Outphasing Amplifier

Abstract

To provide an out-phasing amplifier capable of suppressing loss.SOLUTION: An out-phasing amplifier comprises: a first amplifier 12 that amplifies a first signal S1; a second amplifier 14 that amplifies a second signal in which a phase difference from the first signal is changed; and a synthesizer having a first transmission line 21 in which a third signal S3 output from the first amplifier passes, a second transmission line 23 in which a fourth signal S4 output from the second amplifier passes, a first binding circuit 22 that is provided separated from the first transmission line and bounded to the first transmission line, a second binding circuit 24 that is provided separated from the second transmission line and bounded to the second transmission line, and a node N1 that synthesizes the third signal passed through the first transmission line and the fourth signal passed through the second transmission line.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an outphasing amplifier. [Background technology]

[0002] An outphasing amplifier is known as an amplifier that amplifies high-frequency signals such as microwaves. The outphasing amplifier includes a signal processor that converts an input signal into two signals with different phases and a constant amplitude depending on the amplitude of the input signal and outputs two signals, two amplifiers that respectively amplify the two signals output from the signal processor, and a combiner that combines the two output signals amplified by the two amplifiers into one output signal. It is known to provide a stub or the like in a transmission line along which the signals amplified by the amplifiers are transmitted (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-12578 A Summary of the Invention [Problem to be solved by the invention]

[0004] When a coupling circuit such as a stub is directly connected to a transmission line, the coupling between the transmission line and the coupling circuit becomes large. This reduces the isolation between the transmission line and the coupling circuit, and increases the loss of the transmission line. In addition, it becomes difficult to fine-tune the reactance added to the transmission line by the coupling circuit.

[0005] The present disclosure has been made in consideration of the above problems, and aims to reduce losses. [Means for solving the problem]

[0006] One embodiment of the present disclosure is an outphasing amplifier comprising: a first amplifier that amplifies a first signal; a second amplifier that amplifies a second signal whose phase difference with the first signal changes; a first transmission line through which a third signal output from the first amplifier passes; a second transmission line through which a fourth signal output from the second amplifier passes; a first coupling circuit that is provided at a distance from the first transmission line and coupled to the first transmission line; a second coupling circuit that is provided at a distance from the second transmission line and coupled to the second transmission line; and a combiner that comprises a node that combines the third signal that has passed through the first transmission line and the fourth signal that has passed through the second transmission line. Effect of the Invention

