An electromagnetic leakage suppression structure and its application

Abstract

The present application provides an electromagnetic leakage suppression structure and its application. The electromagnetic leakage suppression structure is located between the stacked metal plates and the printed circuit board; the surface of the metal plate is provided with a first through hole, and the surface of the printed circuit board is provided with a second through hole; the projection of the first through hole in the direction perpendicular to the metal plate coincides with the projection of the second through hole in the direction perpendicular to the metal plate; the electromagnetic leakage suppression structure includes more than one concentric annular protrusion, and is arranged on the periphery of the metal plate surface corresponding to the first through hole; when electromagnetic waves pass through the gap between the metal plate and the printed circuit board, the electromagnetic leakage suppression structure confines the electromagnetic waves to propagate within the channel between the first through hole and the second through hole. The present application can form a high-impedance barrier between the metal plate and the printed circuit board, reduce the possibility of electromagnetic waves leaking into the external environment, and improve the working efficiency and reliability of the system.

Description

Technical Field

[0001] This application relates to the technical field of microwave circuits, and particularly to an electromagnetic leakage suppression structure and its application. Background Art

[0002] In a wireless communication system, waveguide structures based on printed circuit boards such as microstrip lines and substrate integrated waveguides are widely used in the design of communication transceiver components due to their low cost, ease of manufacturing, and high integration. However, in millimeter-wave frequency band application scenarios, waveguide structures based on printed circuit boards will bring relatively high dielectric losses. Metal waveguides have no dielectric losses and lower conductor losses, so they are widely used in millimeter-wave and terahertz bands.

[0003] Currently, a modular design is usually adopted in millimeter-wave communication systems. For example, a waveguide antenna is assembled from a transceiver component based on a printed circuit board and a metal waveguide to simultaneously meet the requirements of signal transceiver and low-loss transmission. However, in the actual application process, the above-assembled antenna structure is prone to electromagnetic leakage problems, seriously affecting the efficiency and stability of the communication system. Summary of the Invention

[0004] In view of the problems mentioned above, this application is proposed to provide an electromagnetic leakage suppression structure and its application that can overcome or at least partially solve the problems, including:

[0005] An electromagnetic leakage suppression structure is located between a stacked metal plate and a printed circuit board; wherein, a first through hole is provided on the surface of the metal plate, and a second through hole is provided on the surface of the printed circuit board; the projection of the first through hole in the direction perpendicular to the metal plate coincides with the projection of the second through hole in the direction perpendicular to the metal plate.

[0006] The electromagnetic leakage suppression structure includes more than one annular protrusion arranged concentrically; the annular protrusion is provided on the periphery of the metal plate corresponding to the first through hole.

[0007] When electromagnetic waves pass through the gap between the metal plate and the printed circuit board, the electromagnetic leakage suppression structure confines the electromagnetic waves to propagate in the channel between the first through hole and the second through hole.

[0008] Preferably, a groove is provided on the surface of the metal plate facing the printed circuit board; the annular protrusion is provided inside the groove; the shape of the groove is adapted to the shape of the annular protrusion.

[0009] Preferably, the height of the annular protrusion in the direction perpendicular to the metal plate is equal to the depth of the groove in the direction perpendicular to the metal plate.

[0010] Preferably, the shape of the innermost annular protrusion is adapted to the shape of the first through hole.

[0011] Preferably, the shapes of adjacent annular protrusions are adapted to each other.

[0012] Preferably, the wall thickness of each annular protrusion is uniformly arranged.

[0013] Preferably, the gap widths between adjacent annular protrusions are uniformly arranged; the gap width between the outermost annular protrusion and the side wall of the groove is uniformly arranged.

[0014] An antenna board assembly based on the electromagnetic leakage suppression structure according to any one of the above, comprising: a metal plate and a printed circuit board arranged in a stacked manner; wherein, a first through hole is provided on the surface of the metal plate, and a second through hole is provided on the surface of the printed circuit board; the projection of the first through hole in the direction perpendicular to the metal plate coincides with the projection of the second through hole in the direction perpendicular to the metal plate; the electromagnetic leakage suppression structure is provided between the metal plate and the printed circuit board.

