Coupler with 90-degree
The asymmetrical 90-degree coupler design addresses the issue of increased circuit size by reducing capacitor capacitance and maintaining effective signal phase distribution, resulting in a compact and efficient circuit for radio frequency signal distribution.
Patent Information
- Application Number
- JP2024088876
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-05-31
- Publication Date
- 2025-12-11
AI Technical Summary
Existing 90-degree couplers increase in circuit size when distributing low-frequency radio frequency signals due to the need for increased capacitance to match impedance with circuits having low characteristic impedance.
A 90-degree coupler design with asymmetrical capacitor connections, where the capacitance of one capacitor is smaller than the other, and inductors are electromagnetically coupled, reducing the overall circuit size while maintaining effective signal phase distribution.
The design achieves a reduced circuit scale with improved impedance matching and signal phase distribution, enhancing the performance of the 90-degree coupler as a divider or combiner circuit.
Smart Images
Figure 2025181102000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a 90-degree coupler. [Background technology]
[0002] A 90-degree coupler is included in a distribution circuit that distributes a radio frequency (RF) signal (see, for example, FIG. 2). In a power amplifier circuit 901 shown in FIG. 2, a 90-degree coupler 90 is provided between a matching circuit 22 and inductors 981 and 982.
[0003] The 90-degree coupler 90 includes capacitors 91 and 92, inductors 93 and 94, and a resistive element 95. The capacitor 91 has one end connected to the matching circuit 22 and the other end connected to an inductor 981. The inductor 93 has one end connected to one end of the capacitor 91 and the other end connected to an inductor 982. The inductor 94 has one end connected to the other end of the capacitor 91 and the other end connected to ground via the resistive element 95. The capacitor 92 has one end connected to the other end of the inductor 93 and the other end connected to the other end of the inductor 94. Summary of the Invention [Problem to be solved by the invention]
[0004] For example, when distributing a low-frequency radio frequency signal using the 90-degree coupler 90, it may be necessary to increase the capacitance of the capacitor in order to match the impedance with a circuit having a low characteristic impedance. In this case, the circuit size of the 90-degree coupler 90 increases.
[0005] The present invention has been made in view of the above circumstances, and has an object to provide a 90-degree coupler that can reduce the circuit scale. [Means for solving the problem]
[0006] A 90-degree coupler according to one aspect of the present invention comprises: a first capacitor having one end connected to a first terminal and the other end connected to a first amplifier; a first inductor having one end connected to the first terminal and the other end connected to a second amplifier; a second inductor having one end connected to the other end of the first capacitor and the other end connected to ground via a resistive element, and electromagnetically coupled to the first inductor; and a second capacitor having one end connected to the first terminal and the other end connected to the other end of the second inductor. [Effects of the Invention]
[0007] According to the present invention, it is possible to provide a 90-degree coupler that can reduce the circuit scale. [Brief explanation of the drawings]
[0008] [Figure 1] FIG. 2 is a circuit diagram of a power amplifier circuit 101. [Figure 2] FIG. 9 is a circuit diagram of a power amplifier circuit 901 as a reference example. [Figure 3] 10 is a diagram showing frequency changes in the difference between the phase of the amplified signal RF3 at the port P2 of the 90-degree coupler 70 and the phase of the amplified signal RF2 at the port P3. [Figure 4] 10 is a diagram showing frequency changes in the difference between the phase of the amplified signal RF3 at the port P2 of the 90-degree coupler 90 and the phase of the amplified signal RF2 at the port P3. [Figure 5] FIG. 10 is a diagram showing the frequency change of loss in a 90-degree coupler 70. [Figure 6] FIG. 10 is a diagram showing the frequency change of loss in a 90-degree coupler 90. [Figure 7] FIG. 2 is a circuit diagram of a power amplifier circuit 102. [Figure 8] 10 is a diagram showing the frequency change of loss when the capacitance of capacitor 92 is set smaller than the capacitance of capacitor 91 in 90-degree coupler 90. FIG. [Figure 9]This figure shows the frequency change of the difference between the phase of the amplified signal RF3 at port P2 and the phase of the amplified signal RF2 at port P3 when the capacitance of capacitor 92 in 90-degree coupler 90 is made smaller than the capacitance of capacitor 91. DETAILED DESCRIPTION OF THE INVENTION
[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the same elements are given the same reference numerals, and redundant explanations will be omitted as much as possible.
