connected to the power amplifier 12. The selection terminal 533 is connected to the low-noise amplifier 22. Within the switch circuit 53, the common terminal 531 is connectable to the selection terminals 532 and 533.

[0056] In such a connection configuration, the switch circuit 53 can exclusively connect the common terminal 531 to the selection terminals 532 and 533, for example, based on a control signal from the RFIC 3. The switch circuit 53 is configured, for example, by an SPDT (Single-Pole Double-Throw) type switch circuit. Note that the switch circuit 53 does not necessarily have to be included in the high-frequency circuit 1.

[0057] Any combination of switch circuits 51 to 53 may be included in one semiconductor integrated circuit. For example, all of switch circuits 51 to 53 may be included in one semiconductor integrated circuit. For another example, switch circuits 51 and 52 may be included in one semiconductor integrated circuit, and in this case, switch circuit 53 may be included in another semiconductor integrated circuit. For another example, switch circuits 51 and 53 may be included in one semiconductor integrated circuit, and in this case, switch circuit 52 may be included in the other semiconductor integrated circuit. For another example, switch circuits 52 and 53 may be included in one semiconductor integrated circuit, and in this case, switch circuit 51 may be included in the other semiconductor integrated circuit.

[0058] [1.3. Communication Mode and Coupler Operation] Next, the communication mode of the high-frequency circuit 1 and the operation of the coupler 41 will be described with reference to FIGS.

[0059] [1.3.1. First Mode and Forward Operation (FWD)] First, the forward operation in the first mode will be described with reference to Fig. 3. Fig. 3 is a diagram showing the first mode and forward operation in the high-frequency circuit 1 according to this embodiment. In the following figures, dashed arrows represent transmission paths and reception paths of high-frequency signals, and solid lines in the switch circuit represent paths between terminals connected to each other.

[0060] In the first mode and forward operation, the high-frequency circuit 1 can simultaneously transmit and receive transmit signals and receive signals of bands A and B using the antenna 2a, and can feed back a portion of the transmit signals of bands A and B to the RFIC 3 using the coupler 41 and the switch circuit 52.

[0061] 3, in the first mode, the switch circuit 51 connects the common terminal 511 to the selection terminals 513 and 514. The switch circuit 52 connects the input terminal 521 to the output terminal 524 and connects the input terminal 522 to the phase adjustment circuit 520. The switch circuit 53 switches the connection of the common terminal 531 between the selection terminals 532 and 533 over time.

[0062] As a result, the transmit signal of band A is transmitted from the RFIC 3 to the antenna 2a via the radio frequency input terminal 111, the power amplifier 11, the filter 33, the switch circuit 51, the coupler 41, and the antenna connection terminal 101. The receive signal of band A is transmitted from the antenna 2a to the RFIC 3 via the antenna connection terminal 101, the coupler 41, the switch circuit 51, the filter 31, the low noise amplifier 21, and the radio frequency output terminal 121. The transmit signal of band B is transmitted from the RFIC 3 to the antenna 2a via the radio frequency input terminal 112, the power amplifier 12, the switch circuit 53, the filter 32, the switch circuit 51, the coupler 41, and the antenna connection terminal 101. The receive signal of band B is transmitted from the antenna 2a to the RFIC 3 via the antenna connection terminal 101, the coupler 41, the switch circuit 51, the filter 32, the low noise amplifier 22, and the radio frequency output terminal 122.

[0063] A part of the high frequency signal transmitted from the switch circuit 51 to the antenna connection terminal 101 is fed back to the RFIC 3 from the coupler 41 via the switch circuit 52 and the feedback terminal 131 (forward operation). On the other hand, the high frequency signal transmitted from the antenna connection terminal 101 to the switch circuit 51 is terminated by the phase adjustment circuit 520 and is not fed back to the RFIC 3.

[0064] [1.3.2. First Mode and Reverse Operation (REV)] Next, the reverse operation in the first mode will be described with reference to Fig. 4. Fig. 4 is a diagram showing the first mode and reverse operation in the high-frequency circuit 1 according to this embodiment. In the first mode and reverse operation, the high-frequency circuit 1 can simultaneously transmit and receive transmission signals and reception signals of bands A and B using the antenna 2a, and can feed back part of the reception signals of bands A and B to the RFIC 3 using the coupler 41 and the switch circuit 52.

[0065] 4, in the first mode, the switch circuit 51 connects the common terminal 511 to the selection terminals 513 and 514. The switch circuit 52 connects the input terminal 521 to the phase adjustment circuit 520 and connects the input terminal 522 to the output terminal 524. The switch circuit 53 switches the connection of the common terminal 531 between the selection terminals 532 and 533 over time.

[0066] As a result, the transmit signal of band A is transmitted from the RFIC 3 to the antenna 2a via the radio frequency input terminal 111, the power amplifier 11, the filter 33, the switch circuit 51, the coupler 41, and the antenna connection terminal 101. The receive signal of band A is transmitted from the antenna 2a to the RFIC 3 via the antenna connection terminal 101, the coupler 41, the switch circuit 51, the filter 31, the low noise amplifier 21, and the radio frequency output terminal 121. The transmit signal of band B is transmitted from the RFIC 3 to the antenna 2a via the radio frequency input terminal 112, the power amplifier 12, the switch circuit 53, the filter 32, the switch circuit 51, the coupler 41, and the antenna connection terminal 101. The receive signal of band B is transmitted from the antenna 2a to the RFIC 3 via the antenna connection terminal 101, the coupler 41, the switch circuit 51, the filter 32, the low noise amplifier 22, and the radio frequency output terminal 122.

[0067] A portion of the high-frequency signal transmitted from the antenna connection terminal 101 to the switch circuit 51 is fed back to the RFIC 3 from the coupler 41 via the switch circuit 52 and the feedback terminal 131 (reverse operation). On the other hand, the high-frequency signal transmitted from the switch circuit 51 to the antenna connection terminal 101 is terminated by the phase adjustment circuit 520 and is not fed back to the RFIC 3.

[0068] [1.3.3. Second Mode] Next, the second mode will be described with reference to Fig. 5. Fig. 5 is a diagram showing the second mode of the high-frequency circuit 1 according to this embodiment. In the second mode, the high-frequency circuit 1 can simultaneously transmit and receive transmission signals and reception signals of band A and SRS of band B.

[0069] 5 , in the second mode, the switch circuit 51 connects the common terminal 511 to the selection terminal 513 and connects the common terminal 512 to the selection terminal 514. The switch circuit 52 connects the input terminal 523 to the phase adjustment circuit 520. The switch circuit 53 connects the common terminal 531 to the selection terminal 532.

[0070] As a result, the transmission signal of band A is transmitted from the RFIC 3 to the antenna 2a via the radio frequency input terminal 111, the power amplifier 11, the filter 33, the switch circuit 51, the coupler 41, and the antenna connection terminal 101. The reception signal of band A is transmitted from the antenna 2a to the RFIC 3 via the antenna connection terminal 101, the coupler 41, the switch circuit 51, the filter 31, the low noise amplifier 21, and the radio frequency output terminal 121. The SRS of band B is transmitted from the RFIC 3 to the antenna 2b via the radio frequency input terminal 112, the power amplifier 12, the switch circuit 53, the filter 32, the switch circuit 51, and the antenna connection terminal 102.

[0071] At this time, the phase adjustment circuit 520 adjusts the phase so as to reduce the change in phase between the first mode and the second mode in the reception band of Band A when viewing the filter 32 from the antenna connection terminal 101. This suppresses the change in phase caused by switching from the first mode to the second mode and from the second mode to the first mode, and suppresses a decrease in the throughput of the reception signal of Band A.

