Balun and power amplifier circuit

Abstract

This invention provides a balun and power amplifier circuit capable of suppressing frequency changes in impedance when viewed from the carrier amplifier to the subsequent stage when the peak amplifier is turned off. [Solution] The balun comprises: a first wire having one end connected to a carrier amplifier and the other end connected to a first reference potential; a second wire having one end connected to a peak amplifier and the other end connected to the first reference potential; a third wire having one end and the other end connected to a terminal, and coupled to the first wire; a fourth wire having one end connected to the one end of the third wire and the other end, and coupled to the second wire; and a fifth wire having one end connected to the other end of the fourth wire and the other end open, and electromagnetically coupled to the fourth wire.

Description

Technical Field

[0001] The present invention relates to a balun and a power amplifier circuit.

Background Art

[0002] A Doherty amplifier used as a power amplifier for wireless communication and the like is known (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The transformer described in Patent Document 1 includes an input-side coil and an output-side coil. One end of the input-side coil is connected to the output terminal of the carrier amplifier through a capacitor. The other end of the input-side coil is connected to the output terminal of the peak amplifier through a capacitor and a phase line. One end of the output-side coil is connected to the signal output terminal. The other end of the output-side coil is connected to the ground.

[0005] Although the transformer of Patent Document 1 magnetically couples the input-side coil and the output-side coil, in a high-frequency band such as the sub-terahertz band, for example, the influence of the parasitic capacitance between the lines becomes large. For this reason, the original performance of the transformer may not be exhibited. When a merchant balun is used instead of the transformer, this problem can be addressed, but a new problem occurs in that when the peak amplifier is turned off, the frequency change of the impedance seen from the carrier amplifier to the subsequent stage becomes large.

[0006] This invention has been made in view of these circumstances, and aims to provide a balun and power amplifier circuit that can suppress the frequency change of impedance when viewed from the carrier amplifier to the subsequent stage when the peak amplifier is turned off. [Means for solving the problem]

[0007] A balun according to one aspect of the present invention comprises: a first wiring having one end connected to a carrier amplifier and the other end connected to a first reference potential; a second wiring having one end connected to a peak amplifier and the other end connected to the first reference potential; a third wiring having one end and the other end connected to a terminal, and coupled to the first wiring; a fourth wiring having one end connected to the one end of the third wiring and the other end, and coupled to the second wiring; and a fifth wiring having one end connected to the other end of the fourth wiring and the other end being open, and electromagnetically coupled to the fourth wiring.

[0008] A power amplifier circuit according to another aspect of the present invention includes: a carrier amplifier that amplifies a first signal and outputs a first amplified signal from a first output terminal; a peak amplifier that amplifies a second signal having a different phase from the first signal and outputs a second amplified signal from a second output terminal; a first wiring having one end connected to the first output terminal and the other end connected to a first reference potential; a second wiring having one end connected to the second output terminal and the other end connected to the first reference potential; a third wiring having one end and the other end supplying an output signal, and coupled to the first wiring; a fourth wiring having one end connected to the one end of the third wiring and the other end, and coupled to the second wiring; and a fifth wiring having one end connected to the other end of the fourth wiring and an open other end, and electromagnetically coupled to the fourth wiring. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a balun and power amplifier circuit that can suppress the frequency change of impedance when viewed from the carrier amplifier to the subsequent stage when the peak amplifier is turned off. [Brief explanation of the drawing]

[0010] [Figure 1] This is the circuit diagram of power amplifier circuit 201. [Figure 2] This is a circuit diagram of power amplifier circuit 291, which is an example. [Figure 3] This figure shows the simulation results of the frequency change of S11 on a Smith chart when both the carrier amplifier 51c and the peak amplifier 51p are operating in the power amplifier circuit 291, which is an example of a power amplifier circuit. [Figure 4] This figure shows the simulation results of the frequency change of S21 when both the carrier amplifier 51c and the peak amplifier 51p are operating in the power amplifier circuit 291, which is an example of a power amplifier circuit. [Figure 5] This figure shows the simulation results of the frequency change of S11 when the peak amplifier 51p is in the OFF state, compared to Figure 3, on a Smith chart. [Figure 6] This figure shows the simulation results of the frequency change of S21 when the peak amplifier 51p is in the OFF state, compared to Figure 4. [Figure 7] This is a schematic circuit diagram to explain why the frequency change of S11 becomes large in the power amplifier circuit 291. [Figure 8] This diagram illustrates the frequency change of S11 on the Smith chart in the power amplifier circuit 201. [Figure 9] This is a schematic circuit diagram to explain why the frequency change of S11 is suppressed in the power amplifier circuit 201. [Figure 10] This figure shows the simulation results of the frequency change of S21 when the peak amplifier 51p is in the off state in the power amplifier circuit 201. [Figure 11] This figure shows the simulation results of the frequency change of S11 when the peak amplifier 51p is in the off state in the power amplifier circuit 201, on a Smith chart. [Figure 12] This is a plan view of the Balun 101 from above. [Figure 13]It is a circuit diagram of the power amplifier circuit 202. [Figure 14] It is a diagram showing the simulation result of the frequency change of S11 on a Smith chart when both the carrier amplifier 51c and the peak amplifier 51p are operating in the power amplifier circuit 202. [Figure 15] It is a plan view of the balun 102 seen from above. [Figure 16] It is a circuit diagram of the power amplifier circuit 203. [Figure 17] It is a diagram showing the simulation result of the frequency change of S11 on a Smith chart when both the carrier amplifier 51c and the peak amplifier 51p are operating in the power amplifier circuit 203. [Figure 18] It is a plan view of the balun 103 seen from above. [Figure 19] It is a circuit diagram of the power amplifier circuit 204. [Figure 20] It is a circuit diagram of the power amplifier circuit 205.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the same elements are denoted by the same reference numerals, and redundant descriptions are omitted as much as possible.

[0012] [First Embodiment] The power amplifier circuit 201 according to the first embodiment will be described. FIG. 1 is a circuit diagram of the power amplifier circuit 201. As shown in FIG. 1, the power amplifier circuit 201 includes a carrier amplifier 51c, a peak amplifier 51p, capacitors 62p, 62c and 63, a balun 101, wirings 303a and 304a, and capacitors 303b and 304b.

