High-frequency module, communication device, and control method

Abstract

The present invention comprises: a first terminal (T1) for allowing a transmission signal to pass therethrough; a second terminal (T2) for allowing a reception signal to pass therethrough; a third terminal (T3) for allowing a transmission signal and a reception signal to pass therethrough; a converter (Tr1) for outputting, on the basis of the transmission signal having passed through the first terminal, a first transmission signal and a second transmission signal having a phase reversed with respect to that of the first transmission signal; a first amplifier (FA1) for amplifying the first transmission signal and the second transmission signal; a second amplifier (LA1) for amplifying the reception signal and outputting the amplified reception signal to the second terminal; a first line (SL1) having one end (E1) to which the first transmission signal amplified by the first amplifier is inputted, and having the other end (E2) which is grounded; a second line (SL2) having one end (E3) to which the second transmission signal amplified by the first amplifier is inputted, and having the other end (E4) which is grounded; a third line (SL3) having one end (E6) connected to the third terminal, and being disposed alongside the first line; a fourth line (SL4) having one end (E7) connected to the other end (E5) of the third line, and being disposed alongside the second line; a fifth line (SL5) having one end (E10) connected to the other end (E8) of the fourth line, and having the other end (E9) connected to the input terminal of the second amplifier; and a first switch (SW1) provided between the other end (E9) of the fifth line and the ground.

Description

High frequency module, communication device, and control method

[0001] The present invention generally relates to a high-frequency module, a communication device including the same, and a control method, and more particularly to a technique for improving isolation between a transmission circuit and a reception circuit.

[0002] 2. Description of the Related Art Known electronic devices capable of transmitting and receiving radio frequency (RF) radio waves include electronic devices that have separate antennas for transmission and reception, and electronic devices that have a common antenna for both transmission and reception.

[0003] U.S. Patent No. 10,715,204 (Patent Document 1) discloses an electronic device having a common antenna for both transmission and reception. The common antenna in Patent Document 1 is provided with a power amplifier for transmission and a low-noise amplifier for reception, and a switch is used to switch between the transmission circuit and the reception circuit.

[0004] U.S. Pat. No. 1,071,5204

[0005] In a magnetic field coupling transformer such as that described in Patent Document 1, when a switch is used to switch between transmission and reception coupling, a switch made of semiconductor is generally used. In this case, even when the switch is in a non-conducting state, a part of the high frequency wave inevitably passes through the switch due to the parasitic capacitance generated in the switch, which reduces the isolation characteristics between the transmission circuit and the reception circuit and can cause noise.

[0006] The present invention has been made to solve these problems, and its object is to improve the isolation characteristics between transmission and reception circuits in a high-frequency module that transmits and receives high-frequency signals using an antenna.

[0007] A high frequency module according to the present invention includes a first terminal for passing a transmission signal, a second terminal for passing a reception signal, a third terminal for passing the transmission signal and the reception signal, a converter for outputting a first transmission signal and a second transmission signal having an opposite phase to the first transmission signal based on the transmission signal that has passed through the first terminal, a first amplifier for amplifying each of the first transmission signal and the second transmission signal, a second amplifier for amplifying the reception signal and outputting the amplified reception signal to the second terminal, and a first transmission signal amplified by the first amplifier at one end. a first line to which a second transmission signal amplified by a first amplifier is input and whose other end is grounded; a second line to which a second transmission signal amplified by a first amplifier is input and whose other end is grounded; a third line having one end connected to a third terminal and arranged side by side with the first line; a fourth line having one end connected to the other end of the third line and arranged side by side with the second line; a fifth line having one end connected to the other end of the fourth line and the other end connected to an input terminal of the second amplifier; and a first switch provided between the other end of the fifth line and the ground.

[0008] A control method according to the present invention is a control method used for a high-frequency module, the high-frequency module including a first terminal for passing a transmission signal, a second terminal for passing a reception signal, a third terminal for passing the transmission signal and the reception signal, a converter for outputting a first transmission signal and a second transmission signal having an opposite phase to the first transmission signal based on the transmission signal passed through the first terminal, a first amplifier for amplifying each of the first transmission signal and the second transmission signal, a second amplifier for amplifying the reception signal and outputting the amplified reception signal to the second terminal, and a converter for outputting the first transmission signal amplified by the first amplifier to one end. a first line having one end to which a second transmission signal amplified by the first amplifier is input and the other end to which is grounded, a second line having one end to which a second transmission signal amplified by the first amplifier is input and the other end to which is grounded, a third line having one end connected to the third terminal and arranged side by side with the first line, a fourth line having one end connected to the other end of the third line and arranged side by side with the second line, a fifth line having one end connected to the other end of the fourth line and the other end connected to an input terminal of the second amplifier, and a first switch provided between the other end of the fifth line and the ground. The control method includes the steps of: setting the first switch to a non-conductive state when receiving radio waves; and setting the first switch to a conductive state when transmitting radio waves.

[0009] According to one aspect, a high-frequency module includes a first terminal that passes a transmission signal, a second terminal that passes a reception signal, a third terminal that passes the transmission signal and the reception signal, a converter that outputs a first transmission signal and a second transmission signal that is opposite in phase to the first transmission signal based on the transmission signal that has passed through the first terminal, a first amplifier that amplifies each of the first transmission signal and the second transmission signal, a second amplifier that amplifies the reception signal and outputs the amplified reception signal to the second terminal, and a third terminal that outputs the second transmission signal amplified by the first amplifier to one end. The antenna includes a first line to which a first transmission signal is input and whose other end is grounded, a second line to which a second transmission signal amplified by a first amplifier is input at one end and whose other end is grounded, a third line having one end connected to a third terminal and electromagnetically coupled to the first line, a fourth line having one end connected to the other end of the third line and electromagnetically coupled to the second line, a fifth line having one end connected to the other end of the fourth line and the other end connected to an input terminal of the second amplifier, and a first switch provided between the other end of the fifth line and ground.