[0007] According to the present disclosure, losses can be suppressed. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram of an amplifier according to a first embodiment. [Diagram 2] FIG. 2 is a circuit diagram of an amplifier according to a first comparative example. [Diagram 3] FIG. 3 is a circuit diagram of circuits A to C. [Figure 4] FIG. 4 is a diagram showing the insertion loss S21 versus frequency in a transmission line. [Diagram 5] FIG. 5 is a circuit diagram of an amplifier according to a first modification of the first embodiment. [Figure 6] FIG. 6 is a circuit diagram of an amplifier according to a second modification of the first embodiment. [Figure 7] FIG. 7 is a circuit diagram of an amplifier according to a third modification of the first embodiment. [Figure 8] FIG. 8 is a plan view of an output circuit in the third modification of the first embodiment. [Figure 9] FIG. 9 is a circuit diagram of an amplifier according to a fourth modification of the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Description of the embodiments of the present disclosure] First, the contents of the embodiments of the present disclosure will be listed and described. (1) One embodiment of the present disclosure is an outphasing amplifier including a first amplifier that amplifies a first signal, a second amplifier that amplifies a second signal whose phase difference with the first signal changes, a first transmission line through which a third signal output from the first amplifier passes, a second transmission line through which a fourth signal output from the second amplifier passes, a first coupling circuit that is provided away from the first transmission line and coupled to the first transmission line, a second coupling circuit that is provided away from the second transmission line and coupled to the second transmission line, and a combiner that includes a node that combines the third signal that has passed through the first transmission line and the fourth signal that has passed through the second transmission line. This makes it possible to suppress losses. (2) It is preferable that the first coupling circuit adds to the first transmission line a reactance component opposite to the reactance component of the first transmission line alone in the band of the outphasing amplifier, and the second coupling circuit adds to the second transmission line a reactance component opposite to the reactance component of the second transmission line alone in the band. (3) It is preferable that the first coupling circuit includes a first coupling line coupled to the first transmission line and a first stub connected to the first coupling line, and the second coupling circuit includes a second coupling line coupled to the second transmission line and a second stub connected to the second coupling line. (4) It is preferable that the dielectric substrate has a surface, the first transmission line includes a first line pattern provided on the surface, the second transmission line includes a second line pattern provided on the surface, the first coupled line includes a third line pattern provided on the surface and spaced apart from the first line pattern and the second line pattern on the surface, the second coupled line includes a fourth line pattern provided on the surface and spaced apart from the first line pattern and the second line pattern on the surface, the first stub is provided on the surface and connected to the third line pattern on the surface, and the second stub is provided on the surface and connected to the fourth line pattern on the surface. (5) It is preferable that the first stub includes a short stub whose length is shorter than 1 / 4 of the wavelength at the center frequency of the band of the outphasing amplifier, or an open stub whose length is longer than 1 / 4 and shorter than 1 / 2 of the wavelength, and the second stub includes a short stub whose length is shorter than 1 / 4 of the wavelength, or an open stub whose length is longer than 1 / 4 and shorter than 1 / 2 of the wavelength. (6) It is preferable that the first coupling circuit and the second coupling circuit share a portion. (7) It is preferable that the electrical length of the first transmission line is greater than 1 / 8 and less than 3 / 8 of the wavelength at the center frequency of the band of the outphasing amplifier, and the electrical length of the second transmission line is greater than 1 / 8 and less than 3 / 8 of the wavelength. (8) It is preferable that the combiner includes a capacitor shunt-connected to a node between the first amplifier and the first transmission line, and an inductor shunt-connected to a node between the second amplifier and the second transmission line. (9) It is preferable that the digital video signal processing device further comprises a signal processing unit that changes a phase difference between the first signal and the second signal based on an input signal, and outputs the first signal and the second signal to the first amplifier and the second amplifier, respectively.

[0010] [Details of the embodiment of the present disclosure] Specific examples of outphasing amplifiers according to embodiments of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0011] Fig. 1 is a block diagram of an amplifier according to a first embodiment. As shown in Fig. 1, in the outphasing amplifier, an amplifier 12 (first amplifier) ​​and an amplifier 14 (second amplifier) ​​are connected in parallel between an input terminal Tin and an output terminal Tout. A high-frequency signal is input to the input terminal Tin as an input signal Sin. A signal processing unit 16 processes the input signal Sin and outputs it as two signals S1 (first signal) and S2 (second signal).

[0012] The signal S1 is input to the amplifier 12 via the matching circuit 32. The matching circuit 32 matches the output impedance of the signal processing unit 16 with the input impedance of the amplifier 12. The amplifier 12 amplifies the input signal S1 and outputs a signal S3 (third signal). The signal S3 is output to the combiner 10 via the matching circuit 30. The matching circuit 30 matches the output impedance of the amplifier 12 with the input impedance of the combiner 10. The signal S2 is input to the amplifier 14 via the matching circuit 33. The matching circuit 33 matches the output impedance of the signal processing unit 16 with the input impedance of the amplifier 14. The amplifier 14 outputs a signal S4 (fourth signal) by amplifying the input signal S2. The signal S4 is output to the combiner 10 via the matching circuit 31. The matching circuit 31 matches the output impedance of the amplifier 14 with the input impedance of the combiner 10. The combiner 10 combines the signals S3 and S4. The combined signal is outputted as an output signal Sout from an output terminal Tout.