[0013] The carrier amplifier 51c and the peak amplifier 51p include amplification transistors (not shown). The balun 101 includes wirings 111 (first wiring), 112 (second wiring), 113 (third wiring), 114 (fourth wiring) and 115 (fifth wiring). The balun 101 is, for example, a merchant balun.

[0014] In this embodiment, the transistor is composed of a bipolar transistor, such as a heterojunction bipolar transistor (HBT). However, the transistor may also be composed of other types of transistors, such as a metal-oxide-semiconductor field-effect transistor (MOSFET). In that case, the base, collector, and emitter should be read as the gate, drain, and source, respectively.

[0015] In the power amplifier circuit 201, the carrier amplifier 51c and the peak amplifier 51p operate as Doherty amplifiers.

[0016] The carrier amplifier 51c amplifies the signal RF3 (first signal) supplied from the preceding circuit and outputs the amplified signal RF5 (first amplified signal) from the output terminal 51ca (first output terminal).

[0017] The peak amplifier 51p amplifies the signal RF4 (second signal) supplied from the preceding circuit and outputs the amplified signal RF6 (second amplified signal) from the output terminal 51pa (second output terminal).

[0018] Signal RF4 has a different phase from signal RF3. In this embodiment, for example, signal RF3 has a phase difference of approximately 180° from signal RF4. The frequencies of signals RF3 and RF4 are, for example, included in the subterahertz band. Specifically, the frequencies of signals RF3 and RF4 are included in the 90GHz to 300GHz range.

[0019] In detail, the amplifying transistor included in the carrier amplifier 51c is operated by the power supply voltage VDD supplied through the wiring 304a, which functions as an inductor, and the output terminal 51ca. Capacitor 304b is a bypass capacitor and has one end to which the power supply voltage VDD is supplied and the other end connected to ground. Here, the potential of ground is an example of a first reference potential.

[0020] The amplifying transistor included in the carrier amplifier 51c operates in, for example, Class A or Class AB mode depending on the bias supplied from the bias circuit (not shown).

[0021] The amplifying transistor included in the peak amplifier 51p is operated by the power supply voltage VDD, which is supplied through the wiring 303a, which functions as an inductor, and the output terminal 51pa. Capacitor 303b is a bypass capacitor and has one end to which the power supply voltage VDD is supplied and the other end connected to ground.

[0022] The amplification transistor included in the peak amplifier 51p operates in, for example, class C mode, due to the bias supplied from the bias circuit (not shown).

[0023] The transmission line 501c has one end connected to the output terminal 51ca of the carrier amplifier 51c, and the other end through which the amplified signal RF5 is transmitted.

[0024] The transmission line 501p has one end connected to the output terminal 51pa of the peak amplifier 51p, and the other end through which the amplified signal RF6 is transmitted.

[0025] Capacitors 62c and 62p, for example, have a DC blocking function and are provided on transmission lines 501c and 501p, respectively. Capacitors 62c and 62p may also have a function of matching the impedance between the carrier amplifier 51c and peak amplifier 51p and the balun 101.

[0026] In detail, the capacitor 62c has one end connected to the output terminal 51ca of the carrier amplifier 51c through a portion of the transmission line 501c, and the other end connected to the wiring 111 through the other portion of the transmission line 501c.

[0027] Capacitor 62p has one end connected to the output terminal 51pa of peak amplifier 51p through a portion of the transmission line 501p, and the other end connected to the wiring 112 through the other portion of the transmission line 501p.

[0028] The balun 101 combines the amplified signals RF5 and RF6 supplied from the carrier amplifier 51c and the peak amplifier 51p, respectively, and converts them into a single-ended output signal RFout. The balun 101 also matches the impedance between the carrier amplifier 51c and the peak amplifier 51p and the circuit downstream of the output terminal 32, such as an antenna.

[0029] More specifically, the wiring 111 in the balun 101 has one end connected to the carrier amplifier 51c and the other end connected to the first reference potential. More specifically, the wiring 111 has one end connected to the output terminal 51ca of the carrier amplifier 51c and the other end connected to ground. More specifically, one end of the wiring 111 is connected to the other end of the line 501c. The amplified signal RF5 output from the carrier amplifier 51c is supplied to one end of the wiring 111.

[0030] Wiring 112 has one end connected to the peak amplifier 51p and the other end connected to the first reference potential. More specifically, wiring 112 has one end connected to the output terminal 51pa of the peak amplifier 51p and the other end connected to ground. More specifically, one end of wiring 112 is connected to the other end of line 501p. The amplified signal RF6 output from the peak amplifier 51p is supplied to one end of wiring 112.

[0031] Wiring 113 has one end and the other end connected to output terminal 32. Wiring 113 is coupled to wiring 111. This coupling is, for example, a coupling between lines. In detail, the other end of wiring 113 is connected to line 502 through which the output signal RFout is transmitted. The other end of wiring 113 supplies the output signal RFout to output terminal 32 through line 502.

[0032] Wiring 114 has one end connected to one end of wiring 113 and the other end, and is coupled to wiring 112. This coupling is, for example, a coupling between two railway tracks.

[0033] Wiring 115 has one end connected to the other end of wiring 114 and the other end open, and is electromagnetically coupled to wiring 114. This coupling is, for example, the coupling between two lines.

[0034] Each of the wires 111, 112, and 115 is a quarter-wavelength line. More specifically, the time required for the amplified signal RF5 or RF6 to be transmitted from one end to the other of wire 111, 112, or 115 is approximately one-quarter of the period of the amplified signal RF5 or RF6. In other words, the electrical length of each of the wires 111, 112, and 115 is approximately one-quarter of the wavelength of the amplified signal RF5 or RF6.

[0035] The track 502 has one end connected to the other end of the wiring 113 and the other end connected to the output terminal 32.

[0036] The capacitor 63 is provided on the line 502. More specifically, the capacitor 63 has one end connected to the other end of the wiring 113 through a portion of the line 502, and the other end connected to the output terminal 32 through another portion of the line 502.