[0010] [First embodiment] A power amplifier circuit 101 according to a first embodiment will be described. FIG. 1 is a circuit diagram of the power amplifier circuit 101. As shown in FIG. 1, a semiconductor device 1 includes the power amplifier circuit 101. The semiconductor device 1 is, for example, a semiconductor chip on which the power amplifier circuit 101 is formed. Specifically, the semiconductor device 1 is an MMIC (Microwave Monolithic Integrated Circuit). The power amplifier circuit 101 is a circuit that operates as a Doherty amplifier or a balanced amplifier that amplifies a radio frequency signal.
[0011] The power amplifier circuit 101 includes capacitors 60, 61, 62, 63, 303, and 310, matching circuits 21, 22, and 23, a combining circuit 42, transistor elements 50, 51 (first amplifier) and 52 (second amplifier), a 90-degree coupler 70, inductors 81 (third inductor) and 82 (fourth inductor), bias circuits 150, 151, and 152, resistive elements 160, 161, and 162, and inductors 300, 313, and 314.
[0012] In this embodiment, the transistor element is configured by a bipolar transistor such as a heterojunction bipolar transistor (HBT). Note that the transistor element may be configured by other transistors such as a metal-oxide-semiconductor field-effect transistor (MOSFET). In that case, the base, collector, and emitter may be replaced with the gate, drain, and source, respectively.
[0013] Matching circuit 21 in power amplifier circuit 101 is provided between input terminal 31 (first terminal) and capacitor 60, and matches the impedance between capacitor 60 and a circuit (not shown) provided in the preceding stage of input terminal 31.
[0014] The capacitor 60 is provided, for example, for DC blocking, and has one end connected to the input terminal 31 via the matching circuit 21, and the other end.
[0015] The transistor element 50 is a driver stage amplifier. Specifically, the transistor element 50 has a base connected to the other end of the capacitor 60, an emitter connected to ground, and a collector. The transistor element 50 amplifies an input signal RFin supplied to its base from the input terminal 31 via the matching circuit 21 and the capacitor 60, and outputs an amplified signal RF1 from its collector. The input signal RFin is, for example, a radio frequency signal.
[0016] The bias circuit 150 generates a bias to be supplied to the base of the transistor element 50 and outputs it from a bias supply terminal 150a. The bias supply terminal 150a is connected to the base of the transistor element 50 via a resistor element 160.
[0017] Voltage supply terminal T1 supplies power supply voltage Vcc for operating transistor element 50 and is connected to the collector of transistor element 50 through inductor 300. Capacitor 310 is provided between voltage supply terminal T1 and ground and functions as a filter for attenuating harmonics.
[0018] The matching circuit 22 has one end connected to the collector of the transistor element 50 and the other end. The matching circuit 22 matches the impedance between the transistor element 50 and the 90-degree coupler 70.
[0019] The 90-degree coupler 70 has ports P1, P2, P3, and P4. The ports P1 and P4 are an input port and an isolation port, respectively. The ports P2 and P3 are output ports. In this embodiment, the 90-degree coupler 70 functions as a distribution circuit.
[0020] The port P1 is connected to the other end of the matching circuit 22. The amplified signal RF1 (first signal) is supplied from the collector of the transistor element 50 through the matching circuit 22 to the port P1.
[0021] The 90-degree coupler 70 splits the amplified signal RF1 supplied to the port P1 into an amplified signal RF2 (second signal) and an amplified signal RF3 (third signal).
[0022] The amplified signal RF3 has a phase that lags behind the phase of the amplified signal RF2 by 45 degrees or more and 135 degrees or less. In this embodiment, the amplified signal RF3 has a phase that lags behind the phase of the amplified signal RF2 by approximately 90 degrees.
[0023] The port P3 supplies the amplified signal RF2 to the input terminal of the transistor element 51. The port P2 supplies the amplified signal RF3 to the input terminal of the transistor element 52.
[0024] More specifically, the 90-degree coupler 70 includes capacitors 71 (first capacitor) and 72 (second capacitor), inductors 73 (first inductor) and 74 (second inductor), and a resistive element 75.
