Broadband directional coupler

Abstract

The invention discloses a broadband directional coupler, which comprises an input port, an output port, a coupling port and a coupling assembly, and is characterized in that the coupling assembly comprises a first coupling network and a compensation network; the first coupling network is connected with the input port, the output port and the compensation network; and the coupling port is connected to the compensation network. The broadband directional coupler provided by the scheme can be suitable for a high-power directional coupler with a flat full-band coupling coefficient of 1kHz-500MHz, is small in insertion loss and stable in use, and still has better performance for a low-band.

Description

Technical Field

[0001] The present invention belongs to the field of coupling technology, and particularly relates to a broadband directional coupler. Background Art

[0002] A directional coupler is a commonly used RF component that can couple a part of the power from the main transmission path and output it to a specific port to achieve the purpose of online monitoring of the forward transmission power and the reflected power.

[0003] In a broadband high-power RF measurement system, in addition to requiring the directional coupler to have small insertion loss, large power capacity, and good directivity, extremely high requirements are also placed on the bandwidth. The directional coupler with a cavity structure has the characteristics of large power capacity, good directivity, and small insertion loss of the main line, and is widely used in medium and high-power systems. However, due to size limitations, it is difficult for the directional coupler with a cavity structure to cover lower frequency bands.

[0004] The existing low-insertion-loss directional couplers have a narrow bandwidth, while the couplers with a wide bandwidth are difficult to achieve low insertion loss and have a low power capacity. The broadband high-power measurement system has to adopt a combination of multiple directional couplers to achieve wide-band coverage, which increases the error introduced by multiple switching of test ports in actual use and is not conducive to the automatic control of the test system. Therefore, the existing low-insertion-loss directional couplers need to be further improved and developed. Summary of the Invention

[0005] The purpose of the present invention is to provide a broadband directional coupler for the above problems.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions: A broadband directional coupler includes an input port, an output port, a coupling port, and a coupling component. The coupling component includes a first coupling network and a compensation network; The first coupling network is connected to the input port, the output port, and the compensation network; The coupling port is connected to the compensation network.

[0007] In the above broadband directional coupler, the input port is connected to an input cable having an inner conductor and an outer conductor; The first coupling network includes a second resistor R2, a third resistor R3, and a fourth resistor R4; The inner conductor of the input cable is connected to one end of the second resistor R2 and the output port, and the end of the second resistor R2 far from the input port is connected to the compensation network; The outer conductor of the input cable is connected to one end of the fourth resistor R4. The end of the fourth resistor R4 far from the input port is connected to the output port, and between the fourth resistor R4 and the output port, one end of the third resistor R3 is connected. The end of the third resistor R3 far from the output port is connected to the compensation network.

[0008] In the above broadband directional coupler, the resistance value of the second resistor R2 is 1K - 10K ohms, the resistance value of the third resistor R3 is 10 ohms - 100 ohms, and the resistance value of the fourth resistor R4 is 0.1 - 1 ohm.

[0009] In the above broadband directional coupler, the fourth resistor R4 is formed by connecting several resistors in parallel, and the parallel connection of several resistors makes the resistance value of the fourth resistor R4 be 0.1 - 1 ohm.

[0010] In the above broadband directional coupler, the first coupling network includes a circuit board and a resistor integration unit arranged on the circuit board, and the resistor integration unit includes a resistor integration area, an outer conductor connection area, and a first through hole and a second through hole opened on the circuit board; The several resistors forming the fourth resistor R4 are circumferentially and uniformly arranged on the circuit board to form the annular resistor integration area; The outer conductor connection area is located within the annular area of the resistor integration area, and the outer conductor connection area has an annular structure, and the outer conductor connection area coincides with the annular central axis of the resistor integration area; The first through hole is opened at the center position of the outer conductor connection area; The second through hole is opened outside the outer conductor connection area and inside the resistor integration area or extends inward from the annular line of the resistor integration area; The central connection line of the first through hole and the second through hole coincides with the symmetry axis of the resistor integration area; The outer conductor connection area is electrically connected to the resistor integration area, and the outer conductor is electrically connected to the outer conductor connection area so that the outer conductor is connected to the fourth resistor R4; The inner conductor passes through the first through hole and is connected to the second resistor R2, and after passing through the second through hole, the inner conductor is connected to the compensation network.