[0010] According to the present invention, in a high-frequency module that uses a switch to switch between transmission and reception circuits, a line (fifth line) is connected between a low-noise amplifier and a main line of a Marchand balun, and during transmission, the switch connected to the line (fifth line) is turned on, thereby converting the impedance of the reception circuit as seen from the antenna to an open state. This prevents signals in the transmission frequency band from being transmitted to the reception circuit, thereby improving the isolation characteristics between the transmission and reception circuits.

[0011] FIG. 1 is a schematic configuration diagram of a communication device according to a first embodiment. FIG. 2 is a circuit diagram showing a detailed configuration of a power amplifier according to the first embodiment. FIG. 3 is a diagram for explaining the pass characteristics of a balun during transmission. FIG. 4 is a diagram for explaining the characteristics of a low-pass filter constituted by a capacitor and a line. FIG. 5 is a plan view showing a balun and a line according to the first embodiment. FIG. 6 is a circuit diagram showing a detailed configuration of a power amplifier according to a comparative example. FIG. 7 is a diagram showing a flowchart of processing executed in a control circuit according to the first embodiment. FIG. 8 is a circuit diagram showing a detailed configuration of a power amplifier according to a second embodiment. FIG. 9 is a diagram showing an insertion loss of an LC parallel resonant circuit constituted by a capacitor and a line according to the second embodiment. FIG. 10 is a diagram showing a flowchart of processing executed in a control circuit according to the second embodiment. FIG. 11 is a circuit diagram showing a detailed configuration of a power amplifier according to a third embodiment. FIG. 12 is a diagram showing an insertion loss of an LC parallel resonant circuit constituted by a capacitor and a line according to the third embodiment. FIG. 13 is a circuit diagram showing a detailed configuration of a power amplifier according to a modified example.

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and description thereof will not be repeated.

[0013] First Embodiment The general configuration of a high-frequency module 100 and a communication device 1000 according to a first embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing the general configuration of the communication device 1000 according to the first embodiment.

[0014] <Overall Configuration> The following describes the circuit configuration of the communication device 1000. The communication device 1000 is a device used in a communication system, and is, for example, a mobile terminal such as a smartphone or a tablet, or a personal computer with a communication function. As shown in FIG. 1 , the communication device 1000 in the first embodiment includes a high-frequency module 100, a power supply circuit 200, a signal processing circuit 300, and an antenna 30.

[0015] The high-frequency module 100 is connected to an antenna 30 for transmitting and receiving radio waves. The signal processing circuit 300 includes a baseband integrated circuit (BBIC) 310 and a radio frequency integrated circuit (RFIC) 320 that constitute a baseband signal processing circuit.

[0016] The high-frequency module 100 includes a control circuit 120 and a power amplifier 110. The high-frequency module 100 transmits high-frequency (radio frequency: RF) signals between an RFIC 320 and an antenna 30. The RFIC 320 processes the high-frequency signals transmitted and received between the RFIC 320 and the power amplifier 110.

[0017] The RFIC 320 up-converts the intermediate frequency (IF) signal input from the BBIC 310 into a high-frequency signal (transmission signal), and transmits the generated high-frequency signal to the connection terminal T1 of the power amplifier 110. The power amplifier 110 amplifies the transmission signal transmitted from the RFIC 320 and outputs it to the antenna 30 via the connection terminal T3. The antenna 30 transmits the transmission signal input from the connection terminal T3 as a radio wave.

[0018] A high-frequency signal (received signal) received by the antenna 30 is amplified with low noise by the power amplifier 110 and then transmitted to the RFIC 320 via the connection terminal T2. The RFIC 320 down-converts the received signal amplified with low noise by the power amplifier 110 into an IF signal, and outputs the generated IF signal to the BBIC 310.

[0019] In communication device 1000 according to the first embodiment, the transmission frequency band is 120 GHz to 140 GHz. That is, the center frequency of the transmission frequency band is 130 GHz. In some aspects, the transmission band of communication device 1000 may be another band, such as 130 GHz to 150 GHz or 140 GHz to 160 GHz.

[0020] The power supply circuit 200 generates a power supply voltage based on information transmitted from the BBIC 310. The generated power supply voltage is supplied to a switch, an amplifier, and the like, which will be described later, included in the power amplifier 110. The control circuit 120 controls the switch, the amplifier, and the like, which will be described later, included in the power amplifier 110, based on a control signal output from the RFIC 320. Note that some or all of the functions of the control circuit 120 may be implemented inside the signal processing circuit 300.

[0021] <Circuit Configuration> Fig. 2 is a circuit diagram showing a detailed configuration of power amplifier 110 according to embodiment 1. Referring to Fig. 2, power amplifier 110 includes connection terminals T1 to T3, a transformer Tr1, a driver amplifier DA1, a power amplifier FA1, a balun 130, a low-noise amplifier LA1, a line SL5, a capacitor C1, a switch SW1, and matching circuits MN1 to MN3.

[0022] The following describes the components included in the power amplifier 110 (transformer Tr1, driver amplifier DA1, power amplifier FA1, matching circuits MN1 and MN2, and balun 130) along the signal path of the power amplifier 110 during transmission. A transmission signal output from the RFIC 320 to the power amplifier 110 is input to one end of the primary winding of the transformer Tr1 via a connection terminal T1. The other end of the primary winding of the transformer Tr1 is connected to a ground electrode (reference potential).

[0023] The transformer Tr1 converts a transmission signal input to the connection terminal T1 into two signals of opposite phases. More specifically, the transmission signal input to the connection terminal T1 is converted into a transmission signal that is input to the driver amplifier DA1 from an end H1 of the secondary winding and a transmission signal that is input to the driver amplifier DA1 from an end H2 of the secondary winding. In other words, a differential signal is input to the driver amplifier DA1 from the end H1 and the end H2.