[0072] [1.4. Summary] As described above, the high-frequency circuit 1 according to this embodiment includes the antenna connection terminal 101 for transmitting and receiving high-frequency signals, the antenna connection terminal 102 for transmitting SRS, the filter 31 having a pass band including the reception band of band A, the filter 32 having a pass band including the transmission band of band B, the common terminal 511 connected to the antenna connection terminal 101, the common terminal 512 connected to the antenna connection terminal 102, the selection terminal 513 connected to the filter 31, and the selection terminal 514 connected to the filter 32. the coupler 41 including a main line 411 connected to a path connecting the antenna connection terminal 101 and a common terminal 511, and a sub-line 412 that can be coupled to the main line 411; an input terminal 521 connected to one end of the sub-line 412; an input terminal 522 connected to the other end of the sub-line 412; an input terminal 523 connected to a signal path connecting the antenna connection terminal 101 and the filter 31; an output terminal 524; and a switch circuit 52 including a phase adjustment circuit 520 switchably connected to the input terminals 521 to 523.

[0073] This allows the phase adjustment circuit 520, which can be connected to the sub-line 412, to be connected to the signal path connecting the antenna connection terminal 101 and the filter 31. Therefore, the phase adjustment circuit 520 can be used not only as a termination circuit for the coupler 41, but also for phase adjustment of the signal path. This prevents an increase in the number of phase adjustment circuits, contributing to the miniaturization of the high-frequency circuit 1. Furthermore, by performing phase adjustment using the phase adjustment circuit 520, phase changes in the signal path can be suppressed, and a decrease in reception throughput due to SRS transmission can be suppressed.

[0074] Also, for example, in the high-frequency circuit 1 according to this embodiment, band A may be the FDD band, and the high-frequency circuit 1 may further include a filter 33 connected to the selection terminal 513 and having a passband that includes the transmission band of band A.

[0075] This makes it possible to support transmission and reception of signals in the FDD band.

[0076] Furthermore, for example, in the high-frequency circuit 1 according to this embodiment, band B may be a TDD band, and the combination of bands A and B may be a band combination that allows simultaneous communication.

[0077] This makes it possible to support transmission and reception of signals in the TDD band.

[0078] Furthermore, for example, in the high-frequency circuit 1 according to this embodiment, in the first mode for transmitting and receiving signals of band A and transmitting and receiving signals of band B via the antenna connection terminal 101, the switch circuit 51 may connect the common terminal 511 to the selection terminals 513 and 514, and the switch circuit 52 may connect the input terminal 521 to the output terminal 524 and connect the input terminal 522 to the phase adjustment circuit 520, or may connect the input terminal 521 to the phase adjustment circuit 520 and connect the input terminal 522 to the output terminal 524.

[0079] This makes it possible to realize simultaneous transmission and reception of signals in bands A and B and feedback of signals in bands A and B in the first mode.

[0080] Furthermore, for example, in the high-frequency circuit 1 according to this embodiment, in the second mode for transmitting and receiving signals of band A via the antenna connection terminal 101 and transmitting SRS of band B via the antenna connection terminal 102, the switch circuit 51 may connect the common terminal 511 to the selection terminal 513 and the common terminal 512 to the selection terminal 514, and the switch circuit 52 may connect the input terminal 523 to the phase adjustment circuit 520.

[0081] This makes it possible to transmit and receive signals in band A and transmit SRS in band B in the second mode. At this time, since the phase adjustment circuit 520 is connected to the signal path, it is possible to suppress phase changes between the first mode and the second mode, and it is possible to suppress a decrease in reception throughput in band A due to SRS transmission.

[0082] Furthermore, for example, in the high-frequency circuit 1 according to this embodiment, the switch circuits 51 and 52 may be included in the same integrated circuit.

[0083] This can contribute to miniaturization of the high frequency circuit 1.

[0084] Furthermore, for example, in the high-frequency circuit 1 according to this embodiment, the phase adjustment circuit 520 may include a variable capacitance 5201 and a variable resistance 5202 .

[0085] This allows the phase adjustment circuit 520 to be easily implemented.

[0086] In addition, the communication device 5 according to this embodiment includes an RFIC 3 configured to process high-frequency signals, and a high-frequency circuit 1 configured to transmit high-frequency signals between the RFIC 3 and the antennas 2a and 2b.

[0087] This allows the effects of the high frequency circuit 1 to be realized in the communication device 5.

[0088] (Embodiment 2) Next, embodiment 2 will be described. In this embodiment, the main difference from embodiment 1 above is that the communication device is provided with two antennas for transmitting and receiving signals in bands A and B. Below, this embodiment will be described with reference to the drawings, focusing on the differences from embodiment 1 above.

[0089] The circuit configuration of a communication device 5A and a high-frequency circuit 1A according to this embodiment will be described with reference to Fig. 6. Fig. 6 is a circuit configuration diagram of a communication device 5A according to this embodiment.

[0090] 6 is an exemplary circuit configuration, and the communication device 5A may be implemented using any of a wide variety of circuit implementations and circuit technologies, and therefore the description of the communication device 5A provided below should not be construed as limiting.

[0091] [2.1 Circuit Configuration of Communication Device 5A] First, the circuit configuration of the communication device 5A according to this embodiment will be described with reference to Fig. 6. The communication device 5A includes a high-frequency circuit 1A, antennas 2a, 2b, and 2c, an RFIC 3, and a BBIC 4.

[0092] The high-frequency circuit 1A can transmit high-frequency signals between the antennas 2a, 2b, and 2c and the RFIC 3. The circuit configuration of the high-frequency circuit 1A will be described later.

[0093] The antenna 2c is connected to the antenna connection terminal 103 of the high-frequency circuit 1A. The antenna 2c can receive a high-frequency signal from the high-frequency circuit 1A and transmit it to the outside of the communication device 5A. The antenna 2c can also receive a high-frequency signal from the outside of the communication device 5A and output it to the high-frequency circuit 1A. The antenna 2c does not have to be included in the communication device 5A. The communication device 5A may further include one or more antennas in addition to the antennas 2a, 2b, and 2c.

[0094] [2.2. Circuit Configuration of High-Frequency Circuit 1A] Next, the circuit configuration of the high-frequency circuit 1A according to this embodiment will be described with reference to Fig. 6. The high-frequency circuit 1A includes power amplifiers 11 and 12, low-noise amplifiers 21 and 22, filters 31, 32, and 33, couplers 41 and 42, switch circuits 51A, 52A, and 53, antenna connection terminals 101, 102, and 103, high-frequency input terminals 111 and 112, high-frequency output terminals 121 and 122, and a feedback terminal 131.

[0095] The antenna connection terminal 103 is an example of a third antenna connection terminal and is a terminal for transmitting and receiving high-frequency signals. The antenna connection terminal 101 is connected to the antenna 2c outside the high-frequency circuit 1A, and is connected to the switch circuit 51A inside the high-frequency circuit 1A via the coupler 42.

[0096] The coupler 42 is an example of a second coupler and is a bidirectional coupler. The coupler 42 includes a main line connected between the antenna connection terminal 103 and the common terminal 515, and a sub-line 422 that can be coupled to the main line 421. The main line 421 is an example of a second main line, one end of which is connected to the common terminal 515 of the switch circuit 51A and the other end of which is connected to the antenna connection terminal 103. The sub-line 422 is an example of a second sub-line, one end of which is connected to an input terminal 526 of the switch circuit 52 and the other end of which is connected to an input terminal 527 of the switch circuit 52. The coupler 42 can terminate one end of the sub-line 422 and extract a signal from the other end of the sub-line 422. Note that the coupler 42 is not limited to a bidirectional coupler.

