Radar absorbing structure

Abstract

The present invention relates to a radar-absorbing structure (1) comprising fibers (2), a binding agent (3) located on the fibers (2) and enabling the fibers (2) to bind to other fibers (2).

Description

[Technical field]

[0001] The present invention relates to a radar absorbing structure that allows for the absorption of radio waves. [Background technology]

[0002] Radar absorbing structures / materials reflect at least a possible percentage of incident electromagnetic waves within the operating frequency range, thereby converting a large portion of the electromagnetic energy into heat and attenuating it. Radar absorbing materials (RAMs) absorb / reduce reflected radar electromagnetic energy, thus reducing the radar cross section. The operation of radar absorbing materials is based on impedance matching or attenuation of the incident electromagnetic waves, utilizing the properties of magnetic and dielectric materials. Radar absorbing materials can be used on air, land, and sea platforms, where low radar cross section is very important. By using radar absorbing materials on these platforms, the radio waves reaching the surface of the platform are highly absorbed, greatly lowering the target detection range of the radar system. There are four basic techniques to reduce the radar cross section of air, space, and / or sea vehicles: shaping, radar absorbing materials, passive cancellation, and active cancellation. Among these techniques, shaping and radar absorbing materials are the most efficient techniques.

[0003] Chinese patent application CN105647333, which forms part of the state of the art, describes a method for preparing a radar protective coating consisting of a rare earth transition metal intermetallic compound / ferrite composite. The system includes the steps of producing a radar absorbing coating, including a method for producing a radar absorbing coating consisting of a rare earth transition metal intermetallic compound. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] China Patent Publication No. 105647333 Summary of the Invention [Problem to be solved by the invention]

[0005] The radar absorbing structure developed according to the present invention allows the production of highly durable structures with very low maintenance costs without the need for frequent replacement of materials as the number of flights increases.

[0006] A further object of the present invention is to develop structures that absorb radio waves more efficiently, not only by creating materials that are more mechanically durable due to the geometric advantages of the materials used, but also by forming structures with tunable electrical conductivity due to these advantages.

[0007] It is yet a further object of the present invention to devise a radar absorbing structure which is more reliable, efficient and low cost. [Means for solving the problem]

[0008] To achieve the object of the present invention, a radar absorbing structure is realized, as defined in claim 1 and its subclaims, comprising fibres and at least one binding agent enabling said fibres to bond to other fibres so as to create structural integrity between the fibres.

[0009] The radar absorbing structure of the present invention comprises at least one barrier coating arranged over the fiber surface to increase the strength of the fiber and reduce wear, at least one rod in the form of graphene and / or graphene-based nanoribbons on said barrier coating, which is electrically conductive and capable of minimizing the value of its radar cross section by guiding radio waves when subjected to the influence of radio waves, at least one particle provided on a binding agent that allows the rods on the fiber surface to better adhere to the surface, thereby allowing the binding of the rods to the fiber, increasing the strength of the fiber and extending its useful life, and a fiber allowing the absorption of radio waves reaching an aviation and / or space and / or marine vehicle by the rods.

[0010] One embodiment of the present invention includes anisotropically conductive rods arranged on the barrier coating at a direction angle predetermined by a user according to the direction of incidence of radio waves, thereby forming a radar absorbing structure having anisotropic conductivity.

[0011] One embodiment of the present invention includes a layer formed by a combination of fibers and a binding agent that has radar absorbing material properties and is capable of absorbing radio waves that reach an aviation / space / marine vehicle.

[0012] One embodiment of the present invention includes at least one layer constructed from a fiberglass composite material.

[0013] One embodiment of the present invention includes at least one layer constructed from a carbon fiber composite material.

[0014] One embodiment of the present invention includes at least one component formed by assembling multiple layers.

[0015] One embodiment of the present invention includes fibers positioned and / or arranged in the direction of the incidence angle of radio waves reaching the member from a radio wave source and / or other source.

[0016] One embodiment of the present invention includes an aircraft fuselage formed by assembling the above-described components.

[0017] One embodiment of the present invention includes a layer made of fiberglass reinforcing fabric located closest to the exterior surface of the aircraft fuselage, which is more exposed to radio waves, and a layer made of carbon fiber reinforcing fabric located furthest from the exterior surface of the aircraft fuselage.

[0018] One embodiment of the present invention includes rods having a lower density and / or length closer to the aircraft fuselage in contact with the atmosphere than the density and / or length of the rods further from the exterior surface of the aircraft fuselage, with the density and / or length of the rods gradually increasing with distance from the exterior surface of the aircraft fuselage.

[0019] One embodiment of the present invention includes a rod coated onto a barrier coating by chemical vapor deposition (CVD) and / or spray coating methods.

[0020] One embodiment of the present invention includes particles formed from transition metals.

[0021] One embodiment of the present invention includes particles formed from iron-based nanoparticles.

