Electromagnetic leakage suppression structure and application thereof

Abstract

The invention provides an electromagnetic leakage suppression structure and application thereof. The electromagnetic leakage suppression structure is located between the metal plate and the printed circuit board which are stacked; a first through hole is formed in the surface of the metal plate; a second through hole is formed in 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 comprises more than one annular bulge which is concentrically arranged and 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 limits the electromagnetic waves to spread in a channel between the first through hole and the second through hole. According to the invention, a high-impedance barrier can be formed between the metal plate and the printed circuit board, the possibility that electromagnetic waves are leaked to the external environment is reduced, and the working efficiency and reliability of the system are improved.

Description

Technical Field

[0001] The present application relates to the field of microwave circuit technology, and in particular to an electromagnetic leakage suppression structure and its application. Background Art

[0002] In wireless communication systems, 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 higher dielectric loss. Metal waveguides have no dielectric loss and have lower conductor loss, so they are widely used in millimeter wave and terahertz bands.

[0003] At present, millimeter wave communication systems usually adopt modular design, for example, assembling a waveguide antenna from a transceiver component based on a printed circuit board and a metal waveguide to simultaneously meet the needs of signal transceiver and low-loss transmission. However, in actual applications, the above assembled antenna structure is prone to electromagnetic leakage problems, which seriously affects the efficiency and stability of the communication system. Summary of the invention

[0004] In view of the above-mentioned problems, the present application is proposed to provide an electromagnetic leakage suppression structure and its application that overcomes the problems or at least partially solves the problems, including: 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; 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 one or more concentrically arranged annular protrusions; the annular protrusions are arranged on the periphery of the surface 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 restricts the electromagnetic waves from propagating in a channel between the first through hole and the second through hole.

[0005] Preferably, 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.

[0006] Preferably, a height of the annular protrusion in a direction perpendicular to the metal plate is equal to a depth of the groove in a direction perpendicular to the metal plate.

[0007] Preferably, the shape of the innermost annular protrusion is adapted to the shape of the first through hole.

[0008] Preferably, the shapes of adjacent annular protrusions are adapted to each other.

[0009] Preferably, the wall thickness of each of the annular protrusions is uniformly set.

[0010] Preferably, the gap widths between adjacent annular protrusions are uniformly set; and the gap widths between the outermost annular protrusion and the side wall of the groove are uniformly set.

[0011] An antenna board assembly based on the electromagnetic leakage suppression structure described in any one of the above items comprises: 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; 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; and the electromagnetic leakage suppression structure is provided between the metal plate and the printed circuit board.

[0012] Preferably, there are at least one of the first through hole and the second through hole.

[0013] Preferably, 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.

[0014] This application has the following advantages: In view of the problem that the existing waveguide antenna assembled by 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 setting 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 the 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 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 includes more than one concentrically arranged annular protrusions; the annular protrusions are arranged on the surface of the metal plate corresponding to the periphery of the first through hole; when the electromagnetic wave passes through the gap between the metal plate and the printed circuit board, the electromagnetic leakage suppression structure limits the electromagnetic wave to propagate in the channel between the first through hole and the second through hole.

[0015] The electromagnetic leakage suppression structure can form a high-impedance barrier between the metal plate and the printed circuit board, effectively limiting the propagation of electromagnetic waves in the channel between the first through hole and the second through hole, thereby reducing the possibility of electromagnetic waves leaking into the external environment and improving the working efficiency and reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the description of the present application will be briefly introduced below. Obviously, the drawings described below are only part of the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 It is a structural schematic diagram of a metal plate and an electromagnetic leakage suppression structure in an antenna plate assembly provided in an embodiment of the present application; Figure 2 is a structural schematic diagram of a printed circuit board in an antenna board assembly provided in an embodiment of the present application; Figure 3 is a schematic cross-sectional structure diagram of an antenna panel assembly provided in one embodiment of the present application; Figure 4 is a graph showing the return loss of an antenna panel assembly according to an embodiment of the present application as a function of frequency; Figure 5 is a graph showing the variation of the isolation of the antenna panel assembly with the frequency provided by an embodiment of the present application; Figure 6 is a graph showing the variation of insertion loss between through holes of an antenna board assembly as a function of frequency provided by an embodiment of the present application; Figure 7 It is a gap electric field energy distribution diagram of the antenna panel assembly provided in a ratio of the present application; Figure 8 This is a gap electric field energy distribution diagram of an antenna panel assembly provided in one embodiment of the present application.

[0018] The reference numerals in the drawings of the specification are as follows: 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 DESCRIPTION

[0019] In order to make the purpose, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0020] By analyzing 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 limitations of the flatness of the printed circuit board, there may be tiny gaps in the connection between the two layers of the board. These gaps will cause significant electromagnetic leakage problems in the millimeter wave frequency band, seriously affecting the efficiency and stability of the communication system.