[0025] Capacitor 71 has one end connected to the other end of matching circuit 22 and the other end connected to transistor element 51 via inductor 81 and capacitor 61 .
[0026] Inductor 73 has one end connected to the other end of matching circuit 22 and the other end connected to transistor element 52 via inductor 82 and capacitor 62 .
[0027] Inductor 74 has one end connected to the other end of capacitor 71 and the other end connected to ground via resistive element 75, and is electromagnetically coupled to inductor 73. The coupling coefficient k of inductors 73 and 74 is, for example, 0.8.
[0028] The capacitor 72 has one end connected to the other end of the matching circuit 22 and the other end connected to the other end of the inductor 74 .
[0029] One end of capacitor 71, one end of inductor 73, and one end of capacitor 72 correspond to port P1. The other end of capacitor 71 and one end of inductor 74 correspond to port P3. The other end of inductor 73 corresponds to port P2. The other end of inductor 74 and the other end of capacitor 72 correspond to port P4.
[0030] The capacitance of capacitor 72 is smaller than the capacitance of capacitor 71. In this embodiment, the capacitances of capacitors 72 and 71 are, for example, 5 pF and 15 pF, respectively. In other words, the capacitance of capacitor 72 is approximately one-third the capacitance of capacitor 71. This allows the areas of the two electrodes that make up capacitor 72 to be reduced, thereby reducing the circuit size of the 90-degree coupler 70.
[0031] The inductor 81 is provided between the other end of the capacitor 71 and the transistor element 51. Specifically, the inductor 81 has one end connected to the other end of the capacitor 71 and the other end connected to the base of the transistor element 51 via the capacitor 61. The capacitor 61 is provided, for example, to block DC.
[0032] The inductor 82 is provided between the other end of the inductor 73 and the transistor element 52. Specifically, the inductor 82 has one end connected to the other end of the inductor 73 and the other end connected to the base of the transistor element 52 via the capacitor 62. The capacitor 62 is provided, for example, to block DC.
[0033] The transistor element 51 is a carrier amplifier. Specifically, the transistor element 51 has a base (input terminal), an emitter connected to ground, and a collector. The transistor element 51 amplifies the amplified signal RF2 supplied to the base from the port P3 of the 90-degree coupler 70 through the inductor 81 and the capacitor 61, and outputs an amplified signal RF4 from the collector.
[0034] The bias circuit 151 generates a first bias to be supplied to the base of the transistor element 51 through the resistor element 161 and outputs it from a bias supply terminal 151a. The bias supply terminal 151a is connected to the base of the transistor element 51 through the resistor element 161. In this embodiment, the transistor element 51 performs class A operation or class AB operation due to the first bias supplied from the bias circuit 151.
[0035] The transistor element 52 is a peak amplifier. Specifically, the transistor element 52 has a base (input terminal), an emitter connected to ground, and a collector. The transistor element 52 amplifies the amplified signal RF3 supplied to the base from the port P2 of the 90-degree coupler 70 through the inductor 82 and the capacitor 62, and outputs an amplified signal RF5 from the collector.
[0036] The bias circuit 152 generates a low bias or a high bias to be supplied to the base of the transistor element 52 through a resistor element 162 and outputs it from a bias supply terminal 152a. The bias supply terminal 152a is connected to the base of the transistor element 52 through the resistor element 162.
[0037] In this embodiment, the bias circuit 152 switches the bias point (operating point or operating class) of the transistor element 52 between, for example, a low bias point and a high bias point higher than the low bias point. For example, the bias circuit 152 supplies the transistor element 52 with either a low bias or a high bias higher than the low bias.
[0038] When a high bias is supplied to the transistor element 52, the power amplifier circuit 101 is in a balanced mode. At this time, the bias point of the transistor element 52 becomes a high bias point, and the transistor element 52 operates in, for example, class A or class AB. This causes the power amplifier circuit 101 to operate as a balanced amplifier.
[0039] On the other hand, when a low bias is supplied to the transistor element 52, the power amplifier circuit 101 enters the Doherty mode. At this time, the bias point of the transistor element 52 becomes a low bias point, and the transistor element 52 operates, for example, in class AB or class B. This causes the power amplifier circuit 101 to operate as a Doherty amplifier.