[0024] The power amplifier 110 of the first embodiment includes a driver amplifier DA1 in the driver stage and a power amplifier FA1 in the output stage. The driver amplifier DA1 and the power amplifier FA1 amplify a differential signal. While FIG. 2 illustrates a single amplifier as the driver amplifier DA1, the driver amplifier DA1 may be composed of multiple amplifiers. Specifically, for example, the power amplifier 110 may include, as the driver amplifier DA1, an amplifier that amplifies the transmission signal input from the terminal H1 and an amplifier that amplifies the transmission signal input from the terminal H2. Similarly, the power amplifier FA1 may be composed of multiple amplifiers.

[0025] The matching circuit MN1 is provided between the power amplifier FA1 and the balun 130, and performs impedance matching between the power amplifier FA1 and the balun 130. The high-frequency signal matched by the matching circuit MN1 is transmitted to the balanced terminal TB1 of the balun 130. Similarly, the matching circuit MN2 is also provided between the power amplifier FA1 and the balun 130, and performs impedance matching between the power amplifier FA1 and the balun 130. The high-frequency signal matched by the matching circuit MN2 is transmitted to the balanced terminal TB2 of the balun 130.

[0026] The balun 130 includes a pair of balanced terminals TB1 and TB2, an unbalanced terminal TB3, a connection terminal TB4, lines SL1 and SL2, and a main line ML1. The main line ML1 is configured by connecting lines SL3 and SL4 in series. If the wavelength of the high-frequency signal to be passed is λ, each of the lines SL1 to SL4 has an electrical length of λ / 4. In other words, the main line ML1 has an electrical length of λ / 2.

[0027] In the first embodiment, the balun 130 converts a balanced signal (differential signal) input to the balanced terminals TB1 and TB2 into an unbalanced signal and outputs it from the unbalanced terminal TB3. Note that the balun 130 can also be used to convert an unbalanced signal input to the unbalanced terminal TB3 into a balanced signal and output it from the balanced terminals TB1 and TB2.

[0028] Balun 130 is a so-called Marchand balun in which two lines SL1 and SL2, each having a length of λ / 4, are coupled to a main line ML1 having a length of 1 / 2 the wavelength λ (λ / 2) connected to unbalanced terminal TB3. In this type of Marchand balun, the lengths of main line ML1 and lines SL1 to SL4 are appropriately set in accordance with the center frequency (130 GHz) of the pass band of balun 130.

[0029] 2, an end E1 of the line SL1 is connected to the balanced terminal TB1. An end E2 of the line SL1 is connected to the ground potential. Similarly, an end E3 of the line SL2 is connected to the balanced terminal TB2. An end E4 of the line SL2 is also connected to the ground potential.

[0030] An end E6 of the line SL3 included in the main line ML1 is connected to the unbalanced terminal TB3. An end E5 of the line SL3 is connected to an end E7 of the line SL4. An end E8 of the line SL4 included in the main line ML1 is connected to the connection terminal TB4.

[0031] The line SL1, which is a balanced line, is arranged alongside the line SL3 of the main line ML1, which is an unbalanced line. The lines SL1 and SL3 are electromagnetically coupled. Similarly, the line SL2, which is a balanced line, is arranged alongside the line SL4 of the main line ML1, which is an unbalanced line. The lines SL2 and SL4 are electromagnetically coupled. As described above, the phase of the high-frequency signal input to the line SL1 via the balanced terminal TB1 is opposite to the phase of the high-frequency signal input to the line SL2 via the balanced terminal TB2. Due to the electromagnetic field coupling between the lines SL1 and SL3 and the electromagnetic field coupling between the lines SL2 and SL4, the transmission signals output to the unbalanced terminal TB3 are in phase.

[0032] In the Marchand balun having such a configuration, a balanced signal (differential signal) input to the balanced terminal TB1 (input terminal) and the balanced terminal TB2 (input terminal) is transmitted to the main line ML1 by electromagnetic coupling and output as an unbalanced signal from the unbalanced terminal TB3 (output terminal). The unbalanced signal output from the unbalanced terminal TB3 is transmitted to the antenna 30 via the connection terminal T3.

[0033] Next, the components included in the power amplifier 110 (line SL5, matching circuit MN3, low-noise amplifier LA1, capacitor C1, and switch SW1) will be described along the signal path of the power amplifier 110 during reception. A received signal received by the antenna 30 is transmitted to the unbalanced terminal TB3 of the balun 130 via the connection terminal T3. The received signal is then transmitted to the connection terminal TB4 via the main line ML1.

[0034] An end E10 of the line SL5 is connected to the connection terminal TB4. The line SL5 has an electrical length of, for example, less than λ / 4. A matching circuit MN3 is connected to an end E9 of the line SL5. The matching circuit MN3 is provided between the low-noise amplifier LA1 and the end E9 of the line SL5, and performs impedance matching between the low-noise amplifier LA1 and the line SL5. The received signal matched by the matching circuit MN3 is transmitted to the input terminal of the low-noise amplifier LA1.

[0035] The low-noise amplifier LA1 is connected between the connection terminal T2 and the matching circuit MN3. The low-noise amplifier LA1 amplifies the received signal with low noise and then outputs the amplified signal to the connection terminal T2. Furthermore, in the first embodiment, as shown in FIG. 2, a capacitor C1 is connected to the end E9 of the line SL5. One end of a switch SW1 is connected to the capacitor C1. The other end of the switch SW1 is connected to the ground electrode.

[0036] In the first embodiment, the control circuit 120 controls the switch SW1 to a conductive state during transmission when radio waves are transmitted by the communication device 1000, and controls the switch SW1 to a non-conductive state during reception when radio waves are received. In the first embodiment, the electrical length of the line SL5 and the capacitance value of the capacitor C1 are adjusted so that when the switch SW1 is controlled to a conductive state during radio wave transmission, the impedance when looking from the connection terminal TB4 to the input terminal of the low-noise amplifier LA1 is in an open state.