[0037] The combined wiring of wires 113 and 114 is a half-wavelength line. More specifically, the time required for the output signal RFout to be transmitted from the other end of wire 113 to the other end of wire 114 is approximately half the period of the output signal RFout. In other words, the electrical length from the other end of wire 113 to the other end of wire 114 is approximately half the wavelength of the output signal RFout. Note that each of wires 113 and 114 is, for example, a quarter-wavelength line.

[0038] In this embodiment, the balun 101 has been described as being connected to the output side of the carrier amplifier 51c and the peak amplifier 51p, but the embodiment is not limited to this configuration. The balun 101 may also be connected to the input side of the carrier amplifier 51c and the peak amplifier 51p.

[0039] [Reference example] The power amplifier circuit 291, which is an example, will be described. Figure 2 is the circuit diagram of the power amplifier circuit 291, which is an example.

[0040] The power amplifier circuit 291 includes a balun 901 instead of a balun 101, compared to the power amplifier circuit 201 (see Figure 1). The balun 901 does not have wiring 115, compared to the balun 101 (see Figure 1). That is, wiring 114 has one end connected to one end of wiring 113 and the other end open, and is coupled to wiring 112.

[0041] Figure 3 shows the simulation results of the frequency change of S11 on a Smith chart when both the carrier amplifier 51c and the peak amplifier 51p are operating in the power amplifier circuit 291, which is an example of a power amplifier circuit. Here, S11 is the S-parameter of the signal incident from the carrier amplifier 51c to the capacitor 62c.

[0042] As shown in Figure 3, S11 at frequencies of 120 GHz, 130 GHz, and 140 GHz, which are included in the fundamental frequency band of the amplified signal RF5, is represented by Lchr, Mchr, and Hchr, respectively.

[0043] Figure 4 shows the simulation results of the frequency change of S21 when both the carrier amplifier 51c and the peak amplifier 51p are operating in the power amplifier circuit 291, which is a reference example. Here, S21 is the S-parameter of the signal passing from the carrier amplifier 51c through the balun 901. The vertical axis shows S21 in units of "dB". The horizontal axis shows the frequency in units of "GHz".

[0044] As shown in Figures 3 and 4, the impedance between the carrier amplifier 51c and the peak amplifier 51p and the circuit after the output terminal 32 is matched, thereby suppressing the reflection of the fundamental wave of the amplified signal RF5.

[0045] Figure 5 shows the simulation results of the frequency change of S11 when the peak amplifier 51p is in the off state, compared to Figure 3, on a Smith chart. When the peak amplifier 51p in the power amplifier circuit 291 is in the off state, S11 at frequencies of 120 GHz, 130 GHz, and 140 GHz is represented by Lchrb, Mchrb, and Hchrb, respectively.

[0046] Figure 6 shows the simulation results of the frequency change of S21 when the peak amplifier 51p is in the off state, compared to Figure 4. Note that Figure 6 can be interpreted in the same way as Figure 4.

[0047] As shown in Figures 5 and 6, in the 120GHz to 140GHz range, the frequency change of S11 becomes larger compared to the frequency change of S11 when both the carrier amplifier 51c and the peak amplifier 51p are operating (see Figure 3) (see Figure 5).

[0048] For S21, the frequency change is almost flat when both the carrier amplifier 51c and the peak amplifier 51p are operating in the 120GHz to 140GHz range (see Figure 4), but drops at higher frequencies when the peak amplifier 51p is off (see Figure 6).

[0049] Figure 7 is a schematic circuit diagram illustrating the reason why the frequency change of S11 becomes large in the power amplifier circuit 291. As shown in Figure 7, when the peak amplifier 51p is off, wiring 112 does not function, so wiring 114 is simply connected to the other end of wiring 113.

[0050] Wiring 114 functions as an inductive open stub, and the input impedance to wiring 114 has a strong frequency dependence. As a result, the frequency change of S11 becomes large in the range of 120 GHz to 140 GHz (see Figure 5).

[0051] Furthermore, among the signals generated by the coupling between wirings 111 and 113, the reflected wave reflected by wiring 114 exhibits a large frequency dependence. As a result, the frequency change of S21 does not become nearly flat in the 120GHz to 140GHz range, but rather drops on the high-frequency side (see Figure 6).

[0052] [effect] Figure 8 illustrates the frequency change of S11 on the Smith chart in the power amplifier circuit 201. In Figure 8, the curve Ci shows the change in S11 when the peak amplifier 51p is transitioned from the ON state to the OFF state, when wiring 114 and wiring 115 are arranged to be electromagnetically coupled.

[0053] Curve Cir shows the change in S11 when the peak amplifier 51p is transitioned from the ON state to the OFF state, in the case where wiring 114 and wiring 115 are arranged so as not to be electromagnetically coupled.

[0054] Figure 9 is a schematic circuit diagram illustrating why the frequency change of S11 is suppressed in the power amplifier circuit 201.

[0055] As shown in Figures 8 and 9, in the power amplifier circuit 201, wire 115 is connected to the other end of wire 114.

[0056] If wiring 114 and wiring 115 are not electromagnetically coupled, wirings 114 and 115 function as inductive open stubs, causing S11 to change away from the real axis towards the inductive side, as shown by curve Cir. In such a case, the frequency change of S11 becomes large.

[0057] In contrast, in the power amplifier circuit 201, since the wiring 114 is electromagnetically coupled with the wiring 115, the wirings 114 and 115 can be capacitively coupled, thus suppressing the inductive properties of the wirings 114 and 115 in the power amplifier circuit 201.

[0058] Specifically, as shown by curve Ci, S11 can be changed on the capacitance side, i.e., the real axis side, of curve Cir, thus suppressing the frequency change of S11. Since the frequency dependence of the input impedance to wiring 114 can be reduced, the frequency dependence of the reflected wave reflected by wiring 114 among the signals generated by the coupling between wirings 111 and 113 can be reduced.

[0059] Figure 10 shows the simulation results of the frequency change of S21 when the peak amplifier 51p is in the off state in the power amplifier circuit 201. As shown in Figure 10, the power amplifier circuit 201 can make the frequency change of S21 almost flat in the range of 120 GHz to 140 GHz.

[0060] Figure 11 shows the simulation results of the frequency change of S11 when the peak amplifier 51p is in the off state in the power amplifier circuit 201, on a Smith chart. When the peak amplifier 51p in the power amplifier circuit 201 is in the off state, S11 at frequencies of 120 GHz, 130 GHz, and 140 GHz are represented by Lchb, Mchb, and Hchb, respectively.