[0040] Voltage supply terminal T2 supplies power supply voltage Vcc for operating transistor elements 51 and 52, and is connected to the collector of transistor element 51 and the collector of transistor element 52 via inductors 313 and 314, respectively. Capacitor 303 is provided between voltage supply terminal T2 and ground, and functions as a filter that attenuates harmonics.
[0041] The combining circuit 42 reduces the phase difference between the amplified signals RF4 and RF5 supplied from the transistor elements 51 and 52, respectively, and combines the amplified signals RF4 and RF5 to generate the output signal RFout. The combining circuit 42 outputs the output signal RFout to the output terminal 32 via the capacitor 63 and the matching circuit 23.
[0042] In this embodiment, the combining circuit 42 includes capacitors 202 and 205 and inductors 211 , 212 and 225 .
[0043] Inductor 212 has one end connected to the collector of transistor element 52, and the other end. Inductor 225 has one end connected to the other end of inductor 212 via capacitor 202, and the other end connected to ground. Capacitor 205 has one end connected to the other end of inductor 212, and the other end connected to node N1. Inductor 211 has one end connected to the collector of transistor element 51, and the other end connected to node N1.
[0044] Capacitor 63 is provided for DC blocking, and has one end connected to node N1 and the other end.
[0045] The matching circuit 23 is provided between the capacitor 63 and the output terminal 32, and matches the impedance between the capacitor 63 and a circuit (not shown) provided in the subsequent stage of the output terminal 32.
[0046] (Reference example) A power amplifier circuit 901 of a reference example will be described. Fig. 2 is a circuit diagram of the power amplifier circuit 901 of a reference example. Compared to the power amplifier circuit 101 shown in Fig. 1, the power amplifier circuit 901 includes a 90-degree coupler 90 and inductors 981 and 982 instead of the 90-degree coupler 70 and inductors 81 and 82, respectively.
[0047] As described above, in the 90-degree coupler 70, one end of the capacitor 72 is connected to one end of the inductor 73. On the other hand, in the 90-degree coupler 90, one end of the capacitor 92 is connected to the other end of the inductor 93.
[0048] The coupling coefficient k of the inductors 93 and 94 is, for example, 0.8. The capacitance of the capacitor 92 is approximately the same as the capacitance of the capacitor 91. In this embodiment, the capacitance of the capacitors 91 and 92 is, for example, 15 pF. In other words, the capacitance of the capacitor 92 is about three times the capacitance of the capacitor 72. This results in a large circuit size for the 90-degree coupler 90.
[0049] (effect) 3 is a diagram showing frequency change of the difference between the phase of the amplified signal RF3 at port P2 of the 90-degree coupler 70 and the phase of the amplified signal RF2 at port P3. The vertical axis represents the phase difference in degrees, and the horizontal axis represents frequency in MHz.
[0050] 4 is a diagram showing frequency changes in the difference between the phase of the amplified signal RF3 at port P2 of the 90-degree coupler 90 and the phase of the amplified signal RF2 at port P3. Note that FIG. 4 can be viewed in the same way as FIG.
[0051] As shown in Figures 3 and 4, in the power amplifier circuit 101, the phase difference between the amplified signal RF3 and the amplified signal RF2 is approximately -90°, allowing the 90-degree coupler 70 to function as a distribution circuit as well as or better than the 90-degree coupler 90.
[0052] In the power amplifier circuits 101 and 901, the impedance Zc (see FIGS. 1 and 2) when looking from one end of the capacitor 61 toward the input terminal 31 is preferably about 8+j×10 ohms, for example, where j is an imaginary unit.
[0053] The impedance Zp (see FIGS. 1 and 2) when looking from one end of the capacitor 62 to the input terminal 31 side is preferably about 8+j×10 ohms, for example.
[0054] The impedance Zd (see FIGS. 1 and 2) when looking from the collector of the transistor element 50 to the output terminal 32 side is preferably, for example, about 30 to 50 ohms.
[0055] For example, when the reference impedance is set to 8 ohms, the S-parameter (hereinafter sometimes referred to as S33) of port P3 (see Figure 1) in the 90-degree coupler 70 can contain more positive imaginary components than the S-parameter (hereinafter sometimes referred to as S33r) of port P3 (see Figure 3) in the 90-degree coupler 90.
