Branch line coupler

Abstract

A branch-line coupler includes a first transmission line, a second transmission line, a first bent transmission line, and a second bent transmission line. The first transmission line includes a first elongated transmission line, a first branch transmission line, and a second branch transmission line. The first elongated transmission line extends along a predetermined direction. The first branch transmission line has a first slit, and the second branch transmission line has a second slit. The first and second branch transmission lines are axially symmetrical about a first axis. The first and second transmission lines are also axially symmetrical about a second axis orthogonal to the first axis. The first bent transmission line is electrically connected to the endpoints of the first and second transmission lines on the same side, while the second bent transmission line is electrically connected to the endpoints of the first and second transmission lines on the opposite side.

Description

Technical Field

[0001] This application relates to a coupler, and more particularly to a 3dB branch line coupler. Background Technology

[0002] As is well known, directional couplers are commonly used in many microwave circuits to address issues related to power distribution. With the development of mobile and satellite communication technologies, miniaturization of communication equipment has become increasingly important for portability and mobility. Branch line couplers are widely used in microwave integrated circuits and monolithic integrated circuits. Traditional branch line couplers, such as the 3dB branch line coupler, consist of four quarter-wavelength transmission lines. However, this architecture of traditional branch line couplers occupies a considerable amount of printed circuit board (PCB) area. Summary of the Invention

[0003] In view of this, one embodiment of this application provides a miniaturized branch line coupler structure.

[0004] One embodiment of this application discloses a branch line coupler, including: a first port, a second port, a third port, and a fourth port, respectively serving as an input terminal, a through terminal, a coupling terminal, and an isolation terminal; a first transmission line, including: a first elongated transmission line having a first end electrically connected to the first port and a first second end electrically connected to the second port, the first elongated transmission line extending along a predetermined direction; a first branch transmission line electrically connected to the first end and having a first slit; a second branch transmission line electrically connected to the first and second ends and having a second slit, wherein the first branch transmission line and the second branch transmission line are axially symmetrical about a first axis; a second transmission line... The transmission line includes: a second elongated transmission line having a second first end electrically connected to the third port and a second second end electrically connected to the fourth port, the second elongated transmission line extending along the predetermined direction; a third branch transmission line electrically connected to the second first end and having a third slit; a fourth branch transmission line electrically connected to the second second end and having a fourth slit, wherein the third branch transmission line and the fourth branch transmission line are axially symmetrical with respect to the first axis; a first bent transmission line electrically connected between the first port and the fourth port; and a second bent transmission line electrically connected between the second port and the third port.

[0005] According to one embodiment of this application, the first branch transmission line includes a spiral branch, and the first slit is located between the spiral branch and the first bent transmission line.

[0006] According to one embodiment of this application, the first branch transmission line further includes an elongated branch and a fifth slit located between the spiral branch and the elongated branch.

[0007] According to one embodiment of this application, the first branch transmission line further includes an L-shaped branch and a fifth slit located between the spiral branch and the L-shaped branch.

[0008] According to one embodiment of this application, the first bent transmission line includes a fifth branch transmission line, the fifth branch transmission line including: a fifth first branch extending along the predetermined direction; a fifth second branch extending along the predetermined direction; and a fifth third branch connecting the fifth first branch and the fifth second branch to the terminals of the second bent transmission line.

[0009] According to one embodiment of this application, the fifth branch transmission line further includes a fifth fourth branch extending along the predetermined direction, and the fifth fourth branch is close to the terminal of the second bent transmission line and connected to the fifth third branch.

[0010] According to one embodiment of this application, the second bent transmission line includes a sixth branch transmission line, the sixth branch transmission line including: a sixth first branch extending along the predetermined direction; a sixth second branch extending along the predetermined direction; a sixth third branch connecting the sixth first branch and the sixth second branch near the terminals of the first bent transmission line; and a sixth fourth branch extending along the predetermined direction, the sixth fourth branch connecting the sixth third branch near the terminals of the first bent transmission line.

[0011] According to one embodiment of this application, the first transmission line and the second transmission line are axially symmetrical with respect to a second axis orthogonal to the first axis.

[0012] According to one embodiment of this application, the branch line coupler further includes: a first connection portion electrically connected to the first port, the first transmission line, and the first bent transmission line; a second connection portion electrically connected to the second port, the first transmission line, and the second bent transmission line; a third connection portion electrically connected to the third port, the second transmission line, and the second bent transmission line; and a fourth connection portion electrically connected to the fourth port, the second transmission line, and the first bent transmission line.