[0061] As shown in Figure 11, the power amplifier circuit 201 can suppress the frequency change of S11 in the range of 120 GHz to 140 GHz.

[0062] [Layout of Balan 101] This section describes the layout of Balun 101. Each drawing may show the x, y, and z axes. The x, y, and z axes form a right-handed three-dimensional Cartesian coordinate system. Hereinafter, the direction of the arrow on the x axis may be referred to as the x-axis+ side, and the direction opposite to the arrow may be referred to as the x-axis- side, and the same applies to the other axes. The z-axis+ side and z-axis- side may also be referred to as the "upper side" and "lower side," respectively. Furthermore, the planes perpendicular to the x, y, or z axes may be referred to as the yz plane, zx plane, or xy plane, respectively. Here, the direction of rotation clockwise when viewed from the upper side to the lower side is defined as the clockwise direction cw. The direction of rotation counterclockwise when viewed from the upper side to the lower side is defined as the counterclockwise direction ccw.

[0063] Figure 12 is a plan view of the balun 101 from above. As shown in Figure 12, the wirings 111, 112, 113, 114, and 115 are formed by metal electrodes 611, 612 (third conductive member), 613, 614 (first conductive member), and 615 (second conductive member), respectively.

[0064] In detail, wiring 111 is formed by a metal electrode 611 extending from one end of wiring 111 to the other end of wiring 111. Wiring 112 is formed by a metal electrode 612 extending from one end of wiring 112 to the other end of wiring 112. Wiring 113 is formed by a metal electrode 613 extending from one end of wiring 113 to the other end of wiring 113. Wiring 114 is formed by a metal electrode 614 extending from one end of wiring 114 to the other end of wiring 114. Wiring 115 is formed by a metal electrode 615 extending from one end of wiring 115 to the other end of wiring 115.

[0065] The metal electrodes 611, 612, 613, 614, and 615 are provided along the first surface. In this embodiment, the first surface is substantially parallel to the xy plane. The first surface is, for example, the surface of a semiconductor chip. The first surface may also be the surface of an insulating layer provided inside the semiconductor chip.

[0066] The metal electrodes 611 and 612 have a shape that is symmetrical with respect to a plane parallel to the zx plane (hereinafter sometimes referred to as the plane of symmetry Ps). The capacitors 62c and 62p have a shape that is symmetrical with respect to the plane of symmetry Ps. The transmission lines 501c and 501p have a shape that is symmetrical with respect to the plane of symmetry Ps.

[0067] The metal electrode 611 includes extended portions 611a and 611b and a corner portion 611c. At the corner portion 611c, the direction of extension changes. In this embodiment, the direction of extension of the metal electrode 611 extending from one end of the wiring 111 to the other end of the wiring 111 changes from the y-axis + direction to the x-axis + direction at the corner portion 611c.

[0068] The metal electrode 612 includes extended portions 612a and 612b and a corner portion 612c (third corner portion). At the corner portion 612c, the direction of extension changes. In this embodiment, the direction of extension of the metal electrode 612 extending from one end of the wiring 112 to the other end of the wiring 112 changes from the y-axis direction to the x-axis direction at the corner portion 612c.

[0069] The extended portion 611a and the extended portion 612a extend from the corner portion 611c and the corner portion 612c, respectively, so as to move closer to each other.

[0070] Specifically, the extension 611a extends from the corner 611c in the y-axis direction. A transmission line 501c is connected to the x-axis side of the extension 611a. A capacitor 62c is provided on the transmission line 501c. The transmission line 501c electrically connects the extension 611a and the carrier amplifier 51c.

[0071] The extension 612a extends from the corner 612c in the y-axis direction. A transmission line 501p is connected to the x-axis side of the extension 612a. A capacitor 62p is provided on the transmission line 501p. The transmission line 501p electrically connects the extension 612a and the peak amplifier 51p.

[0072] The extended portion 611b and the extended portion 612b extend in the same direction from the corner portion 611c and the corner portion 612c, respectively.

[0073] Specifically, the extended portion 611b extends from the corner portion 611c in the x-axis+ direction. A portion of the extended portion 611b on the x-axis+ side is electrically connected to an electrode having the potential of ground through the interlayer via 701c.

[0074] The extended portion 612b extends from the corner portion 612c in the x-axis+ direction. A portion of the extended portion 612b on the x-axis+ side is electrically connected to an electrode having the potential of ground via 701p.

[0075] The metal electrode 613 includes extended portions 613a and 613b and a corner portion 613c. The corner portion 613c is located inward from the corner portion 611c and extends parallel to the corner portion 611c.

[0076] In this embodiment, the extension direction of the metal electrode 613, which extends from one end of the wiring 113 to the other end of the wiring 113, changes from the y-axis + direction to the x-axis + direction at the corner portion 613c.

[0077] The metal electrode 614 includes extended portions 614a and 614b (first extended portions) and a corner portion 614c (first corner portion). The corner portion 614c is located inside the corner portion 612c and extends alongside the corner portion 612c. In other words, the corner portion 612c is located outside the corner portion 614c and extends alongside the corner portion 614c.

[0078] In this embodiment, the extension direction of the metal electrode 614, which extends from one end of the wiring 114 to the other end of the wiring 114, changes from the y-axis direction to the x-axis direction at the corner portion 614c.

[0079] The extensions 613a and 614a extend from the corners 613c and 614c, respectively, moving closer to each other. Specifically, extension 613a is located on the x-axis+ side of extension 611a and extends parallel to extension 611a in the y-direction from corner 613c. Extension 614a is located on the x-axis+ side of extension 612a and extends parallel to extension 612a in the y-direction from corner 614c, connecting with extension 613a.

[0080] The extensions 613b and 614b extend along the x-axis direction (first direction). Specifically, the extensions 613b and 614b extend in the same direction from the corners 613c and 614c, respectively. More specifically, the extension 613b is located on the y-axis side of the extension 611b and extends parallel to the extension 611b from the corner 613c toward the x-axis direction. The extension 614b is located on the y-axis direction of the extension 612b and extends parallel to the extension 612b from the corner 614c toward the x-axis direction.