[0011] In the above broadband directional coupler, the compensation network includes a first compensation circuit and a second compensation circuit connected in series; The first compensation circuit includes a first compensation resistor R11 and a second compensation resistor R12 connected in series. A first compensation inductor L1 is connected in parallel with the first compensation resistor R11 and the second compensation resistor R12. A first compensation capacitor C1 is connected between the first compensation resistor R11 and the second compensation resistor R12. One end of the first compensation capacitor C1, which is far from the first compensation resistor R11 and the second compensation resistor R12, is connected to a third compensation resistor R13, and the end of the third compensation resistor R13 far from the first compensation capacitor C1 is grounded. The second compensation circuit is a π-type compensation circuit including a fourth compensation resistor R14, a fifth compensation resistor R15, and a sixth compensation resistor R16.

[0012] In the above broadband directional coupler, the input port, the output port, and the coupling port are all grounded.

[0013] In the above broadband directional coupler, the coupling component further includes a first ground isolation device T1 and a second ground isolation device T2; The first ground isolation device T1 is located between the first coupling network and the output port; The second ground isolation device T2 is located between the first coupling network and the compensation network.

[0014] In the above broadband directional coupler, the coupling component further includes a second coupling network. The first coupling network and the second coupling network are symmetrically docked through the first ground isolation device T1; The coupling port is connected to the first coupling network through the compensation network and the second ground isolation device T2; The input port is connected to one end of the first coupling network far from the second coupling network, and the output port is connected to one end of the second coupling network far from the first coupling network; One end of the second coupling network corresponding to the first coupling network for connecting the coupling port is connected to the output port through a second compensation network and an isolation port.

[0015] In the above broadband directional coupler, the second coupling network includes a sixth resistor R6, a seventh resistor R7, and a ninth resistor R9 that are mirror-symmetrical to the second resistor R2, the third resistor R3, and the fourth resistor R4 of the first coupling network respectively, and the first coupling network and the second coupling network have the same network structure and resistor values. Similarly, the second compensation network has the same circuit structure as the compensation network.

[0016] The advantages of the present invention are as follows: The broadband directional coupler provided by this solution can be applied to high-power directional couplers with a flat coupling coefficient in the full frequency band of 1 kHz to 500 MHz. It not only has small insertion loss and stable operation, but also has good performance in the low-frequency band. Brief Description of the Drawings

[0017] Figure 1 It is a schematic diagram of the connection relationship of the broadband directional coupler in Embodiment 1 of the present invention; Figure 2 It is a schematic circuit structure diagram of the broadband directional coupler in Embodiment 1 of the present invention; Figure 3 It is a schematic diagram of the connection relationship of the compensation network of the broadband directional coupler in Embodiment 1 of the present invention; Figure 4 It is a schematic diagram of the structure of the coupling network of the broadband directional coupler in Embodiment 1 of the present invention; Figure 5 It is a schematic diagram of the connection relationship of the broadband directional coupler in Embodiment 2 of the present invention; Figure 6 It is a schematic circuit structure diagram of the broadband directional coupler in Embodiment 2 of the present invention; Figure 7 It is a schematic circuit structure diagram of the broadband directional coupler in Embodiment 3 of the present invention; Figure 8 It is a schematic diagram of the connection of the coupling network of the broadband directional coupler in Embodiment 3 of the present invention during simulation sampling; Figure 9 It is the measured result of the insertion loss of the broadband directional coupler of the present invention on a network analyzer; Figure 10 It is the measured result of the coupling degree of the broadband directional coupler of the present invention on a network analyzer; Figure 11 It is the measured result of the low-frequency isolation of the broadband directional coupler of the present invention; Figure 12 It is the frequency response result of the compensation network of the broadband directional coupler of the present invention during simulation sampling.

[0018] Reference Numerals: Input Port 101; Output Port 102; Coupling Port 103; Coupling Network 104; Compensation Network 105; Oscilloscope 106; Isolation Port 107; Resistance Integration Region 201; Outer Conductor Connection Region 202; First Perforation 203; Second Perforation 204. Detailed Description of the Embodiments Embodiment 1

[0019] The broadband directional coupler provided by this solution includes an input port 101, an output port 102, a coupling port 103, and a coupling component. The input port 101, the output port 102, and the coupling port 103 are arranged on the outer shell of the coupler, and the coupling component is arranged inside the outer shell, and the outer shell is a metal outer shell.