[0056] As a result, the inductance of inductor 81 (see Figure 1) that matches the impedance between 90-degree coupler 70 and capacitor 61 can be made smaller than the inductance of inductor 981 (see Figure 2) that matches the impedance between 90-degree coupler 90 and capacitor 61.
[0057] Specifically, the inductance of the inductor 81 is 1.4 nH and the inductance of the inductor 981 is 1.6 nH. This allows the circuit scale of the inductor 81 to be smaller than the circuit scale of the inductor 981.
[0058] Furthermore, for example, when the reference impedance is set to 8 ohms, the S parameter (hereinafter sometimes referred to as S22) of port P2 (see Figure 1) in the 90-degree coupler 70 can contain more positive imaginary components than the S parameter (hereinafter sometimes referred to as S22r) of port P2 (see Figure 2) in the 90-degree coupler 90.
[0059] As a result, the inductance of inductor 82 (see Figure 1) that matches the impedance between 90-degree coupler 70 and capacitor 62 can be made smaller than the inductance of inductor 982 (see Figure 2) that matches the impedance between 90-degree coupler 90 and capacitor 62.
[0060] Specifically, the inductance of the inductor 82 is 1.3 nH and the inductance of the inductor 982 is 1.8 nH. This allows the circuit scale of the inductor 82 to be smaller than the circuit scale of the inductor 982.
[0061] 5 is a diagram showing the frequency change of loss in the 90-degree coupler 70. The vertical axis represents loss in units of "dBm," and the horizontal axis represents frequency in units of "MHz."
[0062] As shown in FIG. 5, the curve THR indicates the frequency change of the loss when a radio frequency signal passes through a path from port P1 to capacitor 62 via inductor 73, port P2, and inductor 82 in power amplifier circuit 101 (see FIG. 1).
[0063] A curve CPL indicates the frequency change of loss when a radio frequency signal passes through a path from port P1 to capacitor 61 via capacitor 71, port P3, and inductor 81 in power amplifier circuit 101 (see FIG. 1).
[0064] 6 is a diagram showing the frequency change of loss in the 90-degree coupler 90. Note that FIG. 6 can be read in the same way as FIG.
[0065] As shown in FIG. 6, a curve THRr indicates the frequency change of loss when a radio frequency signal passes through a path from port P1 in power amplifier circuit 901 (see FIG. 2) to capacitor 62 via inductor 93, port P2, and inductor 982.
[0066] A curve CPLr indicates the frequency change of loss when a radio frequency signal passes through a path from port P1 to capacitor 61 via capacitor 91, port P3, and inductor 981 in power amplifier circuit 901 (see FIG. 2).
[0067] As described above, S33 contains a larger positive imaginary component than S33r, which makes it possible to reduce the amount of impedance transformation by inductor 81 compared to the amount of impedance transformation by inductor 981, thereby improving the loss indicated by curve CPL compared to the loss indicated by curve CPLr.
[0068] Furthermore, S22 contains a larger positive imaginary component than S22r, which makes it possible to reduce the amount of impedance transformation by inductor 82 compared to the amount of impedance transformation by inductor 982, thereby improving the loss indicated by curve THR compared to the loss indicated by curve THRr.
[0069] [Second embodiment] A power amplifier circuit 102 according to a second embodiment will be described. From the second embodiment onwards, descriptions of matters common to the first embodiment will be omitted, and only differences will be described. In particular, similar effects resulting from similar configurations will not be mentioned in each embodiment.
[0070] Fig. 7 is a circuit diagram of the power amplifier circuit 102. As shown in Fig. 7, the power amplifier circuit 102 differs from the power amplifier circuit 101 according to the first embodiment in that it includes a capacitor 64 and inductors 83 and 84 instead of the matching circuit 22 and inductors 81 and 82.
[0071] Capacitor 64 has one end connected to the collector of transistor element 50 and the other end connected to one end of capacitor 71 in 90-degree coupler 70. Capacitor 64 matches the impedance between transistor element 50 and 90-degree coupler 70.
[0072] Inductor 83 has one end connected to the other end of capacitor 71 and the other end connected to ground.
