Directional coupler device based on power divider

Abstract

The invention discloses a directional coupler device based on a power divider, and relates to the technical field of directional couplers, and the power divider is used for dividing input power into a plurality of equal or unequal power outputs. Comprising a first port, a second port, a third port, a first microstrip line, a second microstrip line, a third microstrip line, a fourth microstrip line, a fifth microstrip line, a sixth microstrip line, a seventh microstrip line, a first isolation resistor and a second isolation resistor. The frequency working range of the directional coupler can be expanded by increasing the order of the power divider, the directionality of the directional coupler is high, high port isolation can be achieved due to the fact that isolation resistors exist in output ports of the power divider, and therefore the high directionality of the directional coupler is achieved, and due to the fact that only microstrip lines, chip resistors and differential conversion devices are arranged, the circuit is simple, and cost is low. The directional coupler is simple in structure and easy to debug, can realize low insertion loss by using an unequal power divider, can be used for a vector network analyzer, and can output a reflected signal of a test port to a receiver of the vector network analyzer to obtain amplitude information and phase information of the reflected signal.

Description

Technical Field

[0001] The invention relates to the technical field of directional couplers, in particular to a directional coupler device based on a power divider. Background Art

[0002] Directional coupler is a multi-port device commonly used in RF microwave measurement. It can identify forward waves and reverse waves and can be used for transmitter power control. It can also be used to monitor the matching of antenna and feeder systems. In conjunction with detectors and level indicators, it can be used as a power meter and standing wave meter. It can also be used as a front-end device of a vector network analyzer to extract the reflected signal of the vector network test port and combine it with the vector network's own transmission signal. Through arithmetic processing, the voltage standing wave ratio, return loss and impedance of the input port of the device under test can be obtained.

[0003] In the HF and VHF bands, transmission line transformers are a common structural form for implementing directional couplers. They are usually wound on a magnetic ring, are relatively large in size, and have complex processes. As the operating frequency gradually increases, the influence of distributed parameters becomes more and more obvious, and the reliability of the equipment decreases accordingly. The frequency coverage of vector network analyzers ranges from a few kHz to a few GHz, and even up to hundreds of GHz. It is becoming increasingly difficult for directional couplers to cover from low frequency to high frequency.

[0004] In the process of implementing the above equipment solution, there are the following problems in the prior art.

[0005] As the operating frequency of existing vector network analyzers continues to increase, the design, structure and installation of directional couplers are becoming more and more complicated, and the workload of debugging and maintenance is huge.

[0006] The directional coupler has the problem of large insertion loss, which affects the maximum power of the output end of the vector network analyzer or increases the hardware cost of the entire vector network analyzer. Summary of the invention

[0007] In order to solve the deficiencies mentioned in the above background technology, an object of the present invention is to provide a directional coupler device based on a power divider.

[0008] In a first aspect, the purpose of the present invention can be achieved by the following technical solutions: 1. A directional coupler device based on a power divider, comprising:

[0009] Power divider: used to divide the input power into several equal or unequal power outputs, including: a first port, a second port, a third port, a first microstrip line, a second microstrip line, a third microstrip line, a fourth microstrip line, a fifth microstrip line, a sixth microstrip line, a seventh microstrip line, a first isolation resistor and a second isolation resistor;

[0010] Load: used to absorb the radio frequency signal energy input from the first port and output from the second port of the microstrip power divider, and prevent the output radio frequency signal from being reflected back from the second port;

[0011] Differential to single-ended circuit: used to convert the voltage difference across the second isolation resistor, i.e., the differential mode signal, into a common mode signal, which is a single-ended circuit connection method that is convenient for users to use.

[0012] In combination with the first aspect, in certain implementations of the first aspect, the device also includes: the first port is used to receive an input RF signal, the power divider divides the input RF signal into two RF signals, which flow to the second port and the third port respectively, the second port outputs one of the two RF signals, and the third port outputs the other of the two RF signals.

[0013] In combination with the first aspect, in certain implementations of the first aspect, the device also includes: the first microstrip line is a strip transmission line, which is arranged along the direction of the input RF signal, one end of the first microstrip line is connected to the first port, and the other end of the first microstrip line is connected to one end of the fourth microstrip line and the fifth microstrip line.