[0013] The signal processing unit 16 is, for example, a signal processing unit, which digitally processes the input signal Sin and outputs signals S1 and S2. The signal processing unit 16 determines the phase difference between signals S1 and S2 depending on the amplitude of the input signal Sin. For example, when the amplitude of the input signal Sin is large, the phase difference between signals S1 and S2 is made small. When the amplitude of the input signal Sin is small, the phase difference between signals S1 and S2 is made large. The amplitudes of the signals S1 and S2 are almost constant regardless of the amplitude of the input signal Sin, and are set to, for example, amplitudes equivalent to the saturation power of the amplifiers 12 and 14.

[0014] The amplifiers 12 and 14 are, for example, FETs (Field Effect Transistors), and the sources of the FETs are grounded, the signals S1 or S2 are input to the gates, and the signals S3 or S4 are output from the drains. The FETs are, for example, GaNFETs or LDMOSs (Laterally Diffused Metal Oxide Semiconductors). The amplifiers 12 and 14 may each be provided with a multi-stage FET. The sizes (for example, gate widths and gate lengths) of the FETs of the amplifiers 12 and 14 are approximately the same, and the bias voltages (for example, gate bias voltages and drain bias voltages) are approximately the same. The matching circuits 30 to 33 are designed, for example, so that the efficiency is maximized when a signal of saturated power is input to the amplifiers 12 and 14. This increases the efficiency when the amplifiers 12 and 14 amplify the signals S1 and S2.

[0015] The combiner 10 is, for example, a Chireix combiner. The combiner 10 includes a capacitor C1, an inductor L1, transmission lines 21 and 23, and coupling circuits 22 and 24. The capacitor C1 is shunt-connected to a node N2 through which a signal S3 passes. The inductor L1 is shunt-connected to a node N3 through which a signal S4 passes. The transmission lines 21 and 23 transmit signals S3 and S4, respectively. The first and second ends of the transmission line 21 are connected to nodes N2 and N1, respectively. The first and second ends of the transmission line 23 are connected to nodes N3 and N1, respectively. The capacitor C1 and the inductor L1 adjust the phases of the voltage and current of the signals S3 and S4 to suppress reactive power. The electrical length of the transmission lines 21 and 23 is about λ / 4. λ is the wavelength at the center frequency of the band of the outphasing amplifier. The transmission lines 21 and 23 are impedance conversion circuits that convert the output impedance of the matching circuits 30 and 31 to twice the standard impedance (for example, 100 Ω). As a result, the impedance seen from the output terminal Tout at the node N1 becomes the standard impedance (for example, 50 Ω). The coupling circuits 22 and 24 are coupled to the transmission lines 21 and 23, respectively, and add a reactance component opposite to the reactance component of the transmission lines 21 and 23 to the transmission lines 21 and 23. The node N1 combines the signals S3 and S4. The amplitude of the combined output signal Sout depends on the phase difference between the signals S3 and S4 (i.e., the phase difference between the signals S1 and S2).

[0016] In the outphasing amplifier, the signal processing unit 16 makes the phase difference between the signals S1 and S2 close to 0° when the amplitude of the input signal Sin is large, and makes the phase difference between the signals S1 and S2 close to 180° when the amplitude of the input signal Sin is small. The amplitude of the signals S1 and S2 is the amplitude at which the amplifiers 12 and 14 are most efficient (for example, the amplitude corresponding to the saturation power). The phase difference between the signals S3 and S4 is almost equal to the phase difference between the signals S1 and S2. When the amplitude of the input signal Sin is large, the phase difference between the signals S3 and S4 is close to 0°, so the amplitude of the output signal Sout is large. When the amplitude of the input signal Sin is small, the phase difference between the signals S3 and S4 is close to 180°, so the amplitude of the output signal Sout is small. In this way, the amplitude of the output signal Sout, which is a combination of the signals S3 and S4, corresponds to the amplitude of the input signal Sin. The amplifiers 12 and 14 amplify the signals S1 and S2 at the amplitude at which the efficiency is most improved. Therefore, in the outphasing amplifier, the efficiency can be improved regardless of the amplitude of the input signal Sin.