[0013] According to one embodiment of this application, the first connecting portion, the second connecting portion, the third connecting portion and the fourth connecting portion are transmission lines.

[0014] According to an embodiment of this application, the branch line coupler can effectively reduce the area of ​​the coupler by using a multi-branch design of the first branch transmission line and the second branch transmission line, and by adding a bending design to the first bending transmission line and the second bending transmission line.

[0015] Compared with prior art, the advantages of the present invention are obvious. The branch line coupler designed in this invention has better performance and occupies less area, making it very suitable for application in mobile communication products. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the branch line coupler according to an embodiment of this application.

[0017] Figure 2 for Figure 1 An enlarged schematic diagram of the first transmission line of the branch line coupler shown.

[0018] Figure 3 The image shows the S-parameter simulation curves of a branch line coupler according to an embodiment of this application.

[0019] Figure 4 The figure shows a simulation curve of the S-parameter of the isolation between the two output ports of the branch line coupler according to an embodiment of this application.

[0020] Figure 5 This is a diagram showing the phase difference between the two output ports of a branch line coupler according to an embodiment of this application.

[0021] Figure 6 This is a diagram showing the difference in output amplitude between the two output terminals of a branch line coupler according to an embodiment of this application.

[0022] Figure 7 This is a schematic diagram of a traditional branch line coupler.

[0023] Figure 8 The image shows the S-parameter simulation curves for a traditional branch-line coupler.

[0024] Explanation of main component symbols

[0025] 100: Branch line coupler

[0026] C1, C2, C3, C4, C5, C6: Curves

[0027] J1, J2, J3, J4: Connecting parts

[0028] P1: First port

[0029] P2: Second port

[0030] P3: Third port

[0031] P4: Fourth Port

[0032] P111, P112: Endpoints

[0033] St11, St12, St21, St22: Slit

[0034] T1: First transmission line

[0035] T2: Second transmission line

[0036] T3: First Bend-Type Transmission Line

[0037] T4: Second Bend Type Transmission Line

[0038] T11: First long strip transmission line

[0039] T12: First branch transmission line

[0040] T13: Second Branch Transmission Line

[0041] T121, T131: Spiral branching

[0042] T122, T132: Long, narrow branches

[0043] T1210, T1211, T1213, T1215, T1217, T1219, T1221, T1223, T311, T313, T315, T317: Branch segments

[0044] X, Y: Axis lines

[0045] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0046] To facilitate understanding and implementation of this invention by those skilled in the art, the invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that this invention provides many applicable inventive concepts, which can be implemented in various specific forms. Those skilled in the art can utilize the details described in these or other embodiments, as well as other available structural, logical, and electrical variations, to implement the invention without departing from its spirit and scope.

[0047] This specification provides different embodiments to illustrate the technical features of different implementations of the invention. The configuration of elements in the embodiments is for illustrative purposes only and is not intended to limit the invention. Repetition of some reference numerals in the embodiments is for simplification and does not imply any correlation between different embodiments. The same element numbers used in the illustrations and specification represent the same or similar elements. The illustrations in this specification are simplified and not drawn to scale. For clarity and convenience, directional terms (e.g., top, bottom, upper, lower, and diagonal) are used in relation to the accompanying illustrations. The directional terms used in the following description, unless explicitly used within the scope of the appended claims, are not intended to limit the scope of the invention.

[0048] Furthermore, in describing some embodiments of this application, the specification describes the methods and / or procedures of this application in a specific order of steps. However, since the methods and procedures are not necessarily performed according to the specific order of steps described, they are not limited to that specific order. Those skilled in the art will understand that other orders are also possible implementations. Therefore, the specific order of steps described in the specification is not intended to limit the scope of the patent application. Moreover, the scope of the patent application for the methods and / or procedures is not limited to the order of execution steps written therein, and those skilled in the art will understand that adjusting the order of execution steps does not depart from the spirit and scope of the invention.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. Some embodiments of this application are described in detail below with reference to the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0050] Figure 1 This diagram shows a schematic representation of a branch line coupler according to an embodiment of this application. (See also...) Figure 1 According to one embodiment of this application, a branch line coupler 100 is provided, including a first port P1, a second port P2, a third port P3 and a fourth port P4, as well as a first transmission line T1, a second transmission line T2, a first bent transmission line T3 and a second bent transmission line T4.

