Directional coupler, high frequency module, and communication device

Abstract

To provide a directional coupler capable of improving directivity by suppressing changes in impedance of a phase shift circuit on a high frequency side.SOLUTION: A directional coupler 1 includes a main line 2, a first sub-line 31, a second sub-line 32, and a phase shift circuit 5. The phase shift circuit 5 is connected in series between the first sub-line 31 and the second sub-line 32. The phase shift circuit 5 includes a first inductor L1, a second inductor L2, and a capacitor C1. The first inductor L1 and the second inductor L2 are connected between the first sub-line 31 and the second sub-line 32 and are connected in series with each other. The capacitor C1 is connected between a connection point N1 between the first inductor L1 and the second inductor L2 and the ground. The magnitude of a first coupling M1 between the first inductor L1 and the second inductor L2 is greater than the magnitude of a second coupling M2 between the first inductor L1 and the main line 2 and the magnitude of a third coupling M3 between the second inductor L2 and the main line 2.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a directional coupler, a high-frequency module, and a communication device, and more particularly to a directional coupler including a phase-shift circuit connected between a first sub-line and a second sub-line, a high-frequency module including the directional coupler, and a communication device including the high-frequency module. [Background technology]

[0002] The directional coupler described in Patent Document 1 includes a main line, a first sub-line, a second sub-line, and a phase shift circuit. The first sub-line and the second sub-line are connected in series via the phase shift circuit. By connecting the phase shift circuit between the first sub-line and the second sub-line, it is possible to reduce loss of high-frequency band signals passing through the main line when detecting low-frequency band signals. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2023 / 127694 Summary of the Invention [Problem to be solved by the invention]

[0004] In the directional coupler described in Patent Document 1, the phase shift circuit includes an inductor connected in series to a first sub-line and a second sub-line. When the inductor is placed near the main line, the inductor and the main line are magnetically coupled. When the inductor and the main line are magnetically coupled, the impedance of the phase shift circuit on the high frequency side changes, resulting in a deterioration in the directivity of the directional coupler.

[0005] In view of the above problems, an object of the present invention is to provide a directional coupler, a high-frequency module, and a communication device that can improve directivity by suppressing changes in impedance of a phase shift circuit on the high-frequency side. [Means for solving the problem]

[0006] A directional coupler according to one aspect of the present invention includes a main line, a first sub-line, a second sub-line, and a phase shift circuit. The first sub-line and the second sub-line are connected in series with each other. The phase shift circuit is connected in series between the first sub-line and the second sub-line. The phase shift circuit includes a first inductor, a second inductor, and a capacitor. The first inductor and the second inductor are connected between the first sub-line and the second sub-line and are connected in series with each other. The capacitor is connected between a connection point between the first inductor and the second inductor and ground. The first inductor and the second inductor are coupled to each other and to the main line. The magnitude of the first coupling between the first inductor and the second inductor is greater than the magnitude of the second coupling between the first inductor and the main line and the magnitude of the third coupling between the second inductor and the main line.

[0007] A directional coupler according to one aspect of the present invention includes a main line, a first sub-line, a second sub-line, and a phase shift circuit. The first sub-line and the second sub-line are connected in series with each other. The phase shift circuit is connected in series between the first sub-line and the second sub-line. The phase shift circuit includes a first inductor, a second inductor, and a capacitor. The first inductor and the second inductor are connected between the first sub-line and the second sub-line and are connected in series with each other. The capacitor is connected between a connection point between the first inductor and the second inductor and ground. The main line, the first sub-line, the second sub-line, the first inductor, the second inductor, and the capacitor are provided on the same substrate. The distance between the first inductor and the main line and the distance between the second inductor and the main line are each longer than the distance between the first inductor and the second inductor.

[0008] A radio-frequency module according to one aspect of the present invention includes the directional coupler, an antenna terminal, a plurality of filters, and an antenna switch, the antenna switch switching between connection and disconnection between a signal path leading to the antenna terminal and the plurality of filters, and the main line of the directional coupler constituting a partial section of the signal path.

[0009] A communication device according to one aspect of the present invention includes the high-frequency module and a signal processing circuit, the signal processing circuit being connected to the high-frequency module and processing a high-frequency signal. [Effects of the Invention]

[0010] The directional coupler, high-frequency module, and communication device according to the aspects of the present invention have the advantage that the change in impedance of the phase shift circuit on the high-frequency side can be suppressed, thereby improving the directivity. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a configuration diagram of the first mode of the directional coupler according to the first embodiment. [Figure 2] FIG. 2 is a configuration diagram of the second mode of the directional coupler of the above embodiment. [Figure 3] FIG. 3 is a configuration diagram showing a state in which the phase shift circuit and the main line are electromagnetically coupled. [Figure 4] FIG. 4 is a perspective view showing a layered structure of the directional coupler according to the second embodiment. [Figure 5] FIG. 5 is a perspective view showing a layered structure of the directional coupler according to the third embodiment. [Figure 6] FIG. 6 is a perspective view showing a layered structure of the directional coupler according to the fourth embodiment. [Figure 7] FIG. 7 is a perspective view showing a layered structure of the directional coupler according to the fifth embodiment. [Figure 8] FIG. 8 is a configuration diagram illustrating an example of a communication device and a high-frequency module according to the sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, directional couplers, high-frequency modules, and communication devices according to first to sixth embodiments will be described with reference to the drawings.

[0013] (1) Embodiment 1 (1-1) Overview of directional couplers An overview of the directional coupler 1 according to the first embodiment will be described with reference to FIG. 3. As shown in FIG. 3, the directional coupler 1 includes a main line 2, a first sub-line 31, a second sub-line 32, and a phase-shift circuit 5. The first sub-line 31 and the second sub-line 32 are connected in series with each other. The phase-shift circuit 5 is connected in series between the first sub-line 31 and the second sub-line 32. The phase-shift circuit 5 includes a first inductor L1, a second inductor L2, and a capacitor C1. The first inductor L1 and the second inductor L2 are connected between the first sub-line 31 and the second sub-line 32 and are connected in series with each other. The capacitor C1 is connected between a connection point N1 between the first inductor L1 and the second inductor L2 and ground. The first inductor L1 and the second inductor L2 are coupled to each other and to the main line 2. The magnitude of the first coupling M1 between the first inductor L1 and the second inductor L2 is greater than the magnitude of the second coupling M2 between the first inductor L1 and the main line 2 and the magnitude of the third coupling M3 between the second inductor L2 and the main line 2.

[0014] According to this configuration, the magnitude of the first coupling M1 is larger than the magnitude of the second coupling M2 and the magnitude of the third coupling M3, and therefore, the change in impedance of the phase shift circuit 5 on the high frequency side can be suppressed, and as a result, the directivity of the phase shift circuit 5 can be improved.

[0015] (1-2) Directional coupler details The directional coupler 1 according to the first embodiment will be described in detail with reference to FIG.

[0016] The directional coupler 1 is used, for example, in a high-frequency module of a communication device. The high-frequency module is, for example, a module that is compatible with the 4G (fourth generation mobile communication) standard, the 5G (fifth generation mobile communication) standard, and Wi-Fi (registered trademark). As shown in FIG. 1 , the directional coupler 1 is a device that extracts a part of a high-frequency signal flowing in a section (main line 2) of a signal path in the high-frequency module as a detection signal from a sub-line 3 that is electromagnetically coupled to the main line 2. By monitoring the detection signal, it is possible to monitor the high-frequency signal flowing in the main line 2. The directional coupler 1 will be described in detail below.

[0017] 1, the directional coupler 1 includes a main line 2, a sub-line 3, a termination circuit 4, a phase-shift circuit 5, a first changeover switch 6, a second changeover switch 7, and a termination switch 8. The directional coupler 1 further includes a plurality of connection terminals 9 (three in the illustrated example).

[0018] The multiple connection terminals 9 are terminals that can be connected to an external circuit (not shown). The multiple connection terminals 9 include first to third connection terminals 91 to 93. The first connection terminal 91 functions as an input / output terminal that inputs a high-frequency signal from, for example, an antenna terminal to the main line 2 and outputs a high-frequency signal from the main line 2 to the antenna terminal. The second connection terminal 92 functions as an input / output terminal that inputs a high-frequency signal from, for example, an external circuit to the main line 2 and outputs a high-frequency signal from the main line 2 to the external circuit. The third connection terminal 93 functions as a coupling terminal that outputs a detection signal extracted from the sub-line 3 to, for example, an external circuit.

[0019] The main line 2 is a line through which a high-frequency signal to be detected flows. The main line 2 has a first end 2a and a second end 2b, which are both ends of the main line 2 in the longitudinal direction. The first end 2a of the main line 2 is connected to a first connection terminal 91. The second end 2b of the main line 2 is connected to a second connection terminal 92. The main line 2 has an inductor L3 (hereinafter referred to as a third inductor L3) (see FIG. 3). The third inductor L3 has, for example, a parasitic inductance formed in the main line 2.

[0020] The sub-line 3 is electromagnetically coupled to the main line 2 and extracts, as a detection signal, a part of the high-frequency signal flowing through the main line 2. The sub-line 3 has a first sub-line 31 and a second sub-line 32.

[0021] The first sub-line 31 has a first end 31a and a second end 31b, which are both ends of the first sub-line 31 in the longitudinal direction. The first end 31a of the first sub-line 31 is connected to a common terminal 6a (described later) of the first changeover switch 6. The second end 31b of the first sub-line 31 is connected to a third connection terminal 93. The first sub-line 31 is electromagnetically coupled to the main line 2.

[0022] The second sub-line 32 has a first end 32a and a second end 32b, which are both ends in the longitudinal direction of the second sub-line 32. The first end 32a of the second sub-line 32 is connected to a selection terminal 8c (described later) of the termination switch 8. The second end 32b of the second sub-line 32 is connected to a terminal 7b (described later) of the second changeover switch 7. Like the first sub-line 31, the second sub-line 32 is electromagnetically coupled to the main line 2.

[0023] Here, the first sub-line 31 and the second sub-line 32 are aligned along the longitudinal direction of the main line 2. Furthermore, the length B1 of the first sub-line 31 and the length B2 of the second sub-line 32 may be the same as or different from each other. In the first embodiment, the length B1 of the first sub-line 31 and the length B2 of the second sub-line 32 are the same as each other.