[0017] [Description of coupling circuit] The function of the coupling circuit will be described using a comparative example. Fig. 2 is a circuit diagram of an amplifier according to comparative example 1. In Fig. 2, matching circuits 30 to 33 are omitted. As shown in Fig. 2, comparative example 1 does not include coupling circuits 22 and 24. The other configurations are the same as those of embodiment 1.

[0018] Fig. 3 is a circuit diagram of circuits A to C. Fig. 4 is a diagram showing the insertion loss S21 versus frequency in the transmission lines 21 and 23. In Fig. 4, dashed line 52 shows S21 of the transmission lines 21 and 23 alone, dashed line 54 shows S21 added to the transmission lines 21 and 23 by the coupling circuits 22, 22a, 24, and 24a, and solid line 50 shows S21 obtained by combining dashed lines 52 and 54.

[0019] As shown in Fig. 3, in circuit A, the transmission lines 21 and 23 are connected between the nodes N2 and N1, and the coupling circuits 22 and 24 are not provided. As shown by the dashed line 52 in Fig. 4, the transmission lines 21 and 23 alone have an inductive component, so that S21 becomes smaller as the frequency increases.

[0020] In the circuit B of FIG. 3, the coupling circuits 22a and 24a are connected to the transmission lines 21 and 23. The coupling circuits 22a and 24a are, for example, shunt-connected inductors. The coupling circuits 22a and 24a add an inductive component to the transmission lines 21 and 23. As shown by the dashed line 54 in FIG. 4, the S21 added to the transmission lines 21 and 23 by the coupling circuits 22a and 24a increases as the frequency increases. If the coupling circuits 22a and 24a are properly designed, the inductive component added to the transmission lines 21 and 23 of the dashed line 54 compensates for the inductive component of the transmission lines 21 and 23 of the dashed line 54. As a result, the S21 of the circuit B is almost constant and does not depend on the frequency, as shown by the solid line 50.

[0021] However, in circuit B, coupling circuits 22a and 24a are connected to transmission lines 21 and 23 via connection line 27. Therefore, the coupling between transmission lines 21 and 23 and coupling circuits 22a and 24a is strong. Therefore, signals S3 and S4 leak to coupling circuits 22a and 24a, and the insertion loss of transmission lines 21 and 23 increases. In addition, the dielectric components adjusted in coupling circuits 22 and 24 are directly added to transmission lines 21 and 23, making it difficult to fine-tune the inductive components added to transmission lines 21 and 23. For this reason, it is difficult to adjust the frequency dependence of S21 to be small, as shown by solid line 50 in FIG. 4.

[0022] In the circuit C of FIG. 3, the coupling circuits 22 and 24 are separated from the transmission lines 21 and 23. The coupling circuits 22 and 24 include a coupling line 25 coupled to the transmission lines 21 and 23, and a stub 26 having a first end connected to the coupling line 25. The coupling line 25 is spaced apart from the transmission lines 21 and 23 and extends in the direction in which the transmission lines 21 and 23 extend. The distance D1 between the transmission lines 21 and 23 and the coupling line 25 is set so that the coupling coefficient is a desired value. The stub 26 is, for example, a short stub, and has a first end connected to the transmission lines 21 and 23 and a second end connected to the ground. The stub 26 may be an open stub. When the stub 26 is a short stub, the length D2 of the stub 26 is set to be smaller than λ / 4, so that the stub 26 becomes inductive and an inductive component is added to the coupling line 25. Thus, an inductive component is added to the transmission lines 21 and 23. When the stub 26 is an open stub, by setting the length D2 of the stub 26 to be greater than λ / 4 and less than λ / 2, a dielectric component is added to the transmission lines 21 and 23. As a result, as shown in Figure 4, S21 of the circuit C is almost constant and does not depend on the frequency.