[0022] One embodiment of the present invention includes components for use in air and / or space and / or marine vehicles. [Brief description of the drawings]

[0023] A radar absorbing structure realised to achieve the objects of the invention is shown in the accompanying drawing. [Figure 1] FIG. 1 shows a schematic diagram of a radar absorbing structure. [Diagram 2] FIG. 2 shows a schematic diagram of an aircraft fuselage. [Diagram 3] FIG. 3 shows a cross-sectional view of the layers.

[0024] Numbers are assigned to the components in each drawing, and the parts corresponding to these numbers are as follows. 1. Radar absorbing structure 2. Fiber 3. Binding agent 4. Barrier Coating 5. Rod 6. Particles 601.Transition metal particles 602. Iron-based particles 7. Layers 8. Materials 9. Aircraft fuselage (W) Radio Waves DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The radar absorbing structure (1) comprises fibers (2) and at least one binding agent (3) that allows the fibers (2) to be bound to other fibers (2) (Figures 1 and 3).

[0026] The radar absorbing structure (1) of the present invention comprises at least one barrier coating (4) arranged to cover the surface of the fiber (2), at least one rod (5) which is graphene and / or graphene-based nanoribbon arranged on the barrier coating (4), at least one particle (6) arranged on the binding agent (3) that enables the rod (5) to adhere to the fiber (2), and the fiber (2) that enables radar absorption by the rod (5) (Figure 3).

[0027] The fibers (2) used herein are used in the manufacture of aviation and / or space and / or marine vehicles. The binding agent (3) allows the fibers (2) to bond together, thus forming structural integrity for the fibers (2).

[0028] The radar absorbing structure (1) is generally used in aviation and / or space and / or marine vehicles, and can reduce the radar cross section formed under the influence of radio waves (W) on the vehicle by absorbing the radio waves (W) that impinge on the aviation and / or space and / or marine vehicle. To increase the strength of the fiber (2), the barrier coating (4) is used. Thus, it is possible to extend the material life. However, the barrier coating (4) ensures that the aviation and / or space and / or marine vehicles are protected from the heat to which they are exposed, minimizing the problem of wear and tear as the navigation of the aviation and / or space and / or marine vehicles increases. The rods (5) are electrically conductive graphene and / or graphene-based nanoparticle materials arranged on the barrier coating (4) and guide the electric current resulting from the radio waves that reach the aviation and / or space and / or marine vehicle. In this way, the influence of the radio waves (W) can be reduced by creating electrical conductivity in a specific direction. Particles (6) that provide stronger adhesion between rods (5) and fibers (2) to prevent wear and / or replacement of the fibers (2) after a certain number of journeys, wherein the rods (2) are graphene and / or graphene-based nanoribbons, are disposed on the barrier coating (3).

[0029] In one embodiment of the present invention, the radar absorbing structure (1) comprises rods (5) arranged on the barrier coating (4) in a direction predefined by the user. The rods (5) have an anisotropic structure and can redirect the radio waves (W) by forming an electrical network and are arranged at an angle on the barrier coating (4). The rods (5) are made of graphene and / or graphene-based nanoparticle materials and are arranged on the barrier coating (4) at an angle so as to almost completely contact the rods on the other fibers. In this way, the radio waves (W) are directed in a desired direction and the electrical conductivity is adjusted. Adjusting the electrical conductivity in a desired direction also enhances the absorption of the radio waves (W). The rods (5) can also weaken the effect of lightning strikes.

[0030] In one embodiment of the invention, the radar absorbing structure (1) comprises at least one layer (7) made of fibers (2) and a binding agent (3).

[0031] In one embodiment of the present invention, the radar absorbing structure (1) comprises a layer (7) made of glass fiber reinforced fabric (2). The layer (7) made of glass fiber reinforced fabric (2) has insulating properties and can reduce the reflection of radio waves (W) when exposed to the radio waves (W). Since the layer (7) has insulating properties, the electrical conductivity in the direction of the incident radio waves (W) is reduced. Thus, the electrical conductivity is directional. However, the layer (7) is oriented in the direction of the incident radio waves (W) and does not produce secondary waves (secondary waves, edge waves, traveling waves, edge diffraction).

[0032] In one embodiment of the present invention, the radar absorbing structure (1) comprises a layer (7) made of carbon fiber reinforced fabric (2). The layer (7) made of carbon fiber reinforced fabric (2) is electrically conductive and absorbs the incident radio waves (W) and converts the resulting energy into thermal and / or electrical energy. In this way, it is ensured that the radio waves (W) survive in aerial and / or space and / or marine vehicles.

[0033] In one embodiment of the present invention, the radar absorbing structure (1) comprises at least one member (8) made up of layers (7). The members (8) make the radar absorbing structure (1) suitable for use in aviation and / or space and / or marine vehicles (FIG. 2).

[0034] In one embodiment of the invention, the radar absorbing structure (1) comprises fibers (2) arranged in the direction of incidence of the radio waves (W) arriving at the member (8). The fibers (2) are arranged in the direction of incidence of the radio waves (W) arriving at the air and / or space and / or marine vehicle, ensuring that no electric field is generated in this direction.

