TWI666820B - Branch coupler with selective output power ratio - Google Patents

Abstract

The invention is a branch coupler with selective output power ratio, which is arranged on a substrate to cover a transmission line group. The transmission line group includes a first transmission line, a second transmission line, a third transmission line, and a fourth transmission line. The first transmission line includes a first transmission line. A main section, a first transverse section, a first extension section, and a second extension section; the second transmission line includes the second main section and the first longitudinal section; the third transmission line includes the third main section, the second transverse section, The third extension and the fourth extension. The fourth transmission line includes a fourth main section and a second longitudinally extending section, wherein a first embedded portion is recessed on the top edge of the first main section. A second embedded portion is recessed on the outer side of the second main section. A third embedded portion is recessed on the bottom edge of the third main section. A fourth embedded portion is recessed on the outer side of the fourth main section. Connected or unconnected to the first and second extensions through the first transverse extension, connected or disconnected to the first and third main extensions respectively, and connected to the second transverse extension respectively. The third extension segment and the fourth extension segment are connected or not connected, and the second longitudinal extension segment is connected or not connected to the third main segment and the first main segment, respectively, to determine the output proportion distribution, which allows users to adjust according to the use needs. The output power ratio is very convenient in the construction of the system.

Description

Branch coupler with selective output power ratio

The present invention relates to a branch coupler with a selected output power ratio, in particular to a branch coupler technology that can determine the proportion of circuit output proportions by disconnecting or connecting parallel transmission lines.

According to the evolution of human technology, the wireless communication system has been advancing by leaps and bounds. The design of high-frequency microwave circuits has attracted attention. The utilization rate and demand in the electronics industry are increasing day by day. The direction of circuit design is shrinking and the cost is decreasing. Circuit function adjustment, reducing circuit size, and maintaining good circuit characteristics are the goals of today's high-frequency microwave circuit designers. The coupler is shown in reference [1-5]. It has a fixed phase shift characteristic and can be designed according to user needs. It can be used in many aspects. For example, the power splitter is shown in reference [6]. The amplifier is shown in reference [7], the Butler matrix is shown in reference [8], and the antenna array is shown in reference [9-10].

Furthermore, traditional branch couplers are symmetrical left and right and up and down, including input ports, output ports, coupling ports, and isolation ports. The basic structure is that the electrical length of the transmission line is a quarter wavelength ( θ = 90 °), where the output Port | S ₂₁ | and coupling port | S ₃₁ | The output power ratio is determined by the impedance of the transmission line. The phase difference between the two output signals is 90 degrees, and the input port | S ₁₁ | and the isolated port | S ₄₁ | According to the use requirements of different environments, the output power ratio of the output port and the coupling port can be more flexibly changed. Therefore, how to develop a set of trunk coupler technology that can increase circuit function adjustability, reduce circuit size, and maintain good circuit characteristics has become a technical issue that the relevant industry-academia industry is eager to solve and challenge.

According to the current knowledge, no patent or paper has been proposed for a branch coupler that allows users to adjust the output power ratio according to their needs. Based on the urgent needs of the electronics industry, the inventors have continuously With the efforts of research and development, a set of technical concepts different from the above technical documents has finally been developed.

The main purpose of the present invention is to provide a branch coupler with a selected output power ratio, which mainly determines the proportion of the output power of the circuit by not connecting or connecting the parallel transmission lines, thereby achieving a variety of output power by a circuit. The proportional distribution function allows users to adjust the output power ratio according to the use requirements, which is very convenient in the construction of the system. The technical means adopted to achieve the above purpose is based on a substrate overlying a transmission line group. The transmission line group includes a first transmission line, a second transmission line, a third transmission line, and a fourth transmission line. The first transmission line includes a first main section and a first transverse extension section. , The first extension section and the second extension section, the second transmission line includes the second main section and the first longitudinal extension section, and the third transmission line includes the third main section, the second transverse extension section, the third extension section, and the fourth extension section . The fourth transmission line includes a fourth main section and a second longitudinally extending section; wherein the first main section is recessed with a first embedded portion on the top edge; the second main section is recessed with a second embedded portion on the outer edge; the third The bottom edge of the main section is recessed with a third embedded portion; the outer side of the fourth main section is recessed with a fourth embedded portion, which is connected to or disconnected from the first extension section and the second extension section through the first transverse extension section, respectively. 1. The first longitudinal extension is connected or disconnected with the first and third main sections, the second transverse extension is connected or disconnected with the third and fourth extension sections, and the second longitudinal section is connected with or disconnected, respectively. The third main segment and the first main segment are connected or not connected to determine the output proportion allocation.