[0023] Furthermore, since the coupling circuits 22 and 24 are not connected to the transmission lines 21 and 23, the coupling between the coupling circuits 22 and 24 and the transmission lines 21 and 23 is weak. This makes it possible to suppress leakage of the signals S3 and S4 to the coupling circuits 22 and 24, and to suppress losses in the transmission lines 21 and 23. Also, the dielectric component added to the transmission lines 21 and 23 becomes smaller than the dielectric component adjusted in the coupling circuits 22 and 24. This makes it easier to finely adjust the inductive component added to the transmission lines 21 and 23, and makes it easier to adjust the frequency dependence of S21 to be small, as shown by the solid line 50 in FIG. 4.

[0024] [Modification 1 of Example 1] FIG. 5 is a circuit diagram of an amplifier according to a first modification of the first embodiment. In FIG. 5, matching circuits 30 to 33 are omitted. The same applies to the following figures. As shown in FIG. 5, in the first modification of the first embodiment, the coupling circuits 22 and 24 include coupling lines 25a and 25b and stubs 26a and 26b, respectively. The stubs 26a and 26b are short stubs, and have a length shorter than λ / 4. The ends 27a of the stubs 26a and 26b are shared. The tip of the end 27a is connected to the ground. The other configurations are the same as those of the first embodiment, and description thereof will be omitted.

[0025] In the outphasing amplifier, the output signals S3 and S4 of the amplifiers 12 and 14 are, in principle, input to the combiner 10 at the same timing. In other words, the timing of input to the transmission lines 21 and 23 is also considered to be the same, and the characteristics required for the coupling circuits 22 and 24 can be designed for the signals S3 and S4 input at the same timing. Therefore, it is possible to realize stable characteristics and reduce the area of ​​the coupling circuits without worrying that sharing the ends 27a of the stubs 26a and 26b increases the difficulty of designing the coupling circuits 22 and 24.

[0026] [Modification 2 of Example 1] FIG. 6 is a circuit diagram of an amplifier according to a second modification of the first embodiment. As shown in FIG. 6, in the second modification of the first embodiment, the stubs 26a and 26b are open stubs, and the length is longer than λ / 4 and shorter than λ / 2. The end 27b of the stubs 26a and 26b is shared. The tip of the end 27b is open. The other configurations are the same as those of the first modification of the first embodiment, and therefore description thereof will be omitted. The effect obtained by sharing the end 27b of the stubs 26a and 26b is also the same as that of the first modification of the first embodiment.

[0027] [Modification 3 of Example 1] FIG. 7 is a circuit diagram of an amplifier according to the third modification of the first embodiment. As shown in FIG. 7, in the third modification of the first embodiment, the stubs 26a and 26b include a short stub and an open stub. The length of the short stub is shorter than λ / 4, and the length of the open stub is longer than λ / 4 and shorter than λ / 2. The end 27a of the short stub is shared by the coupling circuits 22 and 24, and the end 27b of the open stub is shared by the coupling circuits 22 and 24. By providing both the short stub and the open stub, it becomes easy to adjust the frequency characteristics of the coupling circuits 22 and 24. The other configurations are the same as those of the first and second modifications of the first embodiment, and the description thereof will be omitted. The effect obtained by sharing the end 27a of the short stub and the end 27b of the open stub with the coupling circuits 22 and 24, respectively, is also the same as that of the first modification of the first embodiment.