[0015] Preferably, one or more first through holes and one or more second through holes are respectively provided.

[0016] Preferably, the shapes of the first through hole and the second through hole are one or a combination of several of rectangle, ellipse, waist shape, T shape, cross shape, dumbbell shape and concave shape.

[0017] The present application has the following advantages:

[0018] Aiming at the problem that the existing waveguide antenna assembled from a transceiver component based on a printed circuit board and a metal waveguide is prone to electromagnetic leakage, the present application provides a solution of arranging an annular protrusion array between a metal plate and a printed circuit board to limit the propagation path of electromagnetic waves, specifically: an electromagnetic leakage suppression structure located between the stacked metal plate and printed circuit board; wherein, a first through hole is provided on the surface of the metal plate, and a second through hole is provided on the surface of the printed circuit board; the projection of the first through hole in the direction perpendicular to the metal plate coincides with the projection of the second through hole in the direction perpendicular to the metal plate; the electromagnetic leakage suppression structure includes one or more concentric annular protrusions; the annular protrusions are arranged on the periphery of the metal plate corresponding to the first through hole; when electromagnetic waves pass through the gap between the metal plate and the printed circuit board, the electromagnetic leakage suppression structure confines the electromagnetic waves to propagate in the channel between the first through hole and the second through hole.

[0019] The electromagnetic leakage suppression structure can form a high-impedance barrier between the metal plate and the printed circuit board, effectively restricting the propagation of electromagnetic waves in the channel between the first through hole and the second through hole, thereby reducing the possibility of electromagnetic wave leakage to the external environment and improving the working efficiency and reliability of the system. Description of the Drawings

[0020] To more clearly illustrate the technical solutions of the present application, the drawings required for use in the description of the present application will be briefly introduced below. Obviously, the drawings in the following description are only a part of the embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0021] Figure 1 is a schematic structural diagram of a metal plate and an electromagnetic leakage suppression structure in an antenna board assembly provided by an embodiment of the present application;

[0022] Figure 2 is a schematic structural diagram of a printed circuit board in an antenna board assembly provided by an embodiment of the present application;

[0023] Figure 3 is a schematic cross-sectional structural diagram of an antenna board assembly provided by an embodiment of the present application;

[0024] Figure 4 is a graph showing the variation of return loss of an antenna board assembly provided by an embodiment of the present application with frequency;

[0025] Figure 5 is a graph showing the variation of isolation of an antenna board assembly provided by an embodiment of the present application with frequency;

[0026] Figure 6 is a graph showing the variation of insertion loss between through holes of an antenna board assembly provided by an embodiment of the present application with frequency;

[0027] Figure 7 is a distribution diagram of gap electric field energy of an antenna board assembly provided by a comparative example of the present application;

[0028] Figure 8 is a distribution diagram of gap electric field energy of an antenna board assembly provided by an embodiment of the present application.

[0029] The reference numerals in the drawings of the specification are as follows:

[0030] 10. Metal plate; 11. First through hole; 12. Groove; 20. Printed circuit board; 21. Second through hole; 30. Electromagnetic leakage suppression structure; 31. Annular protrusion. Detailed Embodiments

[0031] To make the objectives, features, and advantages of this application more apparent and understandable, the following further elaborates on this application in conjunction with the accompanying drawings and specific embodiments. Apparently, the described embodiments are part of this application, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts fall within the scope of protection of this application.

[0032] Through the analysis of the prior art, the inventors found that at the connection between the printed circuit board and the metal waveguide, due to metal processing errors and the limitation of the flatness of the printed circuit board, there may be minute gaps at the connection part of the two layers of boards. These gaps will cause significant electromagnetic leakage problems in the millimeter-wave frequency band, seriously affecting the efficiency and stability of the communication system.