[0097] The switch circuit 51A is an example of a first switch circuit, and includes common terminals 511, 512, and 515, and selection terminals 513 and 514. The common terminal 515 is an example of a third common terminal, and is connected to the antenna connection terminal 103. In the switch circuit 51A, the common terminals 511, 512, and 515 can be connected to the selection terminals 513 and 514, respectively.

[0098] In such a connection configuration, the switch circuit 51A can connect the common terminals 511, 512, and 515 to the selection terminals 513 and 514 based on, for example, a control signal from the RFIC 3. The switch circuit 51A is configured as, for example, a multi-connection type switch circuit.

[0099] The switch circuit 52A is an example of a second switch circuit, and includes phase adjustment circuits 520 and 525, input terminals 521, 522, 523, 526, 527 and 528, and an output terminal 524.

[0100] The phase adjustment circuit 520 is an example of a first phase adjustment circuit, and is switchably connected to the input terminals 521, 522, and 528. The phase adjustment circuit 520 can function as a termination circuit for the coupler 41, and can also adjust the phase of the path connecting the antenna connection terminal 101 and the filters 31 and 33. The phase adjustment circuit 520 includes, for example, a variable capacitance and a variable resistance, similar to the first embodiment.

[0101] The phase adjustment circuit 525 is an example of a second phase adjustment circuit, and is switchably connected to the input terminals 523, 526, and 527. The phase adjustment circuit 525 can function as a termination circuit for the coupler 42, and can also adjust the phase of the path connecting the antenna connection terminal 103 and the filters 31 and 33. Note that the phase adjustment circuit 525 includes, for example, a variable capacitance and a variable resistance, similar to the phase adjustment circuit 520.

[0102] The input terminal 526 is an example of a fourth input terminal and is connected to one end of the sub-line 422. The input terminal 527 is an example of a fifth input terminal and is connected to the other end of the sub-line 422. The input terminal 528 is an example of a sixth input terminal and is connected to a signal path connecting the antenna connection terminal 103 and the coupler 42. The input terminal 528 may also be connected to a signal path connecting the coupler 42 and the filters 31 and 33. In the switch circuit 52A, the input terminals 526 and 527 are each connectable to the output terminal 524 and the phase adjustment circuits 520 and 525, and the input terminal 528 is connectable to the phase adjustment circuits 520 and 525.

[0103] In such a connection configuration, the switch circuit 52A can connect the input terminals 521 to 523 and 526 to 528 to the phase adjustment circuits 520 and 525 and the output terminal 524 based on, for example, a control signal from the RFIC 3. The switch circuit 52A is configured as, for example, a multi-connection type switch circuit.

[0104] Any combination of switch circuits 51A, 52A, and 53 may be included in a single semiconductor integrated circuit. For example, all of switch circuits 51A, 52A, and 53 may be included in a single semiconductor integrated circuit. For example, switch circuits 51A and 52A may be included in a single semiconductor integrated circuit, and in this case, switch circuit 53 may be included in another semiconductor integrated circuit. For example, switch circuits 51A and 53 may be included in a single semiconductor integrated circuit, and in this case, switch circuit 52A may be included in another semiconductor integrated circuit. For example, switch circuits 52A and 53 may be included in a single semiconductor integrated circuit, and in this case, switch circuit 51A may be included in another semiconductor integrated circuit.

[0105] [2.3. Communication Mode and Coupler Operation] Next, the communication mode of the high-frequency circuit 1A and the operation of the couplers 41 and 42 will be described with reference to FIGS.

[0106] [2.3.1. First Mode and Forward Operation (FWD)] First, the forward operation in the first mode will be described with reference to Fig. 7. Fig. 7 is a diagram showing the first mode and forward operation in the high-frequency circuit 1A according to this embodiment.

[0107] In the first mode and forward operation, the high-frequency circuit 1A can simultaneously transmit and receive transmit signals and receive signals of bands A and B using the antenna 2a, and can feed back a portion of the transmit signals of bands A and B to the RFIC 3 using the coupler 41 and the switch circuit 52A.

[0108] 7, in the first mode and forward operation, switch circuit 51A connects common terminal 511 to selection terminals 513 and 514. Switch circuit 52A connects input terminal 521 to output terminal 524 and connects input terminal 522 to phase adjustment circuit 520. Switch circuit 53 switches the connection of common terminal 531 between selection terminals 532 and 533 over time.

[0109] As a result, the transmit signal of band A is transmitted from the RFIC 3 to the antenna 2a via the radio frequency input terminal 111, the power amplifier 11, the filter 33, the switch circuit 51A, the coupler 41, and the antenna connection terminal 101. The receive signal of band A is transmitted from the antenna 2a to the RFIC 3 via the antenna connection terminal 101, the coupler 41, the switch circuit 51A, the filter 31, the low noise amplifier 21, and the radio frequency output terminal 121. The transmit signal of band B is transmitted from the RFIC 3 to the antenna 2a via the radio frequency input terminal 112, the power amplifier 12, the switch circuit 53, the filter 32, the switch circuit 51A, the coupler 41, and the antenna connection terminal 101. The receive signal of band B is transmitted from the antenna 2a to the RFIC 3 via the antenna connection terminal 101, the coupler 41, the switch circuit 51A, the filter 32, the low noise amplifier 22, and the radio frequency output terminal 122.

[0110] A part of the high frequency signal transmitted from the switch circuit 51A to the antenna connection terminal 101 is fed back to the RFIC 3 from the coupler 41 via the switch circuit 52A and the feedback terminal 131 (forward operation). On the other hand, the high frequency signal transmitted from the antenna connection terminal 101 to the switch circuit 51A is terminated by the phase adjustment circuit 520 and is not fed back to the RFIC 3.

[0111] [2.3.2. First Mode and Reverse Operation (REV)] Next, the reverse operation in the first mode will be described with reference to Fig. 8. Fig. 8 is a diagram showing the first mode and reverse operation in the high-frequency circuit 1A according to this embodiment. In the first mode and reverse operation, the high-frequency circuit 1A can simultaneously transmit and receive transmission signals and reception signals of bands A and B using the antenna 2a, and can feed back part of the reception signals of bands A and B to the RFIC 3 using the coupler 41 and the switch circuit 52A.

[0112] 8, in the first mode and in reverse operation, switch circuit 51A connects common terminal 511 to selection terminals 513 and 514. Switch circuit 52A connects input terminal 521 to phase adjustment circuit 520 and input terminal 522 to output terminal 524. Switch circuit 53 switches the connection of common terminal 531 between selection terminals 532 and 533 over time.

[0113] As a result, the transmit signal of band A is transmitted from the RFIC 3 to the antenna 2a via the radio frequency input terminal 111, the power amplifier 11, the filter 33, the switch circuit 51A, the coupler 41, and the antenna connection terminal 101. The receive signal of band A is transmitted from the antenna 2a to the RFIC 3 via the antenna connection terminal 101, the coupler 41, the switch circuit 51A, the filter 31, the low noise amplifier 21, and the radio frequency output terminal 121. The transmit signal of band B is transmitted from the RFIC 3 to the antenna 2a via the radio frequency input terminal 112, the power amplifier 12, the switch circuit 53, the filter 32, the switch circuit 51A, the coupler 41, and the antenna connection terminal 101. The receive signal of band B is transmitted from the antenna 2a to the RFIC 3 via the antenna connection terminal 101, the coupler 41, the switch circuit 51A, the filter 32, the low noise amplifier 22, and the radio frequency output terminal 122.

