Directional coupler and printed circuit board

Abstract

The invention discloses a directional coupler and a printed circuit board. The directional coupler comprises a first metal layer, a second metal layer and a dielectric layer; the first metal layer and the second metal layer are respectively arranged on two opposite surfaces of the dielectric layer; the first metal layer comprises a transmission line extending along a first direction; the second metal layer comprises a coupling line, and the coupling line comprises a first coupling part, a second coupling part and a third coupling part which are parallel to the transmission line and are electrically connected in sequence; in the first direction, at least part of the first coupling part is located on one side of the second coupling part, and at least part of the third coupling part is located on the other side of the second coupling part; and along the thickness direction of the directional coupler, the orthographic projection of the second coupling part is located in the orthographic projection of the transmission line. The size of the directional coupler can be reduced, and the coupling performance is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of couplers, and in particular to a directional coupler and a printed circuit board. Background Art

[0002] Directional couplers have important applications in circuit systems. Directional couplers can transmit signals or energy while achieving appropriate electrical isolation or matching. Directional couplers can be used in power monitoring, source output power stabilization, signal source isolation and other scenarios.

[0003] However, existing directional couplers have disadvantages such as large size and poor coupling performance. Summary of the invention

[0004] The present invention provides a directional coupler and a printed circuit board, so as to reduce the size of the directional coupler and improve the coupling performance.

[0005] According to one aspect of the present invention, there is provided a directional coupler, the directional coupler comprising a first metal layer, a second metal layer and a dielectric layer;

[0006] The first metal layer and the second metal layer are respectively arranged on two opposite sides of the dielectric layer;

[0007] The first metal layer includes a transmission line extending along a first direction; the second metal layer includes a coupling line, the coupling line includes a first coupling portion, a second coupling portion and a third coupling portion which are parallel to and electrically connected to the transmission line in sequence; along the first direction, at least a portion of the first coupling portion is located on one side of the second coupling portion, and at least a portion of the third coupling portion is located on the other side of the second coupling portion;

[0008] Wherein, along the thickness direction of the directional coupler, the orthographic projection of the second coupling portion is located within the orthographic projection of the transmission line.

[0009] Optionally, the orthographic projection of the first coupling portion along the thickness direction of the directional coupler and the orthographic projection of the third coupling portion along the thickness direction of the directional coupler are offset by a corresponding preset distance in opposite directions relative to the transmission line; the value range of the preset distance is 0 to 1.5w, where w is the width of the transmission line.

[0010] Optionally, along the thickness direction of the directional coupler, the orthographic projection of the first coupling portion is connected to the orthographic projection of the transmission line; and the orthographic projection of the third coupling portion is connected to the orthographic projection of the transmission line.

[0011] Optionally, an orthographic projection of the first coupling portion along the thickness direction of the directional coupler and an orthographic projection of the transmission line along the thickness direction of the directional coupler are offset in opposite directions by the same preset distance.

[0012] Optionally, the preset distance is determined by a design value of coupling and a design value of directivity of the directional coupler.

[0013] Optionally, along the first direction, the first coupling portion is located on one side of the second coupling portion, and the third coupling portion is located on the other side of the second coupling portion;

[0014] The length of the first coupling portion, the length of the second coupling portion, and the length of the third coupling portion are determined by a design value of the coupling degree of the directional coupler.

[0015] Optionally, the second metal layer further includes a first connecting portion and a second connecting portion;

[0016] One end of the first connection portion is connected to the first coupling portion, and the other end of the first connection portion is connected to the second coupling portion; one end of the second connection portion is connected to the second coupling portion, and the other end of the second coupling portion is connected to the third coupling portion;

[0017] The first connection portion is parallel to the second connection portion, and an angle between an extending direction of the first connection portion and the first direction is less than 90 degrees.