[0081] The metal electrode 615 is provided inside the corner portion 614c. More specifically, the metal electrode 615 includes extended portions 615a and 615b (second extended portion) and the corner portion 615c.

[0082] The corner section 615c (second corner section) is located inside the corner section 614c and extends parallel to it. At the corner section 615c, the direction of extension changes. In this embodiment, the direction of extension of the metal electrode 615, which extends from one end of the wiring 115 to the other end of the wiring 115, changes from the x-axis direction to the y-axis direction at the corner section 615c.

[0083] The extended portion 615a extends from the corner portion 615c in the y-axis direction. The extended portion 615b connects to the extended portion 614b through the U-shaped portion 616 and extends alongside the extended portion 614b.

[0084] In detail, the extension portion 615b extends from the corner portion 615c in the x-axis+ direction. The U-shaped portion 616 is provided on the x-axis+ side of the extension portions 615b and 614b. The x-axis+ side of the extension portion 615b and the x-axis+ side of the extension portion 614b are connected through the U-shaped portion 616.

[0085] [Second Embodiment] The power amplifier circuit 202 according to the second embodiment will now be described. In the second embodiment and subsequent embodiments, descriptions of matters common to the first embodiment will be omitted, and only the differences will be described. In particular, similar effects and advantages due to similar configurations will not be mentioned sequentially for each embodiment.

[0086] Figure 13 is a circuit diagram of the power amplifier circuit 202. As shown in Figure 13, the power amplifier circuit 202 differs from the power amplifier circuit 201 according to the first embodiment in that the electrical length of the wiring 115 is shorter.

[0087] The power amplifier circuit 202, compared to the power amplifier circuit 201 shown in Figure 1, includes a balun 102 instead of a balun 101. The electrical length of the wiring 115 in the balun 102 is shorter than the electrical length of the wiring 115 in the balun 101.

[0088] Specifically, the wiring 115 is a line having an electrical length greater than one-eighth and less than one-quarter of the wavelength of the signal RF3 that the carrier amplifier 51c amplifies.

[0089] Figure 14 shows the simulation results of the frequency change of S11 on a Smith chart when both the carrier amplifier 51c and the peak amplifier 51p are operating in the power amplifier circuit 202.

[0090] As shown in Figure 14, by shortening the electrical length of the wiring 115, S11 in the 120GHz to 140GHz range can be shifted towards the capacitance side compared to the case shown in Figure 3.

[0091] [Layout of Balan 102] The layout of the balun 102 will now be described. Figure 15 is a plan view of the balun 102 as seen from above. As shown in Figure 15, in the balun 102, the metal electrode 615 does not include the extended portion 615a and the corner portion 615c, compared to the balun 101 shown in Figure 12. That is, the metal electrode 615 includes the extended portion 615b.

[0092] The x-axis negative side of the extension portion 615b is open. The x-axis positive side of the extension portion 615b is connected to the extension portion 614b through the U-shaped portion 616.

[0093] [Third Embodiment] A power amplifier circuit 203 according to the third embodiment will now be described. Figure 16 is a circuit diagram of the power amplifier circuit 203. As shown in Figure 16, the power amplifier circuit 203 differs from the power amplifier circuit 201 according to the first embodiment in that the electrical length of the wiring 115 is longer.

[0094] The power amplifier circuit 203, compared to the power amplifier circuit 201 shown in Figure 1, includes a balun 103 instead of a balun 101. The electrical length of the wiring 115 in the balun 103 is longer than the electrical length of the wiring 115 in the balun 101.

[0095] Specifically, the wiring 115 is a line having an electrical length greater than one-quarter and less than three-eighths of the wavelength of the signal RF3 that the carrier amplifier 51c amplifies.

[0096] Figure 17 shows the simulation results of the frequency change of S11 on a Smith chart when both the carrier amplifier 51c and the peak amplifier 51p are operating in the power amplifier circuit 203.

[0097] As shown in Figure 17, by increasing the electrical length of the wiring 115, S11 in the 120GHz to 140GHz range can be shifted towards the induction side compared to the case shown in Figure 3.

[0098] [Layout of Balan 103] The layout of the balun 103 will now be described. Figure 18 is a plan view of the balun 103 from above. As shown in Figure 18, in the balun 103, compared to the balun 101 shown in Figure 12, the extended portion 615a of the metal electrode 615 is longer in the y-axis direction and shorter in the x-axis direction.

[0099] [Fourth Embodiment] A power amplifier circuit 204 according to the fourth embodiment will now be described. Figure 19 is a circuit diagram of the power amplifier circuit 204. As shown in Figure 19, the power amplifier circuit 204 differs from the power amplifier circuit 201 according to the first embodiment in that the power supply voltage VDD (first reference potential) is supplied from the other end of wiring 111 and the other end of 112.

[0100] Compared to the power amplifier circuit 201 shown in Figure 1, the power amplifier circuit 204 does not have capacitors 62c and 62p, nor wiring 303a and 304a.

[0101] One end of the wiring 111 is connected to the output terminal 51ca of the carrier amplifier 51c via the line 501c. The other end of the wiring 111 is supplied with the power supply voltage VDD. The capacitor 304b has one end connected to the other end of the wiring 111 and the other end connected to ground.

[0102] One end of the wiring 112 is connected to the output terminal 51pa of the peak amplifier 51p via the line 501p. The other end of the wiring 112 is supplied with the power supply voltage VDD. The capacitor 303b has one end connected to the other end of the wiring 112 and the other end connected to ground.

[0103] This configuration allows wirings 111 and 112 to function as choke coils. Furthermore, the DC-blocking capacitors 62c and 62p can be reduced. This allows the power amplifier circuit 204 to be smaller in scale compared to the power amplifier circuit 201.

[0104] [Fifth Embodiment] A power amplifier circuit 205 according to the fifth embodiment will now be described. Figure 20 is a circuit diagram of the power amplifier circuit 205. As shown in Figure 20, the power amplifier circuit 205 differs from the power amplifier circuit 201 according to the first embodiment in that a driver stage amplifier and an antenna are further shown.

