Directional coupler

Abstract

The utility model discloses a directional coupler, relates to the related technical field of microwave transmission, and is used for solving the technical problem of large loss of an existing directional coupler. The directional coupler comprises an insulating substrate which comprises a body and a supporting table, the body is provided with a first surface and a second surface which are oppositely arranged in the third direction, a groove is formed in the first surface, and the supporting table is composed of a first supporting part, a second supporting part and a third supporting part which are arranged at the groove bottom of the groove in a protruding mode; the first supporting part and the second supporting part are arranged in a spaced mode in the first direction and extend in the second direction, the third supporting part is connected with the first supporting part and the second supporting part, and the wall faces, back to the bottom of the groove, of the first supporting part, the second supporting part and the third supporting part are close to the second surface relative to the first surface; the transmission line comprises a first transmission line arranged on the first supporting part, a second transmission line arranged on the second supporting part and a third transmission line arranged on the third supporting part, and the third transmission line is connected with the first transmission line and the second transmission line.

Description

Technical Field

[0001] The present application relates to the technical field related to microwave transmission technology, and in particular to a directional coupler. Background Art

[0002] As humans enter the information age, wireless communication technology has developed rapidly. From mobile phones, wireless LANs, Bluetooth, etc., it has become an indispensable part of social life and development. Among them, directional couplers can be used for signal isolation, separation and mixing in modern wireless communication systems, such as power monitoring, source output power stabilization, signal source isolation, transmission and reflection sweep frequency testing, etc. Due to its advantages such as low insertion loss and small size, it has been widely used.

[0003] A directional coupler is a power distribution element that allows energy to propagate in a certain order and rule. There are many ways to implement a directional coupler, such as coupling branch lines, coupling holes, and coupling gaps. The definition of a directional coupler in microwave engineering is: any reciprocal, lossless, matched four-port network is a directional coupler.

[0004] The technical indicators of directional couplers include several key parameters, such as operating frequency band, insertion loss, coupling, directivity and isolation. The insertion loss mainly refers to the power loss ratio of the dominant signal from the input to the output, which mainly includes coupling loss, heat loss inside the medium and radiation loss. The above losses will cause the signal to attenuate and distort during transmission. Therefore, it is necessary to design and develop a low-loss directional coupler. Utility Model Content

[0005] The present application provides a directional coupler, which can solve the problem of high loss of the existing directional coupler.

[0006] To achieve the above-mentioned purpose, the directional coupler provided in the present application has a first direction, a second direction and a third direction intersecting in pairs, and the directional coupler comprises:

[0007] An insulating substrate, comprising a body and a support platform, wherein the body has a first surface and a second surface arranged opposite to each other in the third direction, a groove is arranged on the first surface, and the support platform is composed of a first support portion, a second support portion and a third support portion protruding from the bottom of the groove, the first support portion and the second support portion are arranged at intervals along the first direction and extend along the second direction, the third support portion connects the first support portion and the second support portion, and the wall surfaces of the first support portion, the second support portion and the third support portion facing away from the bottom of the groove are close to the second surface relative to the first surface;

[0008] The transmission line includes a first transmission line arranged on the first supporting part, a second transmission line arranged on the second supporting part, and a third transmission line arranged on the third supporting part, wherein the third transmission line connects the first transmission line and the second transmission line.

[0009] In some embodiments of the present application, the directional coupler further includes:

[0010] A conductive cover plate is covered on the first surface and enclosed with the body to form a cavity. There is a gap between the first transmission line, the second transmission line and the third transmission line and the conductive cover plate.

[0011] In some embodiments of the present application, a connecting protrusion is convexly provided at the bottom of the groove, and the connecting protrusion () is connected to the conductive cover plate. The connecting protrusion is located between the first support portion and the second support portion, and is located on both sides of the third support portion in the second direction.

[0012] In some embodiments of the present application, there are at least two connecting protrusions, and the wall surface of each connecting protrusion facing the conductive cover plate is flush with the first surface. The wall surface of the conductive cover plate facing the first surface is a flat surface and fits the first surface.