[0114] A portion of the high-frequency signal transmitted from the antenna connection terminal 101 to the switch circuit 51A is fed back to the RFIC 3 from the coupler 41 via the switch circuit 52A and the feedback terminal 131 (reverse operation). On the other hand, the high-frequency signal transmitted from the switch circuit 51A to the antenna connection terminal 101 is terminated by the phase adjustment circuit 520 and is not fed back to the RFIC 3.

[0115] [2.3.3. Second Mode and Forward Operation (FWD)] Next, the forward operation in the second mode will be described with reference to Fig. 9. Fig. 9 is a diagram showing the second mode and forward operation in the high-frequency circuit 1A according to this embodiment.

[0116] In the second mode and forward operation, the high-frequency circuit 1A can simultaneously transmit and receive transmission signals and reception signals of band A using the antenna 2a, and can feed back a portion of the transmission signal of band A to the RFIC 3 using the coupler 41 and the switch circuit 52A. Furthermore, the high-frequency circuit 1A can transmit an SRS of band B using the antenna 2b.

[0117] 9 , in the second mode and forward operation, switch circuit 51A connects common terminal 511 to selection terminal 513 and connects common terminal 512 to selection terminal 514. Switch circuit 52A connects input terminal 521 to output terminal 524, connects input terminal 522 to phase adjustment circuit 520, and connects input terminal 523 to phase adjustment circuit 525. Switch circuit 53A connects common terminal 531 to selection terminal 532.

[0118] As a result, the transmission signal of band A is transmitted from the RFIC 3 to the antenna 2a via the radio frequency input terminal 111, the power amplifier 11, the filter 33, the switch circuit 51A, the coupler 41, and the antenna connection terminal 101. The reception signal of band A is transmitted from the antenna 2a to the RFIC 3 via the antenna connection terminal 101, the coupler 41, the switch circuit 51A, the filter 31, the low noise amplifier 21, and the radio frequency output terminal 121. The SRS of band B is transmitted from the RFIC 3 to the antenna 2b via the radio frequency input terminal 112, the power amplifier 12, the switch circuit 53, the filter 32, the switch circuit 51A, and the antenna connection terminal 102.

[0119] At this time, the phase adjustment circuit 525 adjusts the phase so as to reduce the change in the phase of the filter 31 between the first mode and the second mode as seen from the antenna connection terminal 101. This suppresses the change in phase caused by switching from the first mode to the second mode and from the second mode to the first mode, and suppresses a decrease in the throughput of the received signal of band A.

[0120] A part of the high frequency signal transmitted from the switch circuit 51A to the antenna connection terminal 101 is fed back to the RFIC 3 from the coupler 41 via the switch circuit 52A and the feedback terminal 131 (forward operation). On the other hand, the high frequency signal transmitted from the antenna connection terminal 101 to the switch circuit 51A is terminated by the phase adjustment circuit 520 and is not fed back to the RFIC 3.

[0121] [2.3.4. Second Mode and Reverse Operation (REV)] Next, the reverse operation in the second mode will be described with reference to FIG. 10 . FIG. 10 is a diagram showing the second mode and reverse operation in the high-frequency circuit 1A according to this embodiment. In the second mode and reverse operation, the high-frequency circuit 1A can simultaneously transmit and receive transmission signals and reception signals of band A using the antenna 2a, and can feed back a portion of the reception signal of band A to the RFIC 3 using the coupler 41 and the switch circuit 52A. Furthermore, the high-frequency circuit 1A can transmit an SRS of band B using the antenna 2b.

[0122] 10 , in the second mode and in reverse operation, the switch circuit 51A connects the common terminal 511 to the selection terminal 513 and connects the common terminal 512 to the selection terminal 514. The switch circuit 52A connects the input terminal 521 to the phase adjustment circuit 520, the input terminal 522 to the output terminal 524, and the input terminal 523 to the phase adjustment circuit 525. The switch circuit 53A connects the common terminal 531 to the selection terminal 532.

[0123] As a result, the transmission signal of band A is transmitted from the RFIC 3 to the antenna 2a via the radio frequency input terminal 111, the power amplifier 11, the filter 33, the switch circuit 51A, the coupler 41, and the antenna connection terminal 101. The reception signal of band A is transmitted from the antenna 2a to the RFIC 3 via the antenna connection terminal 101, the coupler 41, the switch circuit 51A, the filter 31, the low noise amplifier 21, and the radio frequency output terminal 121. The SRS of band B is transmitted from the RFIC 3 to the antenna 2b via the radio frequency input terminal 112, the power amplifier 12, the switch circuit 53, the filter 32, the switch circuit 51A, and the antenna connection terminal 102.

[0124] At this time, the phase adjustment circuit 525 adjusts the phase so as to reduce the change in phase between the first mode and the second mode in the reception band of Band A when viewing the filter 32 from the antenna connection terminal 101. This suppresses the change in phase caused by switching from the first mode to the second mode and from the second mode to the first mode, and suppresses a decrease in the throughput of the reception signal of Band A.

[0125] A portion of the high-frequency signal transmitted from the antenna connection terminal 101 to the switch circuit 51A is fed back to the RFIC 3 from the coupler 41 via the switch circuit 52A and the feedback terminal 131 (reverse operation). On the other hand, the high-frequency signal transmitted from the switch circuit 51A to the antenna connection terminal 101 is terminated by the phase adjustment circuit 520 and is not fed back to the RFIC 3.

[0126] [2.3.5. Third Mode and Forward Operation (FWD)] First, the forward operation in the third mode will be described with reference to Fig. 11. Fig. 11 is a diagram showing the third mode and the forward operation in the high-frequency circuit 1A according to this embodiment.

[0127] In the third mode and forward operation, the high-frequency circuit 1A can simultaneously transmit and receive transmit signals and receive signals of bands A and B using the antenna 2c, and can feed back a portion of the transmit signals of bands A and B to the RFIC 3 using the coupler 42 and the switch circuit 52A.

[0128] 11 , in the third mode and forward operation, switch circuit 51A connects common terminal 515 to selection terminals 513 and 514. Switch circuit 52A connects input terminal 526 to output terminal 524 and connects input terminal 527 to phase adjustment circuit 525. Switch circuit 53 switches the connection of common terminal 531 between selection terminals 532 and 533 over time.

[0129] As a result, the transmit signal of band A is transmitted from the RFIC 3 to the antenna 2c via the radio frequency input terminal 111, the power amplifier 11, the filter 33, the switch circuit 51A, the coupler 42, and the antenna connection terminal 103. The receive signal of band A is transmitted from the antenna 2c to the RFIC 3 via the antenna connection terminal 103, the coupler 42, the switch circuit 51A, the filter 31, the low noise amplifier 21, and the radio frequency output terminal 121. The transmit signal of band B is transmitted from the RFIC 3 to the antenna 2c via the radio frequency input terminal 112, the power amplifier 12, the switch circuit 53, the filter 32, the switch circuit 51A, the coupler 42, and the antenna connection terminal 103. The receive signal of band B is transmitted from the antenna 2c to the RFIC 3 via the antenna connection terminal 103, the coupler 42, the switch circuit 51A, the filter 32, the low noise amplifier 22, and the radio frequency output terminal 122.

[0130] A part of the high frequency signal transmitted from the switch circuit 51A to the antenna connection terminal 103 is fed back to the RFIC 3 from the coupler 42 via the switch circuit 52A and the feedback terminal 131 (forward operation). On the other hand, the high frequency signal transmitted from the antenna connection terminal 103 to the switch circuit 51A is terminated by the phase adjustment circuit 525 and is not fed back to the RFIC 3.