[0024] In the first mode, of the first sub-line 31 and the second sub-line 32, only the first sub-line 31 is used as the sub-line 3. Note that in the first mode, of the first sub-line 31 and the second sub-line 32, only the second sub-line 32 may be used as the sub-line 3. In the second mode, both the first sub-line 31 and the second sub-line 32 are used as the sub-line 3. More specifically, in the second mode, a series circuit in which a phase-shift circuit 5 is connected between the first sub-line 31 and the second sub-line 32 is used as the sub-line 3.

[0025] The termination circuit 4 is a circuit for terminating either the first sub-line 31 or the second sub-line 32. More specifically, in the first mode, the termination circuit 4 terminates the first sub-line 31. In the second mode, the termination circuit 4 terminates the second sub-line 32 in a series circuit in which the first sub-line 31, the phase shift circuit 5, and the second sub-line 32 are connected in series in this order. The termination circuit 4 has a variable resistor 4a and a variable capacitor 4b. The variable resistor 4a is connected between the common terminal 8a of the termination switch 8 and ground. The variable capacitor 4b is connected in parallel to the variable resistor 4a. That is, the variable capacitor 4b is also connected between the common terminal 8a of the termination switch 8 and ground.

[0026] By adjusting the resistance value of the variable resistor 4a and the capacitance value of the variable capacitor 4b, it is possible to adjust the characteristics (e.g., directivity) of the directional coupler 1. More specifically, in this embodiment, in the second mode, the phase shift circuit 5 is connected between the first sub-line 31 and the second sub-line 32, and therefore the characteristics (e.g., directivity) of the directional coupler 1 may change due to the phase shift circuit 5. By adjusting the resistance value of the variable resistor 4a and the capacitance value of the variable capacitor 4b, it is possible to improve the above-mentioned change in the characteristics of the directional coupler 1. Note that the termination circuit 4 may include a resistor with a fixed resistance value instead of the variable resistor 4a. Also, the termination circuit 4 may include a capacitor with a fixed capacitance value instead of the variable capacitor 4b.

[0027] The phase-shift circuit 5 is a circuit connected between the first sub-line 31 and the second sub-line 32 used as the sub-line 3 in the second mode to adjust the phase of the sub-line 3. That is, the phase-shift circuit 5 adjusts the phase of the sub-line 3 in the second mode to suppress leakage of high-frequency signals from the main line 2 to the sub-line 3. That is, the phase-shift circuit 5 improves loss of high-frequency signals among signals flowing through the main line 2 when multiple sub-lines (the first sub-line 31 and the second sub-line 32) are connected in series for detection. The phase-shift circuit 5 is provided on the signal path R1 between the first end 31a of the first sub-line 31 and the second end 32b of the second sub-line 32. More specifically, the phase-shift circuit 5 has a first end 5a and a second end 5b. A first terminal 5a of the phase shift circuit 5 is connected to a selection terminal 6c of the first changeover switch 6, and a second terminal 5b of the phase shift circuit 5 is connected to a terminal 7a of the second changeover switch 7.

[0028] The phase shift circuit 5 includes, for example, a first inductor L1, a second inductor L2, and a capacitor C1. That is, the phase shift circuit 5 includes a low-pass filter configured with the first inductor L1, the second inductor L2, and the capacitor C1. The first inductor L1 and the third inductor L3 are connected in series between both ends (the first terminal 5a and the second terminal 5b) of the phase shift circuit 5. The first inductor L1 and the third inductor L3 are connected in series with each other. The capacitor C1 is connected between the connection point N1 between the first inductor L1 and the second inductor L2 and ground.

[0029] As shown in FIG. 3 , the first inductor L1 and the second inductor L2 of the phase shift circuit 5 are magnetically coupled to each other. This magnetic coupling is referred to as a first coupling M1. The phase shift circuit 5 is also electromagnetically coupled to the main line 2. More specifically, the first inductor L1 of the phase shift circuit 5 is magnetically coupled to the third inductor L3 of the main line 2. This magnetic coupling is referred to as a second coupling M2. The second inductor L2 of the phase shift circuit 5 is also magnetically coupled to the third inductor L3 of the main line 2. This magnetic coupling is referred to as a third coupling M3. The magnitude of the first coupling M1 between the first inductor L1 and the second inductor L2 is greater than the magnitude of the second coupling M2 between the first inductor L1 and the third inductor L3 and the magnitude of the third coupling M3 between the second inductor L2 and the third inductor L3. This suppresses changes in impedance of the phase shift circuit 5 on the high-frequency side, as will be described later, and as a result, improves the directivity of the phase shift circuit 5.

[0030] In the first embodiment, the main line 2, the first sub-line 31, the second sub-line 32, the first inductor L1, the second inductor L2, and the capacitor C1 are provided on the same substrate. As shown in FIG. 3 , the distance W2 between the first inductor L1 and the main line 2 (hereinafter referred to as the second distance W2) and the distance W3 between the second inductor L2 and the main line 2 (hereinafter referred to as the third distance W3) are greater than the distance W1 between the first inductor L1 and the second inductor L2 (hereinafter referred to as the first distance W1). Generally, the magnetic field coupling between A and B decreases as the distance between A and B increases, and increases as the distance between A and B decreases. Therefore, since the second distance W2 and the third distance W3 are each greater than the first distance W1, the magnitude of the first coupling M1 increases compared to the magnitude of the second coupling M2 and the magnitude of the third coupling M3.

[0031] 1, the first changeover switch 6 and the second changeover switch 7 are switches for switching between a first mode in which only the first sub-line 31 is used as the sub-line 3, and a second mode in which both the first sub-line 31 and the second sub-line 32 are used as the sub-line 3. In other words, the first changeover switch 6 and the second changeover switch 7 are switches for switching the line length of the sub-line 3 between two stages.

[0032] The first changeover switch 6 is provided between the first sub-line 31 and the phase shift circuit 5, and switches between connection and disconnection between the first sub-line 31 and the phase shift circuit 5. The first changeover switch 6 has a common terminal 6a and a plurality of (two in the illustrated example) selection terminals 6b and 6c. The common terminal 6a is connected to a first end 31a of the first sub-line 31. The selection terminal 6b is connected to a selection terminal 8b of the termination switch 8. The selection terminal 6c is connected to a first end 5a of the phase shift circuit 5.

[0033] The first changeover switch 6 connects the common terminal 6a and the selection terminal 6b in the first mode, and connects the common terminal 6a and the selection terminal 6c in the second mode (i.e., does not connect the common terminal 6a and the selection terminal 6b). As a result, the first sub-line 31 and the termination circuit 4 are connected in the first mode, and the first sub-line 31 and the phase-shift circuit 5 are connected in the second mode.

[0034] The second changeover switch 7 is provided between the phase shift circuit 5 and the second sub-line 32, and switches between connection and disconnection between the phase shift circuit 5 and the second sub-line 32. The second changeover switch 7 has two terminals 7a and 7b. The terminal 7a is connected to the second end 5b of the phase shift circuit 5, and the terminal 7b is connected to the second end 32b of the second sub-line 32.

[0035] The second changeover switch 7 does not connect the terminals 7a and 7b in the first mode, and connects the terminals 7a and 7b in the second mode, so that the phase shift circuit 5 is not connected to the second sub-line 32 in the first mode, and the phase shift circuit 5 is connected to the second sub-line 32 in the second mode.

[0036] The termination switch 8 is a switch for switching the connection destination of the termination circuit 4 to either the first sub-line 31 or the second sub-line 32. The termination switch 8 has a common terminal 8a and a plurality of (two in the illustrated example) selection terminals 8b and 8c. The common terminal 8a is connected to the termination circuit 4. The selection terminal 8b is connected to the selection terminal 6b of the first changeover switch 6. The selection terminal 8c is connected to the first end 32a of the second sub-line 32.

[0037] The termination switch 8 connects the common terminal 8a and the selection terminal 8b in the first mode, and connects the common terminal 8a and the selection terminal 8c in the second mode, thereby connecting the first sub-line 31 and the termination circuit 4 in the first mode, and connecting the second sub-line 32 and the termination circuit 4 in the second mode.

[0038] The directional coupler 1 has a first mode and a second mode. The first mode is a mode for detecting signals in a first frequency band among high-frequency signals flowing through the main line 2. The second mode is a mode for detecting signals in a second frequency band among high-frequency signals flowing through the main line 2. The first frequency band corresponds to a frequency band of 1 GHz to 3 GHz (i.e., MB (middle band) and HB (high band)), for example, and the second frequency band corresponds to a frequency band below 1 GHz (i.e., LB (low band)), for example. That is, the first frequency band is a band with a higher frequency than the second frequency band. In the directional coupler 1, the first mode is the HB mode corresponding to MB (middle band) and HB (high band), and the second mode is the LB mode corresponding to LB (low band).

[0039] In addition, in the first mode, the directional coupler 1 uses the first sub-line 31 as the sub-line 3, and in the second mode, uses a series circuit in which a phase-shift circuit 5 is connected between the first sub-line 31 and the second sub-line 32 as the sub-line 3.

[0040] (1-3) Operation (1-3-1) First mode 1, in the first mode, the directional coupler 1 connects the common terminal 8a and the selection terminal 8b of the termination switch 8, connects the common terminal 6a and the selection terminal 6b of the first changeover switch 6, and does not connect the terminals 7a and 7b of the second changeover switch 7. As a result, the first sub-line 31 is connected between the third connection terminal 93 (i.e., the coupling terminal) and the termination circuit 4. As a result, of the first sub-line 31 and the second sub-line 32, only the first sub-line 31 is used as the sub-line 3. In this case, the line length of the sub-line 3 is the same as the line length B1 of the first sub-line 31.

[0041] In the first mode, the directional coupler 1 extracts a portion of the first signal in the first frequency band from the high-frequency signal flowing through the main line 2 as a detection signal from the sub-line 3 (i.e., the first sub-line 31), and outputs the detection signal from the third connection terminal 93 to an external device (e.g., a detector).

[0042] (1-3-2) Second mode As shown in FIG. 2, in the second mode, the directional coupler 1 connects the common terminal 8a and the selection terminal 8c of the termination switch 8, connects the common terminal 6a and the selection terminal 6c of the first changeover switch 6, and connects the terminals 7a and 7b of the second changeover switch 7. As a result, the first sub-line 31 and the second sub-line 32 are connected in series with each other, and the phase-shift circuit 5 is connected in series therebetween. A series circuit consisting of the first sub-line 31, the second sub-line 32, and the phase-shift circuit 5 is connected between the third connection terminal 93 (i.e., the coupling terminal) and the termination circuit 4. As a result, the above-mentioned series circuit is used as the sub-line 3. In this case, the line length of the sub-line 3 is the sum of the line length B1 of the first sub-line 31 and the line length B2 of the second sub-line 32 (i.e., B1 + B2).