[0020] As Figure 1 shown, the coupling component includes a coupling network 104 and a compensation network 105. The coupling network 104 is connected to the input port 101, the output port 102, and the compensation network, and the compensation network 105 is connected between the coupling port 103 and the coupling network 104. The input port 101, the output port 102, and the coupling port 103 are grounded respectively, and the coupling port 103 can be grounded by connecting to the outer shell.

[0021] Specifically, as Figure 2 shown, the coupling network 104 includes a second resistor R2, a third resistor R3, and a fourth resistor R4. For the convenience of description, for the second resistor R2, the third resistor R3, and the fourth resistor R4, Figure 2 the end with a solid circle mark is called the input end of the corresponding resistor, and the other end is called the output end of the corresponding resistor.

[0022] The inner conductor of the input cable of the input port 101 is connected to the input end of the second resistor R2 and the output port 102, and the output end of the second resistor R2 is connected to the compensation network 105. The outer conductor of the input cable of the input port 101 is connected to the input end of the fourth resistor R4, the output end of the fourth resistor R4 is connected to the output port 102, and the input end of the third resistor R3 is connected between the fourth resistor R4 and the output port 102, and the output end of the third resistor R3 is connected to the compensation network 105.

[0023] The resistance value of the second resistor R2 is preferably a relatively large resistance value in the order of several thousand ohms, such as 5000 ohms. The third resistor R3 is preferably a relatively small resistance value in the order of several tens of ohms, such as 50 ohms. The fourth resistor R4 uses an even smaller resistance value, such as 0.5 ohms.

[0024] Specifically, as Figure 3As shown, the compensation network 105 includes a first compensation circuit and a second compensation circuit, and the first compensation circuit is connected in series with the second compensation circuit. Among them, the first compensation circuit includes a first compensation resistor R11, a second compensation resistor R12, a third compensation resistor R13, a first compensation inductor L1, and a first compensation capacitor C1. The first compensation resistor R11 and the second compensation resistor R12 are connected in series, and the first compensation inductor L1 is connected in parallel with the first compensation resistor R11 and the second compensation resistor R12. A first compensation capacitor C1 is connected between the first compensation resistor R11 and the second compensation resistor R12, and one end of the first compensation capacitor C1 far from the first compensation resistor R11 and the second compensation resistor R12 is connected to the third compensation resistor R13, and the other end of the third compensation resistor R13 far from the first compensation capacitor C1 is grounded.

[0025] The second compensation circuit is a π-type compensation circuit, specifically including a fourth compensation resistor R14, a fifth compensation resistor R15, and a sixth compensation resistor R16. The fifth compensation resistor R15 is connected in series with the first compensation circuit, and a fourth compensation resistor R14 is connected between the fifth compensation resistor R15 and the first compensation circuit, and one end of the fourth compensation resistor R14 not connected to the fifth compensation resistor R15 is grounded. The other end of the fifth compensation resistor R15 far from the first compensation circuit is connected to the sixth compensation resistor R16, and the other end of the sixth compensation resistor R16 is grounded. Figure 3 The port on the left in is connected to the coupling port 103, and the port on the right is connected to the resistors R2 and R3.

[0026] Further, as Figure 4 shown, the fourth resistor R4 is preferably composed of a plurality of resistors connected in parallel. In this embodiment, it is composed of ten 5-ohm resistors connected in parallel, and specifically, it is formed by integrating in a resistor integration unit to form the fourth resistor R4. The resistor integration unit includes a resistor integration area 201, an outer conduction connection area 202, and a through hole. The resistor integration area 201 is an annular area composed of ten 5-ohm resistors evenly distributed circumferentially, and the ten 5-ohm resistors in the resistor integration area 201 are evenly distributed on the annular area. The outer conduction connection area 202 is arranged in the annular area, and the outer conduction connection area 202 is also an annular structure and coincides with the central axis of the annular area. The through hole is used for component connection. A first through hole 203 is arranged in the outer conduction connection area 202, that is, the first through hole 203 is provided at the center of the annular area, and the outer conduction connection area 202 is around the first through hole 203. A conductive medium is provided on the outer conduction connection area 202, and the conductive medium on the outer conduction connection area 202 is connected to one end of the ten parallel 5-ohm resistors in the resistor integration area 201, that is, connected to the input of the fourth resistor R4. When the outer conductor of the input cable of the input port 101 is connected to the conductive medium on the outer conduction connection area 202, the connection between the outer conductor of the input cable and the fourth resistor R4 is realized. The ten 5-ohm resistors in the resistor integration area 201 can be chip resistors.