[0028] FIG. 8 is a plan view of an output circuit in the third modified example of the first embodiment. As shown in FIG. 8, a conductor pattern 42 is provided on a substrate 40. The substrate 40 is a dielectric substrate made of resin such as FR-4 (Flame Retardant Type 4) or ceramic, and a metal layer to which a ground potential is supplied is provided on the lower surface. The conductor pattern 42 is a metal layer made of, for example, copper or gold. The conductor pattern 42 includes conductor patterns 42a to 42d and line patterns 43a to 43f. Amplifiers 12 and 14, capacitors C1 to C3, and inductor L1 are mounted on the substrate 40. The amplifiers 12 and 14 are, for example, semiconductor chips mounted in a package. The capacitors C1 to C3 are, for example, chip capacitors such as multilayer ceramic capacitors, and the inductor L1 is a chip inductor such as a multilayer chip inductor.

[0029] The matching circuits 30 and 31 include conductor patterns 42a and 42b and capacitors C2 and C3. The output leads of the amplifiers 12 and 14 are electrically connected to the ends of the conductor patterns 42a and 42b, respectively. The conductor patterns 42a and 42b are patterns whose widths increase toward the capacitors C2 and C3. The capacitors C2 and C3 are connected between the conductor patterns 42a and 42b and the ends of the line patterns 43a and 43b, respectively.

[0030] The line patterns 43a and 43b form the transmission lines 21 and 23, which are microstrip lines, respectively, together with a ground metal layer provided on the lower surface of the substrate 40. The line patterns 43a and 43b are connected to each other at a node N1. The capacitor C1 and the inductor L1 are connected between the line patterns 43a and 43b and the conductor patterns 42c and 42d, respectively. The conductor patterns 42c and 42d are connected to the ground via through vias. As a result, the capacitor C1 and the inductor L1 are shunt-connected at the nodes N2 and N3.

[0031] The line patterns 43c and 43d form coupled lines 25a and 25b, which are microstrip lines, together with a ground metal layer provided on the lower surface of the substrate 40. The line patterns 43a and 43b are separated from the line pattern 43c on the substrate 40. The characteristic impedances of the transmission lines 21, 23 and the coupled lines 25a and 25b are approximately the same. That is, the widths of the line patterns 43a and 43b and the line patterns 43c and 43d are approximately the same. The line patterns 43e and 43f form the stubs 26a and 26b, respectively. The widths of the line patterns 43e and 43f may be the same as or different from the widths of the line patterns 43a and 43b.

[0032] [Variation 4 of Example 1] Fig. 9 is a circuit diagram of an amplifier according to the fourth modification of the first embodiment. As shown in Fig. 9, in the fourth modification of the first embodiment, the transmission lines 21 and 23 are shunt-connected to the capacitors C4 and C5, respectively. This allows the substantial electrical length between the nodes N2 and N3 and N1 to be approximately λ / 4 even if the electrical length of the transmission lines 21 and 23 is shorter than λ / 4. The electrical length of the transmission lines 21 and 23 is, for example, λ / 8. The other configurations are the same as those of the third modification of the first embodiment, and therefore description thereof will be omitted.

[0033] According to the first embodiment and its modified example, the coupling circuit 22 (first coupling circuit) is provided away from the transmission line 21 (first transmission line) and is coupled to the transmission line 21, and the coupling circuit 24 (second coupling circuit) is provided away from the transmission line 23 (second transmission line) and is coupled to the transmission line 23. This makes it possible to reduce the coupling coefficient between the coupling circuits 22 and 24 and the transmission lines 21 and 23, as compared with the case where the coupling circuits 22 and 24 are directly connected to the transmission lines 21 and 23, as in the circuit B of FIG. 3. This makes it possible to suppress the signals S3 and S4 propagating through the transmission lines 21 and 23 from leaking to the coupling circuits 22 and 24, and suppress the loss of the transmission lines 21 and 23. In addition, as in the circuit C, it becomes easy to adjust the reactance components added to the transmission lines 21 and 23.

[0034] The coupling circuits 22 and 24 may add any reactance components to the transmission lines 21 and 23, respectively. For example, the harmonic processing circuit and the fundamental matching circuit in the output matching circuit in Patent Document 1 may be used as the coupling circuits 22 and 24.