[0043] As a result, the line length (B1+B2) of the sub-line 3 in the second mode is longer than the line length B1 of the sub-line 3 in the first mode. As a result, in the second mode, it becomes possible to extract, as a detected signal, a second signal in a second frequency band that is a lower frequency band than in the first mode from the main line 2 to the sub-line 3. That is, in the second mode, the directional coupler 1 extracts, as a detected signal, a part of the first signal in the second frequency band, of the high-frequency signal flowing through the main line 2, from the sub-line 3, and outputs the detected signal from the third connection terminal 93 to an external device (e.g., a detector).

[0044] (1-4) Impedance of sub-line 3 With reference to FIG. 3, the suppression of changes in impedance of the sub-line 3 will be described. As shown in FIG. 3, the phase shift circuit 5 is electromagnetically coupled to the main line 2. When the phase shift circuit 5 and the main line 2 are electromagnetically coupled, the impedance of the entire sub-line 3 (the series circuit of the first sub-line 31, the phase shift circuit 5, and the second sub-line 32) changes. More specifically, when the phase shift circuit 5 and the main line 2 are electromagnetically coupled, capacitive coupling occurs between the main line 2 and the electrical circuit on the first sub-line 31 side of the phase shift circuit 5, forming a capacitance C2 (parasitic capacitance). Furthermore, when the phase shift circuit 5 and the main line 2 are electromagnetically coupled, capacitive coupling occurs between the main line 2 and the electrical circuit on the second sub-line 32 side of the phase shift circuit 5, forming a capacitance C3 (parasitic capacitance). When the phase shift circuit 5 and the main line 2 are capacitively coupled in this way, the first inductor L1 of the phase shift circuit 5 is magnetically coupled to the third inductor L3 of the main line 2, and the second inductor L2 of the phase shift circuit 5 is magnetically coupled to the third inductor L3 of the main line 2. The magnetic field coupling between the first inductor L1 and the third inductor L3 (second coupling M2) and the magnetic field coupling between the second inductor L2 and the third inductor L3 (third coupling M3) increase the impedance of the entire sub-line 3 on the high frequency side.

[0045] In the phase shift circuit 5, the first inductor L1 and the second inductor L2 are magnetically coupled to each other. The magnetic field coupling (first coupling M1) between the first inductor L1 and the second inductor L2 reduces the impedance of the phase shift circuit 5. That is, the impedance due to the first coupling M1 cancels out the impedances due to the inductors L1 and L2, the second coupling M2, and the third coupling M3. More specifically, the impedance provided to the phase shift circuit 5 by the first coupling M1 is negatively multiplied by the impedance provided to the phase shift circuit 5 by the capacitor C1. Furthermore, the impedance provided to the phase shift circuit 5 by the second coupling M2 and the third coupling M3 is positively multiplied by the impedance provided to the phase shift circuit 5 by the capacitor C1 (i.e., impedances with an inverse sign). In the first embodiment, the magnitude of the first coupling M1 is greater than the magnitude of each of the second coupling M2 and the third coupling M3. Therefore, the first coupling M1 suppresses (i.e., improves) the increase in the impedance of the entire sub-line 3 on the high frequency side caused by the second coupling M2 and the third coupling M3. As a result, the directivity of the directional coupler 1 is improved. This allows the characteristics of the directional coupler 1 to be broadened.

[0046] (1-5) Effects The directional coupler 1 according to the first embodiment includes a main line 2, a first sub-line 31, a second sub-line 32, and a phase-shift circuit 5. The first sub-line 31 and the second sub-line 32 are connected in series with each other. The phase-shift circuit 5 is connected in series between the first sub-line 31 and the second sub-line 32. The phase-shift circuit 5 includes a first inductor L1, a second inductor L2, and a capacitor C1. The first inductor L1 and the second inductor L2 are connected between the first sub-line 31 and the second sub-line 32 and are connected in series with each other. The capacitor C1 is connected between a connection point N1 between the first inductor L1 and the second inductor L2 and ground. The first inductor L1 and the second inductor L2 are coupled to each other and to the main line 2. The magnitude of the first coupling M1 between the first inductor L1 and the second inductor L2 is greater than the magnitude of the second coupling M2 between the first inductor L1 and the main line 2 and the magnitude of the third coupling M3 between the second inductor L2 and the main line 2.

[0047] With this configuration, the magnitude of the first coupling M1 is greater than the magnitude of the second coupling M2 and the magnitude of the third coupling M3, and therefore it is possible to suppress changes in the impedance of the phase shift circuit 5 on the high frequency side, thereby improving the directivity of the phase shift circuit 5. Furthermore, it is possible to obtain wideband characteristics as the characteristics of the phase shift circuit 5.

[0048] More specifically, the impedance provided to the phase shift circuit 5 by the second coupling M2 and the third coupling M3 is a plus multiple of the impedance provided to the phase shift circuit 5 by the capacitor C1. Furthermore, the impedance provided to the phase shift circuit 5 by the first coupling M1 is a minus multiple of the impedance provided to the phase shift circuit 5 by the capacitor C1. In the present disclosure, the magnitude of the first coupling M1 is greater than the magnitudes of the second coupling M2 and the third coupling M3. Therefore, the impedance provided by the first coupling M1 can effectively suppress the impedance provided by the second coupling M2 and the third coupling M3. This suppresses changes in the impedance of the phase shift circuit 5 on the high-frequency side. As a result, the directivity of the phase shift circuit 5 can be improved.

[0049] Now, consider a directional coupler of the comparative example. The directional coupler of the comparative example has a configuration similar to the directional coupler 1 of the first embodiment, except that it has the second coupling M2 and the third coupling M3, but does not have the first coupling M1. In the directional coupler of the comparative example, like the directional coupler 1 of the first embodiment, the second coupling M2 and the third coupling M3 provide impedance to the phase-shift circuit 5. However, because the directional coupler of the comparative example does not have the first coupling M1, impedance is not provided to the phase-shift circuit 5 by the first coupling M1, as in the directional coupler 1 of the first embodiment. Therefore, in the directional coupler of the comparative example, the impedance of the phase-shift circuit 5 increases compared to the directional coupler 1 of the first embodiment. This increase deteriorates the directivity of the directional coupler of the comparative example. In contrast to this, the directional coupler 1 of the first embodiment has the first coupling M1 in addition to the second coupling M2 and the third coupling M3 as described above, and therefore the impedance given to the phase shift circuit 5 by the first coupling M1 can effectively suppress the impedance given to the phase shift circuit 5 by the second coupling M2 and the third coupling M3, and as a result, the directivity of the phase shift circuit 5 can be improved.

[0050] Furthermore, in the directional coupler 1 according to the first embodiment, the main line 2, the first sub-line 31, the second sub-line 32, the first inductor L1, the second inductor L2, and the capacitor C1 are provided on the same substrate. The second distance W2 between the first inductor L1 and the main line 2 and the third distance W3 between the second inductor L2 and the main line 2 are each longer than the first distance W1 between the first inductor L1 and the second inductor L2. This configuration makes it easy to achieve a magnitude relationship in which the magnitude of the first coupling M1 is larger than the magnitude of the second coupling M2 and the magnitude of the third coupling M3.

[0051] The directional coupler 1 according to the first embodiment includes a main line 2, a first sub-line 31, a second sub-line 32, and a phase-shift circuit 5. The first sub-line 31 and the second sub-line 32 are connected in series. The phase-shift circuit 5 is connected in series between the first sub-line 31 and the second sub-line 32. The phase-shift circuit 5 includes a first inductor L1, a second inductor L2, and a capacitor C1. The first inductor L1 and the second inductor L2 are connected between the first sub-line 31 and the second sub-line 32 and are connected in series. The capacitor C1 is connected between a connection point N1 between the first inductor L1 and the second inductor L2 and ground. The main line 2, the first sub-line 31, the second sub-line 32, the first inductor L1, the second inductor L2, and the capacitor C1 are provided on the same substrate. The second distance between the first inductor L1 and the main line 2 and the third distance between the second inductor L2 and the main line 2 are each longer than the first distance W1 between the first inductor L1 and the second inductor L2.

[0052] With this configuration, the second distance W2 between the first inductor L1 and the main line 2 and the third distance W3 between the second inductor L2 and the main line 2 are each longer than the first distance W1 between the first inductor L1 and the second inductor L2. Therefore, the magnitude of the first coupling M1 can be made larger than the magnitude of the second coupling M2 and the magnitude of the second coupling M2, respectively. As a result, changes in the impedance of the phase shift circuit 5 on the high-frequency side can be suppressed, and the directivity of the phase shift circuit 5 can be improved.

[0053] (1-6) Variations The following describes modifications of embodiment 1. In the following description, the same components as those in embodiment 1 are denoted by the same reference numerals, and the description thereof may be omitted.

[0054] (1-6-1) Variation 1 In the first embodiment, the first inductor L1 may be formed by at least a part (for example, the whole) of the first sub-line 31. In this case, the first inductor L1 is formed by an inductor (for example, a parasitic inductor) included in at least a part of the first sub-line 31. In this case, at least a part of the first sub-line 31 is included in the components of the phase shift circuit 5. Furthermore, the second inductor L2 may be formed by at least a part (for example, the whole) of the second sub-line 32. In this case, the second inductor L2 is formed by an inductor (for example, a parasitic inductor) included in at least a part of the second sub-line 32. In this case, at least a part of the second sub-line 32 is included in the components of the phase shift circuit 5. As in the first embodiment, the first modification can also suppress changes in impedance of the phase shift circuit 5 on the high frequency side, thereby improving the directivity of the phase shift circuit 5.

[0055] (2) Embodiment 2 (2-1) Configuration In the second embodiment, an example of the structure of the directional coupler 1 according to the first embodiment (more specifically, the relative positions of the main line 2, the first sub-line 31, and the second sub-line 32) will be described. In the following description, differences from the first embodiment will be mainly described, and the same components as those in the first embodiment will be denoted by the same reference numerals as those in the first embodiment, and the description thereof may be omitted.

[0056] As shown in FIG. 4, the directional coupler 1 according to the second embodiment further includes a substrate 95 in addition to the components of the directional coupler 1 according to the first embodiment.