10‧‧‧ substrate

20‧‧‧ Transmission line group

21‧‧‧The first transmission line

210‧‧‧first main paragraph

210a‧‧‧The first embedded part

211‧‧‧The first horizontal stretch

212‧‧‧first extension

213‧‧‧second extension

22‧‧‧Second transmission line

220‧‧‧Second Main Section

220a‧‧‧Second Embedded Section

221‧‧‧First longitudinal stretch

23‧‧‧Third transmission line

230‧‧‧ third main paragraph

230a‧‧‧The third embedded part

231‧‧‧Second transverse extension

232‧‧‧third extension

233‧‧‧Fourth Extension

24‧‧‧ Fourth Transmission Line

240‧‧‧ Fourth main paragraph

240a‧‧‧Fourth Embedded Section

241‧‧‧Second longitudinal extension

30‧‧‧input port

31‧‧‧Output port

32‧‧‧ isolated port

33‧‧‧Coupling Port

d‧‧‧ clearance

FIG. 1 is a schematic diagram of a circuit architecture of a branch coupler according to the present invention.

Figure 2 is a schematic diagram of the circuit architecture of a traditional branch coupler.

Figure 3 is a comparison diagram of the impedance ratio of the branch coupler.

FIG. 4 is a circuit diagram of a branch coupler according to the present invention.

FIG. 5 is a schematic diagram of a physical circuit implemented by the branch coupler of the present invention without connection.

FIG. 6 is a schematic diagram of the frequency response of a circuit in which the branch coupler of the present invention is not connected.

FIG. 7 is a schematic diagram of a physical circuit connected to a branch coupler of the present invention.

FIG. 8 is a schematic diagram of a frequency response of a circuit in which a branch coupler of the present invention is connected and implemented.

In order to allow your reviewers to further understand the overall technical characteristics of the present invention and the technical means for achieving the purpose of the present invention, detailed descriptions are given with specific embodiments and drawings: In short, the present invention is a selective output power ratio Branch coupler design. The circuit uses a traditional branch coupler as the framework and is replaced by a parallel transmission line structure. The user can adjust the output power ratio according to the use needs. The output power ratio can be selected by connecting or not connecting the transmission line. Achievable. The invention is based on the traditional 2: 1 unequal branch trunk coupler as a framework for design, simulation and experiment. The output ratio is determined by disconnecting or connecting the parallel transmission lines. If the connection is not maintained, the output ratio is maintained at 2: 1. When connected, the output ratio is changed to 1: 2, and the solid circuit is made with a FR-4 circuit board with a thickness of 1.6mm and a relative dielectric constant of 4.3. The simulation and experimental results are very consistent within the scope of the test experiment, verifying the correctness of this circuit design. The present invention is indeed a novel circuit design method. The circuit structure is shown in Figure 1. The circuit is based on a traditional branch coupler, and the transmission lines Z1A and Z2A are connected in parallel. The user can adjust the output ratio according to the use requirements. If the transmission lines Z1A and Z2A are not connected, the circuit output ratio remains unchanged. If the transmission lines Z1A and Z2A are connected, the circuit output ratio is changed to another ratio required by the user. The advantage of the circuit of the present invention is that a coupler with multiple output ratios can be realized by one circuit, which is very convenient in the system construction. In addition, it can be used at different center frequencies, and the circuit has high system support, and can effectively reduce the cost of the entire system construction.