[0013] In some embodiments of the present application, there are at least two connecting protrusions, and the wall surface of each connecting protrusion facing the conductive cover plate is flush with the first surface. The wall surface of the conductive cover plate facing the first surface is provided with a plurality of recessed portions that are recessed in a direction away from the insulating substrate, and the connecting protrusion is located in the corresponding recessed portions.

[0014] In some embodiments of the present application, the number of the third supporting portions is N, and the number of the connecting protrusions is N+1. In the second direction, one of the two outermost connecting protrusions is located between the input port of the first transmission line and the isolation port of the second transmission line, and the other is located between the through port of the first transmission line and the coupling port of the second transmission line. The input port and the isolation port are located on the same side, and the through port and the coupling port are located on the same side.

[0015] In some embodiments of the present application, the groove has a first side wall and a second side wall arranged opposite to each other in the first direction, and the directional coupler further includes:

[0016] A plurality of first conductive layers are respectively disposed on inner side walls of a plurality of the connecting protrusions, wherein the inner side walls are configured as side walls of the connecting protrusions located in the cavity;

[0017] A second conductive layer, disposed on the first side wall;

[0018] The third conductive layer is disposed on the second side wall.

[0019] In some embodiments of the present application, a first gap is formed between the multiple inner side walls of each connecting protrusion and the corresponding first supporting portion, the second supporting portion and the third supporting portion, a second gap is formed between the first supporting portion and the first side wall, and a third gap is formed between the second supporting portion and the second side wall, and the first gap, the second gap and the third gap constitute part of the cavity.

[0020] In some embodiments of the present application, a first protrusion extending toward the first side wall is provided on a side of the first support portion facing the first side wall, a first groove corresponding to the first protrusion and recessed in a direction away from the first support portion is provided on the first side wall, and a second protrusion extending toward the second side wall is provided on the second support portion on a side of the second support portion facing the second side wall, and a second groove corresponding to the second protrusion and recessed in a direction away from the second support portion is provided on the second side wall.

[0021] In some embodiments of the present application, the distances between the side walls of the first support portion, the second support portion, and the third support portion facing the conductive cover plate and the conductive cover plate are equal, and the first transmission line, the second transmission line, and the third transmission line are an integrated structure.

[0022] In the technical solution, the present application is provided with a support platform extending upward along a third direction at the bottom of the groove of the body. Among them, on the one hand, the support platform can provide support for the installation of the transmission line. In another direction, the support platform is composed of a first support portion, a second support portion and a third support portion. Correspondingly, the specific structure of the transmission line and the specific structure of the support platform are adapted to each other, thereby, the support platform can also provide an effective transmission path for the transmission line, and the transmission line can ensure that it has good directivity when performing signal transmission according to the transmission path, thereby reducing the transmission loss of the directional coupler. In addition, the wall surface of the first support portion, the second support portion and the third support portion of the support platform of the present application facing away from the bottom of the groove (i.e., the top surface of the first support portion, the second support portion and the third support portion shown in the figure) is close to the second surface relative to the first surface, so that the groove can provide a semi-enclosed transmission path to the transmission line arranged on the support platform, and the transmission line performs signal transmission according to the semi-enclosed transmission path, which can further ensure that it has good directivity, thereby further reducing the transmission loss of the directional coupler. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 is a structural schematic diagram of a directional coupler provided in an embodiment of the present application;

[0025] Figure 2 is a front view of a directional coupler provided in an embodiment of the present application;

[0026] Figure 3 is a front view of another directional coupler provided in an embodiment of the present application;

[0027] Figure 4 It is a structural schematic diagram of an insulating substrate in a directional coupler provided in an embodiment of the present application;

[0028] Figure 5 is a structural schematic diagram of another directional coupler provided in an embodiment of the present application;

[0029] Figure 6 is a structural schematic diagram of an insulating substrate in another directional coupler provided in an embodiment of the present application;

[0030] Figure 7 It is a structural schematic diagram of an insulating substrate in another directional coupler provided in an embodiment of the present application;

[0031] Figure 8 for Figure 1 The S-parameter curve of the directional coupler shown;

[0032] of the coupler, Fig. 9 For frequencies between 22 GHz and 32 GHz Figure 8 The S shown 2,1 Through parameter and S 3,1 A zoomed-in view of the coupling parameters.