[0051] The first port, P1, is an input port used to input electromagnetic wave signals. The second port, P2, is a through port used to output through electromagnetic wave signals. The third port, P3, is a coupling port used to output coupled electromagnetic wave signals. The fourth port, P4, is an isolation port. It should be noted that the port configurations described here are not intended to limit the invention; those skilled in the art can design the functions of each port according to actual use.

[0052] The first transmission line T1 includes a first elongated transmission line T11, a first branch transmission line T12, and a second branch transmission line T13. The first elongated transmission line T11 has an endpoint P111 electrically connected to a first port P1 and an endpoint P112 electrically connected to a second port P2, and extends along a predetermined direction (the X direction in the diagram). The first branch transmission line T12 is electrically connected to endpoint P111 and includes a spiral branch T121 and an elongated branch T122. A slit St11 is formed between the spiral branch T121 and the first bent transmission line T3, and a slit St12 is formed between the spiral branch T121 and the elongated branch T122. The second branch transmission line T13 is electrically connected to endpoint P112 and includes a spiral branch T131 and an elongated branch T132. There is a slit St21 between the spiral branch T131 and the second bent transmission line T4, and a slit St22 between the spiral branch T131 and the long strip branch T132.

[0053] Figure 2 for Figure 1 An enlarged schematic diagram of the first transmission line T1 of the branch-line coupler shown. (See attached diagram.) Figure 2According to one embodiment of this application, the first transmission line T1 includes a first elongated transmission line T11, a first branch transmission line T12, and a second branch transmission line T13. The first branch transmission line T12 includes a spiral branch T121 and an elongated branch T122. The spiral branch T121 includes branch segments T1210, T1211, T1213, T1215, T1217, and T1219. Branch segment T1210 extends from endpoint P111 towards the second branch transmission line T13; branch segment T1211 extends from branch segment T1210 away from the first elongated transmission line T11; branch segment T1213 extends from branch segment T1211 away from the second branch transmission line T13; branch segment T1215 extends from branch segment T1213 towards the first elongated transmission line T11; branch segment T1217 extends from branch segment T1215 towards the second branch transmission line T13; and branch segment T1219 extends from branch segment T1217 away from the first elongated transmission line T11. It must be noted that the number of branch segments in the spiral branch T121 shown in the figure is merely an example. Those skilled in the art can select an appropriate number of branch segments to form the spiral branch T121 according to the characteristics of the coupler. The elongated branch T122 can be L-shaped, including branch segment T1221 and branch segment T1223. Similarly, those skilled in the art can select an appropriate branch segment T1223 length based on the characteristics of the coupler. In configuration, the first elongated transmission line T11 is parallel to branch segments T1210, T1213, T1217, and T1223, and perpendicular to branch segments T1211, T1215, T1219, and T1221. Furthermore, as shown in the figure, the first branch transmission line T12 and the second branch transmission line T13 are axially symmetrical with respect to the Y-axis; therefore, the specific structure of the second branch transmission line T13 will not be elaborated upon for simplicity.

[0054] Back Figure 1A first bent transmission line T3 is electrically connected between a first port P1 and a fourth port P4, and includes a fifth branch transmission line T31, comprising branch segments T311, T313, and T315. Branch segment T311 extends towards the second bent transmission line T4 along a predetermined direction (X direction in the diagram). Branch segment T313 connects branch segments T311 and T315 near the terminal of the second bent transmission line T4 and extends towards the second transmission line T2 along a direction orthogonal to the predetermined direction (Y direction in the diagram). Branch segment T315 extends away from the second bent transmission line T4 along the X direction. In this embodiment, branch segments T311, T313, and T315 constitute the fifth branch transmission line T31. In other embodiments, the fifth branch transmission line T31 may further include branch segment T317. In terms of configuration, the first elongated transmission line T11 is parallel to branch segments T311, T315, and T317, and perpendicular to branch segment T313. Furthermore, as shown in the figure, the first bent transmission line T3 and the second bent transmission line T4 are axially symmetrical with respect to the Y-axis; therefore, the specific structure of the second bent transmission line T4 will not be described in detail for simplicity. Similarly, the first transmission line T1 and the second transmission line T2 are axially symmetrical with respect to the X-axis; therefore, the specific structure of the second transmission line T2 will not be described in detail for simplicity. According to the embodiments of this application, by using the multi-branch design of the first branch transmission line T12 and the second branch transmission line T13, and by incorporating a bending design into the first bent transmission line T3 and the second bent transmission line T4, the area of ​​the coupler can be effectively reduced.