[0057] The main line 2, the first sub-line 31, the second sub-line 32, and the phase shift circuit 5 are formed on the substrate 95. That is, the main line 2, the first sub-line 31, the second sub-line 32, and the phase shift circuit 5 are formed on the same substrate 95. The substrate 95 is, for example, a silicon substrate. The substrate of the power amplifier and the substrate of the low-noise amplifier provided in the high-frequency module are, for example, silicon substrates. Since the substrate 95 is a silicon substrate, when the directional coupler 1 is provided in the high-frequency module, the directional coupler 1 can be formed using the same substrate (silicon substrate) together with the power amplifier and the low-noise amplifier provided in the high-frequency module.

[0058] The substrate 95 is a multilayer substrate having multiple layers stacked in a thickness direction D1 of the substrate 95. The multiple layers include three layers Q1 to Q3 that are different from one another. The layer Q1 is, for example, the top layer of the three layers Q1 to Q3. The layer Q2 is, for example, the bottom layer of the three layers Q1 to Q3. The layer Q3 is a layer disposed between the layers Q1 and Q2.

[0059] The main line 2 is arranged on layer Q3. As will be described later, the first sub-line 31 is arranged on layer Q1, and the second sub-line 32 is arranged on layer Q2. Therefore, the main line 2 is arranged on layer Q3 between layer Q1 on which the first sub-line 31 is formed and layer Q2 on which the second sub-line 32 is formed. The main line 2 is, for example, linear. More specifically, the main line 2 has a loop-shaped portion 21. The loop-shaped portion 21 has a first end 2a and a second end 2b, and is a winding wound one or more times (one time in the example of FIG. 4). The loop-shaped portion 21 is, for example, a rectangular loop. A wire h1 is connected to the first end 2a of the loop-shaped portion 21. The wire h1 is drawn to the outer periphery of the loop-shaped portion 21 and connected to the first connection terminal 91. A wire h2 is connected to the second end 2b of the loop-shaped portion 21. The wire h2 is drawn out to the outer periphery of the loop-shaped portion 21 and connected to the second connection terminal 92.

[0060] The entire first sub-line 31 constitutes the first inductor L1 of the phase shift circuit 5. That is, the first inductor L1 is constituted by the entire first sub-line 31. The first sub-line 31 is arranged on the layer Q1. The first sub-line 31 is, for example, linear. More specifically, the first sub-line 31 has a loop-shaped portion 311. The loop-shaped portion 311 has a first end 31a and a second end 31b and is a winding wound one or more times (one time in the example of FIG. 4). The loop-shaped portion 311 has, for example, a rectangular loop shape when viewed from above in the thickness direction D1. The loop-shaped portion 311 is arranged on the outer periphery of the main line 2 when viewed from above in the thickness direction D1. That is, the main line 2 is arranged on the inner periphery of the first sub-line 31 when viewed from above in the thickness direction D1. The first end 31a and the second end 31b are disposed, for example, on the opposite side to the first end 2a and the second end 2b of the main line 2 in a plan view from the thickness direction D1. The second end 31b of the loop-shaped portion 311 is connected to a wiring h3. The wiring h3 is drawn to the outer periphery of the loop-shaped portion 311 and connected to a third connection terminal 93. The first end 31a of the loop-shaped portion 311 is connected to a second end 32b of a loop-shaped portion 321 (described later) of the second sub-line 32 via a wiring h4. The wiring h4 is provided across the layers Q1 and Q2. A first changeover switch 6 is connected between the first end 31a and the wiring h4, but is not shown in FIG. 4.

[0061] The entire second sub-line 32 constitutes the second inductor L2 of the phase shift circuit 5. That is, the second inductor L2 is constituted by the entire second sub-line 32. The second sub-line 32 is formed on the layer Q3. The second sub-line 32 is arranged so as to run parallel to the first sub-line 31. Here, "A runs parallel to B" means that when A and B are arranged on different layers, A overlaps with B in the thickness direction D1 and is arranged along B, and when A and B are arranged on the same layer, A is arranged alongside B and along B.

[0062] The second sub-line 32 is, for example, linear. More specifically, the second sub-line 32 has a loop-shaped portion 321. The loop-shaped portion 321 has a first end 32a and a second end 32b and is a winding wound one or more times (one time in the example of FIG. 4). The first end 32a and the second end 32b are arranged, for example, on the opposite side to the first end 2a and the second end 2b of the main line 2 (i.e., the same side as the first end 31a and the second end 31b of the first sub-line 31) in a plan view from the thickness direction D1. The loop-shaped portion 321 has, for example, a rectangular loop shape in a plan view from the thickness direction D1. The loop-shaped portion 321 is, for example, rectangular and of the same shape and size as the loop-shaped portion 311 of the first sub-line 31. At least a portion of the loop-shaped portion 321 and the loop-shaped portion 311 (the entirety of each in the example of FIG. 4) overlaps with each other in the thickness direction D1. The loop-shaped portion 321 is disposed on the outer periphery of the main line 2 in plan view from the thickness direction D1. That is, the main line 2 is disposed on the inner periphery of the second sub-line 32 in plan view from the thickness direction D1. A first end 32a of the loop-shaped portion 321 is connected to the wiring h5. The wiring h5 is connected to ground via the termination switch 8 and the termination circuit 4. A second end 32b of the loop-shaped portion 321 is connected to the first end 31a of the loop-shaped portion 311 of the phase-shift circuit 5 via wiring h4. A second selector switch 7 is connected between the second end 32b and the wiring h4, but is not shown in FIG. 4 . A capacitor C1 is connected between the midpoint of the wiring h4 and ground. The capacitor C1 is disposed on any one of the multiple layers of the substrate 95.

[0063] In the second embodiment, the main line 2 is arranged on the inner periphery side of the first sub-line 31 (ie, the first inductor L1) and the second sub-line 32 (ie, the second inductor L2) in plan view in the thickness direction D1.

[0064] In addition, in embodiment 2, the first sub-line 31 (i.e., the first inductor L1) and the second sub-line 32 (i.e., the second inductor L2) are magnetically coupled (first coupling), the first sub-line 31 (i.e., the first inductor L1) and the main line 2 are magnetically coupled (second coupling), and the second sub-line 32 (i.e., the second inductor L2) and the main line 2 are magnetically coupled (third coupling).

[0065] In the second embodiment, the second distance W2 between the first sub-line 31 (i.e., the first inductor L1) and the main line 2 and the third distance W3 between the second sub-line 32 (i.e., the second inductor L2) and the main line 2 are each longer than the first distance W1 between the first sub-line 31 (i.e., the first inductor L1) and the second sub-line 32 (i.e., the second inductor L2). As a result, the magnitude of the first coupling between the first inductor L1 and the second inductor L2 is greater than the magnitude of the second coupling between the first inductor L1 and the main line 2 (i.e., the third inductor L3) and the magnitude of the third coupling between the second inductor L2 and the main line 2 (i.e., the third inductor L3). As a result, as in the first embodiment, the first coupling reduces the increase in the impedance of the entire sub-line 3 on the high-frequency side due to the second and third couplings. As a result, the directivity of the directional coupler 1 is improved. This allows the characteristics of the directional coupler 1 to be broadened.

[0066] In the second embodiment, the first distance W1 between the first sub-line 31 (i.e., the first inductor L1) and the second sub-line 32 (i.e., the second inductor L2) is the distance between the first sub-line 31 and the second sub-line 32 in the thickness direction D1. In other words, the first distance W1 between the first sub-line 31 and the second sub-line 32 is the distance between the layer Q1 on which the first sub-line 31 is arranged and the layer Q2 on which the second sub-line 32 is arranged. In the second embodiment, the second distance W2 between the first sub-line 31 (i.e., the first inductor L1) and the main line 2 is the narrowest distance between the first sub-line 31 and the main line 2 in a plan view from the thickness direction D1. In addition, the distance between the line A and the line B is the distance between the center of the line A in the width direction and the center of the line B in the width direction in a plan view from the thickness direction D1. Similarly, the third distance W3 between the second sub-line 32 (i.e., the second inductor L2) and the main line 2 is the narrowest distance between the second sub-line 32 and the main line 2 when viewed in a plan view from the thickness direction D1.

[0067] (2-2) Effects In the directional coupler 1 according to the second embodiment, the substrate 95 has multiple layers including a first layer Q1 and a second layer Q2 that are different from each other. The first inductor L1 is provided on the first layer Q1. The second inductor L2 is provided on the second layer Q2. At least a portion (all of the first inductor L1 and the second inductor L2 in the example of FIG. 4 ) of the first inductor L1 and the second inductor L2 are arranged to overlap each other in the thickness direction D1 of the substrate 95. This configuration makes it easy to reduce the first distance W1 between the first inductor L1 and the second inductor L2 in the thickness direction D1 of the substrate 95. As a result, it is easy to increase the first coupling M1 between the first inductor L1 and the second inductor L2 while maintaining the coupling between the main line 2 and the first sub-line 31 and the second sub-line 32.

[0068] Furthermore, in the directional coupler 1 according to the second embodiment, the first inductor L1 and the second inductor L2 include loop-shaped portions 311, 321 that are wound one or more times (one time in the example of FIG. 4). This configuration allows the first inductor L1 and the second inductor L2 to be formed compactly while ensuring inductance.

[0069] Furthermore, in the directional coupler 1 according to the second embodiment, the main line 2 is disposed on the inner peripheral side of the first inductor L1 and the second inductor L2 in a plan view in the thickness direction D1 of the substrate 95. With this configuration, the first inductor L1 and the second inductor L2 are disposed on the outer peripheral side of the main line 2. This makes it easy to increase the size of the first inductor L1 and the second inductor L2, thereby making it easy to increase the inductance of each of the first inductor L1 and the second inductor L2 while maintaining the coupling between the main line 2 and the first sub-line 31 and the second sub-line 32. Furthermore, in a plan view in the thickness direction D1 of the substrate 95, the second distance W2 between the first inductor L1 and the main line 2 and the third distance W3 between the second inductor L2 and the main line 2 can be easily ensured. As a result, the second coupling M2 between the first inductor L1 and the main line 2 and the third coupling M3 between the second inductor L2 and the main line 2 can be easily reduced while maintaining the coupling between the main line 2 and the first sub-line 31 and the second sub-line 32.

[0070] In the directional coupler 1 according to the second embodiment, the main line 2 is provided in a layer Q3 between the first layer Q1 and the second layer Q2 among the multiple layers. This configuration makes it easy to balance the first coupling M1 and the second coupling M2. This makes it easy to adjust the characteristics of the directional coupler 1 to the desired characteristics.

[0071] (2-3) Modifications Modifications of the second embodiment will be described below. The following modifications may be implemented in combination with each other. In the following description, the same components as those in the second embodiment will be denoted by the same reference numerals, and the description thereof may be omitted.

