An ultra-thin microwave shielding structure

Abstract

The application belongs to the technical field of microwave antennas, and particularly relates to an ultra-thin microwave shielding structure, a circuit board, and the circuit board is provided with a slot at the edge thereof, a strip-line circuit is arranged at the middle position of the slot, an adapter is welded on the strip-line circuit, the circuit board is provided with mounting holes at the two sides of the strip-line circuit, and the shielding structure comprises a shielding plate and metal conductive columns connected to the shielding plate, wherein the metal conductive columns correspond to the positions of the mounting holes, the shielding structure is inserted into the mounting holes of the circuit board through the metal conductive columns, and the application can facilitate the wiping connection between the shielding plate and the circuit board, and can improve the microwave electrical performance, reduce energy leakage, and reduce the in-band loss by 0.2-0.4 dB.

Description

Technical Field

[0001] This application belongs to the field of microwave antenna technology, and specifically relates to an ultra-thin microwave shielding structure. Background Technology

[0002] The power divider network, composed of stripline power dividers and connecting components at various levels, is a crucial component of active phased array radar antenna systems, significantly impacting antenna performance and overall radar performance. Low-profile (ultra-thin) power dividers represent the future trend. The various interconnect structures and circuits within the power divider network greatly influence its performance. Different packaging methods are used for components under varying operating conditions. Due to requirements for corrosion and salt spray resistance, some power divider network components need to be placed in sealed metal cavities and laser-welded for encapsulation. Because the stripline circuits are ultra-thin, signal leakage is unavoidable during horizontal interconnection due to material, structural characteristics, and size limitations. Within a sealed metal cavity, multiple signal leaks inevitably lead to mutual interference, such as… Figure 1 As shown. Even if such phenomena do not occur before encapsulation, the laser welding encapsulation process causes a significant temperature rise. Disassembling the assembly fixture after laser encapsulation alters the internal stress state of the component, greatly increasing the probability of signal leakage and mutual interference. Because the component is completely sealed after welding and encapsulation, it cannot be repaired or debugged. Disassembling the cavity and cover plate will inevitably cause deformation of the cavity and microstrip circuit board, rendering them unrepairable. If the performance changes exceed design requirements, it is essentially scrapped. Even for components that remain functional after performance changes, there is no guarantee that their performance will remain stable under different temperature environments and will not undergo uncontrollable changes in subsequent use. Therefore, a technical method is needed to prevent signal leakage and mutual interference without altering the component's structural characteristics and dimensions, and the process should be reversible and simple to operate. Currently, no publicly available literature on such applications has been found. Summary of the Invention

[0003] To address the aforementioned problems, this application provides an ultrathin microwave shielding structure, comprising:

[0004] The circuit board has a slot at its edge, and a stripline circuit is arranged in the middle of the slot; adapter pins are soldered onto the stripline circuit; the circuit board has mounting holes on both sides of the stripline circuit.

[0005] The shielding structure includes a shielding plate and metal conductive posts connected to the shielding plate, wherein the positions of the metal conductive posts correspond to the mounting holes.

[0006] The shielding structure is inserted into the mounting hole via the metal conductive post and connected to the circuit board.

[0007] Preferably, the connection method between the shielding plate and the metal conductive post is as follows:

[0008] The shielding plate has metallized vias, the wall surface of which has a metal plating layer, and metal conductive pillars are fixed in the metallized vias.

[0009] Preferably, the metallized via is a through hole, and the metal conductive post passes through the metallized via and is fixedly connected to the metal shielding layer. The area of ​​the metal shielding layer is larger than the area of ​​the upper surface of the shielding plate. When the shielding structure is inserted into the circuit board, the metal shielding layer overlaps the upper surface of the circuit board.

[0010] Preferably, the metal conductive pillar is welded to the metal shielding layer.

[0011] Preferably, the gap between adjacent metal conductive pillars is less than 0.1 waveguide width.