Please refer to FIG. 3 to FIG. 4, the embodiment for achieving the main purpose of the present invention includes a substrate 10 and a transmission line group 20 disposed on the substrate 10. The transmission line group 20 includes a first transmission line 21, a second transmission line 22, a third transmission line 23, and a fourth transmission line 24 which are connected in a generally rectangular shape in order. The first transmission line 21 includes a first main section 210, a first transversely extending section 211, a first extending section 212, and a second extending section 213. The second transmission line 22 includes a second main section 220 and a first longitudinally extending section 221. The third transmission line 23 includes a third main section 230, a second transversely extending section 231, a third extending section 232, and a fourth extending section 233. The fourth transmission line 24 includes a fourth main section 240 and a second longitudinally extending section 241. The top side of the first main section 210 is recessed with a first embedded portion 210a for accommodating the first transversely extending section 211 and maintaining a gap d between the first transversely extending section 211 and the first main section 210. The first extending section 212 extends outward from the upper edge of one end of the first main section 210, and the second extension section 213 extends outward from the upper edge of the other end of the first main section 210. A second embedded portion 220a is recessed on the outer side of the second main section 220 for receiving the first longitudinally extending section 221 and keeping the first longitudinally extending section 221 and the second main section 220 with a gap d. A third embedded portion 230 a and a third extension portion 232 are recessed at the bottom edge of the third main section 230 for accommodating a second transverse extension section 231 and maintaining a gap d between the second transverse extension section 231 and the third main section 230. Extending outward from the upper edge of one end of the third main section 230, the fourth extending section 233 extends outward from the upper edge of the other end of the third main section 230. A fourth embedding portion 240a is recessed on the outer side of the fourth main section 240 for accommodating the second longitudinally extending section 241 and keeping the second longitudinally extending section 241 and the fourth main section 240 with a gap d. A horizontal extension 211 is connected or not connected to the first extension 212 and the second extension 213, respectively, and the first vertical extension 221 is connected or not connected to the first main section 210 and the third main section 230, respectively. The extension section 231 is connected or not connected with the third extension section 232 and the fourth extension section 233, respectively, and the second longitudinal extension section 241 is connected or disconnected with the third main section 230 and the first main section, respectively, to determine the output proportion distribution.

Then, when one end of the first horizontal extension section 211 is connected to the first extension section 212 and the other end is connected to the second extension section 213, one end of the first longitudinal extension section 221 is connected to the other end of the first main section 210 and the other end is connected to the third One end of the main section 230 is connected, one end of the second transverse extension section 231 is connected to the third extension section 232 and the other end is connected to the fourth extension section 233 and one end of the second longitudinal extension section 241 is connected to the other end of the third main section 230 and the other end When connected to one end of the first main section 210, the output ratio is distributed as 1: 2. Conversely, when one end of the first horizontal extension section 211 is not connected to the first extension section 212 and the other end is not connected to the second extension section 213, one end of the first longitudinal extension section 221 is not connected to the other end of the first main section 210 and the other end. It is not connected to one end of the third main section 230, one end of the second transverse extension section 231 is not connected to the third extension section 232 and the other end is not connected to the fourth extension section 233, and one end of the second longitudinal extension section 241 is connected to the third main section 230. When the other end is not connected and the other end is not connected to one end of the first main section 210, the output ratio is allocated as 2: 1.

Specifically, as shown in FIG. 5, the first extension section 212 and the second extension section 213 are in a long rectangular shape. The right half of the first extension section 212 is located at the upper edge of one end of the first main section 210, and the left half of the first extension section 212 is The left half of the second extension section 213 is located at the upper edge of the other end of the first main section 210, and the right half of the second extension section 213 extends outward. The third extension section 232 and the fourth extension section 233 are in a long rectangular shape. The left half of the third extension section 232 is located at the upper edge of one end of the third main section 230, and the right half of the third extension section 232 extends outward. The right half of the fourth extension section 233 is located at the upper edge of the other end of the third main section 230, and the left half of the fourth extension section 233 extends outward. The first horizontally extending section 211 and the first embedded section 210a are both in a long rectangular shape, and the area of the first horizontally extending section 211 is slightly smaller than the first embedded section 210a and has the above-mentioned gap d. The first extending section 212, the second The top edges of each of the extension section 213 and the first transverse extension section 211 are all aligned; or are almost aligned. The lengths of the first extension 212, the second extension 213, the third extension 232, and the fourth extension 233 are all L ₂ = 10.29 mm, and the line width is W ₂ = 3.1 mm. A first extension 212 and second extension 213, the third extension 232 and fourth extension 233 extending outwardly of each are all projecting length L ₃ = 5mm.