[0072] (2-3-1) Variation 1 In the second embodiment, the loop-shaped portions 21, 311, and 321 of the main line 2, the first sub-line 31, and the second sub-line 32 are rectangular. However, the shapes of the loop-shaped portions 21, 311, and 321 are not limited to rectangular, and may be, for example, circular or polygonal other than quadrangular.

[0073] (2-3-2) Variation 2 In the second embodiment, the loop-shaped portions 21, 311, and 321 of the main line 2, the first sub-line 31, and the second sub-line 32 are wound one turn. However, the loop-shaped portions 21, 311, and 321 may be wound less than one turn, or may be wound two or more turns. When the loop-shaped portions 21, 311, and 321 are wound two or more turns, the turns may be arranged on different layers or on the same layer. When the loop-shaped portions 21, 311, and 321 are wound two or more turns and the turns are arranged on the same layer, the turns may be arranged in order on the inner circumferential side or on the outer circumferential side.

[0074] (3) Embodiment 3 (3-1) Configuration As shown in FIG. 5, the directional coupler 1 according to the third embodiment is configured in the same manner as the directional coupler 1 according to the second embodiment, except that the main line 2 is arranged on the outer periphery of the first sub-line 31 (i.e., the first inductor L1) and the second sub-line 32 (i.e., the second inductor L2) in plan view in the thickness direction D1.

[0075] In the third embodiment, the second distance W2 between the first sub-line 31 (i.e., the first inductor L1) and the main line 2 and the third distance W3 between the second sub-line 32 (i.e., the second inductor L2) and the main line 2 are each longer than the first distance W1 between the first sub-line 31 (i.e., the first inductor L1) and the second sub-line 32 (i.e., the second inductor L2). As a result, the magnitude of the first coupling between the first inductor L1 and the second inductor L2 is greater than the magnitude of the second coupling between the first inductor L1 and the main line 2 (i.e., the third inductor L3) and the magnitude of the third coupling between the second inductor L2 and the main line 2 (i.e., the third inductor L3). As a result, as in the first embodiment, the first coupling reduces the increase in the impedance of the entire sub-line 3 on the high-frequency side due to the second and third couplings. As a result, the directivity of the directional coupler 1 is improved. This allows the characteristics of the directional coupler 1 to be broadened.

[0076] In the third embodiment, as in the second embodiment, the first distance W1 between the first sub-line 31 (i.e., the first inductor L1) and the second sub-line 32 (i.e., the second inductor L2) is the distance between the first sub-line 31 and the second sub-line 32 in the thickness direction D1. In other words, the first distance W1 is the gap between the layer Q1 on which the first sub-line 31 is arranged and the layer Q2 on which the second sub-line 32 is arranged. In the third embodiment, as in the second embodiment, the second distance W2 between the first sub-line 31 (i.e., the first inductor L1) and the main line 2 is the narrowest gap between the first sub-line 31 and the main line 2 in a plan view from the thickness direction D1. Similarly, the third distance W3 between the second sub-line 32 (i.e., the second inductor L2) and the main line 2 is the narrowest distance between the second sub-line 32 and the main line 2 when viewed in a plan view from the thickness direction D1.

[0077] (3-2) Effects In the directional coupler 1 according to the third embodiment, the main line 2 is disposed on the outer periphery side of the first inductor L1 and the second inductor L2 in plan view in the thickness direction D1 of the substrate 95. With this configuration, the main line 2 can prevent the first inductor L1 and the second inductor L2 from being electromagnetically affected by circuits on the outer periphery. Furthermore, in plan view in the thickness direction D1 of the substrate 95, the second distance W2 between the first inductor L1 and the main line 2 and the third distance W3 between the second inductor L2 and the main line 2 can be easily ensured. As a result, the second coupling M2 between the main line 2 and the first inductor L1 and the main line 2 and the third coupling M3 between the second inductor L2 and the main line 2 can be easily reduced.

[0078] (4) Embodiment 4 (4-1) Configuration As shown in FIG. 6, the directional coupler 1 according to the fourth embodiment is configured in the same manner as the directional coupler 1 according to the second embodiment, except that the main line 2 is provided in a layer Q4 of the plurality of layers, which is on the opposite side of the layer Q1 (first layer) from the side of the layer Q2 (second layer).

[0079] In the fourth embodiment, the loop-shaped portion 21 of the main line 2 has the same shape and size (e.g., rectangular) as the loop-shaped portion 311 of the first sub-line 31 and the loop-shaped portion 321 of the second sub-line 32. The main line 2 (i.e., the loop-shaped portion 21) is arranged so as to run parallel to the first sub-line 31 (i.e., the loop-shaped portion 311). At least a portion (all of the main line 2 (i.e., the loop-shaped portion 21) and the first sub-line 31 (i.e., the loop-shaped portion 311) overlap each other in the thickness direction D1.

[0080] In the fourth embodiment, the second distance W2 between the first sub-line 31 (i.e., the first inductor L1) and the main line 2 and the third distance W3 between the second sub-line 32 (i.e., the second inductor L2) and the main line 2 are each longer than the first distance W1 between the first sub-line 31 (i.e., the first inductor L1) and the second sub-line 32 (i.e., the second inductor L2). As a result, the magnitude of the first coupling between the first inductor L1 and the second inductor L2 is greater than the magnitude of the second coupling between the first inductor L1 and the main line 2 (i.e., the third inductor L3) and the magnitude of the third coupling between the second inductor L2 and the main line 2 (i.e., the third inductor L3). As a result, as in the first embodiment, the first coupling reduces the increase in the impedance of the entire sub-line 3 on the high-frequency side due to the second and third couplings. As a result, the directivity of the directional coupler 1 is improved. This allows the characteristics of the directional coupler 1 to be broadened.

[0081] In the fourth embodiment, as in the second embodiment, the first distance W1 between the first sub-line 31 (i.e., the first inductor L1) and the second sub-line 32 (i.e., the second inductor L2) is the distance between the first sub-line 31 and the second sub-line 32 in the thickness direction D1. In other words, the first distance W1 is the gap between the layer Q1 on which the first sub-line 31 is arranged and the layer Q2 on which the second sub-line 32 is arranged. In the fourth embodiment, the second distance W2 between the first sub-line 31 (i.e., the first inductor L1) and the main line 2 is the distance between the first sub-line 31 and the main line 2 in the thickness direction D1. In other words, the second distance W2 is the gap between the layer Q1 on which the first sub-line 31 is arranged and the layer Q4 on which the main line 2 is arranged. Similarly, the third distance W3 between the second sub-line 32 (i.e., the second inductor L2) and the main line 2 is the distance between the second sub-line 32 and the main line 2 in the thickness direction D1. In other words, the third distance W3 is the gap between the layer Q2 on which the second sub-line 32 is arranged and the layer Q4 on which the main line 2 is arranged.

[0082] (4-2) Effects In the directional coupler 1 according to the fourth embodiment, the main line 2 is provided on a layer Q4 of the first layer Q1, which is located on the opposite side of the second layer Q2. This configuration allows the first distance W1 between the first inductor L1 and the second inductor L2 to be easily reduced in the thickness direction D1 of the substrate 95, thereby increasing the first coupling M1. Furthermore, the second distance W2 between the main line 2 and the first inductor L1 and the third distance W3 between the main line 2 and the second inductor L2 can be easily reduced in the thickness direction D1 of the substrate 95, thereby reducing the second coupling M2 and the third coupling M3. As a result, the magnitude of the first coupling M1 can be easily increased relative to the magnitudes of the second coupling M2 and the third coupling M3.

[0083] (4-3) Modification Below, a description will be given of a variation of the fourth embodiment. In the following description, the same components as those in the fourth embodiment will be given the same reference numerals and the description thereof may be omitted.

[0084] In the fourth embodiment, the main line 2 is provided in a layer Q4 of the plurality of layers, which is on the opposite side of the layer Q2 (second layer) in the layer Q1 (first layer). However, the main line 2 may also be provided in a layer of the plurality of layers, which is on the opposite side of the layer Q2 (second layer) in the layer Q1 (first layer). The same effects as those of the fourth embodiment can be achieved by this modification.

[0085] (5) Embodiment 5 (5-1) Configuration As shown in FIG. 7, the directional coupler 1 according to the fifth embodiment is configured in the same manner as the directional coupler 1 according to the second embodiment, except that the main line 2 is formed linearly and is disposed on the outer periphery of the first sub-line 31 and the second sub-line 32.

[0086] In the fifth embodiment, the main line 2 is formed in a straight line. The main line 2 is arranged along one side E1 of the loop-shaped portion 311 of the first sub-line 31 with a gap therebetween in a plan view in the thickness direction D1.

[0087] In the fifth embodiment, the second distance W2 between the first sub-line 31 (i.e., the first inductor L1) and the main line 2 and the third distance W3 between the second sub-line 32 (i.e., the second inductor L2) and the main line 2 are each longer than the first distance W1 between the first sub-line 31 (i.e., the first inductor L1) and the second sub-line 32 (i.e., the second inductor L2). As a result, the magnitude of the first coupling between the first inductor L1 and the second inductor L2 is greater than the magnitude of the second coupling between the first inductor L1 and the main line 2 (i.e., the third inductor L3) and the magnitude of the third coupling between the second inductor L2 and the main line 2 (i.e., the third inductor L3). As a result, as in the first embodiment, the first coupling reduces the increase in the impedance of the entire sub-line 3 on the high-frequency side due to the second coupling and the third coupling. As a result, the directivity of the directional coupler 1 is improved. This allows the characteristics of the directional coupler 1 to be broadened.

[0088] In the fifth embodiment, as in the second embodiment, the first distance W1 between the first sub-line 31 (i.e., the first inductor L1) and the second sub-line 32 (i.e., the second inductor L2) is the distance between the first sub-line 31 and the second sub-line 32 in the thickness direction D1. In other words, the first distance W1 is the gap between the layer Q1 on which the first sub-line 31 is arranged and the layer Q2 on which the second sub-line 32 is arranged. In the fifth embodiment, the second distance W2 between the first sub-line 31 (i.e., the first inductor L1) and the main line 2 is the narrowest gap between the first sub-line 31 and the main line 2 in a plan view from the thickness direction D1. Similarly, the third distance W3 between the second sub-line 32 (i.e., the second inductor L2) and the main line 2 is the narrowest gap between the second sub-line 32 and the main line 2 in a plan view from the thickness direction D1.