[0012] Preferably, the metal conductive pillars satisfy the following conditions:

[0013] s / d < 2; / l < 0.1;

[0014] Where d is the diameter of the metal conductive pillar; s is the spacing between adjacent metal conductive pillars; and l is the width of the transmission waveguide.

[0015] Preferably, the slots in the circuit board include rectangular slots, and the shielding plate has a shape that matches the slot shape as a quadrangular prism.

[0016] The advantages of this application include: by adding multiple metal conductive pillars, it facilitates the contact between the shielding plate and the circuit board, and improves microwave electrical performance, reducing energy leakage and lowering overall in-band loss by 0.2–0.4 dB; by eliminating signal leakage and mutual interference, the efficiency of debugging and testing is significantly improved, reducing manpower, equipment, and time costs. The assembly method of this application is simple and easy to implement, suitable for mass production, significantly improving debugging and testing efficiency, reducing costs, and greatly improving the pass rate and stability of the device. Attached Figure Description

[0017] Figure 1 A schematic diagram illustrating the disadvantages of traditional shielding structures;

[0018] Figure 2 This is a dimensional relationship diagram of the metallized vias and metal conductive pillars in this application;

[0019] Figure 3 This is a schematic diagram of the metal shielding layer of this application;

[0020] Figure 4 This is a schematic diagram of the metallized vias and metal conductive pillars in this application;

[0021] Figure 5This is a schematic diagram of the circuit board structure of this application;

[0022] Figure 6 This is a front view of the shielding structure of this application;

[0023] Figure 7 This is a schematic diagram of the shielding structure and circuit board connection of this application. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0025] like Figures 3-7 As shown, an ultra-thin microwave shielding structure includes:

[0026] The circuit board 1 has a slot at its edge, and a stripline circuit 4 is arranged in the middle of the slot; adapter pins 3 are soldered onto the stripline circuit 4; the circuit board has mounting holes 2 on both sides of the stripline circuit.

[0027] The shielding structure includes a shielding plate 8 and a metal conductive post 7 connected to the shielding plate, wherein the position of the metal conductive post 7 corresponds to the position of the mounting hole 2;

[0028] The shielding structure is inserted into the mounting hole 2 via the metal conductive post 7 and connected to the circuit board 1.

[0029] In some alternative embodiments, the shielding plate 8 is connected to the metal conductive post 7 in the following manner:

[0030] The shielding plate 8 has a metallized via 6, the wall surface of the metallized via 6 has a metal plating layer, and the metal conductive post 7 is fixed in the metallized via 6.

[0031] In some alternative embodiments, the metallized via 6 is a through hole, and the metal conductive post 7 passes through the metallized via 6 and is fixedly connected to the metal shielding layer 5. The area of ​​the metal shielding layer 5 is larger than the area of ​​the upper surface of the shielding plate 8. When the shielding structure is inserted into the circuit board 1, the metal shielding layer 5 overlaps the upper surface of the circuit board 1.

[0032] In some alternative embodiments, the metal conductive pillar 7 is welded to the metal shielding layer 5.

[0033] In some alternative implementations, the gap between adjacent metal conductive pillars 7 is less than 0.1 waveguide width.

[0034] In some alternative embodiments, the metal conductive post 7 satisfies the following condition:

[0035] s / d < 2; (s-d) / l < 0.1;

[0036] Where d is the diameter of the metal conductive pillar; s is the spacing between adjacent metal conductive pillars; and l is the width of the transmission waveguide.

[0037] In some alternative embodiments, the slot of the circuit board (1) includes a rectangular slot, and the shape of the shielding plate (8) includes a quadrangular prism that matches the shape of the slot.

[0038] The preparation and installation methods for this application are as follows:

[0039] (1) Determine the shielding structure dimensions based on the highest operating frequency of the stripline circuit. The relationship between the diameter d of the metal conductive pillars, the spacing s, and the width l of the transmission waveguide is: s / d < 2; (s-d) / l < 0.1. Determine the diameter d of the metal conductive pillars and the spacing (s-d). The length of the metal conductive pillars is consistent with the thickness of the circuit board. Fabricate the shielding circuit board. Based on the location of the metallized vias on the shielding circuit board, design positioning vias at the corresponding positions of the stripline circuit.