[0027] A 0.5-ohm resistor obtained by paralleling ten 5-ohm resistors is used as resistor R4. On the one hand, the lower resistance value of resistor R4 enables the circuit to have better high-frequency characteristics. On the other hand, paralleling multiple resistors can effectively improve the power capacity of the circuit.

[0028] When the outer conductor of the input cable of input port 101 is connected to the conductive medium on the outer conductor connection area 202, the inner conductor of the input cable of input port 101 passes through the first through hole 203 of the resistor integration unit. The inner conductor of the input cable passing through the first through hole 203 is connected to one end of the second resistor R2.

[0029] A second through hole 204 is provided on the resistor integration area 201. The connection line between the first through hole 203 and the second through hole 204 is a symmetry axis of the resistor integration area 201, called the first symmetry axis. On the resistor integration area 201 on both sides of the first symmetry axis, five 5-ohm resistors are respectively distributed. Among them, the resistors on the resistor integration area 201 on both sides of the first symmetry axis are evenly distributed on the resistor integration area 201 on both sides of the first symmetry axis, so that the coupler has higher high-frequency characteristics. At this time, no resistor is provided at the position centrosymmetric to the second through hole 204 with respect to the center of the first through hole 203.

[0030] The output end of the second resistor R2 and the output end of the third resistor R3 are connected through a conductive medium. The conductive medium passes through the second through hole 204 to connect the output end of the second resistor R2 and the output end of the third resistor R3. Alternatively, the inner conductor of the input cable of input port 101 passes through the second through hole 204 and then is connected to the input end of the second resistor R2. Here, no specific limitation is made. It should be noted that when the second resistor R2 is working, due to its relatively large resistance, more heat is generated. Therefore, when the second resistor R2 is fixed, it should be as close as possible to the outer shell of the coupler to ensure the heat dissipation effect of the second resistor R2. According to the fixed position of the second resistor R2, it is then determined whether it is the inner conductor of the input cable or the conductive medium connecting the output end of the second resistor R2 and the output end of the third resistor R3 that passes through the second through hole 204.

[0031] The resistor integration unit is also provided with fixing holes for fixing the resistor integration unit in the outer shell. The specific installation position is not limited here.

[0032] This solution ensures the accuracy of the coupling network 104 through the compensation network 105 and cancels the distributed parameters on the coupling coefficient, which can ensure the flatness of the coupling coefficient in the full frequency band. Embodiment 2

[0033] As Figure 5 and Figure 6As shown, this embodiment is similar to Embodiment 1, except that the coupling component of this embodiment further includes a ground isolation device. A first ground isolation device T1 is connected between the coupling network 104 and the output port 102, and a second ground isolation device T2 is connected between the coupling network 104 and the compensation network 105.

[0034] Specifically, the inner conductor of the input cable of the input port 101 is connected to the input end of the second resistor R2 and the first ground isolation device T1, and the other end of the first ground isolation device T1 is connected to the output port 102. The output end of the second resistor R2 is connected to the second ground isolation device T2.

[0035] The output end of the fourth resistor R4 is connected to the first ground isolation device T1. The fourth resistor R4 is connected to the first ground isolation device T1. The input end of the third resistor R3 is connected between the output end of the fourth resistor R4 and the first ground isolation device T1, the output end of the third resistor R3 is connected to the second ground isolation device T2, and the second ground isolation device T2 is connected to the compensation network. After the output ends of the second resistor R2 and the third resistor R3 are connected, they are connected to the second ground isolation device T2. The ground isolation device can be a coaxial choke, a magnetic ring, or other anti-interference components for suppressing noise.

[0036] One end of the compensation network 105 is connected to the second ground isolation device T2, and the other end is connected to the coupling port 103.