[0105] Compared to the power amplifier circuit 201 shown in Figure 1, the power amplifier circuit 205 further includes a carrier amplifier 50c, a peak amplifier 50p, a capacitor 60, interstage matching circuits 61c and 61p, a patch antenna 64, a balun 151, wiring 301a and 302a, and capacitors 301b and 302b.

[0106] The carrier amplifier 50c and the peak amplifier 50p include an amplifying transistor (not shown). The balun 151 includes wiring 161, 162, 163 and 164.

[0107] The balun 151 distributes the single-ended input signal RFin into signals RF1 and RF2. The balun 151 also matches the impedance between the circuit preceding the input terminal 31 and the carrier amplifier 50c and peak amplifier 50p.

[0108] In detail, the wiring 161, 162, 163, and 164 in balun 151 are the same as the wiring 111, 112, 113, and 114 in balun 101, respectively. In other words, balun 151 is a merchant balun.

[0109] Wiring 163 has one end and the other end to which the input signal RFin is supplied from the input terminal 31 through the capacitor 60. Wiring 161 has one end to which the signal RF1 is supplied to the carrier amplifier 50c and the other end to which it is connected to ground, and it is coupled to wiring 163. This coupling is, for example, a coupling between two lines.

[0110] Wiring 164 has one end connected to one end of wiring 163 and the other end open. Wiring 162 has one end that supplies the signal RF2 to the peak amplifier 50p and the other end connected to ground, and is coupled to wiring 164. This coupling is, for example, a coupling between two lines.

[0111] The carrier amplifier 50c amplifies the signal RF1 supplied from one end of the wiring 161 and outputs the amplified signal RF3 from the output terminal 50ca. The amplifying transistor included in the carrier amplifier 50c is operated by the power supply voltage VDD supplied through the wiring 302a, which functions as an inductor, and the output terminal 50ca. Capacitor 302b is a bypass capacitor and has one end to which the power supply voltage VDD is supplied and the other end connected to ground.

[0112] The peak amplifier 50p amplifies the signal RF2 supplied from one end of the wiring 162 and outputs the amplified signal RF4 from the output terminal 50pa. The amplifying transistor included in the peak amplifier 50p is operated by the power supply voltage VDD supplied through the wiring 301a, which functions as an inductor, and the output terminal 50pa. Capacitor 301b is a bypass capacitor and has one end to which the power supply voltage VDD is supplied and the other end connected to ground.

[0113] Interstage matching circuit 61c matches the impedance between carrier amplifier 51c and carrier amplifier 50c. Interstage matching circuit 61p matches the impedance between peak amplifier 51p and peak amplifier 50p.

[0114] The patch antenna 64 is connected to the output terminal 32. The patch antenna 64 functions as a load for the power amplification circuit 205. When a subterahertz band antenna is constructed using the patch antenna 64, the size of the patch antenna 64 is approximately 1.1 mm.

[0115] The above describes exemplary embodiments of the present invention. In the balun 101, the wiring 111 has one end connected to the carrier amplifier 51c and the other end connected to the first reference potential. The wiring 112 has one end connected to the peak amplifier 51p and the other end connected to the first reference potential. The wiring 113 has one end and the other end connected to the output terminal 32 and is coupled to the wiring 111. The wiring 114 has one end connected to one end of the wiring 113 and the other end and is coupled to the wiring 112. The wiring 115 has one end connected to the other end of the wiring 114 and the other end is open and is electromagnetically coupled to the wiring 114.

[0116] In this configuration, by connecting wiring 115, which is electromagnetically coupled to wiring 114, to the other end of wiring 114, wirings 114 and 115 can be capacitively coupled, thereby suppressing the inductive properties of wirings 114 and 115 in the power amplifier circuit 201. When the peak amplifier 51p is off, the frequency dependence of the input impedance to wiring 114 can be reduced, so the frequency dependence of the reflected wave reflected by wiring 114 among the signals generated by the coupling between wirings 111 and 113 can be reduced. As a result, the frequency change of S21 can be made almost flat. Therefore, the frequency change of impedance when viewed from the carrier amplifier downstream when the peak amplifier is off can be suppressed.

[0117] Furthermore, in balun 101, each of the wires 111, 112, and 115 is a quarter-wavelength line. The combined wires 113 and 114 form a half-wavelength line.

[0118] This configuration allows S11 to be positioned near the real axis on the Smith chart, thereby reducing the frequency dependence of S11. Furthermore, it enables efficient distribution of the input signal and synthesis of the amplified signals amplified by the carrier amplifier 51c and the peak amplifier 51p.

[0119] Furthermore, in balun 103, each of the wires 111 and 112 is a quarter-wavelength line. The combined wires 113 and 114 are a half-wavelength line. Wire 115 is a line with an electrical length greater than one-quarter and less than three-eighths of the wavelength of the signal RF3 amplified by the carrier amplifier 51c.

[0120] This configuration allows S11 to be moved to the inductive side on the Smith chart. Furthermore, it enables efficient distribution of the input signal and synthesis of the amplified signals amplified by the carrier amplifier 51c and the peak amplifier 51p.

[0121] Furthermore, in balun 102, each of the wires 111 and 112 is a quarter-wavelength line. The combined wires 113 and 114 are a half-wavelength line. Wire 115 is a line with an electrical length greater than one-eighth and less than one-quarter of the wavelength of the signal RF3 amplified by the carrier amplifier 51c.

[0122] This configuration allows S11 to be moved to the capacitance side on the Smith chart. Furthermore, it enables efficient distribution of the input signal and synthesis of the amplified signals amplified by the carrier amplifier 51c and the peak amplifier 51p.

[0123] Furthermore, in balun 101, the frequencies of signal RF3 amplified by carrier amplifier 51c and signal RF4 amplified by peak amplifier 51p are included in the subterahertz band.

[0124] For example, when using an MCT (Magnetic Coupled Transformer) balun in the subterahertz band, the parasitic capacitance between the transformer wirings is large, resulting in significant losses and preventing the MCT balun from performing to its full potential. In this way, the balun 101 in the subterahertz band allows for a reduction in the length of wirings 111-114, thereby suppressing an increase in circuit size. Furthermore, by using a balun 101 with a wide bandwidth and low loss due to line coupling, a balun 101 with good performance can be provided.