[0073] Inductor 84 has one end connected to the other end of inductor 73 and the other end connected to ground.
[0074] Although the embodiment described in this specification describes an example in which the 90-degree coupler 70 functions as a divider circuit, the 90-degree coupler of the present invention can be applied not only to dividers but also to combiners. Specifically, a 90-degree coupler 70 may be provided instead of the combiner circuit 42, and the provided 90-degree coupler 70 may combine the amplified signals RF4 and RF5 to generate the output signal RFout. In this case, ports P2 and P3 of the 90-degree coupler 70 serve as input terminals, and port P1 serves as an output terminal.
[0075] Furthermore, in this embodiment, a configuration has been described in which the capacitance of capacitor 72 is smaller than the capacitance of capacitor 71, but this is not limited to this; the capacitance of capacitor 72 may be equal to or greater than the capacitance of capacitor 71.
[0076] An exemplary embodiment of the present invention has been described above. In the power amplifier circuits 101 and 102, the 90-degree coupler 70 includes capacitors 71 and 72, inductors 73 and 74, and a resistive element 75. The capacitor 71 has one end connected to the input terminal 31 and the other end connected to the transistor element 51. The inductor 73 has one end connected to the input terminal 31 and the other end connected to the transistor element 52. The inductor 74 has one end connected to the other end of the capacitor 71 and the other end connected to ground via the resistive element 75, and is electromagnetically coupled to the inductor 73. The capacitor 72 has one end connected to the input terminal 31 and the other end connected to the other end of the inductor 74.
[0077] FIG. 8 shows the frequency change of loss when the capacitance of capacitor 92 in the 90-degree coupler 90 is set smaller than the capacitance of capacitor 91. The interpretation of FIG. 8 is the same as that of FIG. 5. FIG. 9 shows the frequency change of the difference between the phase of amplified signal RF3 at port P2 and the phase of amplified signal RF2 at port P3 when the capacitance of capacitor 92 in the 90-degree coupler 90 is set smaller than the capacitance of capacitor 91. The interpretation of FIG. 9 is the same as that of FIG. 3. As shown in FIGS. 8 and 9, for example, when the capacitance of capacitor 92 in the 90-degree coupler 90 is set smaller than the capacitance of capacitor 91, S22r and S33r can contain many imaginary components. However, the difference between curve THRr and curve CPLr becomes significantly larger at low frequencies, resulting in poor balance. Furthermore, the phase difference between amplified signals RF3 and RF2 deviates from −90°. For this reason, simply reducing the capacitance of capacitor 92 in 90-degree coupler 90 makes it difficult for 90-degree coupler 90 to function well as a divider circuit or combiner circuit. The inventors conducted extensive research to solve this problem and discovered that by using an asymmetric connection where one end of capacitor 72 is connected to one end of inductor 73, rather than a symmetric connection where one end of capacitor 72 is connected to the other end of inductor 73, it is possible to make 90-degree coupler 70 function well as a divider circuit or combiner circuit while reducing the capacitance of capacitor 71 or 72. This makes it possible to provide a 90-degree coupler that allows for a reduced circuit size.
[0078] In the power amplifier circuits 101 and 102, the capacitance of the capacitor 72 is smaller than the capacitance of the capacitor 71.
[0079] In this way, by configuring the capacitance of the capacitor 72 to be smaller than the capacitance of the capacitor 71, the 0-degree coupler 70 can function well as a distribution circuit for the 9 Doherty amplifier and the balanced amplifier.
[0080] In the power amplifier circuit 101, the other end of the capacitor 71 is connected to the transistor element 51 through an inductor 81. The other end of the inductor 73 is connected to the transistor element 52 through an inductor .
[0081] With this configuration, inductor 81 can provide good impedance matching between 90-degree coupler 70 and transistor element 51. Furthermore, since the inductance of inductor 81 can be reduced, the circuit size of inductor 81 can be reduced. Furthermore, inductor 82 can provide good impedance matching between 90-degree coupler 70 and transistor element 52. Furthermore, since the inductance of inductor 82 can be reduced, the circuit size of inductor 82 can be reduced.