[0033] The main reference numerals in the drawings of this application specification are described as follows:

[0034] 1-insulating substrate; 10-body; 101-first surface; 102-second surface; 103-groove; 104-first side wall; 105-second side wall; 11-support platform; 111-first support portion; 112-second support portion; 113-third support portion; 12-connecting protrusion; 14-first interval; 15-second interval; 151-first groove; 16-third interval; 161-second groove;

[0035] 2-conductive cover plate; 21-cavity; 22-recessed portion;

[0036] 3-transmission line; 31-first transmission line; 32-second transmission line; 33-third transmission line;

[0037] 4- first conductive layer;

[0038] 5- second conductive layer;

[0039] 6- The third conductive layer. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0041] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0042] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0043] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0044] In microwave transmission technology, a directional coupler allows energy to propagate in a certain order and rule in the component. The directional coupler includes an input port P1, a through port P2, a coupled port P3, and an isolated port P4. In order to measure the performance of the directional coupler, the following performance parameters need to be introduced, specifically:

[0045] (1) Coupling degree

[0046] When the input port P1 is fed, the other ports are connected to matching loads. The input signal power of the P1 port is W P1 , the output signal power of the coupling port P3 is W P3 , then the coupling degree C is:

[0047]

[0048] When W P1 =2*W P3 When C=3dB, this directional coupler is called a 3dB directional coupler.

[0049] (2) Isolation

[0050] When the input port P1 is fed, the other ports are connected to matching loads. The input signal power of the P1 port is W P1 , the output signal power of the isolation port P4 is W P4 , then the isolation degree I is:

[0051]

[0052] (3) Directionality

[0053] When the input port P1 is fed, the other ports are connected to matching loads. The output signal power of the coupled port P3 is W P3 , the output signal power of the isolation port P4 is W P4 , then the directivity D is:

[0054]

[0055] The relationship between the above three parameters is I=C+D(dB). For an ideal coupler, its directivity and isolation should be close to infinity.

[0056] Therefore, in order to solve the problem that the existing directional coupler has large loss, which causes the signal to be attenuated and distorted during transmission, the present application provides a directional coupler, which mainly improves the directional coupler from the two aspects of directivity and isolation, to ensure that the loss of the directional coupler is low. The technical solution of the present application is described in detail below. It should be noted that the description order of the following embodiments is not intended to limit the preferred order of the embodiments of the present application. In the following embodiments, the description of each embodiment has its own emphasis. For the parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0057] Reference Figure 1 The directional coupler provided in the present application has a first direction X, a second direction Y and a third direction Z intersecting in pairs, and the directional coupler includes an insulating substrate 1 and a transmission line 3. The insulating substrate 1 includes a body 10 and a support platform 11, the body 10 has a first surface 101 and a second surface 102 arranged opposite to each other in the third direction Z, a groove 103 is arranged on the first surface 101, and the support platform 11 is composed of a first support portion 111, a second support portion 112 and a third support portion 113 protruding from the bottom of the groove 103, the first support portion 111 and the second support portion 112 are arranged at intervals along the first direction X and extend along the second direction Y, the third support portion 113 connects the first support portion 111 and the second support portion 112, and the wall surfaces of the first support portion 111, the second support portion 112 and the third support portion 113 facing away from the bottom of the groove 103 are close to the second surface 102 relative to the first surface 101. The transmission line 3 includes a first transmission line 31 disposed on the first support portion 111 , a second transmission line 32 disposed on the second support portion 112 , and a third transmission line 33 disposed on the third support portion 113 . The third transmission line 33 connects the first transmission line 31 and the second transmission line 32 .