[0125] In the balun 101, the wiring 114 is provided along the first surface and is formed by a metal electrode 614 extending from one end of the wiring 114 to the other end. The wiring 115 is provided along the first surface and is formed by a metal electrode 615 extending from one end of the wiring 115 to the other end. The metal electrode 614 includes an extended portion 614b that extends along the x-axis. The metal electrode 615 is connected to the extended portion 614b through a U-shaped portion 616 and includes an extended portion 615b that extends alongside the extended portion 614b.

[0126] In this configuration, the extending sections 614b and 615b, which extend side by side, are connected through the U-shaped section 616. This allows the extension sections 614b and 615b to be routed in a small area while maintaining a constant distance between them. As a result, good electromagnetic coupling can be achieved between the extending sections 614b and 615b while making effective use of space.

[0127] In the balun 101, the wiring 114 is provided along the first surface and is formed by a metal electrode 614 extending from one end of the wiring 114 to the other end. The wiring 115 is provided along the first surface and is formed by a metal electrode 615 extending from one end of the wiring 115 to the other end. The metal electrode 614 includes a corner portion 614c where the direction of extension changes. The metal electrode 615 is provided inside the corner portion 614c.

[0128] In this configuration, by providing the metal electrode 615 with open ends inside the corner portion 614c, which has limited space, it becomes easier to provide wiring that does not have open ends outside the corner portion 614c, which has more space. This makes it easier to design the layout of the balun 101 on the semiconductor chip. Furthermore, since space can be used effectively, the integration density of the semiconductor chip can be improved.

[0129] Furthermore, in the balun 101, the metal electrode 615 includes a corner portion 615c that extends alongside the corner portion 614c.

[0130] In this configuration, the extension portion 615b extends inside the corner portion 614c, alongside the corner portion 614c, allowing the corner portion 615c to be routed while maintaining a constant distance from the corner portion 614c. This enables good electromagnetic coupling between the corner portions 614c and 615c.

[0131] Furthermore, in the balun 101, the wiring 112 is provided along the first surface and is formed by a metal electrode 612 that extends from one end of the wiring 112 to the other end. The metal electrode 612 is provided outside the corner portion 614c and includes a corner portion 612c that extends parallel to the corner portion 614c.

[0132] In this configuration, the corner portion 612c extends alongside the corner portion 614c on its outer side, allowing the corner portion 612c to be routed while maintaining a constant distance from the corner portion 614c. This enables a good connection between the corner portions 614c and 612c.

[0133] Furthermore, in the power amplifier circuit 201, the carrier amplifier 51c amplifies the signal RF3 and outputs the amplified signal RF5 from the output terminal 51ca. The peak amplifier 51p amplifies the signal RF4, which has a different phase from the signal RF3, and outputs the amplified signal RF6 from the output terminal 51pa. Wire 111 has one end connected to the output terminal 51ca and the other end connected to the first reference potential. Wire 112 has one end connected to the output terminal 51pa and the other end connected to the first reference potential. Wire 113 has one end and the other end which supplies the output signal RFout, and is coupled to wire 111. Wire 114 has one end connected to one end of wire 113 and the other end, and is coupled to wire 112. Wire 115 has one end connected to the other end of wire 114 and the other end which is open, and is electromagnetically coupled to wire 114.

[0134] In this configuration, by connecting wiring 115, which is electromagnetically coupled to wiring 114, to the other end of wiring 114, wirings 114 and 115 can be capacitively coupled, thereby suppressing the inductive properties of wirings 114 and 115 in the power amplifier circuit 201. When the peak amplifier 51p is off, the frequency dependence of the input impedance to wiring 114 can be reduced, so the frequency dependence of the reflected wave reflected by wiring 114 among the signals generated by the coupling between wirings 111 and 113 can be reduced. As a result, the frequency change of S21 can be made almost flat. Therefore, the frequency change of impedance when viewed from the carrier amplifier downstream when the peak amplifier is off can be suppressed.

[0135] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. The present invention can be modified or improved without departing from its spirit, and equivalents thereof are also included. That is, any design modifications made to each embodiment by those skilled in the art are also included within the scope of the present invention, as long as they retain the features of the present invention. For example, the elements and their arrangement, materials, conditions, shapes, sizes, etc., of each embodiment are not limited to those exemplified and can be modified as appropriate. Furthermore, each embodiment is illustrative, and it goes without saying that partial substitution or combination of the configurations shown in different embodiments is possible, and these are also included within the scope of the present invention as long as they retain the features of the present invention.

[0136] <1> A first wiring having one end connected to a carrier amplifier and the other end connected to a first reference potential, A second wiring having one end connected to the peak amplifier and the other end connected to the first reference potential, A third wiring having one end and the other end connected to a terminal, and coupled to the first wiring, A fourth wiring having one end connected to the one end of the third wiring and the other end, and coupled to the second wiring, A fifth wiring has one end connected to the other end of the fourth wiring and the other end open, and is electromagnetically coupled to the fourth wiring. Balan.

[0137] <2> <1> The balance described above, Each of the first, second, and fifth wirings is a quarter-wavelength line, The combined third and fourth wiring is a half-wavelength transmission line. Balan.

[0138] <3> <1> The balance described above, A balance according to claim 1, Each of the first and second wirings is a quarter-wavelength line, The third and fourth wiring combined is a half-wavelength line. The fifth wiring is a line having an electrical length greater than one-quarter and less than three-eighth of the wavelength of the signal amplified by the carrier amplifier. Balan.

[0139] <4> <1> The balance described above, A balance according to claim 1, Each of the first and second wirings is a quarter-wavelength line, The third and fourth wiring combined is a half-wavelength line. The fifth wiring is a line having an electrical length greater than one-eighth and less than one-quarter of the wavelength of the signal amplified by the carrier amplifier. Balan.

[0140] <5> <1> from <4> A balance described in any one of the following: The frequency of the signal amplified by the carrier amplifier and the frequency of the signal amplified by the peak amplifier are included in the subterahertz band. Balan.