[0037] The ground isolation device and its installation position proposed in this solution isolate the ground lines of the input port 101, the output port 102, and the coupling port 103, realizing the isolation of low-frequency noise, enabling the signal to return along the outer skin of the coaxial cable on the main transmission path. At the same time, the reference ground of the coupling port is connected to the metal shell of the coupler, cooperating with the Figure 4 coupling network structure shown in Embodiment 1 is adapted to the coaxial cable of the main transmission line, and components with small parasitic parameters are used for packaging. When the frequency is relatively low, the influence of parasitic parameters on the coupling coefficient can be ignored. However, when the frequency exceeds 100 MHz, the coupling coefficient will increase significantly with the increase of the frequency. In this regard, the compensation network proposed in this solution can offset the influence of distributed parameters on the coupling coefficient, thereby ensuring the flatness of the coupling coefficient in the full frequency band. Embodiment 3

[0038] As Figure 7 shown, this embodiment is similar to Embodiment 2, except that the broadband directional coupler of this embodiment includes two coupling components that are mirror-connected to each other, and the first ground isolation device T1 is connected between the two coupling components to simultaneously realize the coupled output of the forward passing signal and the reflected signal. Here, the two coupling components are respectively referred to as the first coupling component and the second coupling component. Figure 7Among them, the one on the left is the first coupling component, and the one on the right is the second coupling component.

[0039] The coupling network of the first coupling component is composed of R2, R3, and R4. Correspondingly, the coupling network of the second coupling component is composed of R6, R7, and R9. The second resistor R2 in the first coupling component and the sixth resistor R6 in the second coupling component are mirror - set and have the same value. The fourth resistor R4 in the first coupling component and the ninth resistor R9 in the second coupling component are mirror - set and have the same value. The third resistor R3 in the first coupling component and the seventh resistor R7 in the second coupling component are mirror - set and have the same value. For the sake of description, in Figure 7 Among them, for the corresponding ends of the resistors R6, R7, and R9 corresponding to the second resistor R2, the third resistor R3, and the fourth resistor R4, they are also marked with solid circles, and the end with the solid circle is called the input end of the corresponding resistor.

[0040] The first resistor R1 in the first coupling component is the internal resistance of the signal source V1, the resistor R5 is the internal resistance of the coupling port 103, the resistor R8 in the second coupling component is the internal resistance of the signal output end, and the resistor R10 is the internal resistance of the isolation port.

[0041] The output end of the first coupling component is connected to the part of the second coupling component corresponding to the output end of the first coupling component, that is Figure 7 Among them, the input ends of R2, R3 are connected to the input ends of R6, R7. The part of the second coupling component corresponding to the input end of the first coupling component is connected to the output port 102, serving as the output end of the coupler, that is, the connection of the input ends of the resistor R6 and the resistor R9 is the output port 102. The compensation network 105 of the second coupling component is connected to the isolation port, serving as the isolation port of the coupler.

[0042] This solution conducts simulation tests on a broadband directional coupler including an isolation port.

[0043] As Figure 8 shown, the red arrow represents voltage - coupling sampling, the green arrow represents current - coupling sampling, and the two converge at the TC point to form a coupling signal.

[0044] Next, the voltage conditions at the TC point during no - load and load matching of the width directional coupler in the present invention will be described: R1 is the internal resistance of the signal source V1, R1 = 50 ohms; R5 is the internal resistance of the coupling port 103, R5 = 50 ohms; R8 is the internal resistance of the signal output end, R8 = 50 ohms; R10 is the internal resistance of the isolation port, R10 = 50 ohms.

[0045] The output voltage when the signal source V1 is load - matched is Vout = 0.5 * V1.

[0046] When the width directional coupler is open-circuited, S1 is open, and the load is much greater than the 50-ohm source impedance, so it can be regarded as open-circuited. At this time, the current in the loop is very small, and the voltage drop generated on R4 can be ignored. The voltage at the TC point is: VTC = V1 * (R5 / / R3) / (R1 + R2 + R5 / / R3) = V1 * 25 / 5075 = 0.004926 * V1; Relative to the matched load, VTC / Vout = 0.009852 = -40.13 dB; VTC is the voltage at the TC point; Vout is the output voltage when the load of the signal source V1 is matched.

[0047] When S1 is closed, the output end of the broadband directional coupler is connected to the load. Ignoring the current on R2 and R6, the current on the main transmission path is: IMain = V1 / (R1 + R8 + R9 + R4) = V1 / 101 Ω; The voltage drop on R4 is V1 * R4 / 101 Ω = V1 * 0.5 / 101 Ω = 0.004950 V1; The component of the voltage drop on R4 generated at the TC point is: VTC1 = 1 / 2 * V1 * R4 / 101 = 0.002475; The component of the voltage on the right side of R1 generated at the TC point is: VTC2 = V1 * (R8 + R9 + R4) / (R1 + R8 + R9 + R4) * (R5 / / R3) / (R1 + R2 + R5 / / R3) = V1 * 51 / 101 * 25 / 5075 = 0.002487 * V1; VTC = VTC1 + VTC2 = 0.004962 * V1; Relative to the matched load, VTC / Vout = 0.009904 = -40.08 dB; IMain is the current on the main transmission path when there is a load; VTC1 is the component of the voltage drop on R4 generated at the TC point; VTC2 is the component of the voltage on the right side of R1 generated at the TC point.