[0021] It should be noted that in any embodiment of the present application, the electromagnetic leakage suppression structure is used for a communication system in the millimeter wave frequency band (for example, a vehicle-mounted waveguide antenna); 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 bonded and connected (with a tiny gap of less than or equal to 0.05 mm); the surfaces of the printed circuit board and the metal plate are respectively provided with through holes for the passage of electromagnetic waves.

[0022] Reference Figure 1-Figure 3 In one embodiment of the present application, an electromagnetic leakage suppression structure 30 is provided, which is located between 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; a projection of the first through hole 11 in a direction perpendicular to the metal plate 10 coincides with a projection of the second through hole 21 in a direction perpendicular to the metal plate 10; The electromagnetic leakage suppression structure 30 includes one or more concentrically arranged annular protrusions 31; the annular protrusions 31 are made of metal, and specifically, the same metal material as the metal plate 10 can be selected; the annular protrusions 31 are arranged on the surface of the metal plate 10 corresponding to the periphery of the first through hole 11; When electromagnetic waves pass through the gap between the metal plate 10 and the printed circuit board 20 , the electromagnetic leakage suppression structure 30 limits the electromagnetic waves to propagate in the channel between the first through hole 11 and the second through hole 21 .

[0023] The electromagnetic leakage suppression structure 30 can form a high impedance barrier between the metal plate 10 and the printed circuit board 20, effectively limiting 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.

[0024] Next, the electromagnetic leakage suppression structure 30 in this exemplary embodiment will be further described.

[0025] In one 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 arranged inside the groove 12 ; and the shape of the groove 12 is adapted to the shape of the annular protrusion 31 .

[0026] By arranging the groove 12 on the surface of the metal plate 10 and arranging the annular protrusion 31 inside the groove 12, a multi-stage shielding structure consisting 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 lateral (i.e., parallel to the surface of the metal plate 10) transmission path, improving the ability to suppress leakage electromagnetic waves, and at the same time forming a local closed space to isolate the electromagnetic coupling effect between the annular protrusion 31 and the external environment, thereby reducing 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 can also protect the annular protrusion 31 from damage during production, transportation or assembly, thereby improving the reliability and durability of the structure.

[0027] In an embodiment of the present application, the height of the annular protrusion 31 in a direction perpendicular to the metal plate 10 is equal to the depth of the groove 12 in a direction perpendicular to the metal plate 10 .

[0028] The depth of the groove 12 is equal to the height of the annular protrusion 31, which 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 surface of the metal plate 10 and the printed circuit board 20, making the annular protrusion 31 fit more closely with the printed circuit board 20, thereby further improving the electromagnetic shielding performance and optimizing the electrical contact performance of the metal plate 10 and the printed circuit board 20.

[0029] As an example, the height of the annular protrusion 31 in a direction perpendicular to the metal plate 10 is from one eighth of a wavelength to one quarter of a wavelength.

[0030] 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 .

[0031] By adapting the shape of the innermost annular protrusion 31 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 matches the opening shape of the first through hole 11, thereby more accurately limiting the propagation path of the electromagnetic wave.

[0032] In one embodiment of the present application, the shapes of adjacent annular protrusions 31 are adapted to each other.

[0033] By adapting the shapes of adjacent annular protrusions 31, it is possible to ensure that a continuous electromagnetic shielding structure is formed between the annular protrusions 31 at each level, reduce the diffraction and leakage path of electromagnetic waves in the shielding structure, and thus enhance the shielding capability of the multi-level annular protrusion structure.

[0034] In one embodiment of the present application, the wall thickness of each of the annular protrusions 31 is uniformly set.

[0035] The wall thickness of the annular protrusion 31 is uniformly set, which can ensure that the annular protrusion 31 has uniform shielding performance when shielding electromagnetic waves, avoid the weak shielding ability of the annular protrusion 31 in certain directions due to the difference in wall thickness, reduce the leakage or irregular scattering path of electromagnetic waves during propagation, and thus optimize the shielding effect. In addition, the uniform wall thickness design also simplifies the processing parameters of the annular protrusion 31, making it easier to maintain dimensional stability during the processing, thereby ensuring product yield and reducing processing costs.

[0036] As an example, the wall thickness of the annular protrusion 31 is from one eighth of a wavelength to one quarter of a wavelength.

[0037] In one embodiment of the present application, the gap widths between adjacent annular protrusions 31 are uniformly set; the gap widths between the outermost annular protrusion 31 and the side wall of the groove 12 are uniformly set.