[0058] In this technical solution, the present application provides a support platform 11 extending upward along a third direction at the bottom of the groove 103 of the main body 10. Among them, on the one hand, the support platform 11 can provide support for the installation of the transmission line 3. In another direction, the support platform 11 is composed of a first support portion 111, a second support portion 112 and a third support portion 113. Correspondingly, the specific structure of the transmission line 3 and the specific structure of the support platform 11 are adapted to each other, thereby, the support platform 11 can also provide an effective transmission path for the transmission line 3. The transmission line 3 can ensure good directivity when transmitting signals according to the transmission path, thereby reducing the transmission loss of the directional coupler.

[0059] In addition, the first support portion 111, the second support portion 112 and the third support portion 113 in the support platform 11 of the present application are opposite to the wall surface of the bottom of the groove 103 (ie Figure 1The top surfaces of the first support portion 111, the second support portion 112 and the third support portion 113 shown are close to the second surface 102 relative to the first surface 101, so that the groove 103 can provide a semi-enclosed transmission path for the transmission line 3 arranged on the support platform 11. The transmission line 3 transmits signals according to the semi-enclosed transmission path, which can further ensure that it has good directivity, thereby further reducing the transmission loss of the directional coupler.

[0060] Among them, "the wall surfaces of the first support portion 111, the second support portion 112 and the third support portion 113 facing away from the bottom of the groove 103 are closer to the second surface 102 relative to the first surface 101", which can also be understood as that the first support portion 111, the second support portion 112 and the third support portion 113 are all located in the groove 103, and the top surfaces of each do not extend out of the groove 103. Or, in other words, in the third direction, the heights of the first support portion 111, the second support portion 112 and the third support portion 113 are all less than the recessed depth of the groove 103. Alternatively, the top surfaces of the first support portion 111, the second support portion 112 and the third support portion 113 do not exceed the first surface 101 (the upper surface of the insulating substrate 1).

[0061] For example, the two side walls of the first support portion 111 and the second support portion 112 in the second direction Y are flush with the two side walls of the insulating substrate 1 in the second direction Y. The third support portion 113 extends along the first direction X, and its two ends are respectively connected to the first support portion 111 and the second support portion 112 to form a support platform 11, and the support platform 11 (i.e., the first support portion 111, the second support portion 112 and the third support portion 113) are an integrated structure with the body 10. Among them, the first transmission line 31 is a main waveguide, the second transmission line 32 is a sub-waveguide, and the third transmission line 33 is a branch waveguide.

[0062] Continue to refer to Figure 1 and Figure 2 The directional coupler further includes a conductive cover plate 2, which is covered on the first surface 101 and enclosed with the body 10 to form a cavity 21, and there are gaps between the first transmission line 31, the second transmission line 32 and the third transmission line 33 and the conductive cover plate 2. Then, the first transmission line 31, the second transmission line 32 and the third transmission line 33 are not in contact with the conductive cover plate 2, so as to ensure that there is a relatively small gap between the first transmission line 31, the second transmission line 32 and the third transmission line 33 and the conductive cover plate 2 relative to the groove bottom of the groove 103 and the conductive cover plate 2, so that the electric field of the transmission line 3 is more concentrated and the electric field distribution is optimized, so that the transmission efficiency is improved, and the signal loss can also be reduced.

[0063] Based on the above embodiment, a connecting protrusion 12 is convexly provided at the bottom of the groove 103, and the connecting protrusion 12 is provided at the bottom of the groove 103 and connected to the conductive cover plate 2. The connecting protrusion 12 is located between the first support portion 111 and the second support portion 112 in the first direction X, and is located on both sides of the third support portion 113. Thus, by providing the connecting protrusion 12, the first transmission line 31 and the second transmission line 32 can be isolated on their transmission paths, and the first transmission line 31 and the second transmission line 32 can be coupled at the coupling channel corresponding to the third support platform 113, thereby further defining the transmission path of the transmission line 3 and its transmission efficiency. In addition, by providing the connecting protrusion 12 and connecting it to the conductive cover plate 2, the supporting strength of the insulating substrate 1 to the conductive cover plate 2 can also be increased, thereby improving the structural strength of the directional coupler.