[0037] More specifically, the inductive component of the line SL5 is connected in series between the input terminal of the low-noise amplifier LA1 and the connection terminal TB4. Therefore, the inductive component of the line SL5 rotates the impedance clockwise on the Smith chart. Furthermore, the capacitance component of the capacitor C1 is provided on a shunt path between the input terminal of the low-noise amplifier LA1 and the connection terminal TB4. The capacitance component of the capacitor C1 also rotates the impedance clockwise on the Smith chart. When the switch SW1, which is connected to ground, is controlled to a conductive state, the impedance between the switch SW1 and the capacitor C1 is short-circuited. In the first embodiment, the electrical length of the line SL5 and the capacitance value of the capacitor C1 are adjusted to rotate the impedance 180 degrees on the Smith chart.

[0038] More specifically, in the first embodiment, the length of the line SL5 is less than λ / 4, and therefore the line SL5 rotates the impedance on the Smith chart by less than 180 degrees. The capacitance value of the capacitor C1 in the first embodiment is adjusted so that, together with the line SL5, the impedance on the Smith chart is rotated by 180 degrees. As a result, the impedance when looking from the connection terminal TB4 to the input terminal of the low-noise amplifier LA1 is in an open state. In other words, transmission of the transmission signal to the line SL5 is suppressed, improving the isolation characteristics between the transmission and reception circuits.

[0039] The length of the line SL5 may be λ / 4 or more. For example, if the length of the line SL5 is λ / 4, the impedance on the Smith chart can be rotated 180 degrees simply by the arrangement of the line SL5, and the impedance when looking at the input terminal of the low-noise amplifier LA1 from the connection terminal TB4 becomes an open state. In this case, the power amplifier 110 does not have a capacitor C1 on the shunt path, but only has a switch SW1.

[0040] Furthermore, if the length of the line SL5 exceeds λ / 4, the arrangement of the line SL5 will cause the impedance on the Smith chart to rotate by more than 180 degrees. In this case, the power amplifier 110 has a configuration that rotates the impedance on the Smith chart counterclockwise. The configuration that rotates the impedance counterclockwise may be a capacitor connected in series between the input terminal of the low-noise amplifier LA1 and the connection terminal TB4, or an inductor provided on a shunt path between the input terminal of the low-noise amplifier LA1 and the connection terminal TB4.

[0041] As will be described later, the order in which the switch SW1 and the capacitor C1 are connected may be reversed. In the first embodiment, the capacitor C1 is disposed between the switch SW1 and the path through which the received signal passes. This makes it possible to reduce the degree of influence that the switch SW1 has on the receiving circuit.

[0042] <Pass Characteristics> Fig. 3 is a diagram illustrating the pass characteristics of the balun 130 during transmission. In Fig. 3, the horizontal axis represents frequency, and the vertical axis represents the insertion loss and return loss of the balun 130. Line Ln1 represents the insertion loss of the balun 130 during transmission. Line Ln2 represents the return loss of the balun 130 during transmission.

[0043] At a frequency of 120 GHz, the insertion loss of the balun 130 is 0.5 dB and the return loss of the balun 130 is 23.4 dB. At a frequency of 130 GHz, the insertion loss of the balun 130 is 0.6 dB and the return loss of the balun 130 is 19.2 dB. At a frequency of 140 GHz, the insertion loss of the balun 130 is 0.7 dB and the return loss of the balun 130 is 20.5 dB.

[0044] 3, by controlling the switch SW1 to the conductive state, the impedance when looking from the connection terminal TB4 to the input terminal of the low-noise amplifier LA1 becomes an open state, thereby reducing insertion loss during transmission. In other words, the high-frequency module 100 of the first embodiment can improve the isolation characteristics between the transmission and reception circuits.

[0045] 2, in the high-frequency module 100 according to the first embodiment, when the switch SW1 is in a conductive state, a low-pass filter is formed by the capacitive component of the capacitor C1 and the inductive component of the line SL5. FIG. 4 is a diagram for explaining the characteristics of the low-pass filter formed by the capacitor C1 and the line SL5.

[0046] In Fig. 4, the horizontal axis represents frequency, and the vertical axis represents the insertion loss of the low-pass filter formed by capacitor C1 and line SL5. Line Ln3 represents the insertion loss of the low-pass filter when capacitor C1 has a capacitance of 2000 fF. Line Ln4 represents the insertion loss of the low-pass filter when capacitor C1 has a capacitance of 1000 fF. Line Ln5 represents the insertion loss of the low-pass filter when capacitor C1 has a capacitance of 500 fF.

[0047] As shown by line Ln3, the insertion loss at a frequency of 130 GHz is 20 dB. As shown by line Ln4, the insertion loss at a frequency of 130 GHz is 26 dB. As shown by line Ln5, the insertion loss at a frequency of 130 GHz is 32 dB. Regardless of the capacitance of capacitor C1, the insertion loss of the low-pass filter increases as the passing frequency increases. Thus, in the high-frequency module 100 of the first embodiment, the higher the frequency band of the transmission signal, the more effectively it is suppressed from being transmitted to the line SL5. This allows the communication device, such as the first embodiment, to further improve the isolation characteristics between the transmission and reception circuits. Furthermore, the high-frequency module 100 of the first embodiment can also suppress the effects of jamming signals in frequency bands higher than the transmission frequency band.

[0048] <Appearance> Fig. 5 is a plan view showing the balun 130 and the line SL5 according to the first embodiment. As shown in Fig. 5, the balun 130 and the line SL5 are formed on a dielectric substrate Sb1. In Fig. 5, the normal direction to the main surface Sf1 of the dielectric substrate Sb1 is the Z-axis, a direction within the plane of the main surface Sf1 is the X-axis, and a direction perpendicular to the X-axis is the Y-axis. The dielectric substrate Sb1 according to the first embodiment is a substrate formed by stacking multiple layers. In one aspect, the dielectric substrate Sb1 may be a single-layer substrate.

[0049] The lines SL1 and SL2, the main line ML1, and the line SL5 included in the balun 130 are formed on the main surface Sf1 of the dielectric substrate Sb1. As shown in Fig. 5, the wiring pattern Pt1, the wiring pattern Pt2, and the wiring pattern Pt3 are formed on the main surface Sf1.