Please refer to FIG. 5 and FIG. 6 for reference. The above-mentioned second transversely extending section 231 and the third embedding section 230a are both long rectangular, and the area of the second transversely extending section 231 is slightly smaller than the third embedding section 230a. Gap d. The bottom edges of the third extension section 232, the fourth extension section 233, and the second transverse extension section 231 are all aligned; or are almost aligned. The first longitudinally extending section 221 and the second embedding section 220a are both in a long rectangular shape, and the area of the first longitudinally extending section 221 is slightly smaller than the second embedding section 220a and has the above-mentioned gap d. The other ends of the first main section 210, one end of the third main section 230, and the outer sides of the first longitudinally extending section 221 are all aligned or almost aligned. The second longitudinally extending section 241 and the fourth embedded section 240a are both long rectangular, and the area of the second longitudinally extending section 241 is slightly smaller than the fourth embedded section 240a and has the gap d. One end of the first main section 210 and the third The other end of the main section 230 and the outer sides of the second longitudinally extending section 241 are all aligned or almost aligned.

Please refer to FIGS. 5 and 6. The lengths of the first transmission line 21 and the third transmission line 23 are both L ₁ = 60.81 mm; the line widths of the first main section 210 and the third main section 230 are W ₃ = 3.9. The length of the inner sides of the first main section 210 and the third main section 230 are both L ₄ = 40.22 mm, and the length of the inner sides of the second main section 220 and the fourth main section 240 are W ₄ = 40.79 mm; The length of one horizontally extending section 211 and the second horizontally extending section 231 are both L ₅ = 39.22 mm, and the line width is W ₅ = 2.23 mm; the lengths of the first and second longitudinally extending sections 221 and 241 are L ₆ = 3.15mm, and the line width is W ₆ = 39.79mm.

When the output ratio is 2: 1, the impedances of the first main section 210 and the second main section 220 are Z ₁₁ = 40.82Ω, and the electrical lengths are both θ = 90 °. The second main section 220 and the fourth main section The impedance of 240 is Z ₂₁ = 70.71Ω, and the electrical length is θ = 90 °.

When the output ratio is 1: 2, the impedance of the first main section 210 and the second main section 220 is Z ₁₂ = 28.87Ω, and the electrical lengths are both θ = 90 °. The second main section 220 and the fourth main section The impedances of 240 are Z ₂₂ = 35.35Ω, and the electrical lengths are θ = 90 °. The impedances of the first transverse stretch 211 and the second transverse stretch 231 are Z _1A = 98.56Ω, and the first longitudinal stretch 221 and The impedance of the second longitudinally extending section 241 is Z _2A = 70.71Ω.

In the embodiment of the circuit analysis and design of the present invention, the structure of a traditional branch coupler is shown in Figs. 2 and 5. Port1 is an input port 30, Port2 is an output port 31, Port3 is a coupling port 32, Port4 is an isolated port 33, and Z ₁ And Z ₂ is the transmission line impedance, θ 1 = θ 2 is the electrical length (traditional electrical length is 90 degrees), and Figure 3 is the impedance ratio of the branch coupler, where the X axis is the impedance of Z ₁ and the Y axis is Z ₂ Impedance, the leftmost point in the example is P2: P3 = 1: 10 Z ₁ = 15.07Ω, Z ₂ = 15.81Ω, the rightmost point in the figure is P2: P3 = 10: 1 Z ₁ = 47.67Ω, Z ₂ = 158.11Ω. As for the circuit analysis of the present invention, the traditional 2: 1 unequal branch trunk coupler is taken as an example for illustration. The circuit architecture is shown in FIG. 1. According to FIG. 3, when the output ratio is 2: 1, Z ₁₁ = 40.82Ω, Z ₂₁ = 70.71Ω, θ = 90 °, when the output ratio is 1: 2 Z ₁₂ = 28.87Ω, Z ₂₂ = 35.35Ω, θ = 90 °, Z _1A = 98.56Ω can be obtained from formulas (1) and (2) , Z _2A = 70.71Ω.