[0048] It can be seen from the above calculation results that when it is open-circuited and the load is matched, the coupling coefficient at the TC point is about -40 dB.

[0049] Figure 9 、 Figure 10 、 Figure 11 For the measured results on the network analyzer, specifically, Figure 9 is the insertion loss on the main transmission path; Figure 10is the coupling degree of the coupling port relative to the input port; since the frequency of the network analyzer cannot reach 1 kHz, an oscilloscope is used in this experiment. Figure 11 is the isolation degree of this solution measured using the oscilloscope's Bode plot function from 50 Hz to 500 kHz, which can confirm that the directivity at 1 kHz in the following text is better than 20 dB. It can be seen that the insertion loss of the directional coupler implemented by this solution is only about 0.2 dB, the coupling coefficient is about -40 dB, and the flatness is better than ±0.2 dB. And from the test results, it can be seen that the directional coupler of this solution still has good performance in the low-frequency band, the directivity at 1 kHz is better than 20 dB, while the general low-insertion-loss directional coupler can only reach about 16 dB.

[0050] such as Figure 12 shown, the red is the frequency response compensating the insertion loss of the compensation network, and the magenta is the frequency response compensating the return loss of the input port of the compensation network. The measured value of the coupling coefficient after the compensation network 105 is as Figure 10 shown, it can be seen that the flatness is better than ±0.2 dB at this time, verifying that this solution can ensure the flatness of the coupling coefficient.

[0051] In summary, the directional coupler provided by this solution has a small insertion loss, high stability from 1 kHz to 500 MHz. In particular, it still has good performance in the low-frequency band, the directivity at 1 kHz is better than 20 dB, and it has excellent flatness in the entire frequency band from 1 kHz to 500 MHz, not higher than 0.2 dB in the whole frequency band. Even when the input power is 200 W, the total loss of the coupler does not exceed 10 W. For a module with an aluminum alloy material main structure, the heat dissipation pressure is very small. Therefore, a power capacity of 200 W can be used to achieve a directional coupler with wide bandwidth, low insertion loss, and high power capacity. Therefore, the directional coupler of this solution is applicable to the application scenarios from 1 kHz to 500 MHz. In addition, this solution avoids the errors introduced by multiple switching of test ports and facilitates the automatic control of the test system.

[0052] The specific embodiments described in this article are only illustrative of the spirit of the present invention. Those skilled in the art of the present invention can make various modifications or supplements to the described specific embodiments or use similar ways to replace them, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0053] Although the terms input port 101; output port 102; coupling port 103; coupling network 104; compensation network 105; oscilloscope 106; isolation port 107; resistor integration region 201; external conduction connection region 202; first via 203; second via 204, etc. are used more frequently in this text, the possibility of using other terms is not excluded. The use of these terms is only for more convenient description and explanation of the essence of the present invention; interpreting them as any additional limitation is contrary to the spirit of the present invention.

Claims

1. A broadband directional coupler, comprising an input port (101), an output port (102), a coupling port (103) and a coupling component, characterized in that: The coupling component comprises a first coupling network (104) and a compensation network (105); The first coupling network (104) is connected to the input port (101), the output port (102), and the compensation network (105); The coupling port (103) is connected to the compensation network (105).

2. The broadband directional coupler according to claim 1, characterized in that: The input port (101) is connected to an input cable having an inner conductor and an outer conductor; The first coupling network (104) comprises a second resistor R2, a third resistor R3 and a fourth resistor R4; The inner conductor of the input cable is connected to one end of the second resistor R2 and the output port (102); the end of the second resistor R2 away from the input port (101) is connected to the compensation network (105); The outer conductor of the input cable is connected to one end of a fourth resistor R4, the end of the fourth resistor R4 away from the input port (101) is connected to the output port (102), and the fourth resistor R4 and the output port (102) are connected to one end of the third resistor R3, and the end of the third resistor R3 away from the output port (102) is connected to the compensation network (105).