[0131] [2.3.6. Third Mode and Reverse Operation (REV)] Next, the reverse operation in the third mode will be described with reference to Fig. 12. Fig. 12 is a diagram showing the third mode and reverse operation in the high-frequency circuit 1A according to this embodiment. In the third mode and reverse operation, the high-frequency circuit 1A can simultaneously transmit and receive transmission signals and reception signals of bands A and B using the antenna 2c, and can feed back a portion of the reception signals of bands A and B to the RFIC 3 using the coupler 42 and the switch circuit 52A.

[0132] 12 , in the third mode and in reverse operation, switch circuit 51A connects common terminal 515 to selection terminals 513 and 514. Switch circuit 52A connects input terminal 526 to phase adjustment circuit 525 and connects input terminal 527 to output terminal 524. Switch circuit 53 switches the connection of common terminal 531 between selection terminals 532 and 533 over time.

[0133] As a result, the transmit signal of band A is transmitted from the RFIC 3 to the antenna 2c via the radio frequency input terminal 111, the power amplifier 11, the filter 33, the switch circuit 51A, the coupler 42, and the antenna connection terminal 103. The receive signal of band A is transmitted from the antenna 2c to the RFIC 3 via the antenna connection terminal 103, the coupler 42, the switch circuit 51A, the filter 31, the low noise amplifier 21, and the radio frequency output terminal 121. The transmit signal of band B is transmitted from the RFIC 3 to the antenna 2c via the radio frequency input terminal 112, the power amplifier 12, the switch circuit 53, the filter 32, the switch circuit 51A, the coupler 42, and the antenna connection terminal 103. The receive signal of band B is transmitted from the antenna 2c to the RFIC 3 via the antenna connection terminal 103, the coupler 42, the switch circuit 51A, the filter 32, the low noise amplifier 22, and the radio frequency output terminal 122.

[0134] A portion of the high-frequency signal transmitted from the antenna connection terminal 103 to the switch circuit 51A is fed back to the RFIC 3 from the coupler 42 via the switch circuit 52A and the feedback terminal 131 (reverse operation). On the other hand, the high-frequency signal transmitted from the switch circuit 51A to the antenna connection terminal 103 is terminated by the phase adjustment circuit 525 and is not fed back to the RFIC 3.

[0135] [2.3.7. Fourth Mode and Forward Operation (FWD)] Next, the forward operation in the fourth mode will be described with reference to Fig. 13. Fig. 13 is a diagram showing the fourth mode and forward operation in the high-frequency circuit 1A according to this embodiment.

[0136] In the fourth mode and forward operation, the high-frequency circuit 1A can simultaneously transmit and receive transmission signals and reception signals of band A using the antenna 2c, and can feed back a portion of the transmission signal of band A to the RFIC 3 using the coupler 42 and the switch circuit 52A. Furthermore, the high-frequency circuit 1A can transmit an SRS of band B using the antenna 2b.

[0137] 13 , in the fourth mode and forward operation, switch circuit 51A connects common terminal 515 to selection terminal 513 and connects common terminal 512 to selection terminal 514. Switch circuit 52A connects input terminal 526 to output terminal 524, input terminal 527 to phase adjustment circuit 525, and input terminal 528 to phase adjustment circuit 520. Switch circuit 53A connects common terminal 531 to selection terminal 532.

[0138] As a result, the transmission signal of band A is transmitted from the RFIC 3 to the antenna 2c via the radio frequency input terminal 111, the power amplifier 11, the filter 33, the switch circuit 51A, the coupler 42, and the antenna connection terminal 103. The reception signal of band A is transmitted from the antenna 2c to the RFIC 3 via the antenna connection terminal 103, the coupler 42, the switch circuit 51A, the filter 31, the low noise amplifier 21, and the radio frequency output terminal 121. The SRS of band B is transmitted from the RFIC 3 to the antenna 2b via the radio frequency input terminal 112, the power amplifier 12, the switch circuit 53, the filter 32, the switch circuit 51A, and the antenna connection terminal 102.

[0139] At this time, the phase adjustment circuit 520 adjusts the phase so as to reduce the change in phase between the third mode and the fourth mode in the reception band of Band A when viewing the filter 32 from the antenna connection terminal 103. This suppresses the change in phase caused by switching from the third mode to the fourth mode and from the fourth mode to the third mode, and suppresses a decrease in the throughput of the reception signal of Band A.

[0140] A part of the high frequency signal transmitted from the switch circuit 51A to the antenna connection terminal 103 is fed back to the RFIC 3 from the coupler 42 via the switch circuit 52A and the feedback terminal 131 (forward operation). On the other hand, the high frequency signal transmitted from the antenna connection terminal 103 to the switch circuit 51A is terminated by the phase adjustment circuit 525 and is not fed back to the RFIC 3.

[0141] [2.3.8. Fourth Mode and Reverse Operation (REV)] Next, the reverse operation in the fourth mode will be described with reference to FIG. 14 . FIG. 14 is a diagram showing the fourth mode and reverse operation in the high-frequency circuit 1A according to this embodiment. In the fourth mode and reverse operation, the high-frequency circuit 1A can simultaneously transmit and receive transmission signals and reception signals of band A using the antenna 2c, and can feed back a portion of the reception signal of band A to the RFIC 3 using the coupler 42 and the switch circuit 52A. Furthermore, the high-frequency circuit 1A can transmit an SRS of band B using the antenna 2b.

[0142] 14 , in the fourth mode, the switch circuit 51A connects the common terminal 515 to the selection terminal 513 and connects the common terminal 512 to the selection terminal 514. The switch circuit 52A connects the input terminal 526 to the phase adjustment circuit 525, connects the input terminal 527 to the output terminal 524, and connects the input terminal 528 to the phase adjustment circuit 520. The switch circuit 53 connects the common terminal 531 to the selection terminal 532.

[0143] As a result, the transmission signal of band A is transmitted from the RFIC 3 to the antenna 2c via the radio frequency input terminal 111, the power amplifier 11, the filter 33, the switch circuit 51A, the coupler 42, and the antenna connection terminal 103. The reception signal of band A is transmitted from the antenna 2c to the RFIC 3 via the antenna connection terminal 103, the coupler 42, the switch circuit 51A, the filter 31, the low noise amplifier 21, and the radio frequency output terminal 121. The SRS of band B is transmitted from the RFIC 3 to the antenna 2b via the radio frequency input terminal 112, the power amplifier 12, the switch circuit 53, the filter 32, the switch circuit 51A, and the antenna connection terminal 102.

[0144] At this time, the phase adjustment circuit 525 adjusts the phase so as to reduce the change in phase between the third mode and the fourth mode in the reception band of Band A when viewing the filter 32 from the antenna connection terminal 103. This suppresses the change in phase caused by switching from the third mode to the fourth mode and from the fourth mode to the third mode, and suppresses a decrease in the throughput of the reception signal of Band A.

[0145] A portion of the high-frequency signal transmitted from the antenna connection terminal 103 to the switch circuit 51A is fed back to the RFIC 3 from the coupler 42 via the switch circuit 52A and the feedback terminal 131 (reverse operation). On the other hand, the high-frequency signal transmitted from the switch circuit 51A to the antenna connection terminal 103 is terminated by the phase adjustment circuit 525 and is not fed back to the RFIC 3.