The design of the branch coupler with the selected output power ratio is verified by the electromagnetic simulation software. The board is FR4 (thickness 1.6mm), the relative permittivity is 4.3, and the structure is optimized and adjusted as shown in Figure 4. Circuit size: L ₁ = 60.81mm, W ₁ = 54.83mm, L ₂ = 10.29mm, W ₂ = 3.1mm, L ₃ = 5mm, W ₃ = 3.9mm, L ₄ = 40.22mm, W ₄ = 40.79mm, L ₅ = 39.22mm , W ₅ = 2.23mm, L ₆ = 3.15mm, W ₆ = 39.79mm. The finished product of the circuit entity after processing by the engraving machine is shown in Figure 5.

Entity then measured by the network analyzer circuit, frequency comparison of actual and simulated results shown in Figure 6 in response to the parallel transmission line structure is not connected, the measurement frequency is from 0 to 2GHz, a size of 0 to -60dB, to the working frequency (f ₀ = 0.915GHz) The reflection loss at the input point | S ₁₁ | and the isolation | S ₄₁ | are below -15dB, the transmission amount | S ₂₁ | is -1.86dB, the coupling amount | S ₃₁ | is -5.1dB, both ends The output is 2: 1. The parallel transmission line structure is connected as shown in Figure 7. It is measured by a network analyzer and compared with the simulation result. The circuit simulation result and the physical circuit frequency response are shown in Figure 8. The measured frequency is from 0 to 2GHz. From 0 to -45dB, the reflection loss at the input point of the operating frequency band ( f ₀ = 0.915GHz) | S ₁₁ | and isolation | S ₄₁ | Below -15dB, the transmission volume | S ₂₁ | is -4.72dB, coupling The amount | S ₃₁ | is -1.77dB, and the output at both ends is 1: 2. The above simulation and measurement results are quite close to expectations.

According to the above specific embodiments, the present invention provides a branch coupler design with a selected output power ratio. The circuit is based on a traditional branch coupler, and is changed to a parallel transmission line structure. The user only needs to connect the parallel connection. Connecting or disconnecting the transmission line can produce different output ratios. The traditional 2: 1 unequal branch trunk coupler is used for the design, simulation and experiment. The output ratio is determined by the connection or non-connection of the parallel transmission lines. If the connection is not maintained, the output ratio is maintained at 2: 1. When connected, the output ratio changes to 1: 2, and the simulation and actual measurement results are quite close. The feasibility of this circuit can be known, and it can be widely used in power distribution systems with different center frequencies.

The above description is only a feasible embodiment of the present invention, and is not intended to limit the patent scope of the present invention. Any equivalent implementation of other changes based on the content, characteristics and spirit of the following claims should be It is included in the patent scope of the present invention. The structural features specifically defined in the present invention are not found in similar items, and are practical and progressive. The patent requirements were clarified, and the application was filed according to the law. I would like to request the Bureau to approve the patent in accordance with the law in order to protect the legitimate rights and interests of the applicant.

references

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[2] S. Kumar, C. Tannous and T. Danshin, “Multisection Broadband Impedance Transform Branch line Hybrid,” IEEE Transactions. Microwave Theory Techniques, vol. 43, no. 11, pp. 2517-2523, Nov. 1995.

[3] M. Muraguchi, T. Yukitake and Y. Naito, “Optimum design of 3-dB branch-line couplers using microstrip line,” IEEE Trans. , Vol. 31, no. 8, pp.674-678, Aug . 1983.