[0064] In some embodiments, Figure 2 As shown, there are at least two connection protrusions 12, and the wall surface of each connection protrusion 12 facing the conductive cover plate 2 is flush with the first surface 101. The wall surface of the conductive cover plate 2 facing the first surface 101 is a flat surface and fits with the first surface 101, thereby ensuring that the structure of the conductive cover plate 2 is a simple flat plate structure, which is convenient for processing. In addition, in order to reduce the transmission loss of the directional coupler, the top surface of the above-mentioned connection protrusion 12 extends to the plane where the first surface 101 is located, so as to achieve isolation of the transmission signal in the third direction Z.

[0065] In other embodiments, reference Figure 3 , Figure 3 The scheme shown and Figure 1 (or Figure 2 ) is only different in that the lower surface of the conductive cover plate 2 is a concave-convex surface. Specifically, a plurality of recessed portions 22 are provided on the wall surface of the conductive cover plate 2 facing the first surface 101, and the recessed portions 22 are recessed in the direction away from the insulating substrate 1. The remaining structures on the first surface 101 of the insulating substrate 1, except for the groove 103, and the connecting protrusions 12 are all located in the corresponding recessed portions 22. Through the concave-convex fit between the connecting protrusions 12 and the recessed portions 22, the insulating substrate 1 and the conductive cover plate 2 can be positioned in the first direction X and the second direction Y, thereby improving the fit accuracy and installation accuracy between the two.

[0066] In some embodiments, there are N third support portions 113 and N+1 connecting protrusions 12. In the second direction Y, one of the two outermost connecting protrusions 12 is located between the input port of the first transmission line 31 and the isolation port of the second transmission line 32, and the other is located between the through port of the first transmission line 31 and the coupling port of the second transmission line 32. The input port and the isolation port are located on the same side, and the through port and the coupling port are located on the same side, so that the two outermost connecting protrusions 12 can isolate the four ports in the directional coupler to improve the isolation of the directional coupler.

[0067] Combination Figure 1 and Figure 4 There are two third supporting portions 113 and three connecting protrusions 12. In the second direction Y, one of the two outermost connecting protrusions 12 is located between the input port of the first transmission line 31 and the isolation port of the second transmission line 32, and the other is located between the through port of the first transmission line 31 and the coupling port of the second transmission line 32.

[0068] Or, combined Figure 5 and Figure 6 There is one third supporting portion 113 and two connecting protrusions 12, one of the two connecting protrusions 12 is located between the input port of the first transmission line 31 and the isolation port of the second transmission line 32, and the other is located between the through port of the first transmission line 31 and the coupling port of the second transmission line 32.

[0069] Or, refer to Figure 7 , there are three third support portions 113, and there are four connecting protrusions 12. In the second direction Y, one of the two outermost connecting protrusions 12 (eg Figure 7 The uppermost connection protrusion 12 is located between the input port of the first transmission line 31 and the isolation port of the second transmission line 32. Figure 7 The lowermost connection protrusion 12 is located between the through port of the first transmission line 31 and the coupling port of the second transmission line 32 .

[0070] Therefore, the present application does not specifically limit the number of the third supporting portions 113 and the connecting protrusions 12. It only needs to be limited that, in the second direction Y, one of the two outermost connecting protrusions 12 is located between the input port of the first transmission line 31 and the isolation port of the second transmission line 32, and the other is located between the through port of the first transmission line 31 and the coupling port of the second transmission line 32. Optionally, two adjacent third transmission lines 33 are separated in the second direction Y by the same connecting protrusion 13.