[0146] [2.4. Summary] As described above, the high-frequency circuit 1A according to this embodiment includes the antenna connection terminals 101 and 103 for transmitting and receiving high-frequency signals, the antenna connection terminal 102 for transmitting SRS, the filter 31 having a pass band including the reception band of band A, the filter 32 having a pass band including the transmission band of band B, the switch circuit 51A including the common terminal 511 connected to the antenna connection terminal 101, the common terminal 512 connected to the antenna connection terminal 102, the common terminal 515 connected to the antenna connection terminal 103, the selection terminal 513 connected to the filter 31, and the selection terminal 514 connected to the filter 32, the coupler 41 including the main line 411 connected to the path connecting the antenna connection terminal 101 and the common terminal 511 and the sub-line 412 that can be coupled to the main line 411, and the antenna connection terminal 102. a coupler 42 including a main line 421 connected to a path connecting the antenna connection terminal 103 and a common terminal 515, and a sub-line 422 that can be coupled to the main line 421; an input terminal 521 connected to one end of the sub-line 412; an input terminal 522 connected to the other end of the sub-line 412; an input terminal 523 connected to a signal path connecting the antenna connection terminal 101 and the filter 31; an input terminal 526 connected to one end of the sub-line 422; an input terminal 527 connected to the other end of the sub-line 422; an input terminal 528 connected to the signal path connecting the antenna connection terminal 103 and the filter 31; an output terminal 524; a phase adjustment circuit 520 switchably connected to the input terminals 521, 522, and 528; and a phase adjustment circuit 525 switchably connected to the input terminals 523, 526, and 527.

[0147] This allows the phase adjustment circuit 520 connectable to the sub-line 412 to be connected to the signal path connecting the antenna connection terminal 103 and the filter 31, and the phase adjustment circuit 525 connectable to the sub-line 422 to be connected to the signal path connecting the antenna connection terminal 101 and the filter 31. Therefore, the phase adjustment circuits 520 and 525 can be used not only as termination circuits for the couplers 41 and 42, but also for adjusting the phase of the signal path. This prevents an increase in the number of phase adjustment circuits, contributing to the miniaturization of the high-frequency circuit 1A. Furthermore, by performing phase adjustment using the phase adjustment circuits 520 and 525, phase changes in the signal path can be suppressed, thereby preventing a decrease in reception throughput due to SRS transmission.

[0148] Also, for example, in the high-frequency circuit 1A according to this embodiment, band A may be the FDD band, and the high-frequency circuit 1A may further include a filter 33 connected to the selection terminal 513 and having a passband that includes the transmission band of band A.

[0149] This makes it possible to support transmission and reception of signals in the FDD band.

[0150] Furthermore, for example, in the high-frequency circuit 1A according to this embodiment, band B may be a TDD band, and the combination of bands A and B may be a band combination that allows simultaneous communication.

[0151] This makes it possible to support transmission and reception of signals in the TDD band.

[0152] Furthermore, for example, in the high-frequency circuit 1A according to this embodiment, in a first mode for transmitting and receiving signals of band A and transmitting and receiving signals of band B via the antenna connection terminal 101, the switch circuit 51A may connect the common terminal 511 to the selection terminals 513 and 514, and the switch circuit 52A may (i) connect the input terminal 521 to the output terminal 524 and connect the input terminal 522 to the phase adjustment circuit 520, or (ii) connect the input terminal 521 to the phase adjustment circuit 520 and connect the input terminal 522 to the output terminal 524.

[0153] This makes it possible to realize simultaneous transmission and reception of signals in bands A and B and feedback of signals in bands A and B in the first mode.

[0154] Furthermore, for example, in the high-frequency circuit 1A according to this embodiment, in the second mode for transmitting and receiving signals of band A via the antenna connection terminal 101 and transmitting SRS of band B via the antenna connection terminal 102, the switch circuit 51A may connect the common terminal 511 to the selection terminal 513 and the common terminal 512 to the selection terminal 514, and the switch circuit 52A may (i) connect the input terminal 521 to the output terminal 524, connect the input terminal 522 to the phase adjustment circuit 520, and connect the input terminal 523 to the phase adjustment circuit 525, or (ii) connect the input terminal 521 to the phase adjustment circuit 520, connect the input terminal 522 to the output terminal 524, and connect the input terminal 523 to the phase adjustment circuit 525.

[0155] This makes it possible to realize, in the second mode, transmission and reception of the signal of band A, feedback of the signal of band A, and transmission of the SRS of band B. At this time, since the phase adjustment circuit 525 is connected to the signal path, it becomes possible to suppress the phase change between the first mode and the second mode, and it is possible to suppress the decrease in reception throughput of band A due to SRS transmission.

[0156] Furthermore, for example, in the high-frequency circuit 1A according to this embodiment, in a third mode for transmitting and receiving signals of band A and transmitting and receiving signals of band B via the antenna connection terminal 103, the switch circuit 51A may connect the common terminal 515 to the selection terminal 513 and the selection terminal 514, and the switch circuit 52A may (i) connect the input terminal 526 to the output terminal 524 and connect the input terminal 527 to the phase adjustment circuit 525, or (ii) connect the input terminal 526 to the phase adjustment circuit 525 and connect the input terminal 527 to the output terminal 524.

[0157] This makes it possible to realize simultaneous transmission and reception of signals in bands A and B and feedback of signals in bands A and B in the third mode.

[0158] Furthermore, for example, in the high-frequency circuit 1A according to the present embodiment, in a fourth mode for receiving a signal of band A via the antenna connection terminal 103 and transmitting an SRS of band B via the antenna connection terminal 102, the switch circuit 51A may connect the common terminal 515 to the selection terminal 513 and the common terminal 512 to the selection terminal 514, and the switch circuit 52A may (i) connect the input terminal 526 to the output terminal 524, connect the input terminal 527 to the phase adjustment circuit 525, and connect the input terminal 528 to the phase adjustment circuit 520, or (ii) connect the input terminal 526 to the phase adjustment circuit 525, connect the input terminal 527 to the output terminal 524, and connect the input terminal 528 to the phase adjustment circuit 520.

[0159] This makes it possible to realize, in the fourth mode, transmission and reception of a signal in band A, feedback of the signal in band A, and transmission of an SRS in band B. At this time, since the phase adjustment circuit 520 is connected to the signal path, it becomes possible to suppress phase changes between the third mode and the fourth mode, and it is possible to suppress a decrease in reception throughput in band A due to SRS transmission.

[0160] Furthermore, for example, in the high-frequency circuit 1A according to the present embodiment, the switch circuit 51A and the switch circuit 52A may be included in the same integrated circuit.

[0161] This can contribute to miniaturization of the high frequency circuit 1A.

[0162] Furthermore, for example, in the high-frequency circuit 1A according to this embodiment, each of the phase adjustment circuit 520 and the phase adjustment circuit 525 may include a variable capacitance and a variable resistance.

[0163] This allows the phase adjustment circuits 520 and 525 to be easily implemented.

[0164] In addition, the communication device 5A of this embodiment includes an RFIC 3 configured to process high-frequency signals, and a high-frequency circuit 1A configured to transmit high-frequency signals between the RFIC 3 and the antennas 2a, 2b, and 2c.

[0165] This allows the effects of the high-frequency circuit 1A to be realized in the communication device 5A.

[0166] (Other Embodiments) While the high-frequency circuit and communication device according to the present invention have been described above based on the embodiments, the high-frequency circuit and communication device according to the present invention are not limited to the above embodiments. The present invention also includes other embodiments realized by combining any of the components in the above embodiments, modifications obtained by applying various modifications to the above embodiments that would occur to those skilled in the art without departing from the spirit of the present invention, and various devices incorporating the above-mentioned high-frequency circuit.

[0167] For example, in the circuit configurations of the various circuits according to the above embodiments, other circuit elements and wiring may be inserted between the paths connecting the circuit elements and signal paths disclosed in the drawings. For example, an impedance matching circuit may be inserted between the amplifier and the filter and / or between the filter and the antenna connection terminal. The impedance matching circuit may be composed of, for example, an inductor and / or a capacitor, but is not limited to such.