[4] J. Reed and GJ Wheeler, "A Method of Analysis of Symmetrical Four-Port Networks," IRE Trans. Microwave Theory and Techniques, vol. 4, no. 4, pp. 246-252, Oct. 1956.

[5] Qiuyi Wu, Yimin Yang, Ying Wang, Xiaowei Shi and Ming Yu, “Characteristic Impedance Control for Branch-Line Coupler Design,” IEEE Microwave and Wireless Components Letters , Vol. 27, pp.123-125, Feb. 2018 .

[6] EJ Wilkinson, “An N-Way Hybrid Power Divider,” IRE Transactions on Microwave Theory and Techniques , vol. 8, no. 1, pp. 116-118, Jan 1960

[7] W. Chen et al., “Design and Linearization of Concurrent Dual-Band Doherty Power Amplifier With Frequency-Dependent Power Ranges,” IEEE Trans. Microwave Theory Tech. , Vol. 59, no. 10, pp. 2537- 2546, Oct. 2011.

[8] Kamil Staszek, Slawomir Gruszczynski and Krzysztof Wincza, "Broadband Measurements ofS-Parameters With the Use of a Single 8 × 8 Butler Matrix," IEEE Transactions on Microwave Theory and Techniques , vol. 62, pp.352-360, Feb . 2014.

[9] Stella Ifeoma Orakwue and Razali Ngah, TA Rahman, Hamza MR Al-Khafaji, “A steerable 28 GHz array antenna using branch line coupler,” Telematics and Future Generation Networks (TAFGEN), 2015 1st International Conference on , vol. 16 , pp. 76-78, May. 2015.

[10] AKM Baki and Nemai Chandra Karmakar, “Staircase power distribution of array antenna for UHF band RFID reader,” Electrical & Computer Engineering (ICECE), 2012 7th International Conference on , pp. 854-857, Dec. 2012. '

Claims (8)