[0035] As shown in FIG. 4, the coupling circuit 22 adds a reactance component to the transmission line 21 that is opposite to the reactance component of the transmission line 21 alone in the band of the outphasing amplifier. The coupling circuit 24 adds a reactance component to the transmission line 23 that is opposite to the reactance component of the transmission line 23 alone in the band. This makes it possible to reduce the frequency dependence of S21 of the transmission lines 21 and 23 to which the coupling circuits 22 and 24 are added, as shown by the solid line 50. As shown by the dashed line 52, the reactance components of the transmission lines 21 and 23 often have an inductive component. In such a case, it is preferable that the reactance components added to the transmission lines 21 and 23 by the coupling circuits 22 and 24 be inductive components, as shown by the dashed line 54.

[0036] As in the first to fourth modifications of the first embodiment, the coupling circuits 22 and 24 include the coupling lines 25a (first coupling line) and 25b (second coupling line) and the stubs 26a (first stub) and 26b (second stub). The coupling lines 25a and 25b are coupled to the transmission lines 21 and 23, respectively. The stubs 26a and 26b are connected to the coupling lines 25a and 25b, respectively. In this manner, by providing the coupling lines 25a and 25b and the stubs 26a and 26b, the coupling circuits 22 and 24 can be realized with a simple configuration.

[0037] 8, the transmission lines 21 and 23 each include a line pattern 43a (first line pattern) and 43b (second line pattern) formed on the upper surface (front surface) of the dielectric substrate 40. The coupled lines 25a and 25b each include a line pattern 43c (third line pattern) and 43d (fourth line pattern) provided on the upper surface of the substrate 40 and spaced apart from the line patterns 43a and 43b on the upper surface of the substrate 40. The stubs 26a and 26b are provided on the upper surface of the substrate 40 and connected to the line patterns 43c and 43d, respectively, on the upper surface of the substrate 40. This allows the coupled circuits 22 and 24 to be formed on the substrate 40.

[0038] The stubs 26a and 26b include short stubs with a length shorter than λ / 4, or open stubs with a length longer than λ / 4 and shorter than λ1 / 2. This allows the coupling circuits 22 and 24 to add an inductive component to the transmission lines 21 and 23, thereby compensating for the inductive components of the transmission lines 21 and 23. The length of the short stubs is preferably λ / 16 or more and 3λ / 16 or less, and the length of the open stubs is preferably 5λ / 16 or more and 7λ / 16 or less.

[0039] As in the first to fourth modifications of the first embodiment, the coupling circuits 22 and 24 are provided to share a portion. This makes it possible to reduce the size of the coupling circuits 22 and 24. When the coupling circuits 22 and 24 include the stubs 26a and 26b, respectively, it is preferable to share the ends 27a and 27b of the stubs 26a and 26b.

[0040] The electrical lengths of the transmission lines 21 and 23 are each greater than λ / 8 and less than 3λ / 8. This allows the transmission lines 21 and 23 to be used as impedance conversion circuits. The electrical lengths of the transmission lines 21 and 23 are each more preferably greater than 3λ / 16 and less than 5λ / 8, and even more preferably λ / 4.

[0041] The combiner 10 includes a capacitor C1 shunt-connected to a node N2 between the amplifier 12 and the transmission line 21, and an inductor L1 shunt-connected to a node N3 between the amplifier 14 and the transmission line 23. This allows the combiner 10 to be a Shearlet combiner.

[0042] The signal processing unit 16 changes the phase difference between two signals S1 (first signal) and S2 (second signal) based on the input signal Sin, and outputs the signals S1 and S2 to the amplifiers 12 and 14, respectively, thereby functioning as an outphasing circuit.