[0014] In combination with the first aspect, in certain implementations of the first aspect, the device also includes: one end of the first isolation resistor is connected to the other end of the fourth microstrip line and to one end of the sixth microstrip line, and the other end of the first isolation resistor is connected to the other end of the fifth microstrip line and to one end of the seventh microstrip line.

[0015] In combination with the first aspect, in certain implementations of the first aspect, the device also includes: one end of the second isolation resistor is connected to the other end of the sixth microstrip line and is also connected to one end of the second microstrip line, and the other end of the second isolation resistor is connected to the other end of the seventh microstrip line and is also connected to one end of the third microstrip line.

[0016] In combination with the first aspect, in some implementations of the first aspect, the device further includes: the other end of the second microstrip line is connected to the second port, and the other end of the third microstrip line is connected to the third port.

[0017] In combination with the first aspect, in some implementations of the first aspect, the device further includes: the resistance values ​​of the first isolation resistor and the second isolation resistor are related to the isolation degree between the second port and the third port.

[0018] In combination with the first aspect, in certain implementations of the first aspect, the device also includes: the lengths of the fourth microstrip line, the fifth microstrip line, the sixth microstrip line and the seventh microstrip line determine the isolation frequency band range of the second port and the third port of the power divider, and the shorter the length of the microstrip line, the higher the frequency at which the isolation effect will be produced.

[0019] In combination with the first aspect, in certain implementations of the first aspect, the device further includes: a coupling coefficient between the spacing between the fourth microstrip line and the fifth microstrip line, the spacing between the sixth microstrip line and the seventh microstrip line, and the impedance of the power divider, wherein the coupling coefficient affects the strength of the isolation.

[0020] In combination with the first aspect, in certain implementations of the first aspect, the device also includes: the line widths of the fourth microstrip line, the fifth microstrip line, the sixth microstrip line and the seventh microstrip line determine the energy distribution from the first port to the second port and the third port, the microstrip line with a small line width has a high impedance and obtains less energy distribution, and the microstrip line with a large line width has a low impedance and obtains more energy distribution.

[0021] Beneficial effects of the present invention:

[0022] The present invention has a wide operating frequency range, and the frequency operating range of the directional coupler can be expanded by increasing the order of the power divider. The directional coupler has high directivity. Since there is an isolation resistor at the output port of the power divider, a high port isolation can be achieved, thereby achieving high directivity of the directional coupler. Since there are only microstrip lines, chip resistors and differential conversion devices, the circuit is simple and easy to debug. By using an unequal power divider, a directional coupler with low insertion loss can be achieved. It can be used in a vector network analyzer, and the reflected signal of the test port can be output to the receiver of the vector network analyzer to obtain the amplitude information and phase information of the reflected signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 is a schematic structural diagram of a power divider according to an embodiment of the present invention;

[0025] Figure 2 is a schematic structural diagram of a directional coupler according to an embodiment of the present invention;

[0026] Figure 3 4 is a diagram showing the test results of the directional coupler according to an embodiment of the present invention.

[0027] In the figure:

[0028] A first port 100, a second port 101, a third port 102, a first microstrip line 103, a second microstrip line 104, a third microstrip line 105, a fourth microstrip line 106, a fifth microstrip line 107, a sixth microstrip line 108, a seventh microstrip line 109, a first isolation resistor 110, and a second isolation resistor 111;

[0029] A first input port 200, a second output port 201, a third output port 202, an isolation resistor 203, a microstrip line 1 204, a microstrip line 205, and a differential to single-ended circuit 206; DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Embodiment 1:

[0032] The following is an introduction to the relevant terms involved in the embodiments of the present application:

[0033] Power divider: A power divider is a device that divides the energy of an input signal into two or more equal or unequal outputs. It can also combine the energy of multiple signals into one output. In this case, it can also be called a combiner. A certain degree of isolation should be ensured between the output ports of a power divider. A power divider is also called an overcurrent divider. It is divided into active and passive types. It can evenly divide a signal into several outputs. Generally, each divided signal has a few dB of attenuation. The signal frequency is different, and the attenuation of different dividers is also different. In order to compensate for the attenuation, an amplifier is added to it to make a passive power divider.