[0089] (5-2) Effects In the directional coupler 1 according to the fifth embodiment, the main line 2 is linear. In a plan view in the thickness direction D1, the main line 2 is disposed on the outer periphery of the first inductor L1 and the second inductor L2. With this configuration, when the main line 2 is linear, the second distance W2 between the main line 2 and the first inductor L1 and the third distance W3 between the main line 2 and the second inductor L2 can be easily made longer than the first distance W1 between the first inductor L1 and the second inductor L2. As a result, the magnitude of the first coupling M1 can be easily made larger than the magnitudes of the second coupling M2 and the third coupling M3.

[0090] (5-3) Modification Below, a description will be given of a variation of the fifth embodiment. In the following description, the same components as those in the fifth embodiment will be given the same reference numerals and the description thereof may be omitted.

[0091] (5-3-1) Variation 1 In the fifth embodiment, the main line 2 is arranged on a layer Q3 between a layer Q1 on which the first sub-line 31 is arranged and a layer Q2 on which the second sub-line 32 is arranged. However, the main line 2 may be arranged on a layer on the opposite side of the layer Q1 from the layer Q2 side, or on a layer on the opposite side of the layer Q2 from the layer Q1 side. This first modification also provides the same effects as the fifth embodiment.

[0092] (6) Embodiment 6 A high-frequency module 100 and a communication device 200 according to the sixth embodiment will be described with reference to Fig. 8. The high-frequency module 100 according to the sixth embodiment is an example of a high-frequency module including the directional coupler 1 according to any one of the first to fifth embodiments (for example, the first embodiment). The communication device 200 according to the sixth embodiment is an example of a communication device including the high-frequency module 100.

[0093] (6-1) Configuration of communication device The communication device 200 is, for example, a mobile terminal (for example, a smartphone) or a wearable terminal (for example, a smart watch). The communication device 200 includes the high-frequency module 100, a signal processing circuit 210, and an antenna 220.

[0094] The high-frequency module 100 is a module that is compatible with, for example, the 4G (fourth generation mobile communication) standard, the 5G (fifth generation mobile communication) standard, and Wi-Fi (registered trademark). The high-frequency module 100 is configured to extract a received signal of a predetermined frequency band from received signals received by an antenna 220, amplify the received signal, and output the amplified signal to a signal processing circuit 210. The high-frequency module 100 is also configured to amplify a transmission signal output from the signal processing circuit 210, convert the amplified signal into a transmission signal of the predetermined frequency band, and output the amplified signal from the antenna 220.

[0095] The signal processing circuit 210 is connected to the high-frequency module 100 and is configured to process high-frequency signals. More specifically, the signal processing circuit 210 processes received signals output from the high-frequency module 100, and also processes transmitted signals output to the high-frequency module 100. The signal processing circuit 210 includes an RF signal processing circuit 211 and a baseband signal processing circuit 212.

[0096] The RF signal processing circuit 211 is, for example, an RFIC (Radio Frequency Integrated Circuit). The RF signal processing circuit 211 is configured to perform signal processing such as down-conversion on a received signal output from the high-frequency module 100 and output the signal to the baseband signal processing circuit 212. The RF signal processing circuit 211 is also configured to perform signal processing such as up-conversion on a transmission signal output from the baseband signal processing circuit 212 and output the signal to the high-frequency module 100. The baseband signal processing circuit 212 is, for example, a BBIC (Baseband Integrated Circuit). The baseband signal processing circuit 212 is configured to output the received signal output from the RF signal processing circuit 211 to the outside. The baseband signal processing circuit 212 is also configured to generate a transmission signal from a baseband signal (e.g., an audio signal and an image signal) input from the outside and output the generated transmission signal to the RF signal processing circuit 211.

[0097] (6-2) High-frequency module configuration The high-frequency module 100 includes a plurality of external connection terminals 110, power amplifiers 151, 152, low-noise amplifiers 161, 162, transmit filters 61T to 64T, receive filters 61R to 64R, output matching circuits 131, 132, matching circuits 141, 142, matching circuits 71 to 74, switches 51 to 55, a diplexer 60, and a directional coupler 1 (coupler).

[0098] The plurality of external connection terminals 110 include an antenna terminal 130, two signal input terminals 111 and 112, two signal output terminals 121 and 122, and a coupler output terminal 181. The antenna terminal 130 is a terminal to which an antenna 220 is connected. The two signal input terminals 111 and 112 are terminals to which transmission signals from a signal processing circuit 210 are input, and are connected to the output section of the signal processing circuit 210. The two signal output terminals 121 and 122 are terminals that output transmission signals from the high-frequency module 100 to the signal processing circuit 210, and are connected to the input section of the signal processing circuit 210. The coupler output terminal 181 is a terminal that outputs a detection signal extracted by the directional coupler 1 to an external device (for example, the signal processing circuit 210).

[0099] Each of the power amplifiers 151 and 152 has an input section and an output section. The input sections of the power amplifiers 151 and 152 are connected to the signal input terminals 111 and 112, and the output sections of the power amplifiers 151 and 152 are connected to the common terminals of the switches 51 and 52 via the output matching circuits 131 and 132. Each of the power amplifiers 151 and 152 amplifies a transmission signal input from the signal input terminal 111 and 112, and outputs the amplified transmission signal to the common terminal of the switches 51 and 52 via the output matching circuits 131 and 132.

[0100] The switch 51 has a common terminal and two selection terminals (a first selection terminal and a second selection terminal). The common terminal of the switch 51 is connected to the power amplifier 151 via the output matching circuit 131. The two selection terminals of the switch 51 are connected to inputs of the transmit filters 61T and 62T, respectively. The switch 51 selectively outputs the output signal of the power amplifier 151 to one of the transmit filters 61T and 62T. The switch 52 has a common terminal and two selection terminals (a first selection terminal and a second selection terminal). The common terminal of the switch 52 is connected to the power amplifier 152 via the output matching circuit 132. The two selection terminals of the switch 52 are connected to inputs of the transmit filters 63T and 64T, respectively. The switch 52 selectively outputs the output signal of the power amplifier 152 to one of the transmit filters 63T and 64T.

[0101] The transmit filter 61T has an input section and an output section. The input section of the transmit filter 61T is connected to a first selection terminal of the switch 51, and the output section of the transmit filter 61T is connected to the switch 55 via a matching circuit 71. The transmit filter 61T passes transmit signals in the transmission band of the first communication band out of the transmit signals amplified by the power amplifier 151. The transmit filter 62T has an input section and an output section. The input section of the transmit filter 62T is connected to a second selection terminal of the switch 51, and the output section of the transmit filter 62T is connected to the switch 55 via a matching circuit 72. The transmit filter 62T passes transmit signals in the transmission band of the second communication band out of the transmit signals amplified by the power amplifier 151.

[0102] The transmit filter 63T has an input section and an output section. The input section of the transmit filter 63T is connected to a first selection terminal of the switch 52, and the output section of the transmit filter 63T is connected to the switch 55 via a matching circuit 73. The transmit filter 63T passes transmit signals in the transmission band of the third communication band out of the transmit signals amplified by the power amplifier 152. The transmit filter 64T has an input section and an output section. The input section of the transmit filter 64T is connected to a second selection terminal of the switch 52, and the output section of the transmit filter 64T is connected to the switch 55 via a matching circuit 74. The transmit filter 64T passes transmit signals in the transmission band of the fourth communication band out of the transmit signals amplified by the power amplifier 152.

[0103] Low-noise amplifiers 161 and 162 each have an input section and an output section. The input sections of low-noise amplifiers 161 and 162 are connected to the common terminals of switches 53 and 54 via matching circuits 141 and 142, respectively. The output sections of low-noise amplifiers 161 and 162 are connected to signal output terminals 121 and 122. Low-noise amplifiers 161 and 162 amplify the received signals output from switches 53 and 54, and output the amplified signals to signal output terminals 121 and 122, respectively.

[0104] The switch 53 has a common terminal and two selection terminals (a first selection terminal and a second selection terminal). The common terminal of the switch 53 is connected to the low-noise amplifier 161 via a matching circuit 141, and the two selection terminals of the switch 53 are connected to the outputs of the receive filters 61R and 62R, respectively. The switch 53 selectively outputs the receive signal from one of the receive filters 61R and 62R to the low-noise amplifier 161. The switch 54 has a common terminal and two selection terminals (a first selection terminal and a second selection terminal). The common terminal of the switch 54 is connected to the low-noise amplifier 162 via a matching circuit 142, and the two selection terminals of the switch 54 are connected to the outputs of the receive filters 63R and 64R, respectively. The switch 54 selectively outputs the receive signal from one of the receive filters 63R and 64R to the low-noise amplifier 162.

[0105] The receive filter 61R has an input section and an output section. The input section of the receive filter 61R is connected to a selection terminal of the switch 55 via a matching circuit 71, and the output section of the receive filter 61R is connected to a first selection terminal of the switch 53. The receive filter 61R passes receive signals in the receive band of the first communication band out of the transmit signals output from the switch 55. The receive filter 62R has an input section and an output section. The input section of the receive filter 62R is connected to a selection terminal of the switch 55 via a matching circuit 72, and the output section of the receive filter 62R is connected to a second selection terminal of the switch 53. The receive filter 62R passes receive signals in the receive band of the second communication band out of the transmit signals output from the switch 55.

[0106] The receive filter 63R has an input section and an output section. The input section of the receive filter 63R is connected to a selection terminal of the switch 55 via a matching circuit 73, and the output section of the receive filter 63R is connected to a first selection terminal of the switch 54. Of the receive signals output from the switch 55, the receive filter 63R passes receive signals in the receive band of the third communication band. The receive filter 64R has an input section and an output section. The input section of the receive filter 64R is connected to a selection terminal of the switch 55 via a matching circuit 74, and the output section of the receive filter 64R is connected to a second selection terminal of the switch 54. Of the receive signals output from the switch 55, the receive filter 64R passes receive signals in the receive band of the fourth communication band.

[0107] Output matching circuit 131 is connected between the output of power amplifier 151 and the common terminal of switch 51, and provides impedance matching between power amplifier 151 and transmit filters 61T and 62T. Output matching circuit 132 is connected between the output of power amplifier 152 and the common terminal of switch 52, and provides impedance matching between power amplifier 152 and transmit filters 63T and 64T. Matching circuit 141 is connected between the input of low-noise amplifier 161 and the common terminal of switch 53, and provides impedance matching between low-noise amplifier 161 and receive filters 61R and 62R. Matching circuit 142 is connected between the input of low-noise amplifier 162 and the common terminal of switch 54, and provides impedance matching between low-noise amplifier 162 and receive filters 63R and 64R.