[0055] In other embodiments, the branch line coupler 100 may further include connecting portions J1, J2, J3, and J4, respectively used for electrically connecting the first port P1, the second port P2, the third port P3, and the fourth port P4. For example, the first transmission line T1 and the first bent transmission line T3 are electrically connected to the first port P1 via connecting portion J1; the first transmission line T1 and the second bent transmission line T4 are electrically connected to the second port P2 via connecting portion J2; the second transmission line T2 and the second bent transmission line T4 are electrically connected to the third port P3 via connecting portion J3; and the second transmission line T2 and the first bent transmission line T3 are electrically connected to the fourth port P4 via connecting portion J4. According to one embodiment of this application, connecting portions J1, J2, J3, and J4 are all transmission lines. In other embodiments, connecting portions J1, J2, J3, and J4 may be microstrip lines or other types of transmission lines.

[0056] According to one embodiment of this application, the length L of the branch line coupler 100 is 4.08 mm and the width H is 6.52 mm. It should be noted that the size of the branch line coupler 100 is determined by the frequency used and is not intended to limit the invention. Those skilled in the art can select branch line couplers of different sizes to meet the requirements of different frequencies according to specific circumstances.

[0057] refer to Figure 3 , Figure 3 This is a simulation graph of the S-parameters of the branch line coupler 100 according to an embodiment of this application. Figure 3 As shown by curve C1, the frequency band where the attenuation of parameter S11 of the branch line coupler 100 of this application is greater than 10dB is approximately 4.8GHz-6.3GHz, corresponding to a center frequency of 5.6GHz. Figure 3 As can be seen from curves C2 and C3, parameters S12 and S13 have a 3dB power loss in the specified frequency band. Parameters S22, S33, and S44 of the second, third, and fourth ports are similar to parameter S11 of the first port, and are not shown in the attached figure.

[0058] See Figure 4 , Figure 4 This is a simulation curve of the S-parameter isolation between the two output ports of the branch-line coupler according to an embodiment of this application. From... Figure 4 As can be seen from curve C4, the two output ports of the branch line coupler described in one embodiment of this application have good isolation in the 4.6GHz-6.6GHz frequency band.

[0059] Please see Figure 5 , Figure 5 Curve C5 represents the phase difference diagram between the outputs of the second port P2 and the third port P3 of the branch line coupler according to an embodiment of this application. Figure 5 It is understood that, according to an embodiment of this application, the second port P2 and the third port P3 of the branch line coupler have a small output phase difference in the frequency band 4.9GHz-6.2GHz. Specifically, the output phase difference between the second port P2 and the third port P3 is less than 10°.

[0060] Please see Figure 6 , Figure 6 Curve C6 represents the difference in output amplitude between the second port P2 and the third port P3 of the branch-line coupler according to an embodiment of this application. Figure 6 It is understood that, according to an embodiment of this application, the second port P2 and the third port P3 of the branch line coupler have a small amplitude output difference in the frequency band 4.9GHz-6.2GHz. Specifically, the output amplitude difference between the second port P2 and the third port P3 is less than 2dB.

[0061] Figure 7 This is a schematic diagram of a conventional branch line coupler. The conventional branch line coupler has a length L of 7.4 mm and a width H of 9.14 mm. According to the branch line coupler 100 described in this embodiment, through the multi-branch design of the first branch transmission line T12 and the second branch transmission line T13, and by adding a bending design to the first bent transmission line T3 and the second bent transmission line T4, the length L of the branch line coupler 100 is 4.08 mm and the width H is 6.52 mm. Compared to the conventional branch line coupler, the area of ​​the coupler is significantly reduced.

[0062] Figure 8 The S-parameter simulation curves of a traditional branch-line coupler are shown below. Figure 8 As shown, the bandwidth of the traditional branch-line coupler with parameter S11 is 4.6GHz-6.6GHz when the attenuation is greater than 10dB, corresponding to a center frequency of 5.6GHz. Parameters S12 and S13 have a 3dB power loss in this frequency band. (Comparison) Figure 3 and Figure 8 It can be seen that the branch line coupler 100 described in the embodiments of this application has a similar effect to the traditional branch line coupler.