[0034] like Figure 1 As shown, a directional coupler device based on a power divider comprises:

[0035] Power divider: used to divide the input power into several equal or unequal power outputs. The Wilkinson power divider is widely used in the microwave radio frequency field due to its advantages of high isolation, wide bandwidth and simple structure. It includes: a first port, a second port, a third port, a first microstrip line, a second microstrip line, a third microstrip line, a fourth microstrip line, a fifth microstrip line, a sixth microstrip line, a seventh microstrip line, a first isolation resistor and a second isolation resistor;

[0036] Load: used to absorb the radio frequency signal energy input from the first port and output from the second port of the microstrip power divider, and prevent the output radio frequency signal from being reflected back from the second port;

[0037] Differential to single-ended circuit: used to convert the voltage difference across the second isolation resistor, i.e., the differential mode signal, into a common mode signal, which is a single-ended circuit connection method that is convenient for users to use.

[0038] The first port 100 is used to receive an input RF signal. The power divider divides the input RF signal into two RF signals, which flow to the second port 101 and the third port 102 respectively. The second port 101 outputs one of the two RF signals, and the third port 102 outputs the other of the two RF signals.

[0039] The first microstrip line 103 is a strip transmission line, which is arranged along the direction of the input RF signal. Figure 1 The first microstrip line is arranged in the horizontal direction, one end of the first microstrip line 103 is connected to the first port 100 , and the other end of the first microstrip line 103 is connected to one end of the fourth microstrip line 106 and the fifth microstrip line 107 .

[0040] One end of the first isolation resistor 110 is connected to the other end of the fourth microstrip line 106 and to one end of the sixth microstrip line 108 . The other end of the first isolation resistor 110 is connected to the other end of the fifth microstrip line 107 and to one end of the seventh microstrip line 109 .

[0041] One end of the second isolation resistor 111 is connected to the other end of the sixth microstrip line 108 and to one end of the second microstrip line 104 . The other end of the first isolation resistor 110 is connected to the other end of the seventh microstrip line 109 and to one end of the third microstrip line 105 .

[0042] The other end of the second microstrip line 104 is connected to the second port 101 .

[0043] The other end of the third microstrip line 105 is connected to the third port 102 .

[0044] In this embodiment, the characteristic impedance of the first microstrip line, the second microstrip line and the third microstrip line are all 50 ohms. The isolation resistor is a small chip package resistor with small parasitic parameters, which can be applied to higher RF signal frequencies. The isolation resistor is set to isolate the second port 101 from the third port 102 so that the RF signal input from the second port 101 does not leak to the third port 102. The resistance of the first isolation resistor 110 and the second isolation resistor 111 is closely related to the isolation degree between the second port 101 and the third port 102. The length of the fourth microstrip line 106, the fifth microstrip line 107, the sixth microstrip line 108 and the seventh microstrip line 109 determines the isolation frequency band range of the second port 101 and the third port 102 of the power divider. The shorter the length of the microstrip line, the higher the frequency at which the isolation effect will be produced. The spacing between the fourth microstrip line 106 and the fifth microstrip line 107, and the spacing between the sixth microstrip line 108 and the seventh microstrip line 109 are related to the coupling coefficient of the power divider impedance, and the coupling coefficient also affects the strength of the isolation. The line widths of the fourth microstrip line 106, the fifth microstrip line 107, the sixth microstrip line 108, and the seventh microstrip line 109 determine the energy distribution from the first port 100 to the second port 101 and the third port 102. The microstrip line with a small line width has a high impedance and obtains less energy distribution, while the microstrip line with a large line width has a low impedance and obtains more energy distribution.

[0045] The power divider has a wide operating frequency range; the directional coupler has high directivity; the circuit is simple and occupies a small area; it can be used in vector network analyzers.

[0046] The power divider can achieve an ultra-wideband operating range by increasing the order, ensuring that the directional coupler can also achieve a wide operating frequency range.

[0047] Since the power divider itself can achieve high isolation through isolation resistors, high directivity of the final directional coupler can be achieved.

[0048] The circuit is simple, with only some microstrip lines, isolation resistors and differential-to-single-ended devices on the circuit board. It occupies a small area, has high maintainability of the device and good production consistency.