[0018] Optionally, the first metal layer further includes a first metal ground, the first metal ground is provided with a first opening, and the transmission line is arranged in the first opening;

[0019] The second metal layer further includes a second metal ground, the second metal ground is provided with a second opening, and the coupling line is arranged in the second opening;

[0020] Along the thickness direction of the directional coupler, the orthographic projection of the first opening coincides with the orthographic projection of the second opening.

[0021] Optionally, the directional coupler further comprises a substrate;

[0022] The substrate is disposed on a side of the first metal layer away from the second metal layer; and / or the substrate is disposed on a side of the second metal layer away from the first metal layer.

[0023] According to another aspect of the present invention, a printed circuit board is provided, comprising the directional coupler as described above; wherein the printed circuit board comprises at least two metal layers and a dielectric layer located between two adjacent metal layers; the first metal layer, the second metal layer and the dielectric layer of the directional coupler are reused by the corresponding metal layers and the dielectric layers in the printed circuit board.

[0024] The technical solution of the embodiment of the present invention adopts a directional coupler including a metal layer, a second metal layer and a dielectric layer; the first metal layer and the second metal layer are respectively arranged on two opposite sides of the dielectric layer; the first metal layer includes a transmission line extending along a first direction; the second metal layer includes a coupling line, and the coupling line includes a first coupling part, a second coupling part and a third coupling part which are parallel to and electrically connected to the transmission line in sequence; along the first direction, at least part of the first coupling part is located on one side of the second coupling part, and at least part of the third coupling part is located on the other side of the second coupling part; wherein, along the thickness direction of the directional coupler, the orthographic projection of the second coupling part is located within the orthographic projection of the transmission line. By arranging the coupling line and the transmission line in different metal layers, the overall size of the directional coupler is made smaller. By arranging the orthographic projection of the second coupling part to be located within the orthographic projection of the transmission line, the length and position of the first coupling part and the third coupling part can be set according to actual needs, and the performance of the directional coupler can be improved by adjusting at least one of the position of the first coupling part, the length of the first coupling part, the length of the second coupling part, the position of the third coupling part and the length of the third coupling part.

[0025] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 A cross-sectional view of a directional coupler provided by an embodiment of the present invention;

[0028] Figure 2 A top view of a first metal layer of a directional coupler provided by an embodiment of the present invention;

[0029] Figure 3 A top view of a second metal layer of a directional coupler provided by an embodiment of the present invention;

[0030] Figure 4 A schematic diagram of the overall structure of a directional coupler provided in an embodiment of the present invention;

[0031] Figure 5 A schematic diagram of the overall structure of another directional coupler provided in an embodiment of the present invention;

[0032] Figure 6 for Figure 5 The coupling performance simulation results of the directional coupler in the figure;

[0033] Figure 7 for Figure 5 Directivity simulation result diagram of the directional coupler;

[0034] Figure 8 A schematic diagram of the overall structure of another directional coupler provided in an embodiment of the present invention;

[0035] Fig. 9 for Figure 8 The coupling performance simulation results of the directional coupler in the figure;

[0036] Fig.10 for Figure 8 Directivity simulation result diagram of the directional coupler;

[0037] Fig.11 for Figure 4 The coupling performance simulation results of the directional coupler in the figure;

[0038] Fig.12 for Figure 4 Figure 2 shows the directivity simulation results of the directional coupler. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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 should fall within the scope of protection of the present invention.