[0063] The branch line coupler 100 described in this application has a 60.67% smaller area than traditional branch line couplers. Furthermore, the branch line coupler 100 exhibits good performance in the 4.6GHz-6.6GHz frequency band, with an attenuation parameter S11 greater than 10dB, and minimal differences in amplitude and phase between the two output ports. By overcoming the drawback of large PCB area requirements of existing technologies, and possessing superior characteristics, it is highly suitable for application in mobile communication products.

[0064] The features of the many embodiments summarized above enable those skilled in the art to better understand the scope of the invention. Those skilled in the art can design or modify other processes and structures based on this disclosure to achieve the same features and / or advantages described in the embodiments of the invention. Those skilled in the art also understand that these equivalent structures do not depart from the spirit and scope of this disclosure, and that they can change, substitute, and modify the features of the invention without departing from the spirit and scope of the invention, and that such changes and modifications should fall within the protection scope of the claims of the invention.

Claims

1. A branch-line coupler, characterized in that, include: The first port, the second port, the third port, and the fourth port are respectively used as the input terminal, the through terminal, the coupling terminal, and the isolation terminal; The first transmission line includes: A first elongated transmission line has a first first end electrically connected to the first port and a first second end electrically connected to the second port, and the first elongated transmission line extends along a predetermined direction. The first branch transmission line is electrically connected to the first terminal and has a first slit; The second branch transmission line is electrically connected to the first and second ends and has a second slit, wherein the first branch transmission line and the second branch transmission line are axially symmetrical about a first axis. The second transmission line includes: The second elongated transmission line has a second first end electrically connected to the third port and a second second end electrically connected to the fourth port, and the second elongated transmission line extends along the predetermined direction. The third branch transmission line is electrically connected to the aforementioned second first end and has a third slit; The fourth branch transmission line is electrically connected to the second end and has a fourth slit, wherein the third branch transmission line and the fourth branch transmission line are axially symmetrical with respect to the first axis. A first bent transmission line is electrically connected between the first port and the fourth port; and The second bent transmission line is electrically connected between the second port and the third port, wherein... The first branch transmission line includes a spiral branch and an L-shaped branch. One end of the spiral branch is electrically connected to the first end, and the other end is suspended. One end of the L-shaped branch is electrically connected to the first end, and the other end extends toward the first bent transmission line and is suspended. The L-shaped branch and the first bent transmission line form a semi-enclosed area, and the spiral branch is located in the semi-enclosed area.

2. The branch line coupler as described in claim 1, characterized in that, The first slit is located between the spiral branch and the first bent transmission line.

3. The branch line coupler as described in claim 1, characterized in that, The aforementioned first branch transmission line further includes a fifth slit located between the aforementioned spiral branch and the aforementioned L-shaped branch.

4. The branch line coupler as described in claim 1, characterized in that, The aforementioned first bent transmission line includes a fifth branch transmission line, which includes: The fifth branch extends along the aforementioned predetermined direction; The fifth and second branches extend along the aforementioned predetermined direction; as well as The fifth third branch connects the fifth first branch and the fifth second branch to the terminal of the second bent transmission line.

5. The branch line coupler as described in claim 4, characterized in that, The aforementioned fifth branch transmission line further includes a fifth fourth branch, which extends along the aforementioned predetermined direction, and the fifth fourth branch is close to the terminal of the aforementioned second bent transmission line and connects to the aforementioned fifth third branch.

6. The branch line coupler as described in claim 1, characterized in that, The aforementioned second bent transmission line includes a sixth branch transmission line, which includes: The sixth branch extends along the aforementioned predetermined direction; The sixth and second branches extend along the aforementioned predetermined direction; The sixth third branch connects the sixth first branch and the sixth second branch to the terminal of the first bent transmission line; as well as The sixth and fourth branches extend along the predetermined direction and are close to the terminals of the first bent transmission line, connecting to the sixth and third branches.

7. The branch line coupler as described in claim 1, characterized in that, The first transmission line and the second transmission line are axially symmetric with respect to a second axis orthogonal to the first axis.

8. The branch line coupler as described in claim 1, characterized in that, Also includes: The first connection portion electrically connects the first port, the first transmission line, and the first bent transmission line. The second connection part is electrically connected to the second port, the first transmission line, and the second bent transmission line. The third connection part is electrically connected to the third port, the second transmission line, and the second bent transmission line. as well as The fourth connection part is electrically connected to the fourth port, the second transmission line, and the first bent transmission line.

9. The branch line coupler as described in claim 8, characterized in that, The first connecting part, the second connecting part, the third connecting part and the fourth connecting part mentioned above are transmission lines.

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