[0050] In the first embodiment, the line SL1 described in FIG. 2 is realized by the wiring pattern Pt1 shown in FIG. 5. The wiring pattern Pt1 has ends E1 and E2. A balanced terminal TB1 is connected to the end E1 of the wiring pattern Pt1. Similarly, the line SL4 described in FIG. 2 is realized by the wiring pattern Pt3 shown in FIG. 5. The wiring pattern Pt3 has ends E3 and E4. A balanced terminal TB2 is connected to the end E3 of the wiring pattern Pt3.

[0051] The main line ML1 described in Fig. 2 is realized by the wiring pattern Pt2 shown in Fig. 3. The wiring pattern Pt2 is connected to the unbalanced terminal TB3. As shown in Fig. 3, the main line ML1 extends from the end E6 toward the negative side in the X-axis direction, and then is wound counterclockwise around the Z-axis passing through point Cp1 as the winding axis. In other words, the main line ML1 has a shape wound around the Z-axis passing through point Cp1 when the dielectric substrate Sb1 is viewed in plan.

[0052] The portion of the wiring pattern Pt2 from end E6 to end E5 corresponds to the line SL3. The portion of the wiring pattern Pt2 from end E7 to end E8 corresponds to the line SL4. The length from end E6 to end E8 is λ / 2. End E8 is connected to the line SL5. The portion of the wiring pattern Pt2 from end E10 to end E9 corresponds to the line SL5.

[0053] As shown in Fig. 5, the line SL1 and the line SL3 are arranged side by side. More specifically, the line SL1 and the line SL3 are arranged to extend along the X-axis direction. The line SL1 is electromagnetically coupled to the line SL3. Similarly, the line SL2 and the line SL4 are arranged side by side. More specifically, the line SL2 and the line SL4 are arranged to extend along the X-axis direction. The line SL2 is electromagnetically coupled to the line SL4.

[0054] <Comparative Example> Fig. 6 is a circuit diagram showing a detailed configuration of a power amplifier 110Z in a comparative example. Unlike the radio-frequency module 100 of the first embodiment, the radio-frequency module 100Z in the comparative example includes, in addition to a matching circuit MN3, an inductor L1Z and a switch SW1Z connected in series between the input terminal of the low-noise amplifier LA1 and the connection terminal T3. Furthermore, in the radio-frequency module 100Z, a switch SW2Z is ​​connected between the connection terminal T3 and the unbalanced terminal TB3. As shown in Fig. 6, the switch SW1Z is provided between the inductor L1Z and the connection node N1, and the switch SW2Z is ​​provided between the unbalanced terminal TB3 and the connection node N1.

[0055] In the configuration of the comparative example, when switching between the transmission circuit and the reception circuit by controlling the conduction states of the switches SW1Z and SW2Z, the parasitic capacitance of the switch SW1Z may cause a portion of the transmission signal to pass through the switch SW1Z even when the switch SW1Z is in a non-conductive state, potentially reducing the isolation between the transmission and reception circuits. In the first embodiment, impedance conversion is performed by the line SL5 and the capacitor C1, so that the impedance when viewing the input terminal of the low-noise amplifier LA1 from the connection terminal TB4 can be set to an open state. In this way, in the first embodiment, it is possible to switch between the transmission and reception circuits while suppressing a reduction in isolation between the transmission and reception circuits more than in the comparative example.

[0056] Furthermore, the high-frequency module 100Z of the comparative example requires a separate area for providing the inductor L1Z on the receiving side, which increases the size of the high-frequency module 100Z. As described with reference to FIG. 2 , the high-frequency module 100 of the first embodiment can achieve impedance matching while using the main line ML1 in common for both transmission and reception. As a result, the high-frequency module 100 of the first embodiment does not need to provide a separate inductor L1Z.

[0057] Furthermore, in the radio-frequency module 100Z of the comparative example, when the switch SW1Z is conductive and the switch SW2Z is ​​non-conductive, the received signal passes through the switch SW1Z and is transmitted from the connection terminal T3 to the connection terminal T2. That is, in the comparative example, the switch SW1Z is disposed on the transmission path of the received signal. Therefore, in the comparative example, loss occurs in the switch SW1Z during transmission of the received signal. Similarly, in the radio-frequency module 100Z of the comparative example, when the switch SW2Z is ​​conductive and the switch SW1Z is non-conductive, the transmission signal input from the connection terminal T1 passes through the switch SW2Z and is transmitted to the connection terminal T3. That is, in the comparative example, loss occurs in the switch SW2Z during transmission of the transmission signal. On the other hand, in the first embodiment, the switch SW1 is not disposed on the transmission paths of the received signal and the transmission signal, so that loss due to the switch SW1 during signal transmission can be suppressed.

[0058] <Processing in Control Circuit 120> Fig. 7 is a diagram showing a flowchart of processing executed in control circuit 120 in embodiment 1. The flowchart shown in Fig. 7 is stored as a program in a storage device included in communication device 1000, and is realized by executing the program by a processing circuit such as a CPU included in control circuit 120. The flowchart shown in Fig. 7 is executed repeatedly at predetermined timings.

[0059] The control circuit 120 controls the switch SW1 to a non-conductive state (step S10). The state of the communication device 1000 is controlled to a receive mode. The control circuit 120 determines whether a transmit command has been received (step S20). The transmit command is transmitted to the control circuit 120 from a CPU or the like provided in the communication device 1000. If a transmit command has not been received (NO in step S20), the control circuit 120 returns the process to step S10.

[0060] If a transmission command is received (YES in step S20), the control circuit 120 controls the switch SW1 to be in a conductive state (step S30). The state of the high-frequency module 100 is controlled to be in a transmission mode. Thereafter, the control circuit 120 determines whether the transmission process has ended (step S40). If the transmission process has not ended (NO in step S40), the control circuit 120 maintains the conductive state of the switch SW1 (step S30).

[0061] When the transmission process is completed (YES in step S40), the control circuit 120 ends the processing of the flowchart and starts executing the flowchart again after a predetermined period of time has elapsed. As a result, the communication device 1000 of embodiment 1 can control the state of the communication device 1000 to the transmission mode when transmitting data, and can control the state of the communication device 1000 to the reception mode when not transmitting data. Note that, in the above example, an example was described in which the transmission mode and the reception mode were switched depending on whether a transmission command was accepted, but the transmission mode and the reception mode may also be switched based on the elapse of a predetermined period of time.