[0040] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0041] Figure 1 A cross-sectional view of a directional coupler provided by an embodiment of the present invention, Figure 2A top view of a first metal layer of a directional coupler provided by an embodiment of the present invention, Figure 3 A top view of a second metal layer of a directional coupler provided by an embodiment of the present invention, Figure 4 A schematic diagram of the overall structure of a directional coupler provided in an embodiment of the present invention, referring to Figures 1 to 4 The directional coupler comprises a first metal layer 11, a second metal layer 13 and a dielectric layer 12; the first metal layer 11 and the second metal layer 13 are respectively arranged on two opposite surfaces of the dielectric layer 12; the first metal layer 11 comprises a transmission line 111 extending along a first direction Y; the second metal layer 13 comprises a coupling line 131, and the coupling line 131 comprises a first coupling portion 1311, a second coupling portion 1312 and a third coupling portion 1313 which are parallel to and electrically connected to the transmission line 11 in sequence; along the first direction Y, at least a portion of the first coupling portion 1311 is located on one side of the second coupling portion 1312, and at least a portion of the third coupling portion 1313 is located on the other side of the second coupling portion 1312; wherein, along the thickness direction of the directional coupler, the orthographic projection of the second coupling portion 1312 is located within the orthographic projection of the transmission line 11.

[0042] Specifically, a directional coupler is a four-port device including a transmission line and a coupling line, and the transmission line and the coupling line are placed in parallel. The power transmitted on the transmission line is coupled to the coupling line, and the power on the coupling line propagates in one direction, that is, the coupling end of the coupling line has power output, and the isolation end of the coupling line has no power output.

[0043] In the related art, the coupling line and the transmission line are both placed horizontally, so the size of the directional coupler is relatively large. In this embodiment, the transmission line 111 and the coupling line 131 are arranged on different metal layers, that is, arranged in the vertical direction, so that a smaller area can be occupied in the horizontal direction, which is conducive to reducing the size of the directional coupler. Among them, the dielectric layer 12 plays the role of insulation and providing mechanical support.

[0044] In addition, a first direction Y, a second direction X and a third direction Z are defined, wherein the first direction Y, the second direction X and the third direction Z are mutually perpendicular, and the third direction Z is the thickness direction of the directional coupler. The width of the coupling line 131 is the same as the width of the transmission line 111. The width of the coupling line 131 refers to the dimension of the coupling line 131 along the second direction X, and the width of the transmission line 111 refers to the dimension of the transmission line 111 along the second direction X. The orthographic projection of the second coupling portion 1312 is located within the orthographic projection of the transmission line 111, that is, along the third direction Z, the orthographic projection of the second coupling portion 1312 coincides with the orthographic projection of a portion of the line segment of the transmission line 111. The power on the transmission line 111 can be coupled to the second coupling portion 1312. The lengths of the first coupling portion 1311, the second coupling portion 1312 and the third coupling portion 1313, and the positions of the first coupling portion 1311 and the third coupling portion 1312 affect the directivity and coupling of the directional coupler. Therefore, the directivity and coupling of the directional coupler can be affected by adjusting the lengths of the first coupling portion 1311, the second coupling portion 1312 and the third coupling portion 1313, and the positions of the first coupling portion 1311 and the third coupling portion 1312. In addition, it should be noted that, in this embodiment, along the first direction Y, the first coupling portion 1311 is at least partially located on one side of the second coupling portion 1312, that is, along the second direction X, the orthographic projections of the first coupling portion 1311 and the second coupling portion 1312 at least partially do not overlap; similarly, along the second direction X, the orthographic projections of the third coupling portion 1313 and the second coupling portion 1312 at least partially do not overlap. Preferably, one end of the first coupling portion 1311 away from the second coupling portion 1312 is flush with one end of the transmission line 111 in the second direction X, and one end of the third coupling portion 1313 away from the second coupling portion 1313 is flush with the other end of the transmission line 111 in the second direction X, thereby improving the coupling performance between the coupling line of the directional coupler and the transmission line.