[0043] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the claims, not by the above meaning, and is intended to include all modifications within the scope and meaning equivalent to the claims. [Explanation of symbols]

[0044] C1~C5 capacitors L1 Inductor N1~N3 nodes S1~S4 signals (1st signal~4th signal) Sin input signal Sout Output signal Tin Input terminal Tout output terminal 10 Synthesizer 12, 14 Amplifier (1st Amplifier, 2nd Amplifier) 16 Signal Processing Section 21, 23 Transmission line (first transmission line, second transmission line) 22, 24 Coupling circuit (1st coupling circuit, 2nd coupling circuit) 22a, 24a coupling circuit 25 Coupled Lines 25a, 25b coupled lines (first coupled line, second coupled line) 26 Stub 26a, 26b stubs (first stub, second stub) 27a, 27b ends 30~33 Matching circuit 40 Substrate 42, 42a to 42d Conductive patterns 43a~43f track pattern

Claims

1. a first amplifier for amplifying a first signal; a second amplifier that amplifies a second signal whose phase difference with respect to the first signal changes; a combiner including: a first transmission line through which a third signal output from the first amplifier passes; a second transmission line through which a fourth signal output from the second amplifier passes; a first coupling circuit provided away from the first transmission line, not connected to the first transmission line, and coupled to the first transmission line; a second coupling circuit provided away from the second transmission line, not connected to the second transmission line, and coupled to the second transmission line; and a node that combines the third signal that has passed through the first transmission line and the fourth signal that has passed through the second transmission line; An outphasing amplifier comprising:

2. the first coupling circuit adds an inductive component to the first transmission line that is opposite to an inductive component of the first amplifier and the first transmission line alone connected to the node in a band of the outphasing amplifier; 2. The outphasing amplifier of claim 1, wherein the second coupling circuit adds an inductive component to the second transmission line that is opposite to an inductive component of the second amplifier and the second transmission line alone connected to the node in the band.

3. the first coupling circuit includes a first coupling line coupled to the first transmission line and a first stub connected to the first coupling line; The outphasing amplifier of claim 1 or 2, wherein the second coupling circuit comprises: a second coupled line coupled to the second transmission line; and a second stub connected to the second coupled line.

4. a dielectric substrate having a surface; the first transmission line includes a first line pattern provided on the surface, the second transmission line includes a second line pattern provided on the surface, the first coupled line includes a third line pattern provided on the surface and spaced apart from the first line pattern and the second line pattern on the surface; the second coupled line includes a fourth line pattern provided on the surface and spaced apart from the first line pattern and the second line pattern on the surface; the first stub is provided on the front surface and is connected to the third line pattern at the front surface; 4. The outphasing amplifier according to claim 3, wherein the second stub is provided on the surface and is connected to the fourth line pattern at the surface.

5. the first stub includes a short stub having a length shorter than ¼ of a wavelength at a center frequency of a band of the outphasing amplifier, or an open stub having a length longer than ¼ and shorter than ½ of the wavelength; 5. The outphasing amplifier according to claim 3, wherein the second stub comprises a short stub having a length shorter than 1 / 4 of the wavelength, or an open stub having a length longer than 1 / 4 and shorter than 1 / 2 of the wavelength.

6. The outphasing amplifier according to claim 3 , wherein the first coupling circuit and the second coupling circuit are provided sharing an end of the first stub and an end of the second stub.

7. the electrical length of the first transmission line is greater than ⅛ and less than ⅔ of a wavelength at a center frequency of the band of the outphasing amplifier; The outphasing amplifier according to claim 1 , wherein the electrical length of the second transmission line is greater than ⅛ and less than ⅜ of the wavelength.

8. 8. An outphasing amplifier as claimed in any one of claims 1 to 7, wherein the combiner comprises a capacitor connected in shunt to a node between the first amplifier and the first transmission line, and an inductor connected in shunt to a node between the second amplifier and the second transmission line.

9. The outphasing amplifier according to any one of claims 1 to 8, further comprising a signal processing unit that changes a phase difference between the first signal and the second signal based on an input signal, and outputs the first signal and the second signal to the first amplifier and the second amplifier, respectively.

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