A branch coupler with a selected output power ratio includes a substrate and a transmission line group disposed on the substrate. The transmission line group includes a first transmission line, a second transmission line, and a A third transmission line and a fourth transmission line; the first transmission line includes a first main section, a first transverse extension section, a first extension section, and a second extension section; the second transmission line includes a second main section and a A first longitudinal extension, the third transmission line includes a third main section, a second transverse extension, a third extension, and a fourth extension, and the fourth transmission line includes a fourth main section and a second A longitudinally extending section; wherein, a first embedded section is recessed at the top edge of the first main section for accommodating the first transversely extending section and maintaining a gap between the first transversely extending section and the first main section; The extension section extends outward from the upper edge of one end of the first main section, and the second extension section extends outward from the upper edge of the other end of the first main section; A second embedded portion that accommodates the extension section and maintains a gap between the first longitudinal extension section and the second main section; the bottom of the third main section A recessed third embedding portion is provided for accommodating a second transversely extending section and keeping a gap between the second transversely extending section and the third main section, and the third extending section is outward from the upper edge of one end of the third main section. Extension, the fourth extension section extends outward from the upper edge of the other end of the third main section; an outer side of the fourth main section is recessed with a space for the second longitudinal extension and the second longitudinal extension and the The fourth embedded portion of the fourth main section maintains a gap, when one end of the first transverse extension section is connected to the first extension section and the other end is connected to the second extension section, one end of the first longitudinal extension section is connected to the first extension section. The other end of the main section is connected and the other end is connected to one end of the third main section, one end of the second transverse extension section is connected to the third extension section and the other end is connected to the fourth extension section and one end of the second longitudinal extension section is connected to When the other end of the third main section is connected and the other end is connected to one end of the first main section, the output ratio is distributed as 1: 2; when one end of the first horizontal extension section is not connected to the first extension section and the other end is connected to The second extension section is not connected, one end of the first longitudinal extension section is not connected to the other end of the first main section and the other end is not connected to one end of the third main section, and the second horizontal section is not connected. One end of the extension is not connected to the third extension and the other end is not connected to the fourth extension. One end of the second longitudinal extension is not connected to the other end of the third main section and the other end is connected to one end of the first main section. When not connected, the output ratio is assigned as 2: 1. The branch coupler with selective output power ratio as described in claim 1, wherein the first extension section and the second extension section are long rectangular, and the right half of the first extension section is located in the first main section. The left half of the upper edge of one end extends outwardly; the left half of the second extension is located at the upper edge of the other end of the first main section, and the right half extends outward; the first transverse extension And the first embedding portion are both in a long rectangular shape, and the area of the first transverse extending portion is slightly smaller than the first embedding portion and has the gap, the first extending portion, the second extending portion, and the first transverse portion The top edges of the respective extensions are cut to be aligned; or almost aligned; the length of the first extension and the second extension are both L ₂ = 10.29 mm, and the line width is W ₂ = 3.1 mm; The length of each of the extension section and the second extension section protruding outward is L ₃ = 5 mm. The branch coupler with selective output power ratio as described in claim 1, wherein the third extension section and the fourth extension section have a long rectangular shape, and the left half of the third extension section is located at one end of the third main section. The right half of the fourth extension extends outwards; the right half of the fourth extension is located at the upper edge of the other end of the third main segment, and the left half extends outward; the second transverse extension and the The third embedded portion is all in a long rectangular shape, and the area of the second horizontally extending portion is slightly smaller than the third embedded portion and has the gap, the third extending portion, the fourth extending portion, and the second horizontal extending portion. The respective bottom edges of the segments are aligned or almost aligned; the length of the third extension and the fourth extension are both L ₂ = 10.29 mm, and the line width is W ₂ = 3.1 mm; the third The length of each of the extension section and the fourth extension section protruding outward is L ₃ = 5 mm. The branch coupler with selective output power ratio as described in claim 1, wherein the first longitudinally extending section and the second embedded section are both long rectangular, and the area of the first longitudinally extending section is slightly smaller than the The second embedding portion has the gap, and the other ends of the first main section, one end of the third main section, and outer sides of the first longitudinally extending sections are all aligned or almost aligned. The branch coupler with selective output power ratio as described in claim 1, wherein the second longitudinally extending section and the fourth embedding section are both long rectangular, and the area of the second longitudinally extending section is slightly smaller than the The fourth embedding portion is provided with the gap, and one end of the first main section, the other end of the third main section, and the outer sides of the second longitudinally extending section are all aligned or almost aligned. The branch coupler with selective output power ratio as described in claim 1, wherein the lengths of the first transmission line and the third transmission line are both L ₁ = 60.81mm; the first main section and the third main section The line width is W ₃ = 3.9mm; the length of the inner edges of the first main segment and the third main segment are L ₄ = 40.22mm, and the lengths of the inner edges of the second main segment and the fourth main segment are both W ₄ = 40.79 mm; the length of the first and second transverse stretches are both L ₅ = 39.22 mm, and the line width is W ₅ = 2.23 mm; The lengths of the longitudinal extensions are L ₆ = 3.15 mm, and the line widths are W ₆ = 39.79 mm. The branch coupler with selective output power ratio as described in claim 1, wherein when the output ratio is 2: 1, the impedances of the first main section and the second main section are both Z ₁₁ = 40.82Ω, The electrical length is θ = 90 °, the impedance of the second main section and the fourth main section are Z ₂₁ = 70.71Ω, and the electrical length is θ = 90 °. The branch coupler with selective output power ratio as described in claim 1, wherein when the output ratio is 1: 2, the impedances of the first main section and the second main section are both Z ₁₂ = 28.87Ω, The electrical length is θ = 90 °, the impedance of the second main section and the fourth main section are Z ₂₂ = 35.35Ω, and the electrical length is θ = 90 °. The first transverse extension section, the second transverse section The impedance of the extension section is Z _1A = 98.56Ω, and the impedance of the first longitudinal extension section and the second longitudinal extension section is Z _2A = 70.71Ω.