[0045] The technical solution of this embodiment adopts a directional coupler including a metal layer, a second metal layer and a dielectric layer; the first metal layer and the second metal layer are respectively arranged on two opposite sides of the dielectric layer; the first metal layer includes a transmission line extending along a first direction; the second metal layer includes a coupling line, and the coupling line includes a first coupling part, a second coupling part and a third coupling part which are parallel to and electrically connected to the transmission line in sequence; along the first direction, at least part of the first coupling part is located on one side of the second coupling part, and at least part of the third coupling part is located on the other side of the second coupling part; wherein, along the thickness direction of the directional coupler, the orthographic projection of the second coupling part is located within the orthographic projection of the transmission line. By arranging the coupling line and the transmission line in different metal layers, the overall size of the directional coupler is made smaller. By arranging the orthographic projection of the second coupling part to be located within the orthographic projection of the transmission line, the length and position of the first coupling part and the third coupling part can be set according to actual needs, and the performance of the directional coupler can be improved by adjusting at least one of the position of the first coupling part, the length of the first coupling part, the length of the second coupling part, the position of the third coupling part and the length of the third coupling part.

[0046] Optionally, in the above embodiment, the first metal layer 11 and the second metal layer 13 may be copper layers. The material of the dielectric layer 12 is, for example, glass fiber cloth, epoxy resin or polyimide.

[0047] Optionally, continue to refer to Figures 1 to 4 The orthographic projection of the first coupling portion 1311 along the third direction Z and the orthographic projection of the transmission line 111 along the third direction Z are offset in opposite directions relative to the transmission line 111 by a corresponding preset distance; the value range of the preset distance is 0 to 1.5w, where w is the width of the transmission line.

[0048] Specifically, Figure 1 and Figure 3 As shown, the widths of the first coupling part 1311, the second coupling part 1312, the third coupling part 1313 and the transmission line 111 are all w. The first coupling part 1311 and the transmission line 111 are misaligned in the second direction X, and the misaligned distance is the preset distance, wherein the misaligned distance can be understood as the distance between the center line of the first coupling part 1311 and the center line of the transmission line 111 in the second direction X, which is represented by d in the figure. The first coupling part 1311 and the third coupling part 1312 are misaligned in different directions, so that the overall structure of the directional coupler is closer to a symmetrical setting, thereby having higher stability in various frequency bands. Moreover, it can have better directivity and coupling. Of course, in some other embodiments, the first coupling part 1311 and the third coupling part 1312 can also be misaligned in the same direction.

[0049] In addition, the preset distance has a value range of 0 to 1.5w. When the preset distance is 0, the orthographic projections of the corresponding two parts in the third direction Z coincide. For example, when the preset distance corresponding to the first coupling portion 1311 is 0, along the third direction Z, the orthographic projection of the first coupling portion 1311 coincides with the orthographic projection of a portion of the line segment of the transmission line 111; when the preset distance corresponding to the third coupling portion 1311 is 0, along the third direction Z, the orthographic projection of the third coupling portion 1313 coincides with the orthographic projection of a portion of the line segment of the transmission line 111. In some embodiments, the preset distances corresponding to the first coupling portion 1311 and the third coupling portion 1313 are set to be equal, that is, the directional coupler is a symmetrical device, so as to have better stability, coupling and directionality. Figure 5 A schematic diagram of the overall structure of another directional coupler provided in an embodiment of the present invention, Figure 6 for Figure 5 The coupling performance simulation results of the directional coupler in the figure are as follows: Figure 7 for Figure 5 Figure 2 shows the directivity simulation results of the directional coupler. Figure 8 A schematic diagram of the overall structure of another directional coupler provided in an embodiment of the present invention, Fig. 9 for Figure 8 The coupling performance simulation results of the directional coupler in the figure are as follows: Fig.10 for Figure 8 Directivity simulation result diagram of directional coupler, refer to Figures 5 to 10 .exist Figure 5 In the default distance is 0, Figure 8 In the figure, the preset distance is 1.5w. It can be seen from the corresponding simulation result diagram that when the preset distance is in the range of 0 to 1.5w, better coupling performance and directivity can be achieved.

[0050] Preferably, along the thickness direction of the directional coupler, the orthographic projection of the first coupling portion is connected to the orthographic projection of the transmission line; and the orthographic projection of the third coupling portion is connected to the orthographic projection of the transmission line.