[0062] The connection terminals T1, T2, and T3 may correspond to the "first terminal," "second terminal," and "third terminal," respectively, in this disclosure. The lines SL1 to SL5 may correspond to the "first line" to "fifth line," respectively, in this disclosure. The transmission signal input from end H1 to balanced terminal TB1 may correspond to the "first transmission signal" in this disclosure. The transmission signal input from end H2 to balanced terminal TB2 may correspond to the "second transmission signal" in this disclosure. The switch SW1 may correspond to the "first switch" in this disclosure. The capacitor C1 may correspond to the "first capacitor" in this disclosure. The transformer Tr1 may correspond to the "converter" in this disclosure. The power amplifier FA1 may correspond to the "first amplifier" in this disclosure. The low-noise amplifier LA1 may correspond to the "second amplifier" in this disclosure.

[0063] End E1 may correspond to "one end of the first line." End E2 may correspond to "the other end of the first line." End E3 may correspond to "one end of the second line." End E4 may correspond to "the other end of the second line." End E5 may correspond to "the other end of the third line." End E6 may correspond to "one end of the third line." End E7 may correspond to "one end of the fourth line." End E8 may correspond to "the other end of the fourth line." End E9 may correspond to "the other end of the fifth line." End E10 may correspond to "one end of the fifth line."

[0064] [Embodiment 2] In embodiment 2, an example will be described in which a parallel resonator is further included in embodiment 1. Note that in embodiment 2, description of the configuration that overlaps with embodiment 1 will not be repeated.

[0065] 8 is a circuit diagram showing a detailed configuration of a power amplifier 110A according to Embodiment 2. In the high-frequency module 100A according to Embodiment 2, a switch SW2 and a capacitor C2 are arranged in parallel to a line SL5.

[0066] More specifically, the capacitor C2 and the switch SW2 are connected in series between the end E9 and the end E10 of the line SL5. That is, the series-connected capacitor C2 and the switch SW2 are connected in parallel to the line SL5. Note that the connection order of the series-connected capacitor C2 and the switch SW2 may be reversed from that shown in FIG. 8 . In the example of the second embodiment, when the switch SW2 is turned on, an LC parallel resonant circuit is formed by the capacitor C2 and the line SL5.

[0067] 9 is a diagram illustrating the insertion loss of the LC parallel resonant circuit formed by the capacitor C2 and the line SL5 in the second embodiment. FIG. 9 shows the insertion loss from the connection terminal TB4 to the input terminal of the low-noise amplifier LA1, and indicates that the transmission signal is prevented from passing by both the LC parallel resonant circuit in the second embodiment and the low-pass filter in the first embodiment. Line Ln6 represents the insertion loss when the capacitance of the capacitor C2 is 500 fF. Line Ln7 represents the insertion loss when the capacitance of the capacitor C2 is 1000 fF. Line Ln8 represents the insertion loss when the capacitance of the capacitor C2 is 2000 fF.

[0068] As shown in Fig. 9, the inductance of the line SL5 and the capacitance of the capacitor C2 in the LC parallel resonant circuit are set so that an attenuation pole is generated near 130 GHz. As a result, the LC parallel resonant circuit prevents the transmission signal passing through the main line ML1 shown in Fig. 8 from being transmitted to the input terminal of the low-noise amplifier LA1. In other words, in the second embodiment, the LC parallel resonant circuit formed by the capacitor C2 and the line SL5 further ensures isolation between the power amplifier FA1 and the low-noise amplifier LA1.

[0069] Fig. 10 is a diagram showing a flowchart of the processing executed by control circuit 120 in embodiment 2. The flowchart in Fig. 10 is different from the flowchart in Fig. 7 in that steps S10 and S30 are changed to steps S10A and S30A, respectively.

[0070] In step S10A, the control circuit 120 according to the second embodiment controls the switch SW2 in addition to the switch SW1 to a non-conductive state (step S10A). In addition, in step S30A, the control circuit 120 according to the second embodiment controls the switches SW1 and SW2 to a conductive state (step S30A). As a result, in the high-frequency module 100A according to the second embodiment, the LC parallel resonator can more reliably prevent the transmission signal from being input to the reception circuit, thereby further improving the isolation characteristics between the transmission and reception circuits.

[0071] Third Embodiment In the second embodiment, a configuration including switches SW1 and SW2 and capacitors C1 and C2 has been described. In the third embodiment, a configuration including only switch SW2 and capacitor C2 will be described. Note that in the third embodiment, description of the configuration that overlaps with the first and second embodiments will not be repeated.

[0072] 11 is a circuit diagram showing a detailed configuration of a power amplifier 110B according to embodiment 3. In the high-frequency module 100B according to embodiment 3, a switch SW2 and a capacitor C2 are arranged in parallel to a line SL5, as in embodiment 2, but the shunt path described in embodiment 1 is not provided.

[0073] 12 is a diagram showing the insertion loss of the LC parallel resonant circuit formed by the capacitor C2 and the line SL5 in the third embodiment. A line Ln9 indicates the insertion loss of the LC parallel resonant circuit in the third embodiment.

[0074] As shown in Fig. 12, in the LC parallel resonant circuit of the third embodiment, the inductance of the line SL5 and the capacitance of the capacitor C2 are set so as to generate an attenuation pole near 130 GHz. As a result, the LC parallel resonant circuit prevents the transmission signal passing through the main line ML1 shown in Fig. 11 from being transmitted to the input terminal of the low-noise amplifier LA1. In other words, also in the third embodiment, the LC parallel resonant circuit formed by the capacitor C2 and the line SL5 ensures isolation between the power amplifier FA1 and the low-noise amplifier LA1.