[0038] The communication system may be subjected to external vibration or impact loads during operation. In addition, the equipment will generate heat during operation, which may also cause thermal expansion and contraction of the material. The uniform setting of the gap width on the side of the annular protrusion 31 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, thereby adapting to the operation requirements of the communication system in vibration and high temperature environments. In addition, the uniform gap width design also simplifies the processing parameters of the annular protrusion 31, making it easier to maintain dimensional stability during the processing process, thereby ensuring product yield and reducing processing costs.

[0039] As an example, the gap widths 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 of a wavelength to one quarter of a wavelength.

[0040] Reference Figure 1-Figure 3In one embodiment of the present application, there is also provided an antenna board assembly based on the electromagnetic leakage suppression structure 30 described in any of the above embodiments, comprising: 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; a projection of the first through hole 11 in a direction perpendicular to the metal plate 10 coincides with a projection of the second through hole 21 in a direction perpendicular to the metal plate 10; and the electromagnetic leakage suppression structure 30 is provided between the metal plate 10 and the printed circuit board 20.

[0041] 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 limiting 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.

[0042] In an embodiment of the present application, there are more than one first through hole 11 and more than one second through hole 21. 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.

[0043] 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 rectangular, elliptical, waist-shaped, T-shaped, cross-shaped, dumbbell-shaped and concave.

[0044] In a first specific implementation of the present application, an electromagnetic leakage suppression structure 30 is provided, which is located between 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; a projection of the first through hole 11 in a direction perpendicular to the metal plate 10 coincides with a projection of the second through hole 21 in a direction perpendicular to the metal plate 10; The electromagnetic leakage suppression structure 30 includes an annular protrusion 31 made of metal material; the annular protrusion 31 is arranged on the surface of the metal plate 10 corresponding to the periphery of the first through hole 11; the shape of the annular protrusion 31 is adapted to the shape of the first through hole 11; The surface of the metal plate 10 facing the printed circuit board 20 is provided with a groove 12; the annular protrusion 31 is arranged inside the groove 12; the shape of the groove 12 is adapted to the shape of the annular protrusion 31; 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 of which are one eighth of the wavelength; The wall thickness of the annular protrusion 31 is uniformly set to one eighth of the wavelength; The width of the gap between the annular protrusion 31 and the side wall of the groove 12 is uniformly set to one eighth of the wavelength; When electromagnetic waves pass through the gap between the metal plate 10 and the printed circuit board 20 , the electromagnetic leakage suppression structure 30 limits the electromagnetic waves to propagate in the channel between the first through hole 11 and the second through hole 21 .

[0045] In a second specific implementation of the present application, an antenna board assembly for a vehicle-borne conductive antenna is provided, comprising: a metal plate 10 and a printed circuit board 20 which are 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; a projection of the first through hole 11 in a direction perpendicular to the metal plate 10 coincides with a projection of the second through hole 21 in a 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; There are 8 first through holes 11 and 8 second through holes 21 respectively; The first through hole 11 and the second through hole 21 are both in a concave shape; The operating frequency of the on-board conductive antenna is 76 GHz to 77 GHz.

[0046] Electromagnetic simulation verification was performed on the return loss, isolation, insertion loss and electric field strength distribution in the gap of the antenna board assembly provided by the above specific implementation, and the results are as follows: Figure 4 The return loss at each signal port of the metal plate 10 in the antenna plate assembly is shown. It can be seen that in the 76 GHz to 77 GHz frequency band, 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.

[0047] Figure 5 The isolation between the signal ports of the metal plate 10 in the antenna plate assembly is shown. It can be seen that in the 776 GHz to 77 GHz frequency band, the isolation between the ports is less than -55 dB, indicating that the electromagnetic leakage suppression structure 30 can provide effective electromagnetic isolation in the target frequency band.

[0048] 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 776 GHz to 77 GHz frequency band, 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.

[0049] Figure 7 and Figure 8 The electric field energy distribution of the gap between the metal plate 10 and the printed circuit board is shown respectively without the electromagnetic leakage suppression structure 30 and with the electromagnetic leakage suppression structure 30. It can be seen that in the case of the electromagnetic leakage suppression structure 30, the electromagnetic wave propagates in the channel effectively confined between the first through hole 11 and the second through hole 21.

[0050] The above embodiments are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to in detail.

[0051] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the interpretation of the attached claims includes the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present application.

[0052] Finally, it should be noted that in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or terminal device including the elements.

[0053] The electromagnetic leakage suppression structure and its application provided by the present application are introduced in detail above. The principles and implementation methods of the present application are described in this specification using specific embodiments. The description of the above embodiments is only used to help understand the method and its core idea of ​​the present application. At the same time, for those skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present application.

Claims

1. An electromagnetic leakage suppression structure, characterized in that: 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; 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 one or more concentrically arranged annular protrusions; the annular protrusions are arranged on the periphery of the surface 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 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 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; 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; and 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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