[0141] <6> <1> from <5> A balance described in any one of the following: The fourth wiring is provided along the first surface and is formed by a first conductive member extending from one end of the fourth wiring to the other end of the fourth wiring. The fifth wiring is provided along the first surface and is formed by a second conductive member extending from one end of the fifth wiring to the other end of the fifth wiring. The first conductive member includes a first extended portion that extends along a first direction, The second conductive member is connected to the first extended portion through a U-shaped portion and includes a second extended portion that extends parallel to the first extended portion. Balan.

[0142] <7> <1> from <5> A balance described in any one of the following: The fourth wiring is provided along the first surface and is formed by a first conductive member extending from one end of the fourth wiring to the other end of the fourth wiring. The fifth wiring is provided along the first surface and is formed by a second conductive member extending from one end of the fifth wiring to the other end of the fifth wiring. The first conductive member includes a first corner portion where the direction of extension changes, The second conductive member is provided inward from the first corner portion, Balan.

[0143] <8> <7> The balance described above, The second conductive member includes a second corner portion that extends parallel to the first corner portion. Balan.

[0144] <9> <7> or <8> The balance described above, The second wiring is provided along the first surface and is formed by a third conductive member extending from one end of the second wiring to the other end of the second wiring. The third conductive member is provided outside the first corner portion and includes a third corner portion that extends parallel to the first corner portion. Balan.

[0145] <10> A carrier amplifier that amplifies the first signal and outputs the first amplified signal from the first output terminal, A peak amplifier that amplifies a second signal having a different phase from the aforementioned first signal and outputs the second amplified signal from the second output terminal, A first wiring having one end connected to the first output terminal and the other end connected to the first reference potential, A second wiring having one end connected to the second output terminal and the other end connected to the first reference potential, A third wiring having one end and the other end for supplying an output signal, and coupled to the first wiring, A fourth wiring having one end connected to the one end of the third wiring and the other end, and coupled to the second wiring, A fifth wiring has one end connected to the other end of the fourth wiring and the other end open, and is electromagnetically coupled to the fourth wiring. Power amplifier circuit. [Explanation of symbols]

[0146] 31…Input terminals 32…Output terminals 50c, 51c... Carrier amplifier 50pF, 51pF... Peak amplifier 50ca, 51ca, 50pa, 51pa… Output terminals 60…Capacitor 61c, 61p...Interstage matching circuit 62c, 62p, 63... Capacitors 64... Patch antenna 101... Balan 111, 112, 113, 114, 115… wiring 121, 122… Capacitors 151... Balan 161, 162, 163, 164… wiring 201, 202, 203, 204, 205… Power Amplifier Circuits 301a, 302a, 303a, 304a… wiring 301b, 302b, 303b, 304b… Capacitors 501c, 501p, 502...railway 611, 612, 613, 614, 615...metal electrode 611a, 611b, 612a, 612b, 613a, 613b, 614a, 614b, 615a, 615b...extension part 611c, 612c, 613c, 614c, 615c... corner section 616...U-shaped part 701c, 701p... Interlayer vias

Claims

1. A first wiring having one end connected to a carrier amplifier and the other end connected to a first reference potential, A second wiring having one end connected to the peak amplifier and the other end connected to the first reference potential, A third wiring having one end and the other end connected to a terminal, and coupled to the first wiring, A fourth wiring having one end connected to the one end of the third wiring and the other end, and coupled to the second wiring, A fifth wiring has one end connected to the other end of the fourth wiring and the other end open, and is electromagnetically coupled to the fourth wiring. Balan.

2. A balance according to claim 1, Each of the first, second, and fifth wirings is a quarter-wavelength line, The combined wiring of the third and fourth wirings is a half-wavelength line. Balan.

3. A balance according to claim 1, Each of the first and second wirings is a quarter-wavelength line, The combined wiring of the third and fourth wirings is a half-wavelength line. The fifth wiring is a line having an electrical length greater than one-quarter and less than three-eighths of the wavelength of the signal amplified by the carrier amplifier. Balan.

4. A balance according to claim 1, Each of the first and second wirings is a quarter-wavelength line, The combined wiring of the third and fourth wirings is a half-wavelength line. The fifth wiring is a line having an electrical length greater than one-eighth and less than one-quarter of the wavelength of the signal amplified by the carrier amplifier. Balan.

5. A balance according to claim 1, The frequency of the signal amplified by the carrier amplifier and the frequency of the signal amplified by the peak amplifier are included in the subterahertz band. Balan.

6. A balance according to claim 1, The fourth wiring is provided along the first surface and is formed by a first conductive member extending from one end of the fourth wiring to the other end of the fourth wiring. The fifth wiring is provided along the first surface and is formed by a second conductive member extending from one end of the fifth wiring to the other end of the fifth wiring. The first conductive member includes a first extended portion that extends along a first direction, The second conductive member is connected to the first extended portion through a U-shaped portion and includes a second extended portion that extends parallel to the first extended portion. Balan.

7. A balance according to claim 1, The fourth wiring is provided along the first surface and is formed by a first conductive member extending from one end of the fourth wiring to the other end of the fourth wiring. The fifth wiring is provided along the first surface and is formed by a second conductive member extending from one end of the fifth wiring to the other end of the fifth wiring. The first conductive member includes a first corner portion where the direction of extension changes, The second conductive member is provided inward from the first corner portion, Balan.

8. A balance according to claim 7, The second conductive member includes a second corner portion that extends parallel to the first corner portion. Balan.

9. A balance according to claim 8, The second wiring is provided along the first surface and is formed by a third conductive member extending from one end of the second wiring to the other end of the second wiring. The third conductive member is provided outside the first corner portion and includes a third corner portion that extends parallel to the first corner portion. Balan.

10. A carrier amplifier that amplifies the first signal and outputs the first amplified signal from the first output terminal, A peak amplifier that amplifies a second signal having a different phase from the first signal and outputs the second amplified signal from the second output terminal, A first wiring having one end connected to the first output terminal and the other end connected to the first reference potential, A second wiring having one end connected to the second output terminal and the other end connected to the first reference potential, A third wiring having one end and the other end for supplying an output signal, and coupled to the first wiring, A fourth wiring having one end connected to the one end of the third wiring and the other end, and coupled to the second wiring, A fifth wiring has one end connected to the other end of the fourth wiring and the other end open, and is electromagnetically coupled to the fourth wiring. Power amplification circuit.

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