[0051] Specifically, Fig.11 for Figure 4 The coupling performance simulation results of the directional coupler in the figure are as follows: Fig.12 for Figure 4 The directivity simulation result diagram of the directional coupler in Figure 4 In , the preset distance is w. Figures 4 to 11 It can be seen that when the preset distance is w, that is, along the thickness direction of the directional coupler, the orthographic projection of the first coupling part is connected to the orthographic projection of the transmission line; when the orthographic projection of the third coupling part is connected to the orthographic projection of the transmission line, the directional coupler has a relatively Figure 5 and Figure 8The structure shown in the figure has better coupling performance and directivity. In the coupling performance simulation result diagram, the red line represents the insertion loss, the green line represents the coupling degree, and the blue line represents the isolation degree.

[0052] Optionally, the preset distance is determined by a design value of coupling and a design value of directivity of the directional coupler.

[0053] Specifically, in the design stage of the directional coupler, the preset distance can be adjusted according to the design value of the coupling line and the design value of the directivity. For example, the preset distance can be set within the range of 0 to 1.5w, and then the deviation between the actual value of the coupling and directivity and the design value can be analyzed to determine the specific value of the preset distance.

[0054] Optionally, along the first direction Y, the first coupling portion 1311 is entirely located on one side of the second coupling portion 1312, and the third coupling portion 1313 is entirely located on the other side of the second coupling portion 1312; the length of the first coupling portion 1311, the length of the second coupling portion 1312, and the length of the third coupling portion 1313 are determined by the design value of the coupling degree of the directional coupler.

[0055] Specifically, the lengths of the first coupling portion 1311, the second coupling portion 1312, and the third coupling portion 1313 have a great influence on the coupling property of the directional coupler. In the design stage of the directional coupler, if adjusting the preset distance cannot make the coupling property of the directional coupler meet the requirements, the coupling property of the directional coupler can be adjusted by adjusting the length of at least one of the first coupling portion 1311, the second coupling portion 1312, and the third coupling portion 1313. Of course, the operating frequency of the directional coupler can also be adjusted by adjusting the length of at least one of the first coupling portion 1311, the second coupling portion 1312, and the third coupling portion 1313.

[0056] Optionally, refer to Figure 3 The directional coupler further includes a first end 21 and a second end 22, both of which are located in the second metal layer and extend along the second direction X. The first end 21 is connected to the first coupling portion 1311, and the second end 22 is connected to the third coupling portion 1313. One of the first end 21 and the second end 22 serves as a coupling end of the directional coupler, and the other serves as an isolation end of the directional coupler. It can be understood that whether it serves as an isolation end or a coupling end depends on the signal transmission direction in the transmission line 111. It can be understood that one of the two ends of the transmission line 111 serves as an input end, and the other serves as an output end.

[0057] Optionally, continue to refer to Figure 3The second metal layer also includes a first connecting portion 23 and a second connecting portion 24; one end of the first connecting portion 23 is connected to the first coupling portion 1311, and the other end of the first connecting portion 23 is connected to the second coupling portion 1312; one end of the second connecting portion 24 is connected to the second coupling portion 1312, and the other end of the second coupling portion 1312 is connected to the third coupling portion 1313; the first connecting portion 23 is parallel to the second connecting portion 24, and the angle between the extension direction of the first connecting portion 23 and the first direction Y is less than 90 degrees.

[0058] Specifically, the first coupling portion 1311 and the second coupling portion 1312 are electrically connected through the first connection portion 23, and the third coupling portion 1313 and the second coupling portion 1312 are electrically connected through the second connection portion 24. In this embodiment, the first connection portion 23 and the second connection portion 24 are neither parallel to nor perpendicular to the first direction Y, which can improve the continuity of the impedance between the coupling portions on the coupling line, thereby reducing the impact on the coupling performance.