[0168] In each of the above embodiments, the high-frequency circuit may include a filter for a band different from bands A and B. For example, a filter having a pass band that includes the transmission band of band C, which is different from bands A and B, and a filter having a pass band that includes the reception band of band C may be connected to selection terminal 513.

[0169] The following describes the features of the high-frequency circuit and communication device described based on the above embodiments.

[0170] <1> A first antenna connection terminal for transmitting and receiving a high frequency signal, a second antenna connection terminal for transmitting an SRS (Sounding Reference Signal), a first filter having a pass band including a reception band of a first band, a second filter having a pass band including a transmission band of a second band, a first common terminal connected to the first antenna connection terminal, a second common terminal connected to the second antenna connection terminal, a first selection terminal connected to the first filter, and a second selection terminal connected to the second filter, a first coupler including a first main line connected to a path connecting the first antenna connection terminal and the first common terminal, and a first sub-line coupleable with the first main line, a first input terminal connected to one end of the first sub-line, a second input terminal connected to the other end of the first sub-line, a third input terminal connected to a signal path connecting the first antenna connection terminal and the first filter, an output terminal, and a second switch circuit including a first phase adjustment circuit switchably connected to the first input terminal, the second input terminal, and the third input terminal.

[0171] <2> The high-frequency circuit according to <1>, wherein the first band is a frequency division duplex (FDD) band, and the high-frequency circuit further includes a third filter connected to the first selection terminal and having a passband that includes a transmission band of the first band.

[0172] <3> The high-frequency circuit according to <2>, wherein the second band is a time division duplex (TDD) band.

[0173] <4> The high-frequency circuit according to <3>, wherein, in a first mode for transmitting and receiving signals in the first band and transmitting and receiving signals in the second band via the first antenna connection terminal, the first switch circuit connects the first common terminal to the first selection terminal and the second selection terminal, and the second switch circuit connects the first input terminal to the output terminal and connects the second input terminal to the first phase adjustment circuit, or connects the first input terminal to the first phase adjustment circuit and connects the second input terminal to the output terminal.

[0174] <5> The high-frequency circuit according to <3> or <4>, wherein in a second mode for transmitting and receiving signals in the first band via the first antenna connection terminal and transmitting SRS in the second band via the second antenna connection terminal, the first switch circuit connects the first common terminal to the first selection terminal and connects the second common terminal to the second selection terminal, and the second switch circuit connects the third input terminal to the first phase adjustment circuit.

[0175] <6> The high-frequency circuit according to any one of <1> to <5>, wherein the first switch circuit and the second switch circuit are included in the same integrated circuit.

[0176] <7> The high-frequency circuit according to any one of <1> to <6>, wherein the first phase adjustment circuit includes a variable capacitor and a variable resistor.

[0177] <8> A first antenna connection terminal for transmitting and receiving a high frequency signal, a second antenna connection terminal for transmitting an SRS, a third antenna connection terminal for transmitting and receiving a high frequency signal, a first filter having a pass band including a receive band of a first band, a second filter having a pass band including a transmit band of a second band, a first common terminal connected to the first antenna connection terminal, a second common terminal connected to the second antenna connection terminal, a third common terminal connected to the third antenna connection terminal, a first selection terminal connected to the first filter, and a second selection terminal connected to the second filter, a first coupler including a first main line connected to a path connecting the first antenna connection terminal and the first common terminal, and a first sub-line coupleable with the first main line, and a second coupler including a second main line connected to a path connecting the third antenna connection terminal and the third common terminal, and a second sub-line coupleable with the second main line, a first input terminal connected to one end of the first sub-line, a second input terminal connected to the other end of the first sub-line, a third input terminal connected to a signal path connecting the first antenna connecting terminal and the first filter, a fourth input terminal connected to one end of the second sub-line, a fifth input terminal connected to the other end of the second sub-line, a sixth input terminal connected to a signal path connecting the third antenna connecting terminal and the first filter, an output terminal, and a second switch circuit including a first phase adjustment circuit switchably connected to the first input terminal, the second input terminal, and the sixth input terminal, and a second phase adjustment circuit switchably connected to the third input terminal, the fourth input terminal, and the fifth input terminal.

[0178] <9> The high-frequency circuit according to <8>, wherein the first band is an FDD band, and the high-frequency circuit further includes a third filter connected to the first selection terminal and having a passband including a transmission band of the first band.

[0179] <10> The high-frequency circuit according to <9>, wherein the second band is a TDD band.

[0180] <11> The high-frequency circuit according to <10>, wherein, in a first mode for transmitting and receiving signals in the first band and transmitting and receiving signals in the second band via the first antenna connection terminal, the first switch circuit connects the first common terminal to the first selection terminal and the second selection terminal, and the second switch circuit (i) connects the first input terminal to the output terminal and connects the second input terminal to the first phase adjustment circuit, or (ii) connects the first input terminal to the first phase adjustment circuit and connects the second input terminal to the output terminal.

[0181] <12> The high-frequency circuit according to <10> or <11>, wherein in a second mode for transmitting and receiving signals in the first band via the first antenna connection terminal and transmitting SRS in the second band via the second antenna connection terminal, the first switch circuit connects the first common terminal to the first selection terminal and the second common terminal to the second selection terminal, and the second switch circuit (i) connects the first input terminal to the output terminal, connects the second input terminal to the first phase adjustment circuit, and connects the third input terminal to the second phase adjustment circuit, or (ii) connects the first input terminal to the first phase adjustment circuit, connects the second input terminal to the output terminal, and connects the third input terminal to the second phase adjustment circuit.

[0182] <13> The high-frequency circuit according to any one of <10> to <12>, wherein in a third mode for transmitting and receiving signals in the first band and transmitting and receiving signals in the second band via the third antenna connection terminal, the first switch circuit connects the third common terminal to the first selection terminal and the second selection terminal, and the second switch circuit (i) connects the fourth input terminal to the output terminal and connects the fifth input terminal to the second phase adjustment circuit, or (ii) connects the fourth input terminal to the second phase adjustment circuit and connects the fifth input terminal to the output terminal.

[0183] <14> The high-frequency circuit according to any one of <10> to <13>, wherein in a fourth mode for receiving a signal of the first band via the third antenna connection terminal and transmitting an SRS of the second band via the second antenna connection terminal, the first switch circuit connects the third common terminal to the first selection terminal and the second common terminal to the second selection terminal, and the second switch circuit (i) connects the fourth input terminal to the output terminal, connects the fifth input terminal to the second phase adjustment circuit, and connects the sixth input terminal to the first phase adjustment circuit, or (ii) connects the fourth input terminal to the second phase adjustment circuit, connects the fifth input terminal to the output terminal, and connects the sixth input terminal to the first phase adjustment circuit.

[0184] <15> The high-frequency circuit according to any one of <8> to <14>, wherein the first switch circuit and the second switch circuit are included in the same integrated circuit.

[0185] <16> The high-frequency circuit according to any one of <8> to <15>, wherein each of the first phase adjustment circuit and the second phase adjustment circuit includes a variable capacitance and a variable resistance.

[0186] <17> A communication device comprising: a signal processing circuit configured to process a high-frequency signal; and the high-frequency circuit according to any one of <1> to <16> configured to transmit the high-frequency signal between the signal processing circuit and an antenna.

[0187] The present invention can be widely used as a high-frequency circuit disposed in the front end of communication devices such as mobile phones.

