A low-radar-cross-section screen for a ship's louver

Abstract

The application discloses a low-RCS filter screen of a ship louver, and belongs to the technical field of ship ventilation and stealth. The low-RCS filter screen comprises a louver filter screen and a wave-absorbing unit. The louver filter screen has a pore structure, and the material of the louver filter screen is an insulating material with a dielectric constant lower than 6. The wave-absorbing unit is formed by coating and fixing conductive paste on the surface of the louver filter screen according to a designed pattern to form a conductive path. The thickness of the wave-absorbing unit is micron level. When electromagnetic waves irradiate the wave-absorbing unit, the wave-absorbing unit converts the energy of the electromagnetic waves into heat energy by using the resistive material of the wave-absorbing unit, and the heat energy is dissipated through air, so that the effect of absorbing electromagnetic waves is achieved. The application can improve the wave-absorbing effect and ensure the ventilation and air intake capacity of the louver.

Description

Technical Field

[0001] This invention belongs to the field of marine ventilation and stealth technology, specifically relating to a low RCS filter for marine louvers. Background Technology

[0002] Louvers are a key component of a ship's air intake system, providing ventilation, rain protection, and protection against sea waves, salt spray, and dust. Current louver designs primarily consist of a frame, angled shutters, a filter, and an electromagnetic shielding mesh. However, traditional louvers have limited control over radar cross-section (RCS), failing to absorb radar waves and impacting the overall RCS of the ship. Coating the internal filter and electromagnetic shielding mesh with absorbing materials or using honeycomb absorbing materials can effectively absorb radar waves entering the louvers, significantly reducing reflected radar waves and thus lowering the louver's RCS. However, when ordinary absorbing materials are coated onto the filter or electromagnetic shielding mesh, the presence of gaps makes it difficult to control the material thickness and ensure uniformity, resulting in a significant reduction in absorption. Furthermore, the added thickness of the absorbing material severely affects the normal air intake of the louvers. While honeycomb absorbing materials can maintain wind resistance while also ensuring absorption efficiency, they are expensive, have a certain thickness, are difficult to clean of internal dust and other debris, and require replacement after a period of use, leading to excessive operating costs.

[0003] How to reduce the RCS of louvers without introducing too much related engineering work, while ensuring the basic functions of louvers such as air intake, rain protection, sea wave protection, salt spray protection, and dust protection, has become a problem that must be solved. Summary of the Invention

[0004] In view of this, the present invention provides a low RCS filter for marine louvers, which can improve the wave absorption effect while ensuring the ventilation and air intake capacity of the louvers.

[0005] A low RCS filter for marine louvers includes a louver filter and a wave-absorbing unit. The louver filter has a porous structure and is made of an insulating material with a dielectric constant of less than 6. The wave-absorbing unit is formed by coating and fixing a conductive paste onto the surface of the louver filter according to a designed pattern to create a conductive path. The thickness of the wave-absorbing unit is on the micrometer level. When electromagnetic waves irradiate the wave-absorbing unit, the unit uses its own resistive material to convert the energy of the electromagnetic waves into heat energy, which is then dissipated through the air, thereby achieving the effect of absorbing electromagnetic waves.

[0006] Furthermore, the size of the pores in the pore structure is 1 mm.

[0007] Furthermore, the absorbing unit consists of six arms in the same plane, with one end of each arm converging at a point and the included angle between adjacent arms being equal. The size of the absorbing unit needs to be designed according to the frequency band and absorbing performance of the application scenario.

[0008] Furthermore, the process of patterning the absorbing unit is carried out using a PCB pattern mold.

[0009] Furthermore, the manufacturing process of the PCB pattern mold is as follows: First, the designed PCB pattern is drawn on a flat plate, then the pattern part is cut off, and the remaining flat plate is the PCB pattern mold.

[0010] Furthermore, the conductive paste comprises diethylamine, ethanol, resin, conductive powder, dispersant, and defoamer.

[0011] Furthermore, the resin is a polyester resin, a polyurethane resin, a polyamide resin, or a combination of the three, and the conductive powder is carbon black, graphene, or metal powder; the resistivity of the conductive paste is controlled by adjusting the ratio of resin to conductive powder.

[0012] Beneficial effects:

[0013] 1. The filter of this invention uses an insulating material with a low dielectric constant as the medium. The absorbing unit is formed by coating and fixing conductive paste onto the surface of the louver filter according to a designed pattern to form a conductive path. This allows for the rapid manufacture of the absorber, which can be applied to areas where RCS needs to be reduced. At the same time, the pattern mold made using PCB technology, in conjunction with the coating of conductive paste, can quickly and easily form a periodic conductive pattern on its surface. Furthermore, through simulation calculations, by attaching a periodic conductive pattern to the filter surface, radar wave absorption can be effectively achieved, thereby reducing RCS. This invention has the advantages of low cost, high speed, and the ability to operate entirely without the need for robotic manual operation.

[0014] 2. In this invention, the periodic pattern of the absorbing unit is formed by a paste with a thickness of micrometers attached to the surface of the wire mesh. The size of the pores in the pore structure is 1mm, which has a high porosity to ensure its ventilation and air intake capabilities, while also meeting the coating conditions of the absorbing metamaterial.

[0015] 3. When the conductive paste of the present invention fails after long-term use, the conductive paste can be quickly coated using a PCB pattern mold. The conductive paste can be coated using the filter itself as a substrate, which is low-cost, quick, and can be replenished and repaired in real time during wartime.