[0033] It should be noted that in any embodiment of this application, the electromagnetic leakage suppression structure is used in a communication system (such as a vehicle-mounted waveguide antenna) in the millimeter-wave frequency band; the communication system is assembled from a transceiver component based on a printed circuit board and a metal waveguide; wherein, the printed circuit board on the side of the transceiver component and the metal plate on the side of the metal waveguide are adhesively connected (with a minute gap less than or equal to 0.05 mm); through holes for electromagnetic waves to pass through are respectively provided on the surfaces of the printed circuit board and the metal plate.

[0034] Refer to Figures 1 - 3 , in an embodiment of this application, an electromagnetic leakage suppression structure 30 is provided, which is located between the stacked metal plate 10 and the printed circuit board 20; wherein, a first through hole 11 is provided on the surface of the metal plate 10, and a second through hole 21 is provided on the surface of the printed circuit board 20; the projection of the first through hole 11 in the direction perpendicular to the metal plate 10 coincides with the projection of the second through hole 21 in the direction perpendicular to the metal plate 10;

[0035] The electromagnetic leakage suppression structure 30 includes more than one annular protrusion 31 arranged concentrically; the annular protrusion 31 is made of metal, specifically, the same metal material as the metal plate 10 can be selected; the annular protrusion 31 is provided on the periphery of the surface of the metal plate 10 corresponding to the first through hole 11;

[0036] When electromagnetic waves pass through the gap between the metal plate 10 and the printed circuit board 20, the electromagnetic leakage suppression structure 30 confines the electromagnetic waves to propagate within the channel between the first through hole 11 and the second through hole 21.

[0037] The electromagnetic leakage suppression structure 30 can form a high-impedance barrier between the metal plate 10 and the printed circuit board 20, effectively restricting the propagation of electromagnetic waves in the channel between the first through-hole 11 and the second through-hole 21, thereby reducing the possibility of electromagnetic wave leakage to the external environment and improving the working efficiency and reliability of the system.

[0038] Next, the electromagnetic leakage suppression structure 30 in this exemplary embodiment will be further described.

[0039] In an embodiment of the present application, a groove 12 is provided on the surface of the metal plate 10 facing the printed circuit board 20; the annular protrusion 31 is disposed inside the groove 12; the shape of the groove 12 is adapted to the shape of the annular protrusion 31.

[0040] By providing the groove 12 on the surface of the metal plate 10 and disposing the annular protrusion 31 inside the groove 12, a multi-stage shielding structure composed of the annular protrusion 31 and the outer wall of the groove 12 can be formed, thereby further increasing the discontinuity of the electromagnetic wave transverse (i.e., the direction parallel to the surface of the metal plate 10) transmission path, improving the suppression ability of the leaked electromagnetic waves, and at the same time, a local closed space can be formed to isolate the electromagnetic coupling effect between the annular protrusion 31 and the external environment, thereby reducing the electromagnetic interference from the external environment. The groove 12 "embeds" the annular protrusion 31 partially into the surface of the metal plate 10, which can reduce the protruding height of the annular protrusion 31 in the vertical direction, making the overall structure more compact and facilitating the high-integration design of the millimeter-wave communication system. In addition, the groove 12 also provides a fixed accommodation area for the annular protrusion 31, which can reduce the positioning error of the annular protrusion 31 and protect the annular protrusion 31 from being damaged during production, transportation or assembly, thereby improving the reliability and durability of the structure.

[0041] In an embodiment of the present application, the height of the annular protrusion 31 in the direction perpendicular to the metal plate 10 is equal to the depth of the groove 12 in the direction perpendicular to the metal plate 10.

[0042] The equality of the depth of the groove 12 and the height of the annular protrusion 31 can ensure that the top of the annular protrusion 31 is flush with the surface of the groove 12, thereby improving the flatness of the surfaces of the metal plate 10 and the printed circuit board 20, making the fitting of the annular protrusion 31 and the printed circuit board 20 closer, further enhancing the electromagnetic shielding performance, and at the same time optimizing the electrical contact performance between the metal plate 10 and the printed circuit board 20.