3. The broadband directional coupler according to claim 2, characterized in that: The resistance value of the second resistor R2 is 1K-10K ohms, the resistance value of the third resistor R3 is 10-100 ohms, and the resistance value of the fourth resistor R4 is 0.1-1 ohm.

4. The broadband directional coupler according to claim 3, characterized in that: The fourth resistor R4 is formed by connecting a plurality of resistors in parallel, and the plurality of resistors connected in parallel make the resistance of the fourth resistor R4 be 0.1-1 ohm.

5. The broadband directional coupler according to claim 4, characterized in that: The first coupling network (104) comprises a circuit board and a resistor integrated unit arranged on the circuit board, and the resistor integrated unit comprises a resistor integrated region (201) and an external conductive connection region (202); A plurality of resistors constituting the fourth resistor R4 are evenly arranged circumferentially on the circuit board to form the resistor integration area (201) in a ring shape; The external conductive connection area (202) is located in the annular area of ​​the resistor integrated area (201), and the external conductive connection area (202) is in an annular structure, and the annular central axes of the external conductive connection area (202) and the resistor integrated area (201) coincide with each other; The resistor integrated unit further comprises a first through hole (203) and a second through hole (204) formed on the circuit board; The first through hole (203) is opened at the center of the external conductive connection area (202); The second through hole (204) is opened outside the external conductive connection area (202) and inside the resistor integrated area (201) or extends from the ring line of the resistor integrated area (201) to the inside; The central connection line between the first through hole (203) and the second through hole (204) coincides with the symmetry axis of the resistor integrated region (201); The outer conductor connection area (202) is electrically connected to the resistor integrated area (201), and the outer conductor is electrically connected to the outer conductor connection area (202), so that the outer conductor is connected to the fourth resistor R4; The inner conductor passes through the first through hole (203) to be connected to the second resistor R2, and the inner conductor passes through the second through hole (204) to be connected to the compensation network (105).

6. The broadband directional coupler according to claim 1, characterized in that: The compensation network (105) comprises a first compensation circuit and a second compensation circuit connected in series with each other; The first compensation circuit includes a first compensation resistor R11 and a second compensation resistor R12 connected in series, the first compensation resistor R11 and the second compensation resistor R12 are connected in parallel with a first compensation inductor L1, a first compensation capacitor C1 is connected between the first compensation resistor R11 and the second compensation resistor R12, an end of the first compensation capacitor C1 away from the first compensation resistor R11 and the second compensation resistor R12 is connected to a third compensation resistor R13, and an end of the third compensation resistor R13 away from the first compensation capacitor C1 is grounded; The second compensation circuit is a π-type compensation circuit including a fourth compensation resistor R14 , a fifth compensation resistor R15 , and a sixth compensation resistor R16 .

7. The broadband directional coupler according to claim 2, characterized in that: The input port (101), the output port (102), and the coupling port (103) are all grounded; The resistance of the second resistor R2 is 5k ohms, the resistance of the third resistor R3 is 50 ohms, and the resistance of the fourth resistor R4 is 0.5 ohms.

8. The broadband directional coupler according to claim 7, characterized in that: The coupling assembly further includes a first grounding isolation device T1 and a second grounding isolation device T2; The first ground isolation device T1 is located between the first coupling network (104) and the output port (102); The second grounding isolation device T2 is located between the first coupling network (104) and the compensation network (105).

9. The broadband directional coupler according to claim 8, characterized in that: The coupling component further comprises a second coupling network (104), and the first coupling network (104) and the second coupling network (104) are connected to each other in a mirror-symmetrical relationship via the first grounding isolation device T1; The coupling port (103) is connected to the first coupling network (104) via the compensation network (105) and the second grounding isolation device T2; The input port (101) is connected to an end of the first coupling network (104) away from the second coupling network (104), and the output port (102) is connected to an end of the second coupling network (104) away from the first coupling network (104); The second coupling network (104) corresponds to the first coupling network (104) and is used to connect one end of the coupling port (103) to the output port (102) via a second compensation network (105) and an isolation port (107).

10. The broadband directional coupler according to claim 9, characterized in that: The second coupling network (104) comprises a sixth resistor R6, a seventh resistor R7 and a ninth resistor R9 which are mirror-symmetrical to the second resistor R2, the third resistor R3 and the fourth resistor R4 of the first coupling network (104), respectively, and the first coupling network (104) and the second coupling network (104) have the same network structure and resistance values.

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