[0049] The directional coupler device is a radio frequency front-end device used to output the radio frequency signal of the vector network analyzer to the device under test, receive the reflected signal of the radio frequency signal from the device under test, and output the reflected signal to the receiver of the vector network analyzer to obtain the amplitude information and phase information of the reflected signal.

[0050] Based on the power divider provided in the above embodiment, please refer to Figure 2 , Figure 2 It is a schematic diagram of the structure of a directional coupler according to an embodiment. The directional coupler includes a power divider provided in the above embodiment, a 50-ohm load, and a differential-to-single-ended circuit.

[0051] The directional coupler provided in this embodiment includes a first input port 200, a second output port 201, a third output port 202, an isolation resistor 203, a microstrip line 1 204, a microstrip line 205, and a differential to single-ended circuit 206. The remaining structures and functions are exactly the same as the power divider described in the above embodiment, and will not be repeated here.

[0052] In this embodiment, when a signal energy is input through the first input port 200, the signal is divided by the power divider. Since the impedance of the thick microstrip line is small and the signal transmission loss is small, the thick side of the microstrip line is selected as the third output port 202 of the directional coupler, and the third output port 202 is used as the test port of the directional coupler. Thus, the thin side of the microstrip line is selected as the second output port 201 of the directional coupler, and the second output port 201 is used as the isolation port of the directional coupler. The second output port 201 needs to be connected to a 50 ohm load to match the 50 ohm characteristic impedance of the directional coupler test port.

[0053] Microstrip line 1 204 is connected to one of the input differential lines of the differential-to-single-ended circuit 206 at its right angle turn, and microstrip line 205 is connected to the other input differential line of the differential-to-single-ended circuit 206 at its right angle turn. The single-ended output port of the differential-to-single-ended circuit 206 is the coupled output port of the directional coupler.

[0054] When the signal input from the first input port 200 passes through the power divider isolation resistor 203, since the input signal amplitude and phase at both ends of the isolation resistor 203 are consistent, the signal amplitude of the single-ended output port, i.e., the coupled output port, is 0 after the differential-to-single-ended circuit, thereby achieving an extremely high isolation index of the coupled output port. When the signal reflected from the third output port 202 passes through the power divider isolation resistor 203, since there is a difference in the input signal amplitude and phase at both ends of the isolation resistor 203, the signal amplitude of the single-ended output port, i.e., the coupled output port, is not 0 after the differential-to-single-ended circuit, and the signal amplitude of the coupled output port increases with the increase in the amplitude of the reflected signal, thereby achieving the coupling index of the directional coupler. The directional index of the directional coupler is equal to its isolation index minus its coupling index minus its insertion loss index. It can be seen that the directional index of the directional coupler of this embodiment is very high, and the directional coupler can be used in a vector network analyzer. The directional coupler obtained according to this embodiment Figure 3 The test result diagram of the directional coupler shows that based on the directivity index calculation method of the directional coupler, it can be seen that the directivity index of the directional coupler of this embodiment is very good and meets the use requirements of the vector network analyzer analysis.

[0055] When the directional coupler is placed in the RF front end of the vector network analyzer, the first input port 200 is used as the input port of the RF signal, the second output port 201 is connected to a 50-ohm load, and the third output port 202 is used as the output port of the RF signal. When the third output port 202 is connected to the device under test, an RF signal is input from the first input port 200, and the amplitude and phase information of the reflected signal of the RF signal can be extracted through the single-ended output port of the differential to single-ended circuit 206, that is, the coupled output port, and the voltage standing wave ratio, reflection coefficient, return loss, impedance and other information of the device under test can be obtained through simple data processing.

[0056] The directional coupler in this embodiment only includes a power divider, a 50 ohm load and a differential to single-ended circuit, with a small number of components, a simple circuit and a small footprint. Figure 3 From the directivity curve of the directional coupler in FIG. 1 , it can be seen that in this embodiment, the directional coupler can still achieve high directivity within a wide frequency range. By placing the directional coupler in the RF front end of the vector network analyzer, the information of the reflected signal of the coupled output port is extracted, and the vector network analyzer can display the relevant information of the device under test through simple data processing, which can be used for the vector network analyzer.