[0043] As an example, the height of the annular protrusion 31 in the direction perpendicular to the metal plate 10 is one-eighth wavelength to one-quarter wavelength.

[0044] In an embodiment of the present application, the shape of the innermost annular protrusion 31 is adapted to the shape of the first through hole 11.

[0045] By making the shape of the innermost annular protrusion 31 adapted to the shape of the first through hole 11, the annular protrusion 31 can tightly surround the first through hole 11, ensuring that the propagation path of the electromagnetic wave coincides with the opening shape of the first through hole 11, thereby more precisely restricting the propagation path of the electromagnetic wave.

[0046] In an embodiment of the present application, the shapes of adjacent annular protrusions 31 are adapted to each other.

[0047] By making the shapes of adjacent annular protrusions 31 adapted to each other, a continuous electromagnetic shielding structure can be ensured between each stage of the annular protrusions 31, reducing the diffraction and leakage paths of the electromagnetic wave in the shielding structure, thereby enhancing the shielding ability of the multi-stage annular protrusion structure.

[0048] In an embodiment of the present application, the wall thicknesses of the respective annular protrusions 31 are uniformly arranged.

[0049] The uniform arrangement of the wall thicknesses of the annular protrusions 31 can ensure that the annular protrusions 31 have uniform shielding performance when shielding electromagnetic waves, avoiding weak shielding ability in certain directions of the annular protrusions 31 due to wall thickness differences, reducing problems such as leakage or irregular scattering paths of the electromagnetic wave during propagation, thereby optimizing the shielding effect. In addition, the uniform wall thickness design also simplifies the processing parameters of the annular protrusions 31, facilitating the maintenance of dimensional stability during processing, thereby ensuring product yield and reducing processing costs.

[0050] As an example, the wall thickness of the annular protrusion 31 is one-eighth wavelength to one-quarter wavelength.

[0051] In an embodiment of the present application, the gap widths between adjacent annular protrusions 31 are uniformly arranged; the gap widths between the outermost annular protrusion 31 and the side walls of the groove 12 are uniformly arranged.

[0052] During the operation of a communication system, it may be subject to external vibrations or impact loads. In addition, heat is generated during the operation of the device, which may also cause the material to expand and contract thermally. The gap width on the side of the annular protrusion 31 is uniformly set, which can avoid the problem of local stress concentration caused by irregular gap width, thereby improving the vibration resistance and long-term reliability of the structure, so as to meet the operation requirements of the communication system in a vibration and high-temperature environment. In addition, the uniform gap width design also simplifies the processing parameters of the annular protrusion 31, facilitates maintaining dimensional stability during processing, thereby ensuring product yield and reducing processing costs.

[0053] As an example, the gap width between adjacent annular protrusions 31 and the gap width between the outermost annular protrusion 31 and the side wall of the groove 12 are respectively one-eighth wavelength to one-quarter wavelength.

[0054] Referring to Figures 1 - 3 , in an embodiment of the present application, there is also provided an antenna board assembly based on the electromagnetic leakage suppression structure 30 described in any one of the above embodiments, including: a metal plate 10 and a printed circuit board 20 stacked; wherein, a first through hole 11 is provided on the surface of the metal plate 10, and a second through hole 21 is provided on the surface of the printed circuit board 20; the projection of the first through hole 11 in the direction perpendicular to the metal plate 10 coincides with the projection of the second through hole 21 in the direction perpendicular to the metal plate 10; the electromagnetic leakage suppression structure 30 is provided between the metal plate 10 and the printed circuit board 20.

[0055] By providing the electromagnetic leakage suppression structure 30 between the metal plate 10 and the printed circuit board 20, a high-impedance barrier can be formed between the metal plate 10 and the printed circuit board 20, effectively restricting the propagation of electromagnetic waves in the channel between the first through hole 11 and the second through hole 21, thereby reducing the possibility of electromagnetic waves leaking into the external environment and improving the working efficiency and reliability of the system.