[0188] REFERENCE SIGNS LIST 1, 1A High frequency circuit 2a, 2b, 2c Antenna 3 RFIC 4 BBIC 5, 5A Communication device 11, 12 Power amplifier 21, 22 Low noise amplifier 31, 32, 33 Filter 41, 42 Coupler 51, 51A, 52, 52A, 53 Switch circuit 101, 102, 103 Antenna connection terminal 111, 112 High frequency input terminal 121, 122 High frequency output terminal 131 Feedback terminal 411, 421 Main line 412, 422 Sub-line 511, 512, 515, 531 Common terminal 513, 514, 532, 533 Selection terminal 520, 525 Phase adjustment circuit 521, 522, 523, 526, 527, 528 Input terminal 524 Output terminal 5201 Variable capacitance 5202 Variable resistance

Claims

1. A first antenna connection terminal for transmitting and receiving a high frequency signal, a second antenna connection terminal for transmitting an SRS (Sounding Reference Signal), a first filter having a pass band including a reception band of a first band, a second filter having a pass band including a transmission band of a second band, a first common terminal connected to the first antenna connection terminal, a second common terminal connected to the second antenna connection terminal, a first selection terminal connected to the first filter, and a second selection terminal connected to the second filter, a first coupler including a first main line connected to a path connecting the first antenna connection terminal and the first common terminal, and a first sub-line that can be coupled to the first main line, a first input terminal connected to one end of the first sub-line, a second input terminal connected to the other end of the first sub-line, a third input terminal connected to a signal path connecting the first antenna connection terminal and the first filter, an output terminal, and a second switch circuit including a first phase adjustment circuit switchably connected to the first input terminal, the second input terminal, and the third input terminal.

2. The high-frequency circuit according to claim 1, wherein the first band is a frequency division duplex (FDD) band, and the high-frequency circuit further comprises a third filter connected to the first selection terminal and having a passband that includes a transmission band of the first band.

3. The high-frequency circuit according to claim 2, wherein the second band is a time division duplex (TDD) band, and the combination of the first band and the second band is a band combination that allows simultaneous communication.

4. The high-frequency circuit according to claim 3, wherein, in a first mode for transmitting and receiving signals in the first band and transmitting and receiving signals in the second band via the first antenna connection terminal, the first switch circuit connects the first common terminal to the first selection terminal and the second selection terminal, and the second switch circuit connects the first input terminal to the output terminal and connects the second input terminal to the first phase adjustment circuit, or connects the first input terminal to the first phase adjustment circuit and connects the second input terminal to the output terminal.

5. The high-frequency circuit according to claim 3 or 4, wherein in a second mode for transmitting and receiving signals in the first band via the first antenna connection terminal and transmitting SRS in the second band via the second antenna connection terminal, the first switch circuit connects the first common terminal to the first selection terminal and connects the second common terminal to the second selection terminal, and the second switch circuit connects the third input terminal to the first phase adjustment circuit.

6. The high frequency circuit according to any one of claims 1 to 5, wherein the first switch circuit and the second switch circuit are included in the same integrated circuit.

7. The high frequency circuit according to any one of claims 1 to 6, wherein the first phase adjustment circuit includes a variable capacitor and a variable resistor.

8. A first antenna connection terminal for transmitting and receiving high frequency signals, a second antenna connection terminal for transmitting SRS, a third antenna connection terminal for transmitting and receiving high frequency signals, a first filter having a pass band including a receive band of a first band, a second filter having a pass band including a transmit band of a second band, a first common terminal connected to the first antenna connection terminal, a second common terminal connected to the second antenna connection terminal, a third common terminal connected to the third antenna connection terminal, a first selection terminal connected to the first filter, and a second selection terminal connected to the second filter, a first coupler including a first main line connected to a path connecting the first antenna connection terminal and the first common terminal, and a first sub-line coupleable with the first main line, and a second coupler including a second main line connected to a path connecting the third antenna connection terminal and the third common terminal, and a second sub-line coupleable with the second main line, a first input terminal connected to one end of the first sub-line, a second input terminal connected to the other end of the first sub-line, a third input terminal connected to a signal path connecting the first antenna connecting terminal and the first filter, a fourth input terminal connected to one end of the second sub-line, a fifth input terminal connected to the other end of the second sub-line, a sixth input terminal connected to a signal path connecting the third antenna connecting terminal and the first filter, an output terminal, and a second switch circuit including a first phase adjustment circuit switchably connected to the first input terminal, the second input terminal, and the sixth input terminal, and a second phase adjustment circuit switchably connected to the third input terminal, the fourth input terminal, and the fifth input terminal.

9. The high-frequency circuit according to claim 8, wherein the first band is an FDD band, and the high-frequency circuit further comprises a third filter connected to the first selection terminal and having a passband that includes a transmission band of the first band.

10. The high-frequency circuit according to claim 9, wherein the second band is a TDD band, and the combination of the first band and the second band is a band combination that allows simultaneous communication.

11. The high-frequency circuit according to claim 10, wherein, in a first mode for transmitting and receiving signals in the first band and transmitting and receiving signals in the second band via the first antenna connection terminal, the first switch circuit connects the first common terminal to the first selection terminal and the second selection terminal, and the second switch circuit (i) connects the first input terminal to the output terminal and connects the second input terminal to the first phase adjustment circuit, or (ii) connects the first input terminal to the first phase adjustment circuit and connects the second input terminal to the output terminal.

12. The high-frequency circuit according to claim 10 or 11, wherein in a second mode for transmitting and receiving signals in the first band via the first antenna connection terminal and transmitting SRS in the second band via the second antenna connection terminal, the first switch circuit connects the first common terminal to the first selection terminal and the second common terminal to the second selection terminal, and the second switch circuit (i) connects the first input terminal to the output terminal, connects the second input terminal to the first phase adjustment circuit, and connects the third input terminal to the second phase adjustment circuit, or (ii) connects the first input terminal to the first phase adjustment circuit, connects the second input terminal to the output terminal, and connects the third input terminal to the second phase adjustment circuit.

13. The high-frequency circuit according to any one of claims 10 to 12, wherein in a third mode for transmitting and receiving signals in the first band and transmitting and receiving signals in the second band via the third antenna connection terminal, the first switch circuit connects the third common terminal to the first selection terminal and the second selection terminal, and the second switch circuit (i) connects the fourth input terminal to the output terminal and connects the fifth input terminal to the second phase adjustment circuit, or (ii) connects the fourth input terminal to the second phase adjustment circuit and connects the fifth input terminal to the output terminal.

14. The radio frequency circuit according to any one of claims 10 to 13, wherein in a fourth mode for receiving a signal of the first band via the third antenna connection terminal and transmitting an SRS of the second band via the second antenna connection terminal, the first switch circuit connects the third common terminal to the first selection terminal and the second common terminal to the second selection terminal, and the second switch circuit (i) connects the fourth input terminal to the output terminal, connects the fifth input terminal to the second phase adjustment circuit, and connects the sixth input terminal to the first phase adjustment circuit, or (ii) connects the fourth input terminal to the second phase adjustment circuit, connects the fifth input terminal to the output terminal, and connects the sixth input terminal to the first phase adjustment circuit.

15. The high-frequency circuit according to any one of claims 8 to 14, wherein the first switch circuit and the second switch circuit are included in the same integrated circuit.

16. The high-frequency circuit according to any one of claims 8 to 15, wherein each of the first phase adjustment circuit and the second phase adjustment circuit includes a variable capacitance and a variable resistance.

17. A communication device comprising: a signal processing circuit configured to process a high-frequency signal; and a high-frequency circuit according to any one of claims 1 to 16 configured to transmit the high-frequency signal between the signal processing circuit and an antenna.

Images