[0040] (2) Insert the metal conductive pillar into the metallized via of the shielding plate for accurate positioning, and weld it together with the outer shielding copper foil (reflow soldering) to form an integrated shielding structure assembly of the shielding plate, metal conductive pillar and outer shielding copper foil.

[0041] (3) Insert the metal conductive post of the shielding structure component into the positioning through hole of the stripline circuit, and the entire shielding component can be accurately positioned and fixed.

[0042] Two examples are provided below:

[0043] Example 1: A certain type of time-delay power divider, X-band. Using conventional shielding methods, no component met microwave performance requirements due to signal leakage and crosstalk. Based on the specific dimensions of its connection terminals, a value of l = 5mm was used for calculation, with redundancy reserved. The shielding structure used 0.6mm metal conductive pillars with a gap of 0.4mm, the length matching the circuit board thickness, and the shielding plate thickness being 1 / 4 of the circuit board thickness. The outer shielding copper foil extended 4mm beyond the shielding plate (maintaining consistency at SMA connection terminals). Through-holes were fabricated at corresponding locations in the stripline circuit. After adopting the new shielding structure, signal crosstalk was completely eliminated, and all components met design requirements.

[0044] Example 2: A certain type of transmission component operates at a maximum frequency of 18 GHz. A new shielding structure is adopted. Based on the specific dimensions of its connection ends, l = 5 mm is used for calculation, with redundancy reserved. The shielding structure uses 0.7 mm metal conductive pillars with a gap of 0.3 mm. The length is consistent with the circuit board thickness, the shielding plate thickness is 1 / 4 of the circuit board thickness, and the outer shielding copper foil extends 4 mm beyond the shielding plate (SMA connection ends are consistent). Actual testing showed that all components met the design requirements.

[0045] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An ultra-thin microwave shielding structure, characterized in that, include: The circuit board (1) has a slot at its edge, and a stripline circuit (4) is arranged in the middle of the slot; adapter pins (3) are soldered onto the stripline circuit (4); the circuit board has mounting holes (2) on both sides of the stripline circuit. The shielding structure includes a shielding plate (8) and a metal conductive post (7) connected to the shielding plate, wherein the metal conductive post (7) corresponds to the position of the mounting hole (2); The shielding structure is inserted into the mounting hole (2) through the metal conductive post (7) and connected to the circuit board (1); the connection method between the shielding plate (8) and the metal conductive post (7) is as follows: The shielding plate (8) has a metallized via (6), the wall surface of the metallized via (6) has a metal plating layer, and the metal conductive post (7) is fixed in the metallized via (6). The metallized via (6) is a through hole. The metal conductive post (7) passes through the metallized via (6) and is fixedly connected to the metal shielding layer (5). The area of ​​the metal shielding layer (5) is larger than the area of ​​the upper surface of the shielding plate (8). When the shielding structure is inserted into the circuit board (1), the metal shielding layer (5) overlaps on the upper surface of the circuit board (1).

2. The ultra-thin microwave shielding structure as described in claim 1, characterized in that, The metal conductive pillar (7) is welded to the metal shielding layer (5).

3. The ultra-thin microwave shielding structure as described in claim 1, characterized in that, The gap between adjacent metal conductive pillars (7) is less than 0.1 waveguide width.

4. The ultra-thin microwave shielding structure as described in claim 1, characterized in that, The metal conductive pillar (7) satisfies the following conditions: s / d﹤2; (s-d) / l﹤0.1; Where d is the diameter of the metal conductive pillar; s is the spacing between adjacent metal conductive pillars; and l is the width of the transmission waveguide.

5. The ultra-thin microwave shielding structure as described in claim 1, characterized in that, The slots in the circuit board (1) include rectangular slots, and the shape of the shielding plate (8) includes a quadrangular prism that matches the shape of the slots.

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