[0059] It should be noted that Figure 3 Although the first connection portion 23 and the second connection portion 24 are tilted upward as an example, in some other embodiments, they may also be tilted downward. In this embodiment, along the second direction X, the orthographic projection of the first coupling portion 1311 partially overlaps with the second coupling portion 1312; the orthographic projection of the third coupling portion 1313 partially overlaps with the second coupling portion 1312.

[0060] Optionally, in the above embodiment, the width of the first connection portion 23 is smaller than the width of the coupling line, that is, the width of the first connection portion 23 is smaller than w. Preferably, the width of the first connection portion 23 can be set to 0.57w, which is more conducive to reducing the discontinuity of the impedance between the first coupling portion 1311 and the second coupling portion 1312.

[0061] Optionally, in the above embodiment, the width of the second connection portion 24 is smaller than the width of the coupling line, that is, the width of the second connection portion 24 is smaller than w. Preferably, the width of the second connection portion 24 can be set to 0.57w, which is more conducive to reducing the discontinuity of the impedance between the third coupling portion 1313 and the second coupling portion 1312.

[0062] Optionally, refer to Figures 1 to 3 The first metal layer 11 also includes a first metal ground 112, the first metal ground 112 has a first opening H1, and the transmission line 111 is arranged in the first opening H1; the second metal layer 13 also includes a second metal ground 132, the second metal ground 132 has a second opening H2, and the coupling line 131 is arranged in the second opening H2; along the thickness direction of the directional coupler, the orthographic projection of the first opening H1 coincides with the orthographic projection of the second opening H2.

[0063] Specifically, the directional coupler can be directly made in a printed circuit board (PCB). At least two metal layers and a dielectric layer located between the metal layers are provided in the PCB. The first metal layer, the dielectric layer and the second metal layer in the directional coupler can be obtained by reusing two adjacent metal layers and the dielectric layer between them in the PCB. In other words, corresponding transmission lines and coupling lines can be etched in the metal layer of the PCB. Other metal layers in the PCB can be used as grounding layers for different devices on the surface of the PCB. It can be understood that the first metal ground 112 can be a closed pattern, and the second metal layer 132 can also be a closed pattern. In this embodiment, the directional coupler is directly made in the PCB, which can avoid welding physical coupling devices such as waveguides, LTCC (Low Temperature Co-fired Ceramic) or strip lines on the PCB, thereby saving the occupied area of ​​the PCB surface layer, reducing the area and reducing costs.

[0064] Optionally, the directional coupler further includes a substrate 14 ; the substrate 14 is disposed on a side of the first metal layer 11 away from the second metal layer 13 ; and / or the substrate 14 is disposed on a side of the second metal layer 13 away from the first metal layer 11 .

[0065] Specifically, the substrate 14 can provide mechanical support to improve the mechanical stability of the directional coupler. When the directional coupler is made inside the PCB, the first metal layer 11 can be the metal layer closest to the surface of the PCB. Since the transmission line 11 needs to be electrically connected to other integrated devices on the surface of the PCB, and the coupling line needs to connect fewer devices accordingly, and the isolation end may not need a connecting device. Therefore, the first metal layer 11 is closer to the surface of the PCB, and the second metal layer 12 is closer to the bottom layer of the PCB, which can reduce the difficulty of electrically connecting the directional coupler to other devices. In this embodiment, the substrate 14 is preferably arranged on the side of the second metal layer 13 away from the first metal layer 11.

[0066] Furthermore, if the isolation end corresponding to the coupling line needs to be connected to a grounded load resistor, and if the grounded load resistor is welded on the first metal layer, the grounded load resistor can be electrically connected to the isolation end by drilling holes in the first metal layer and the dielectric layer.

[0067] The embodiment of the present invention further provides a printed circuit board, which includes the directional coupler provided by any embodiment of the present invention. The printed circuit board includes at least two metal layers and a dielectric layer located between two adjacent metal layers; the first metal layer, the second metal layer and the dielectric layer of the directional coupler are reused by the corresponding metal layers and dielectric layers in the printed circuit board.