[0071] Please continue to refer to Figure 1 and Figure 4The groove 103 has a first side wall 104 and a second side wall 105 which are arranged opposite to each other in the first direction X. The directional coupler further comprises a plurality of first conductive layers 4, a second conductive layer 5 and a third conductive layer 6. The plurality of first conductive layers 4 are respectively arranged on the inner side walls of the cavity 21 where the plurality of connection protrusions 12 are located. The second conductive layer 5 is arranged on the first side wall 104, and the third conductive layer 6 is arranged on the second side wall 105. In other words, the plurality of first conductive layers 4, the second conductive layer 5 and the third conductive layer 6 are all used to form a part of the wall surface of the cavity 21 to form the boundary of the transmission line 3 for transmitting signals. Through the interaction between the conductive cover plate 2 and the plurality of first conductive layers 4, the microwave signal is further guided and transmitted. At the same time, the multiple first conductive layers 4, the second conductive layers 5 and the third conductive layers 6 can constitute a partial wall surface of the cavity 21, so that the cavity 21 forms a closed structure on the transmission path of the transmission line 3, which can effectively avoid the electric field distribution in the insulating substrate 1 on both sides of the groove 103 in the first direction X, thereby reducing the heat loss inside the medium of the insulating substrate 1, and further helping to reduce the insertion loss of the directional coupler.

[0072] It should be noted that in a traditional microstrip line, the surface current is mainly concentrated on the lower surface of the microstrip line (i.e., the side where the microstrip line is bonded to the dielectric layer, which is equivalent to the lower surface of the transmission line 3 of the present application), and the roughness of the lower surface of the microstrip line is relatively large due to the requirements of the printing process, which makes the surface current distribution during the transmission of the microstrip line very uneven, resulting in additional conductor loss. The transmission line 3 of the present application adopts an inverted manner, so that the current of the transmission line 3 is mainly concentrated on the upper surface in contact with the air, and then most of the electric field is mainly concentrated on the left and right sides of the transmission line 3 and in the cavity 21 above it, and only a very small part of the electric field is distributed inside the insulating substrate 1, and the second surface is relatively smooth, thus avoiding the problem of additional conductor loss caused by the uneven lower surface, and further reducing the loss of the transmission line 3. In summary, this design of the present application can greatly reduce conductor loss, thereby achieving low-loss transmission.

[0073] Please continue to refer to Figure 1 and Figure 4 A first gap 14 is formed between the multiple inner side walls of each connecting protrusion 12 and the corresponding first supporting portion 111, second supporting portion 112 and third supporting portion 113, a second gap 15 is formed between the first supporting portion 111 and the first side wall 104, and a third gap 16 is formed between the second supporting portion 112 and the second side wall 105, so that cavities 21 are formed on both sides of the transmission line 3, so that most of the electric field is mainly concentrated in the cavities 21 on the left and right sides of the transmission line 3 and in the cavity 21 above it.

[0074] Based on the above embodiment, a first protrusion extending toward the first side wall 104 is provided on the side of the first support portion 111 facing the first side wall 104, a first groove 151 corresponding to the first protrusion and recessed in a direction away from the first support portion 111 is provided on the first side wall 104, a second protrusion extending toward the second side wall 105 is provided on the side of the second support portion 112 facing the second side wall 105, and a second groove (161) corresponding to the second protrusion and recessed in a direction away from the second support portion 112 is provided on the second side wall 105, so that the shapes of the first support portion 111 and the second support portion 112 are more matched with the shape of the transmission line 3. At the same time, the widths of the second interval 15 and the third interval 16 in the second direction Y (their dimensions in the first direction X) are ensured to be equal everywhere, so as to ensure that most of the electric field of the transmission line 3 is evenly distributed in the cavity 21.

[0075] Continue to refer to Figure 1 and Figure 2 The distances between the side walls of the first support portion 111, the second support portion 112 and the third support portion 113 facing the conductive cover plate 2 are equal, and the first transmission line 31, the second transmission line 32 and the third transmission line 33 are an integrated structure, so that the electric field of the transmission line 3 is more evenly distributed in the cavity 21.