[0075] 13 is a circuit diagram showing a detailed configuration of a power amplifier 110C according to a modification. In the radio-frequency module 100C according to the modification, the order in which the capacitor C1 and the switch SW1 are connected is reversed from that in the first embodiment. That is, in the modification, the capacitor C1 is provided between the switch SW1 and ground.

[0076] In this specification, "connection" includes both direct connection and indirect connection. More specifically, a direct connection refers to the connection between the capacitor C1 and the switch SW1 in FIG. 2. An indirect connection refers to the connection between the line SL5 and the low-noise amplifier LA1 in FIG. 2. The line SL5 is indirectly connected to the low-noise amplifier LA1 via the matching circuit MN3.

[0077] In this specification, the term "terminal" refers to an element that connects two components, and includes, for example, wiring and bumps. Furthermore, in this specification, the term "terminal" also includes the boundary between two components when the two components are directly connected. For example, as shown in FIG. 5 , the line SL4 and the line SL5 are configured in the same wiring pattern Pt2. In this specification, the boundary between the portion of the wiring pattern Pt2 that functions as the line SL4 and the portion of the wiring pattern Pt2 that functions as the line SL5 is also referred to as a "terminal."

[0078] In the example of Figure 5, a step is provided between end E8 of line SL4 and end E10 of line SL5 to make the line width different. However, in some aspects, the line widths of line SL4 and line SL5 may be the same. Even in this case, in this embodiment, the boundary between the end functioning as line SL4 and the end functioning as line SL5 is referred to as a "connection terminal TB4."

[0079] <Supplementary Note 1> A first terminal that passes a transmission signal; A second terminal that passes a reception signal; A third terminal that passes the transmission signal and the reception signal; A converter that outputs a first transmission signal and a second transmission signal that is in opposite phase to the first transmission signal based on the transmission signal that passed through the first terminal; A first amplifier that amplifies each of the first transmission signal and the second transmission signal; A second amplifier that amplifies the reception signal and outputs the amplified reception signal to the second terminal; A first line having one end to which the first transmission signal amplified by the first amplifier is input and the other end grounded; A second line having one end to which the second transmission signal amplified by the first amplifier is input and the other end grounded; A third line having one end connected to the third terminal and arranged alongside the first line; A fourth line having one end connected to the other end of the third line and arranged alongside the second line; A fifth line having one end connected to the other end of the fourth line and the other end connected to an input terminal of the second amplifier; a first switch provided between the other end of the fifth line and ground.

[0080] <Supplementary Note 2> The high-frequency module according to Supplementary Note 1, further comprising a first capacitor provided between the other end of the fifth line and the first switch.

[0081] <Supplementary Note 3> The high-frequency module according to Supplementary Note 1, further comprising a first capacitor provided between the first switch and ground.

[0082] <Supplementary Note 4> The high-frequency module according to Supplementary Note 2 or Supplementary Note 3, wherein when the first switch is in a conductive state, the first capacitor and the fifth line form a low-pass filter.

[0083] <Supplementary Note 5> The high-frequency module according to any one of Supplementary Notes 1 to 4, further comprising: a second capacitor connected to the fifth line; and a second switch connected to the fifth line, wherein when the second switch is in a conductive state, the second capacitor and the fifth line form a parallel resonator.

[0084] <Supplementary Note 6> A communication device including the high-frequency module according to any one of Supplementary Notes 1 to 5, further comprising an antenna connected to the third terminal.

[0085] <Supplementary Note 7> The communication device according to Supplementary Note 6, further comprising a signal processing circuit that processes a high-frequency signal passing through the high-frequency module.

[0086] <Supplementary Note 8> A control method used for a high frequency module, the high frequency module comprising: a first terminal that passes a transmission signal; a second terminal that passes a reception signal; a third terminal that passes the transmission signal and the reception signal; a converter that outputs a first transmission signal and a second transmission signal that is in opposite phase to the first transmission signal based on the transmission signal that passed through the first terminal; a first amplifier that amplifies each of the first transmission signal and the second transmission signal; a second amplifier that amplifies the reception signal and outputs the amplified reception signal to the second terminal; a first line that receives as input the first transmission signal amplified by the first amplifier at one end and is grounded at the other end; a second line that receives as input the second transmission signal amplified by the first amplifier at one end and is grounded at the other end; a third line that has one end connected to the third terminal and is arranged alongside the first line; and a fourth line that has one end connected to the other end of the third line and is arranged alongside the second line. a fifth line having one end connected to the other end of the fourth line and the other end connected to an input terminal of a second amplifier; and a first switch provided between the other end of the fifth line and ground, wherein the control method comprises the steps of: setting the first switch to a non-conductive state when receiving radio waves; and setting the first switch to a conductive state when transmitting radio waves.

[0087] <Supplementary Note 9> The high-frequency module further includes a second capacitor connected to the fifth line and a second switch connected to the fifth line, wherein a parallel resonator is formed by the second capacitor and the fifth line when the second switch connected to the fifth line is in a conductive state, and the control method includes the steps of: bringing the second switch into a non-conductive state when receiving radio waves; and bringing the second switch into a conductive state when transmitting radio waves.

[0088] <Supplementary Note 10> A first terminal that passes a transmission signal; A second terminal that passes a reception signal; A third terminal that passes the transmission signal and the reception signal; A converter that outputs a first transmission signal and a second transmission signal that is in opposite phase to the first transmission signal based on the transmission signal that passed through the first terminal; A first amplifier that amplifies each of the first transmission signal and the second transmission signal; A second amplifier that amplifies the reception signal and outputs the amplified reception signal to the second terminal; A first line having one end to which the first transmission signal amplified by the first amplifier is input and the other end grounded; A second line having one end to which the second transmission signal amplified by the first amplifier is input and the other end grounded; A third line having one end connected to the third terminal and electromagnetically coupled with the first line; A fourth line having one end connected to the other end of the third line and electromagnetically coupled with the second line; A fifth line having one end connected to the other end of the fourth line and the other end connected to an input terminal of the second amplifier; a first switch provided between the other end of the fifth line and ground.