[0056] In an embodiment of the present application, there is more than one first through hole 11 and second through hole 21 respectively. When there are multiple signal ports at the same time, the electromagnetic leakage suppression structure 30 can provide effective electromagnetic isolation to avoid signal interference between different ports.

[0057] In an embodiment of the present application, the shapes of the first through hole 11 and the second through hole 21 are one or a combination of several of rectangle, ellipse, waist shape, T shape, cross shape, dumbbell shape, and concave shape.

[0058] In the first specific implementation of the present application, an electromagnetic leakage suppression structure 30 is provided, which is located between the stacked metal plate 10 and the printed circuit board 20; wherein, a first through hole 11 is provided on the surface of the metal plate 10, and a second through hole 21 is provided on the surface of the printed circuit board 20; the projection of the first through hole 11 in the direction perpendicular to the metal plate 10 coincides with the projection of the second through hole 21 in the direction perpendicular to the metal plate 10;

[0059] The electromagnetic leakage suppression structure 30 includes an annular protrusion 31 made of metal; the annular protrusion 31 is provided on the periphery of the surface of the metal plate 10 corresponding to the first through hole 11; the shape of the annular protrusion 31 is adapted to the shape of the first through hole 11;

[0060] A groove 12 is provided on the surface of the metal plate 10 facing the printed circuit board 20; the annular protrusion 31 is provided inside the groove 12; the shape of the groove 12 is adapted to the shape of the annular protrusion 31;

[0061] The height of the annular protrusion 31 in the direction perpendicular to the metal plate 10 is equal to the depth of the groove 12 in the direction perpendicular to the metal plate 10, both being one-eighth of the wavelength;

[0062] The wall thickness of the annular protrusion 31 is uniformly set to be one-eighth of the wavelength;

[0063] The gap width between the annular protrusion 31 and the side wall of the groove 12 is uniformly set to be one-eighth of the wavelength;

[0064] When electromagnetic waves pass through the gap between the metal plate 10 and the printed circuit board 20, the electromagnetic leakage suppression structure 30 confines the electromagnetic waves to propagate within the channel between the first through hole 11 and the second through hole 21.

[0065] In the second specific implementation of the present application, an antenna board assembly for an on-vehicle waveguide antenna is provided, including: a stacked metal plate 10 and a printed circuit board 20; wherein, a first through hole 11 is provided on the surface of the metal plate 10, and a second through hole 21 is provided on the surface of the printed circuit board 20; the projection of the first through hole 11 in the direction perpendicular to the metal plate 10 coincides with the projection of the second through hole 21 in the direction perpendicular to the metal plate 10; an electromagnetic leakage suppression structure 30 as described in the first specific implementation is provided between the metal plate 10 and the printed circuit board 20;

[0066] There are 8 first through holes 11 and 8 second through holes 21 respectively;

[0067] The shapes of the first through hole 11 and the second through hole 21 are both concave-shaped;

[0068] The operating frequency of the in-vehicle waveguide antenna is 76 GHz to 77 GHz.

[0069] Electromagnetic simulation verification is carried out on the return loss, isolation, insertion loss and electric field intensity distribution in the gap of the antenna board assembly provided by the above specific implementation, and the results are as follows:

[0070] Figure 4 The return loss at each signal port of the metal plate 10 in the antenna board assembly is shown. It can be seen that in the frequency band of 76 GHz to 77 GHz, the return loss at each port is less than -30 dB, indicating that the impedance matching performance of the electromagnetic leakage suppression structure 30 is good.

[0071] Figure 5 The isolation between each signal port of the metal plate 10 in the antenna board assembly is shown. It can be seen that in the frequency band of 76 GHz to 77 GHz, the isolation between each port is less than -55 dB, indicating that the electromagnetic leakage suppression structure 30 can provide effective electromagnetic isolation in the target frequency band.