[0076] In some embodiments, the first support portion 111, the second support portion 112, the third support portion 113 and the connecting protrusion 12 are all integrated with the main body 10, that is, a wire groove with the above structure is made on the main body 10 by machining or mold opening.

[0077] In summary, the present application limits the signal transmission path of the transmission line 3 by setting a support platform 11 and a connecting protrusion 12 structure in the groove 103 of the body 10 of the insulating substrate 1. In addition, the groove 103, the support platform 11 and the connecting protrusion 12 are used to metallize the side walls of the cavity 21, and cooperate with the conductive cover plate 2 to form a semi-open cavity 21, so as to constrain the electric field to propagate in the air and reduce the loss of the directional coupler. That is, the present application provides a directional coupler, which mainly improves the directional coupler from two aspects of directivity and isolation to ensure that the loss of the directional coupler is low. Specifically, by making the support platform 11 compatible with the structure of the transmission line 3, that is, the two have the same shape of the orthographic projection on the second surface 102, a transmission path is provided for the signal transmission of the transmission line 3, and the directionality of the signal transmission of the transmission line 3 is limited. Furthermore, the inner side wall of the connecting protrusion 12 and the first side wall 104 and the second side wall 105 of the groove 103 are metallized, thereby isolating the cavity 21 from the insulating substrate 1, so as to confine the electric field to propagate in the air of the cavity 21, so as to ensure the isolation of the directional coupler, and further ensure that the directional coupler provided in the present application has low loss.

[0078] in, Figure 8 for Figure 1 The S-parameter curve of the directional coupler shown in Fig. 9 For frequencies between 22 GHz and 32 GHz Figure 8 The S shown 2,1 Through parameter and S 3,1 A partial enlarged view of the coupling parameters. The S parameters of a directional coupler describe the scattering characteristics of the signal from one port to another in the directional coupler. Each port has a corresponding S parameter, usually expressed as S ij Indicates that i and j correspond to different ports, S ij It represents the scattering parameter of the signal transmitted from port j to port i.

[0079] Specifically, Figure 8 As shown, S 1,1 It is a reflection parameter used to characterize the return loss. The smaller the return loss, the better. 2,1 The through parameter is used to characterize and measure the transmission effect of the signal in the directional coupler; S 3,1 The coupling parameter is used to characterize the coupling degree. The smaller the coupling loss of the directional coupler, the greater the coupling degree. 4,1 Isolation parameters are used to characterize the degree of isolation. The greater the isolation of the directional coupler, the better. Figure 8 and Fig. 9 It is known that this application Figure 1 The directional coupler provided is a 3db directional coupler, and the coupling loss in its insertion loss is about 0.05dB to 0.5dB in the frequency range of 22GHz to 32GHz, and the loss of the directional coupler transmitting the signal is about 0.25dB to 0.5dB. In summary, the present application Figure 1 The directional coupler shown has low loss, which is beneficial to reducing attenuation and distortion of the signal during transmission.

[0080] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0081] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims. In addition, the specification uses specific examples to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and its core idea of ​​the present application. The content of this specification should not be understood as a limitation on the present application.

Claims

1. A directional coupler, characterized in that: The directional coupler has a first direction (X), a second direction (Y) and a third direction (Z) intersecting each other, and comprises: An insulating substrate (1) comprises a body (10) and a support platform (11), wherein the body (10) has a first surface (101) and a second surface (102) arranged opposite to each other in the third direction (Z), the first surface (101) being provided with a groove (103), the support platform (11) being composed of a first support portion (111), a second support portion (112) and a third support portion (113) protruding from the bottom of the groove (103), the first support portion (111) and the second support portion (112) being arranged at intervals along the first direction (X) and extending along the second direction (Y), the third support portion (113) connecting the first support portion (111) and the second support portion (112), and the wall surfaces of the first support portion (111), the second support portion (112) and the third support portion (113) facing away from the bottom of the groove (103) being close to the second surface (102) relative to the first surface (101); A transmission line (3) comprises a first transmission line (31) provided on the first supporting portion (111), a second transmission line (32) provided on the second supporting portion (112), and a third transmission line (33) provided on the third supporting portion (113), wherein the third transmission line (33) connects the first transmission line (31) and the second transmission line (32).