[0068] Other devices may also be arranged on the printed circuit board. Since the printed circuit board provided by the embodiment of the present invention includes the directional coupler provided by the embodiment of the present invention, it also has the same beneficial effects, which will not be described in detail here.

[0069] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0070] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A directional coupler, characterized in that: The directional coupler comprises a first metal layer, a second metal layer and a dielectric layer; The first metal layer and the second metal layer are respectively arranged on two opposite sides of the dielectric layer; The first metal layer includes a transmission line extending along a first direction; the second metal layer includes a coupling line, the coupling line includes a first coupling portion, a second coupling portion and a third coupling portion which are parallel to and electrically connected to the transmission line in sequence; along the first direction, at least a portion of the first coupling portion is located on one side of the second coupling portion, and at least a portion of the third coupling portion is located on the other side of the second coupling portion; Wherein, along the thickness direction of the directional coupler, the orthographic projection of the second coupling portion is located within the orthographic projection of the transmission line.

2. The directional coupler according to claim 1, characterized in that The orthographic projection of the first coupling portion along the thickness direction of the directional coupler and the orthographic projection of the third coupling portion along the thickness direction of the directional coupler are offset in opposite directions relative to the transmission line by a corresponding preset distance; the value range of the preset distance is 0 to 1.5w, where w is the width of the transmission line.

3. The directional coupler according to claim 2, characterized in that: Along the thickness direction of the directional coupler, the orthographic projection of the first coupling portion is connected to the orthographic projection of the transmission line; and the orthographic projection of the third coupling portion is connected to the orthographic projection of the transmission line.

4. The directional coupler according to claim 2, characterized in that An orthographic projection of the first coupling portion along the thickness direction of the directional coupler and an orthographic projection of the transmission line along the thickness direction of the directional coupler are offset in opposite directions by the same preset distance.

5. The directional coupler according to claim 2, characterized in that: The preset distance is determined by a design value of the coupling property and a design value of the directivity of the directional coupler.

6. The directional coupler according to claim 1, characterized in that Along the first direction, the first coupling portion is located on one side of the second coupling portion, and the third coupling portion is located on the other side of the second coupling portion; The length of the first coupling portion, the length of the second coupling portion, and the length of the third coupling portion are determined by a design value of the coupling degree of the directional coupler.

7. The directional coupler according to claim 6, characterized in that The second metal layer further includes a first connecting portion and a second connecting portion; One end of the first connection portion is connected to the first coupling portion, and the other end of the first connection portion is connected to the second coupling portion; one end of the second connection portion is connected to the second coupling portion, and the other end of the second coupling portion is connected to the third coupling portion; The first connection portion is parallel to the second connection portion, and an angle between an extending direction of the first connection portion and the first direction is less than 90 degrees.

8. The directional coupler according to claim 1, characterized in that The first metal layer further includes a first metal ground, the first metal ground is provided with a first opening, and the transmission line is arranged in the first opening; The second metal layer further includes a second metal ground, the second metal ground is provided with a second opening, and the coupling line is arranged in the second opening; Along the thickness direction of the directional coupler, the orthographic projection of the first opening coincides with the orthographic projection of the second opening.

9. The directional coupler according to claim 1, characterized in that The directional coupler also includes a substrate; The substrate is disposed on a side of the first metal layer away from the second metal layer; and / or the substrate is disposed on a side of the second metal layer away from the first metal layer.

10. A printed circuit board, characterized in that: The printed circuit board comprises the directional coupler according to any one of claims 1 to 9; wherein the printed circuit board comprises at least two metal layers and a dielectric layer located between two adjacent metal layers; the first metal layer, the second metal layer and the dielectric layer of the directional coupler are reused by the corresponding metal layers and the dielectric layers in the printed circuit board.

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