[0082] In the power amplifier circuits 101 and 102, one end of the capacitor 71 is supplied with an amplified signal RF1 from the input terminal 31. The other end of the capacitor 71 supplies an amplified signal RF2 to the input terminal of the transistor element 51. The other end of the inductor 73 supplies an amplified signal RF3, whose phase lags behind the phase of the amplified signal RF2 by 45 degrees or more and 135 degrees or less, to the input terminal of the transistor element 52.
[0083] With this configuration, the 90-degree coupler 70 can function as a dividing circuit that effectively divides the amplified signal RF1 into the amplified signals RF2 and RF3.
[0084] The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the scope of the present invention. The present invention may be modified or improved without departing from its spirit, and equivalents are also encompassed within the scope of the present invention. In other words, designs modified by those skilled in the art as appropriate are also encompassed within the scope of the present invention as long as they incorporate the characteristics of the present invention. For example, the elements and their arrangements, materials, conditions, shapes, sizes, etc., included in the embodiments are not limited to those illustrated and can be modified as appropriate. Furthermore, the embodiments are merely examples, and partial substitutions or combinations of the configurations shown in different embodiments are naturally possible. These are also encompassed within the scope of the present invention as long as they incorporate the characteristics of the present invention.
[0085] <1> a first capacitor having one end connected to the first terminal and the other end connected to the first amplifier; a first inductor having one end connected to the first terminal and the other end connected to a second amplifier; a second inductor having one end connected to the other end of the first capacitor and the other end connected to ground via a resistive element, the second inductor being electromagnetically coupled to the first inductor; a second capacitor having one end connected to the first terminal and the other end connected to the other end of the second inductor; 90 degree coupler.
[0086] <2> <1> 90-degree coupler according to claim 1, The capacitance of the second capacitor is smaller than the capacitance of the first capacitor. 90 degree coupler.
[0087] <3> <1> or <2> 90-degree coupler according to claim 1, the other end of the first capacitor is connected to the first amplifier through a third inductor; the other end of the first inductor is connected to the second amplifier through a fourth inductor. 90 degree coupler.
[0088] <4> <1> from <3> 90-degree coupler according to any one of the preceding claims, a first signal is supplied to the one end of the first capacitor from the first terminal; the other end of the first capacitor supplies a second signal to an input terminal of the first amplifier; the other end of the first inductor supplies a third signal, having a phase that is delayed from the phase of the second signal by 45 degrees or more and 135 degrees or less, to the input terminal of the second amplifier; 90 degree coupler. [Explanation of symbols]
[0089] 1. Semiconductor devices 21, 22, 23...matching circuit 31...Input terminal 32...Output terminal 42...Synthesis circuit 50, 51, 52...Transistor elements 60, 61, 62, 63, 64...Capacitors 70...90 degree coupler 71, 72...Capacitor 73, 74...Inductors 75...Resistance element 81, 82, 83, 84...Inductors 101, 102...Power amplifier circuit 150, 151, 152...Bias circuit 160, 161, 162...Resistance elements 202, 205, 303, 310... Capacitors 211, 212, 225, 300, 313, 314... inductors P1, P2, P3, P4...Ports T1, T2...Voltage supply terminals N1...Node
Claims
1. a first capacitor having one end connected to the first terminal and the other end connected to the first amplifier; a first inductor having one end connected to the first terminal and the other end connected to a second amplifier; a second inductor having one end connected to the other end of the first capacitor and the other end connected to ground via a resistive element, the second inductor being electromagnetically coupled to the first inductor; a second capacitor having one end connected to the first terminal and the other end connected to the other end of the second inductor; 90 degree coupler.
2. 2. The 90-degree coupler of claim 1, The capacitance of the second capacitor is smaller than the capacitance of the first capacitor. 90 degree coupler.
3. 2. The 90-degree coupler of claim 1, the other end of the first capacitor is connected to the first amplifier through a third inductor; the other end of the first inductor is connected to the second amplifier through a fourth inductor; 90 degree coupler.
4. 2. The 90-degree coupler of claim 1, a first signal is supplied to the one end of the first capacitor from the first terminal; the other end of the first capacitor supplies a second signal to an input terminal of the first amplifier; the other end of the first inductor supplies a third signal, having a phase that is delayed from the phase of the second signal by 45 degrees or more and 135 degrees or less, to the input terminal of the second amplifier; 90 degree coupler.