[0108] The matching circuit 71 is connected between the output part of the transmit filter 61T and the input part of the receive filter 61R and a selection terminal 55b (described later) of the switch 55, and achieves impedance matching between the transmit filter 61T and the receive filter 61R and the switch 55. The matching circuit 72 is connected between the output part of the transmit filter 62T and the input part of the receive filter 62R and a selection terminal 55c (described later) of the switch 55, and achieves impedance matching between the transmit filter 62T and the receive filter 62R and the switch 55. The matching circuit 73 is connected between the output part of the transmit filter 63T and the input part of the receive filter 63R and a selection terminal 55d (described later) of the switch 55, and achieves impedance matching between the transmit filter 63T and the receive filter 63R and the switch 55. The matching circuit 74 is connected between the output part of the transmit filter 64T and the input part of the receive filter 64R and a selection terminal 55e (described later) of the switch 55, and achieves impedance matching between the transmit filter 64T and the receive filter 64R and the switch 55.

[0109] The diplexer 60 has a first filter 60L and a second filter 60H. The first filter 60L has a passband that includes the first to fourth frequency bands. The second filter 60H has a passband that includes a frequency band different from the first to fourth frequency bands. The first filter 60L and the second filter 60H each have two input / output units (a first input / output unit and a second input / output unit). The first input / output unit of each of the first filter 60L and the second filter 60H is connected to the antenna terminal 130 via the directional coupler 1. The second input / output unit of the first filter 60L is connected to a common terminal of the switch 55. Hereinafter, the first input / output unit of the first filter 60L and the first input / output unit of the second filter 60H may be collectively referred to as the "first input / output unit of the diplexer 60."

[0110] The directional coupler 1 has the same configuration as the directional coupler 1 of the first embodiment. The directional coupler 1 extracts a part of a high-frequency signal (received signal) flowing through a section (main line 2) of a signal path between the antenna terminal 130 and the first input / output unit of the diplexer 60 as a detected signal from a sub-line 3 that is electromagnetically coupled to the main line 2. Then, the directional coupler 1 outputs the extracted detected signal to the outside of the high-frequency module 100 (for example, to the signal processing circuit 210) via the coupler output terminal 181.

[0111] Like the directional coupler 1 of the first embodiment, the directional coupler 1 of the present embodiment includes a main line 2, first and second sub-lines 31 and 32, a termination circuit 4, a phase-shift circuit 5, a first changeover switch 6, a second changeover switch 7, a termination switch 8, and connection terminals 91 to 93.

[0112] The first changeover switch, the second changeover switch 7, and the termination switch 8 are provided within the switch 55 and are configured integrally with the switch 55. The connection terminal 91 is connected to the antenna terminal 130, and the connection terminal 92 is connected to the first input / output unit of the diplexer 60. That is, the main line 2 of the directional coupler 1 forms a partial section of the signal path between the antenna terminal 130 and the diplexer 60. The connection terminal 93 is connected to the coupler output terminal 181.

[0113] The switch 55 is an antenna switch and is formed of, for example, a switch IC. The switch 55 switches between connection and disconnection between the signal path S0 leading to the antenna terminal 130 and each of the plurality of signal paths S1 to S4 leading to the plurality of duplexers 61 to 64 (filters). In other words, the switch 55 switches between connection and disconnection between the signal path S0 leading to the antenna terminal 130 and the plurality of duplexers 61 to 64 (filters). As described above, the switch 55 is integrated with the first changeover switch 6, the second changeover switch 7, and the termination switch 8.

[0114] More specifically, the switch 55 includes a common terminal 55a and multiple selection terminals 55b, 55c, 55d, and 55e, a common terminal 6a and two selection terminals 6b and 6c of the first changeover switch 6, two terminals 7a and 7b of the second changeover switch 7, and a common terminal 8a and two selection terminals 8b and 8c of the termination switch 8.

[0115] The common terminal 55a of the switch 55 is connected to the second input / output unit of the first filter 60L, and the multiple selection terminals 55b, 55c, 55d, and 55e of the switch 55 are connected to the first input / output units of the duplexers 61 to 64 via matching circuits 71 to 74, respectively. The common terminal 6a of the switch 55 is connected to the first end 31a of the first sub-line 31 of the directional coupler 1 (see FIG. 1). The selection terminal 6b of the switch 55 is connected to the selection terminal 8c of the switch 55. The selection terminal 6c of the switch 55 is connected to the first end 5a of the phase-shift circuit 5 of the directional coupler 1 (see FIG. 1). The common terminal 8a of the switch 55 is connected to the termination circuit 4 of the directional coupler 1 (see FIG. 1). The selection terminal 8b of the switch 55 is connected to the selection terminal 6b of the switch 55. The selection terminal 8c of the switch 55 is connected to the first end 32a of the second sub-line 32 of the directional coupler 1 (see FIG. 1). Terminal 7a of switch 55 is connected to the second end 5b of the phase shift circuit 5 of the directional coupler 1 (see Figure 1), and terminal 7b of switch 55 is connected to the second end 32b of the second sub-line 32 of the directional coupler 1 (see Figure 1).

[0116] (6-3) Effects The high-frequency module 100 according to the sixth embodiment includes a directional coupler 1, an antenna terminal 130, a plurality of filters 61 to 64, and an antenna switch 55. The antenna switch 55 switches between connection and disconnection between a signal path S0 leading to the antenna terminal 130 and the plurality of filters 61 to 64. The main line 2 of the directional coupler 1 forms a partial section of the signal path S0. This configuration makes it possible to provide a high-frequency module 100 that has the above-described effects of the directional coupler 1.

[0117] Moreover, a communication device 200 according to the sixth embodiment includes the high-frequency module 100 and a signal processing circuit 210. The signal processing circuit 210 is connected to the high-frequency module 100 and processes high-frequency signals. With this configuration, it is possible to provide a communication device 200 that has the above-described effects of the high-frequency module 100.

[0118] The above-described first to sixth embodiments and their modifications may be implemented in combination.

[0119] (7) Mode The above-described embodiments and modifications disclose the following aspects.

[0120] A directional coupler (1) according to a first aspect includes a main line (2), a first sub-line (31), a second sub-line (32), and a phase-shift circuit (5). The first sub-line (31) and the second sub-line (32) are connected in series with each other. The phase-shift circuit (5) is connected in series between the first sub-line (31) and the second sub-line (32). The phase-shift circuit (5) includes a first inductor (L1), a second inductor (L2), and a capacitor (C1). The first inductor (L1) and the second inductor (L2) are connected between the first sub-line (31) and the second sub-line (32) and are connected in series with each other. The capacitor (C1) is connected between a connection point (N1) between the first inductor (L1) and the second inductor (L2) and ground. The first inductor (L1) and the second inductor (L2) are coupled to each other and to the main line (2). The magnitude of the first coupling (M1) between the first inductor (L1) and the second inductor (L2) is greater than the magnitude of the second coupling (M2) between the first inductor (L1) and the main line (2) and the magnitude of the third coupling (M3) between the second inductor (L2) and the main line (2).

[0121] According to this configuration, since the magnitude of the first coupling (M1) is greater than the magnitude of the second coupling (M2), it is possible to suppress changes in the impedance of the phase shift circuit (5) on the high frequency side, thereby improving the directivity of the phase shift circuit (5).In addition, it is possible to obtain wideband characteristics as the characteristics of the phase shift circuit (5).

[0122] In a directional coupler (1) according to the second aspect, the main line (2), the first sub-line (31), the second sub-line (32), the first inductor (L1), the second inductor (L2), and the capacitor (C1) are provided on the same substrate. A distance (W2) between the first inductor (L1) and the main line (2) and a distance (W3) between the second inductor (L2) and the main line (2) are each longer than the distance (W1) between the first inductor (L1) and the second inductor (L2).

[0123] According to this configuration, it is possible to easily implement the magnitude relationship in which the magnitude of the first bond (M1) is greater than the magnitude of the second bond (M2) and the magnitude of the third bond (M3).

[0124] In the directional coupler (1) according to the third aspect, the first inductor (L1) is configured by at least a part of the first sub-line (31) in the second aspect, and the second inductor (L2) is configured by at least a part of the second sub-line (32).

[0125] According to this configuration, when the first inductor (L1) is formed by at least a part of the first sub-line (31) and the second inductor (L2) is formed by at least a part of the second sub-line (32), similarly to the first aspect, it is possible to suppress changes in the impedance of the phase shift circuit (5) on the high frequency side, and as a result, it is possible to improve the directivity of the phase shift circuit (5).

[0126] In a directional coupler (1) according to a fourth aspect, in the third aspect, the substrate (95) has a plurality of layers (Q1 to Q3; Q1, Q2, Q4) stacked in a thickness direction (D1) of the substrate (95). The plurality of layers (Q1 to Q3; Q1, Q2, Q4) include a first layer (Q1) and a second layer (Q2) that are different from each other. The first inductor (L1) is provided on the first layer (Q1). The second inductor (L2) is provided on the second layer (Q2). At least a portion of the first inductor (L1) and the second inductor (L2) are arranged to overlap each other in the thickness direction (D1) of the substrate (95).

[0127] This configuration makes it possible to easily reduce the first distance (W1) between the first inductor (L1) and the second inductor (L2) in the thickness direction (D1) of the substrate (95). As a result, it is possible to easily increase the first coupling (M1) between the first inductor (L1) and the second inductor (L2) while maintaining the coupling between the main line (2) and the first sub-line (31) and the second sub-line (32).

[0128] In a directional coupler (1) according to a fifth aspect, in the fourth aspect, the plurality of layers (Q1-Q3) further includes a third layer (Q3) provided between the first layer (Q1) and the second layer (Q2). The main line (2) is provided in the third layer (Q3) of the plurality of layers.

[0129] According to this configuration, the first coupling (M1) and the second coupling (M2) can be easily balanced, which makes it easy to adjust the characteristics of the directional coupler (1) to the desired characteristics.

[0130] In the directional coupler (1) according to the sixth aspect, in the fourth aspect, the main line (2) is provided in a layer (Q4) of the first layer (Q1) opposite to the second layer (Q2), or in a layer of the second layer (Q2) opposite to the first layer (Q1), among the multiple layers.

[0131] According to this configuration, the first distance (W1) between the first inductor (L1) and the second inductor (L2) in the thickness direction (D1) of the substrate (95) can be easily reduced, thereby easily increasing the first coupling (M1). Furthermore, the second distance (W2) between the main line (2) and the first inductor (L1) and the third distance (W3) between the main line (2) and the second inductor (L2) in the thickness direction (D1) of the substrate (95) can be easily reduced, thereby easily reducing the second coupling (M2) and the third coupling (M3). As a result, the magnitude of the first coupling (M1) can be easily made larger than the magnitudes of the second coupling (M2) and the third coupling (M3).