[0035] In one embodiment of the present invention, the radar absorbing structure (1) includes an aircraft fuselage (9) constructed from a member (8) (Figure 2).

[0036] In one embodiment of the present invention, the radar absorbing structure (1) comprises a layer (7) made of glass fiber reinforced fibers (2) located closer to the outer surface of the aircraft fuselage (9) than the layer (7) made of carbon fiber reinforced fibers (2). The layer (7) made of glass fiber reinforced fibers (2), located closer to the outer surface of the aircraft fuselage (9), reduces the reflection of the incident radio waves (W). The layer (7) made of carbon fiber reinforced fibers (2) converts the radio waves (W) that reach the layer (7) into heat and electrical energy, ensuring that the radio waves (W) do not leave the outer surface of the aircraft fuselage (9).

[0037] In one embodiment of the present invention, the radar absorbing structure (1) comprises rods (5) whose density and / or length gradually increase from the outer surface of the aircraft fuselage (9) towards the inside of the aircraft fuselage (9). The density and / or length of the rods (5) arranged on the barrier coating (4) relatively increase as they move away from the outer surface of the fuselage (9). Thus, ensuring that no P-waves (primary wave) and S-waves (secondary wave) are generated on the aircraft fuselage (9). To absorb P-waves, the impedance value of the layer (7) made of glass fiber reinforced fabric (2) should be equal to the impedance of the atmosphere on the outer surface of the aircraft fuselage (9). However, the impedance value of the radio waves (W) should be different when the radio waves (W) reach the inside of the aircraft fuselage (9). The rods (5) arranged on the layer (7) made of glass fiber reinforced fabric (2) ensure that the impedance value of the layer (7) is equal to the impedance value of the atmosphere by reducing the density and / or length of the rods (5). At the same time, rods (5) arranged on a layer (7) made from high density and / or long carbon fiber reinforcing fibers (2) compared to layers made from glass fiber reinforcing fibers (2) have different impedance values.

[0038] In one embodiment of the present invention, the radar absorbing structure (1) comprises a rod (5) coated on a barrier coating by chemical vapor deposition (CVD) and / or spray coating techniques.

[0039] In one embodiment of the invention, the radar absorbing structure (1) comprises transition metal particles (601) made from a transition metal, which allows the rods (5) to adhere better to the barrier coating and therefore have greater strength.

[0040] In one embodiment of the present invention, the radar absorbing structure (1) comprises iron-based particles (602) in the form of iron-based nanoparticles, which increases the radar absorbing material properties of the radar absorbing structure (1).

[0041] In one embodiment of the invention, the radar absorbing structure (1) comprises a member (8) suitable for use in aviation, and / or space, and / or marine vehicles.

Claims

1. 1. A radar-absorbing structure (1) comprising a fiber (2), at least one binding agent (3) arranged on the fiber (2) enabling the fiber (2) to be bonded to other fibers (2), the radar-absorbing structure (1) being characterized by at least one barrier coating (4) arranged to cover a surface of the fiber (2), at least one rod (5) of graphene and / or graphene-based nanoribbon arranged on the barrier coating (4), at least one particle (6) arranged on the binding agent (3) enabling the rod (5) to adhere to the fiber (2), a fiber (2) enabling radar absorption by the rod (5), at least one layer (7) composed of the fiber (2) and the binding agent (3), at least one member (8) composed of the layer (7), and an aircraft fuselage (9) composed of the member (8).

2. 2. A radar absorbing structure (1) according to claim 1, characterised by the rods (5) being arranged on the barrier coating (4) in a direction predetermined by the user.

3. 3. Radar-absorbing structure (1) according to claim 1 or 2, characterised by a layer (7) made from glass fibre reinforcing fabric (2).

4. 4. Radar-absorbing structure (1) according to any one of claims 1 to 3, characterised by a layer (7) made from carbon fibre reinforcing fabrics (2).

5. 5. A radar absorbing structure (1) according to any one of claims 1 to 4, characterized in that the fibres (2) are arranged in a direction of incidence of radio waves (W) arriving at the element (8).

6. 6. A radar-absorbing structure (1) according to any one of claims 1 to 5, characterised by a layer (7) made of glass fibre reinforcing fibres (2) which is arranged closer to the outer surface of the aircraft fuselage (9) than said layer (7) made of carbon fibre reinforcing fibres (2).

7. 7. The radar absorbing structure (1) according to any one of the preceding claims, characterized by rods (5) which gradually increase in density and / or length from the outer surface of the aircraft fuselage (9) towards the inside of the aircraft fuselage (9).

8. 8. The radar absorbing structure (1) according to any one of the preceding claims, characterized by a rod (5) coated on said barrier coating (4) by chemical vapor deposition (CVD) and / or spray coating methods.

9. 9. A radar absorbing structure (1) according to any one of the preceding claims, characterised by transition metal particles (601) made from a transition metal.

10. 10. The radar absorbing structure (1) according to claim 9, characterized by the iron-based particles (602) being iron-based nanoparticles.

11. A radar absorbing structure (1) as described in any one of claims 1 to 10, characterized by the member (8).

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