2. The directional coupler according to claim 1, characterized in that Also includes: A conductive cover plate (2) is disposed on the first surface (101) and is enclosed with the body (10) to form a cavity (21); and there is a gap between the first transmission line (31), the second transmission line (32) and the third transmission line (33) and the conductive cover plate (2).

3. The directional coupler according to claim 2, characterized in that: A connecting protrusion (12) is provided at the bottom of the groove (103), the connecting protrusion (12) is connected to the conductive cover plate (2), and the connecting protrusion (12) is located between the first supporting portion (111) and the second supporting portion (112), and is located on both sides of the third supporting portion (113) in the second direction (Y).

4. The directional coupler according to claim 3, characterized in that: There are at least two connecting protrusions (12), and the wall surface of each connecting protrusion (12) facing the conductive cover plate (2) is flush with the first surface (101); the wall surface of the conductive cover plate (2) facing the first surface (101) is a flat surface and fits the first surface (101).

5. The directional coupler according to claim 3, characterized in that: There are at least two connecting protrusions (12), and the wall surface of each connecting protrusion (12) facing the conductive cover plate (2) is flush with the first surface (101). The wall surface of the conductive cover plate (2) facing the first surface (101) is provided with a plurality of recessed portions (22) recessed in a direction away from the insulating substrate (1), and the connecting protrusion (12) is located in the corresponding recessed portion (22).

6. The directional coupler according to claim 3, characterized in that: The third supporting parts (113) have N numbers, and the connecting protrusions (12) have N+1 numbers. In the second direction (Y), one of the two outermost connecting protrusions (12) is located between the input port of the first transmission line (31) and the isolation port of the second transmission line (32), and the other is located between the through port of the first transmission line (31) and the coupling port of the second transmission line (32). The input port and the isolation port are located on the same side, and the through port and the coupling port are located on the same side.

7. The directional coupler according to claim 3, characterized in that The groove (103) has a first side wall (104) and a second side wall (105) arranged opposite to each other in the first direction (X), and the directional coupler further comprises: A plurality of first conductive layers (4) are respectively arranged on the inner side walls of the plurality of connecting protrusions (12), the inner side walls being configured as side walls of the connecting protrusions (12) located in the cavity (21); A second conductive layer (5) is disposed on the first side wall (104); The third conductive layer (6) is disposed on the second side wall (105).

8. The directional coupler according to claim 7, characterized in that: A first spacer (14) is formed between the multiple inner side walls of each connecting protrusion (12) and the corresponding first supporting portion (111), the second supporting portion (112) and the third supporting portion (113); a second spacer (15) is formed between the first supporting portion (111) and the first side wall (104); a third spacer (16) is formed between the second supporting portion (112) and the second side wall (105); and the first spacer (14), the second spacer (15) and the third spacer (16) constitute part of the cavity (21).

9. The directional coupler according to claim 8, characterized in that A first protruding portion extending toward the first side wall (104) is provided on a side of the first supporting portion (111) facing the first side wall (104); a first groove (151) corresponding to the first protruding portion and recessed in a direction away from the first supporting portion (111) is provided on the first side wall (104); a second protruding portion extending toward the second side wall (105) is provided on a side of the second supporting portion (112) facing the second side wall (105); and a second groove (161) corresponding to the second protruding portion and recessed in a direction away from the second supporting portion (112) is provided on the second side wall (105).

10. The directional coupler according to claim 2, characterized in that The first supporting portion (111), the second supporting portion (112) and the third supporting portion (113) are at equal distances from a side wall facing the conductive cover plate (2) and the conductive cover plate (2); and the first transmission line (31), the second transmission line (32) and the third transmission line (33) are an integrated structure.

Images