[0132] In the directional coupler (1) according to the seventh aspect, in any one of the third to sixth aspects, the first inductor (L1) and the second inductor (L2) include loop-shaped portions (311, 321) that are wound less than one turn or more than one turn.

[0133] According to this configuration, the first inductor (L1) and the second inductor (L2) can each be formed compactly while ensuring inductance.

[0134] In the directional coupler (1) according to the eighth aspect, in the seventh aspect, the main line (2) is arranged on the inner side of the first inductor (L1) and the second inductor (L2) in a plan view in the thickness direction (D1) of the substrate (95).

[0135] According to this configuration, the first inductor (L1) and the second inductor (L2) are arranged on the outer periphery of the main line 2. This makes it easy to increase the size of the first inductor (L1) and the second inductor (L2), and as a result, it is easy to increase the inductance of each of the first inductor (L1) and the second inductor (L2) while maintaining the coupling between the main line 2 and the first sub-line (31) and the second sub-line (32). In addition, in a planar view from the thickness direction (D1) of the substrate (95), the second distance (W2) between the first inductor (L1) and the main line (2) and the third distance (W3) between the second inductor (L2) and the main line (2) can be easily ensured. As a result, the second coupling (M2) between the first inductor (L1) and the main line (2) and the third coupling (M3) between the second inductor (L2) and the main line (2) can be easily reduced while maintaining the coupling between the main line (2) and the first sub-line (31) and the second sub-line (32).

[0136] In the directional coupler (1) according to the ninth aspect, in the seventh aspect, the main line (2) is arranged on the outer periphery of the first inductor (L1) and the second inductor (L2) in a plan view in the thickness direction (D1) of the substrate (95).

[0137] According to this configuration, the main line (2) can prevent the first inductor (L1) and the second inductor (L2) from being electromagnetically affected by the outer circuit. Furthermore, in a plan view in the thickness direction (D1) of the substrate (95), the second distance (W2) between the first inductor (L1) and the main line (2) and the third distance (W3) between the second inductor (L2) and the main line (2) can be easily ensured. As a result, the second coupling (M2) between the main line (2) and the first inductor (L1) and the third coupling (M3) between the main line (2) and the second inductor (L2) can be easily reduced.

[0138] In a directional coupler (1) according to a tenth aspect, in the seventh aspect, the main line (2) is linear. In a plan view in the thickness direction (D1) of the substrate (95), the main line (2) is arranged on the outer periphery of the first inductor (L1) and the second inductor (L2).

[0139] According to this configuration, when the main line (2) is linear, the second distance (W2) between the main line (2) and the first inductor (L1) and the third distance (W3) between the main line (2) and the second inductor (L2) can be easily made larger than the first distance (W1) between the first inductor (L1) and the second inductor (L2). As a result, the magnitude of the first coupling (M1) can be easily made larger than the magnitudes of the second coupling (M2) and the third coupling (M3).

[0140] A directional coupler (1) according to an eleventh aspect includes a main line (2), a first sub-line (31), a second sub-line (32), and a phase-shift circuit (5). The first sub-line (31) and the second sub-line (32) are connected in series with each other. The phase-shift circuit (5) is connected in series between the first sub-line (31) and the second sub-line (32). The phase-shift circuit (5) includes a first inductor (L1), a second inductor (L2), and a capacitor (C1). The first inductor (L1) and the second inductor (L2) are connected between the first sub-line (31) and the second sub-line (32) and are connected in series with each other. The capacitor (C1) is connected between a connection point (N1) between the first inductor (L1) and the second inductor (L2) and ground. The main line (2), the first sub-line (31), the second sub-line (32), the first inductor (L1), the second inductor (L2), and the capacitor (C1) are provided on the same substrate. The distance between the first inductor (L1) and the main line (2) and the distance between the second inductor (L2) and the main line (2) are each longer than the distance (W1) between the first inductor (L1) and the second inductor (L2).

[0141] According to this configuration, the distance (W2) between the first inductor (L1) and the main line (2) and the distance (W3) between the second inductor (L2) and the main line (2) are each longer than the distance (W1) between the first inductor (L1) and the second inductor (L2). Therefore, the magnitude of the first coupling (M1) can be made larger than the magnitude of the second coupling (M2), respectively. As a result, it is possible to suppress changes in the impedance of the phase shift circuit (5) on the high-frequency side, and improve the directivity of the phase shift circuit (5).

[0142] A high-frequency module (100) according to a twelfth aspect includes a directional coupler (1) according to any one of the first to eleventh aspects, an antenna terminal (130), a plurality of filters (61 to 64), and an antenna switch (55). The antenna switch (55) switches between connection and disconnection between a signal path (S0) leading to the antenna terminal (130) and the plurality of filters (61 to 64). A main line (2) of the directional coupler (1) forms a partial section of the signal path (S0).

[0143] This configuration makes it possible to provide a high frequency module (100) that has the above-mentioned effects of the directional coupler (1).

[0144] A communication device (200) according to a thirteenth aspect includes the high-frequency module (100) according to the twelfth aspect and a signal processing circuit (210). The signal processing circuit (210) is connected to the high-frequency module (100) and processes a high-frequency signal.

[0145] This configuration makes it possible to provide a communication device (200) that has the above-described effects of the high-frequency module (100). [Explanation of symbols]

[0146] 1 Directional coupler 2 Main line 2a 1st end 2b 2nd end 3 Sub-track 4 Termination circuit 4a variable resistor 4b Variable Capacitor 5 Phase shift circuit 5a 1st end 5b 2nd end 6 First changeover switch 6a common terminal 6b Selection terminal 6c Selection terminal 7 Second selector switch 7a,7b terminal 8 Termination Switch 8a common terminal 8b, 8c selection terminal 21 Loop-shaped section 31 First Sub-track 31a 1st end 31b 2nd end 32 Second sub-track 32a 1st end 32b 2nd end 51~55 Switches 55a common terminal 55b~55e selection terminal 60 Diplexer 60H Second Filter 60L 1st filter 61~64 Duplexer (filter) 61R~64R Receiving filter 61T~64T Transmit filter 71~74 Matching circuit 91 First connection terminal 92 Second connection terminal 93 Third connection terminal 95 PCB 100 High Frequency Module 110 External connection terminal 111,112 signal input terminal 121,122 signal output terminal 130 Antenna terminal 131,132 Output matching circuit 141,142 matching circuit 151,152 Power amplifier 161,162 Low noise amplifier 181 Coupler output terminal 200 Communication Equipment 210 Signal Processing Circuit 211 RF signal processing circuit 212 Baseband signal processing circuit 220 Antenna 311,321 Loop-shaped section B1,B2 line length C1 capacitor C2,C2 capacity D1 thickness direction E1 Side h1~h5 wiring L1 First inductor L2 Second inductor L3 Third inductor M1 1st bond M2 2nd connection M3 3rd connection N1 Attachment Point Q1 1st layer (layer) Q2 2nd layer (layer) Q3, Q4 layers R1, S0~S4 signal path W1 1st distance W2 Second distance W3 Third distance

Claims

1. The main line and a first sub-line and a second sub-line connected in series to each other; a phase shift circuit connected in series between the first sub-line and the second sub-line, The phase shift circuit comprises: a first inductor and a second inductor connected between the first sub-line and the second sub-line and connected in series with each other; a capacitor connected between a connection point between the first inductor and the second inductor and ground, the first inductor and the second inductor are coupled to each other and to the main line; a magnitude of a first coupling between the first inductor and the second inductor is greater than a magnitude of a second coupling between the first inductor and the main line and a magnitude of a third coupling between the second inductor and the main line; Directional coupler.

2. the main line, the first sub-line, the second sub-line, the first inductor, the second inductor, and the capacitor are provided on the same substrate, a distance between the first inductor and the main line and a distance between the second inductor and the main line are each longer than a distance between the first inductor and the second inductor; 2. The directional coupler according to claim 1.

3. the first inductor is formed by at least a part of the first sub-line, the second inductor is formed by at least a part of the second sub-line; 3. The directional coupler according to claim 2.

4. the substrate has a plurality of layers stacked in a thickness direction of the substrate, the plurality of layers includes a first layer and a second layer that are different from each other; the first inductor is provided on the first layer, the second inductor is provided on the second layer, At least a portion of the first inductor and at least a portion of the second inductor are arranged to overlap each other in the thickness direction of the substrate.

4. The directional coupler according to claim 3.

5. the plurality of layers further includes a third layer disposed between the first layer and the second layer, the main line is provided on the third layer of the plurality of layers.

5. The directional coupler according to claim 4.

6. the main line is provided in one of the plurality of layers, in the first layer on the side opposite to the second layer, or in the second layer on the side opposite to the first layer, 5. The directional coupler according to claim 4.

7. the first inductor and the second inductor each include a loop-shaped portion wound less than one turn or more than one turn; 7. The directional coupler according to claim 3.

8. the main line is disposed on the inner circumferential side of the first inductor and the second inductor in a plan view in a thickness direction of the substrate.

8. The directional coupler according to claim 7.

9. the main line is disposed on an outer circumferential side of the first inductor and the second inductor in a plan view in a thickness direction of the substrate.

8. The directional coupler according to claim 7.

10. the main line is linear, the main line is disposed on an outer circumferential side of the first inductor and the second inductor in a plan view in a thickness direction of the substrate.

8. The directional coupler according to claim 7.

11. The main line and a first sub-line and a second sub-line connected in series to each other; a phase shift circuit connected in series between the first sub-line and the second sub-line, The phase shift circuit comprises: a first inductor and a second inductor connected between the first sub-line and the second sub-line and connected in series with each other; a capacitor connected between a connection point between the first inductor and the second inductor and ground, the main line, the first sub-line, the second sub-line, the first inductor, the second inductor, and the capacitor are provided on the same substrate, a distance between the first inductor and the main line and a distance between the second inductor and the main line are each longer than a distance between the first inductor and the second inductor; Directional coupler.

12. A directional coupler according to any one of claims 1 to 6; An antenna terminal, Multiple filters and an antenna switch for switching between connection and disconnection between a signal path leading to the antenna terminal and the plurality of filters, the main line of the directional coupler constitutes a partial section of the signal path; High frequency module.

13. The high-frequency module according to claim 12; a signal processing circuit connected to the high-frequency module and processing a high-frequency signal; Communication equipment.

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