[0072] Figure 6 The insertion loss from the first through hole 11 to the second through hole 21 is shown. It can be seen that in the frequency band of 76 GHz to 77 GHz, the insertion loss between each through hole is greater than -0.012 dB, indicating that the electromagnetic leakage suppression structure 30 can provide effective electromagnetic leakage suppression in the target frequency band.

[0073] Figure 7 and Figure 8 The electric field energy distributions of the gap between the metal plate 10 and the printed circuit board are shown respectively in the case of without the electromagnetic leakage suppression structure 30 and with the electromagnetic leakage suppression structure 30. It can be seen that in the case of having the electromagnetic leakage suppression structure 30, the electromagnetic wave is effectively restricted to propagate in the channel between the first through hole 11 and the second through hole 21.

[0074] The above embodiments are all described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same and similar parts among the embodiments, reference can be made to each other.

[0075] Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concepts. Therefore, the interpretation of the appended claims includes the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present application.

[0076] Finally, it should also be noted that in this specification, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or terminal device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or terminal device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or terminal device comprising the said element.

[0077] The above provides a detailed introduction to the electromagnetic leakage suppression structure and its application provided by this application. Specific embodiments are used in this specification to elaborate on the principle and implementation manner of this application. The description of the above embodiments is only used to help understand the method and its core idea of this application; at the same time, for those of ordinary skill in the art, according to the idea of this application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to this application.

Claims

1. An electromagnetic leakage suppression structure, characterized in that: Located between a stacked metal plate and a printed circuit board; wherein the metal plate is provided with a first through hole, and the printed circuit board is provided with a second through hole; and a projection of the first through hole in a direction perpendicular to the metal plate coincides with a projection of the second through hole in a direction perpendicular to the metal plate; The electromagnetic leakage suppression structure comprises a concentrically arranged annular protrusion; the annular protrusion is arranged on the surface of the metal plate corresponding to the periphery of the first through hole; When electromagnetic waves pass through the gap between the metal plate and the printed circuit board, the electromagnetic leakage suppression structure restricts the electromagnetic waves from propagating in a channel between the first through hole and the second through hole.

2. The electromagnetic leakage suppression structure according to claim 1, characterized in that: A groove is provided on the surface of the metal plate facing the printed circuit board; the annular protrusion is arranged inside the groove; and the shape of the groove is adapted to the shape of the annular protrusion.

3. The electromagnetic leakage suppression structure according to claim 2, characterized in that: The height of the annular protrusion in a direction perpendicular to the metal plate is equal to the depth of the groove in a direction perpendicular to the metal plate.

4. The electromagnetic leakage suppression structure according to claim 1, characterized in that: The shape of the innermost annular protrusion is adapted to the shape of the first through hole.

5. The electromagnetic leakage suppression structure according to claim 4, characterized in that: The shapes of adjacent annular protrusions are adapted to each other.

6. The electromagnetic leakage suppression structure according to claim 1, characterized in that: The wall thickness of each annular protrusion is uniformly set.

7. The electromagnetic leakage suppression structure according to claim 2, characterized in that: The gap widths between adjacent annular protrusions are uniformly set; the gap widths between the outermost annular protrusion and the side wall of the groove are uniformly set.

8. An antenna panel assembly based on the electromagnetic leakage suppression structure according to any one of claims 1 to 7, characterized in that: include: A stacked metal plate and a printed circuit board; wherein the metal plate is provided with a first through hole, and the printed circuit board is provided with a second through hole; the projection of the first through hole in a direction perpendicular to the metal plate coincides with the projection of the second through hole in a direction perpendicular to the metal plate; the electromagnetic leakage suppression structure is provided between the metal plate and the printed circuit board.

9. The antenna panel assembly according to claim 8, characterized in that: There is at least one first through hole and at least one second through hole.

10. The antenna panel assembly according to claim 8, characterized in that: The shapes of the first through hole and the second through hole are one or a combination of rectangular, elliptical, waist-shaped, T-shaped, cross-shaped, dumbbell-shaped and concave.

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