[0089] <Supplementary Note 11> A first terminal that passes a transmission signal; A second terminal that passes a reception signal; A third terminal that passes the transmission signal and the reception signal; A converter that outputs a first transmission signal and a second transmission signal that is in opposite phase to the first transmission signal based on the transmission signal that passed through the first terminal; A first amplifier that amplifies each of the first transmission signal and the second transmission signal; A second amplifier that amplifies the reception signal and outputs the amplified reception signal to the second terminal; A first line that receives the first transmission signal amplified by the first amplifier as input to one end and is grounded as the other end; A second line that receives the second transmission signal amplified by the first amplifier as input to one end and is grounded as the other end; A third line that has one end connected to the third terminal and is arranged alongside the first line; A fourth line that has one end connected to the other end of the third line and is arranged alongside the second line; A fifth line that has one end connected to the other end of the fourth line and is connected as the other end to an input terminal of the second amplifier; a second capacitor connected to the fifth line; and a second switch connected to the fifth line, wherein when the second switch connected to the fifth line is in a conductive state, the second capacitor and the fifth line form a parallel resonator.

[0090] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0091] LA1 low noise amplifier, 30 antenna, 100, 100A to 100C, 100Z high frequency module, 110, 110A to 110C, 110Z power amplifier, 120 control circuit, 130 balun, 200 power supply circuit, 300 signal processing circuit, 1000 communication device, C1, C2 capacitor, Cp1 point, DA1 driver amplifier, E1 to E10, H1, H2 end, FA1 power amplifier, L1Z inductor, Ln1 to Ln9 line, ML1 main line, MN1 to MN3 matching circuit, Pt1 to Pt3 wiring pattern, SL1 to SL5 line, SW1, SW2, SW1Z, SW2Z switch, Sb1 dielectric substrate, Sf1 main surface, T1 to T3, TB4 connection terminal, TB1, TB2 Balanced terminal, TB3 Unbalanced terminal, Tr1 Transformer.

Claims

1. A first terminal that passes a transmission signal; a second terminal that passes a reception signal; a third terminal that passes the transmission signal and the reception signal; a converter that outputs a first transmission signal and a second transmission signal that is in opposite phase to the first transmission signal based on the transmission signal that passed through the first terminal; a first amplifier that amplifies each of the first transmission signal and the second transmission signal; a second amplifier that amplifies the reception signal and outputs the amplified reception signal to the second terminal; a first line that receives the first transmission signal amplified by the first amplifier at one end and is grounded at the other end; a second line that receives the second transmission signal amplified by the first amplifier at one end and is grounded at the other end; a third line that has one end connected to the third terminal and is arranged alongside the first line; a fourth line that has one end connected to the other end of the third line and is arranged alongside the second line; a fifth line that has one end connected to the other end of the fourth line and is connected to the input terminal of the second amplifier; a first switch provided between the other end of the fifth line and ground.

2. The high-frequency module according to claim 1, further comprising a first capacitor provided between the other end of the fifth line and the first switch.

3. The high frequency module according to claim 1, further comprising a first capacitor provided between the first switch and ground.

4. The high-frequency module according to claim 2 or 3, wherein when said first switch is in a conductive state, said first capacitor and said fifth line form a low-pass filter.

5. A high-frequency module according to any one of claims 1 to 4, further comprising: a second capacitor connected to the fifth line; and a second switch connected to the fifth line, wherein when the second switch is in a conductive state, a parallel resonator is formed by the second capacitor and the fifth line.

6. A communication device including the high frequency module according to any one of claims 1 to 5, further comprising an antenna connected to the third terminal.

7. The communication device according to claim 6, further comprising a signal processing circuit that processes high-frequency signals passing through said high-frequency module.

8. A control method used for a high frequency module, wherein the high frequency module comprises: a first terminal that passes a transmission signal; a second terminal that passes a reception signal; a third terminal that passes the transmission signal and the reception signal; a converter that outputs a first transmission signal and a second transmission signal that is in opposite phase to the first transmission signal based on the transmission signal that has passed through the first terminal; a first amplifier that amplifies each of the first transmission signal and the second transmission signal; a second amplifier that amplifies the reception signal and outputs the amplified reception signal to the second terminal; a first line that receives as input the first transmission signal amplified by the first amplifier at one end and has its other end grounded; a second line that receives as input the second transmission signal amplified by the first amplifier at one end and has its other end grounded; a third line that has one end connected to the third terminal and is arranged alongside the first line; and a fourth line that has one end connected to the other end of the third line and is arranged alongside the second line. a fifth line having one end connected to the other end of the fourth line and the other end connected to the input terminal of the second amplifier; and a first switch provided between the other end of the fifth line and ground, wherein the control method comprises the steps of: setting the first switch to a non-conductive state when receiving radio waves; and setting the first switch to a conductive state when transmitting radio waves.

9. The control method according to claim 8, wherein the high-frequency module further comprises a second capacitor connected to the fifth line and a second switch connected to the fifth line, and when the second switch connected to the fifth line is in a conductive state, a parallel resonator is formed by the second capacitor and the fifth line, and the control method comprises the steps of: bringing the second switch into a non-conductive state when receiving radio waves; and bringing the second switch into a conductive state when transmitting radio waves.

10. A first terminal for passing a transmission signal; a second terminal for passing a reception signal; a third terminal for passing the transmission signal and the reception signal; a converter for outputting a first transmission signal and a second transmission signal having an opposite phase to the first transmission signal based on the transmission signal passing through the first terminal; a first amplifier for amplifying each of the first transmission signal and the second transmission signal; a second amplifier for amplifying the reception signal and outputting the amplified reception signal to the second terminal; a first line having one end to which the first transmission signal amplified by the first amplifier is input and the other end grounded; a second line having one end to which the second transmission signal amplified by the first amplifier is input and the other end grounded; a third line having one end connected to the third terminal and electromagnetically coupled with the first line; a fourth line having one end connected to the other end of the third line and electromagnetically coupled with the second line; a fifth line having one end connected to the other end of the fourth line and the other end connected to an input terminal of the second amplifier; a first switch provided between the other end of the fifth line and ground.

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