[0057] Based on the same inventive concept, the present invention also provides a computer device, which includes: one or more processors, and a memory for storing one or more computer programs; the program includes program instructions, and the processor is used to execute the program instructions stored in the memory. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is used to implement one or more instructions, specifically for loading and executing one or more instructions in a computer storage medium to implement the above method.

[0058] It needs to be further explained that, based on the same inventive concept, the present invention also provides a computer storage medium, on which a computer program is stored, and the computer program is executed by a processor to execute the above method. The storage medium can adopt any combination of one or more computer-readable media. The computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electrical, magnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples (non-exhaustive list) of computer-readable storage media include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present invention, a computer-readable storage medium can be any tangible medium containing or storing a program, which can be used by an instruction execution system, device or device or used in combination with it.

[0059] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0060] The above shows and describes the basic principles, main features and advantages of the present disclosure. Those skilled in the art should understand that the present disclosure is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present disclosure. Without departing from the spirit and scope of the present disclosure, the present disclosure may have various changes and improvements, and these changes and improvements fall within the scope of the present disclosure to be protected.

Claims

1. A directional coupler device based on a power divider, characterized in that: include: Power divider: used to divide the input power into several equal or unequal power outputs, including: a first port, a second port, a third port, a first microstrip line, a second microstrip line, a third microstrip line, a fourth microstrip line, a fifth microstrip line, a sixth microstrip line, a seventh microstrip line, a first isolation resistor and a second isolation resistor; Load: used to absorb the radio frequency signal energy input from the first port and output from the second port of the microstrip power divider, and prevent the output radio frequency signal from being reflected back from the second port; Differential to single-ended circuit: used to convert the voltage difference across the second isolation resistor, i.e., the differential mode signal, into a common mode signal, which is a single-ended circuit connection method that is convenient for users to use.

2. A directional coupler device based on a power divider according to claim 1, characterized in that: The first port is used to receive an input RF signal, and the power divider divides the input RF signal into two RF signals, which flow to the second port and the third port respectively. The second port outputs one of the two RF signals, and the third port outputs the other of the two RF signals.

3. A directional coupler device based on a power divider according to claim 1, characterized in that: The first microstrip line is a strip transmission line, which is arranged along the direction of the input RF signal. One end of the first microstrip line is connected to the first port, and the other end of the first microstrip line is connected to one end of the fourth microstrip line and the fifth microstrip line.

4. A directional coupler device based on a power divider according to claim 1, characterized in that: One end of the first isolation resistor is connected to the other end of the fourth microstrip line and to one end of the sixth microstrip line, and the other end of the first isolation resistor is connected to the other end of the fifth microstrip line and to one end of the seventh microstrip line.

5. A directional coupler device based on a power divider according to claim 1, characterized in that: One end of the second isolation resistor is connected to the other end of the sixth microstrip line and to one end of the second microstrip line, and the other end of the second isolation resistor is connected to the other end of the seventh microstrip line and to one end of the third microstrip line.

6. A directional coupler device based on a power divider according to claim 1, characterized in that: The other end of the second microstrip line is connected to the second port, and the other end of the third microstrip line is connected to the third port.

7. A directional coupler device based on a power divider according to claim 1, characterized in that: The resistance values ​​of the first isolation resistor and the second isolation resistor are related to the isolation degree between the second port and the third port.

8. A directional coupler device based on a power divider according to claim 1, characterized in that: The lengths of the fourth microstrip line, the fifth microstrip line, the sixth microstrip line and the seventh microstrip line determine the isolation frequency band range of the second port and the third port of the power divider. The shorter the length of the microstrip line, the higher the frequency at which the isolation effect will be produced.

9. A directional coupler device based on a power divider according to claim 8, characterized in that: The coupling coefficient between the spacing between the fourth microstrip line and the fifth microstrip line, the spacing between the sixth microstrip line and the seventh microstrip line, and the impedance of the power divider, wherein the coupling coefficient affects the strength of the isolation.

10. A directional coupler device based on a power divider according to claim 9, characterized in that: The line widths of the fourth microstrip line, the fifth microstrip line, the sixth microstrip line and the seventh microstrip line determine the energy distribution from the first port to the second port and the third port. The microstrip line with a small line width has a high impedance and obtains less energy distribution, while the microstrip line with a large line width has a low impedance and obtains more energy distribution.

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