[0016] 4. This invention can prepare multiple PCB pattern molds for different enemy radar operating frequency bands using the same method, in order to cope with different battlefield environments. Attached Figure Description

[0017] Figure 1 This is a schematic diagram showing the installation position of the low RCS filter of the present invention in a louver;

[0018] Figure 2 This is a schematic diagram showing the distribution of the absorbing units on the filter surface;

[0019] Figure 3 This is a schematic diagram of the external structure of the absorbing unit.

[0020] Among them, 1-window frame; 2-venetian blind; 3-metal air intake; 4-wave absorption unit; 5-venetian blind filter. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0022] This invention provides a low RCS filter for marine louvers. The low RCS filter includes a wave-absorbing unit 4 and a louver filter 5. The louver filter 5 has a porous structure with pores of 1mm in size, ensuring sufficient ventilation while meeting the coating requirements of the wave-absorbing unit 4. The louver filter 5 is made of an insulating material with a dielectric constant lower than 6, such as polytetrafluoroethylene, polyurethane, or polyimide, which are corrosion-resistant and insulating materials. (See attached image) Figure 1 As shown, the window frame 1 and the louvered filter 5 are respectively installed at the front and rear ends of the metal air intake duct 3. The wave-absorbing unit 4 is coated with conductive paste according to the designed pattern and fixed on the surface of the louvered filter 5 to form a conductive path. External air enters the metal air intake duct 3 from the front louvered curtain 2 and then flows to the rear louvered filter 5. When electromagnetic waves irradiate the wave-absorbing unit 4 on the louvered filter 5, the wave-absorbing unit 4 uses its own resistive material to convert the energy of the electromagnetic waves into heat energy, and the heat energy is then dissipated through the air, thereby achieving the effect of absorbing electromagnetic waves.

[0023] The absorption effect of a single absorbing unit 4 is limited. To achieve a better absorption effect, as shown in the attached... Figure 2 As shown, a certain number of wave-absorbing units 4 are set on the louver filter 5. The spacing of the wave-absorbing units 4 affects the wave-absorbing effect and is determined by the target wave-absorbing frequency.

[0024] As attached Figure 3 As shown, the absorbing unit 4 consists of six arms in the same plane. One end of each arm converges at a point, and the included angles between adjacent arms are equal. The size of the absorbing unit needs to be designed according to the frequency band and absorption performance of the application scenario. There are three key parameters for the absorbing unit 4: the width of the arm is W, the included angle between adjacent arms is α, and the width of the entire absorbing unit 11 is L. The size of the absorbing unit 11 needs to be designed according to the frequency band and absorption performance of the application scenario. In this embodiment, L = 9mm, α = 36°, and W = 2mm.

[0025] The absorbing unit 4 is formed by coating conductive paste according to the designed pattern. The coating process is aided by a PCB pattern mold. The PCB pattern mold is a flat plate. The designed PCB pattern is drawn on it, and then the pattern part is cut off. The remaining flat plate is the required PCB pattern mold. The PCB pattern is designed according to the absorbing frequency band and performance required by the application scenario.

[0026] The conductive paste is applied directly to the filter screen. There are requirements for the mesh size of the filter screen and the viscosity of the paste itself. The thickness of the applied conductive paste is not sensitive to the performance.

[0027] The conductive paste is composed of diethylamine, ethanol; resin, conductive powder; dispersant, and defoamer. Preferably, the resin can be polyester resin, polyurethane resin, polyamide resin, or a combination thereof, and the conductive powder can be carbon black, graphene, metal powder, etc. By adjusting the ratio of resin and conductive powder, the resistivity of the conductive paste can be controlled. The preferred resistivity of the conductive paste in this project is 2.5 milliohms per meter. If the conductive paste fails after prolonged use, it should be reapplied according to the mold.

[0028] When exposed to enemy electromagnetic waves, the absorbing metamaterial absorbs the electromagnetic waves entering the louver structure, reducing the electromagnetic wave reflection energy of the louver and effectively suppressing the radar cross-section of the louver. This absorbing structure can achieve an absorption effect of 15dB in the 12GHz±1GHz frequency band, and the absorbing frequency band and performance required for the application scenario can be obtained by changing the parameters of the absorbing metamaterial.

[0029] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A low RCS filter for marine louvers, characterized in that, The device includes a louvered filter and a wave-absorbing unit. The louvered filter has a porous structure with pores of 1 mm in size. The filter is made of an insulating material with a dielectric constant lower than 6. The wave-absorbing unit is formed by coating a conductive paste onto the surface of the filter according to a designed pattern, creating a conductive path. The pattern coating process utilizes a PCB pattern mold. The thickness of the wave-absorbing unit is in the micrometer range. When electromagnetic waves irradiate the unit, it uses its resistive material to convert the energy of the electromagnetic waves into heat energy, which is then dissipated through the air, thus absorbing the electromagnetic waves. The wave-absorbing unit consists of six arms in the same plane, with one end of each arm converging at a point and the included angle between adjacent arms being equal. The size of the wave-absorbing unit needs to be designed according to the frequency band and absorption efficiency of the application scenario. The conductive paste comprises diethylamine, ethanol, resin, conductive powder, dispersant, and defoamer.

2. The low RCS filter screen for marine louvers as described in claim 1, characterized in that, The manufacturing process of the PCB pattern mold is as follows: First, draw the designed PCB pattern on a flat plate, then cut off the pattern part, and the remaining flat plate is the PCB pattern mold.

3. A low RCS filter for marine louvers as described in claim 1 or 2, characterized in that, The resin is polyester resin, polyurethane resin, polyamide resin, or a combination thereof, and the conductive powder is carbon black, graphene, or metal powder; the resistivity of the conductive paste is controlled by adjusting the ratio of resin and conductive powder.

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