Negative conical wave-absorbing honeycomb

Abstract

The invention discloses a negative conical wave-absorbing honeycomb, which comprises a negative conical impedance matching layer, an absorbing layer and a reflecting layer, and is characterized in that the negative conical impedance matching layer, the absorbing layer and the reflecting layer respectively comprise at least one honeycomb layer, and the honeycomb apertures of the negative conical impedance matching layer, the absorbing layer and the reflecting layer are sequentially decreased; the negative tapered impedance matching layer surface includes at least one negative tapered slot. According to the scheme of the invention, when electromagnetic waves are incident to the honeycomb, the negative conical shape design ensures that two surfaces are always in an oblique incidence state in the polarization direction, scattering of the electromagnetic waves is enhanced, reflection is reduced, impedance matching with airwaves is enhanced, the electromagnetic waves are made to be incident into the material to the greatest extent, and the electromagnetic waves are prevented from entering the material to the greatest extent. Multiple times of reflection and refraction of electromagnetic waves in the negative conical structure are increased, electromagnetic wave energy radiated out is effectively reduced, and efficient broadband absorption of the electromagnetic waves is achieved.

Description

Technical Field

[0001] This application relates to the technology of metamaterials, and more specifically, to a negative conical absorbing honeycomb. Background Art

[0002] With the popularization of high-power and high-speed operating electronic devices or smart appliances, etc., electromagnetic radiations such as thermal effects and non-thermal effects have already begun to affect human daily life and even endanger human physical health. Electromagnetic pollution has become the fifth largest pollution after air, water, solid waste, and noise. Using electromagnetic absorbing materials to convert electromagnetic radiation energy into heat energy or other forms of energy is one of the most effective methods for humans to solve the problem of electromagnetic radiation pollution at present. There are also significant demands for electromagnetic protection and anti-electromagnetic interference in fields such as medical treatment, health, and information security; at the same time, in the military aspect, the performance requirements for electromagnetic absorbing materials in stealth, detection and anti-detection technologies, etc. are also constantly increasing. In order to meet the urgent demands for electromagnetic protection in civilian and military fields and solve electromagnetic pollution, conventional electromagnetic absorbing materials have gradually begun to be applied, but they can only effectively absorb electromagnetic waves in specific frequency bands, and the absorption peak and bandwidth are affected by factors such as the type of absorber, material thickness, and density, and industrialization cannot be achieved. Although simply changing the type, structure, and doping amount of the absorber has a certain improvement effect on the absorption effect, it can often only achieve effective absorption (higher than -10 dB) in a specific narrow microwave frequency band.

[0003] Currently, it is difficult for the electromagnetic parameters (such as dielectric constant and magnetic permeability) of traditional absorbing honeycombs to achieve impedance matching in a wide frequency band, resulting in a narrow absorption band. For example, some honeycomb structures are only effective in the 8 - 12 GHz frequency band and cannot cover the low-frequency radar detection requirements. Summary of the Invention

[0004] Aiming at the defect that the existing absorbing honeycombs cannot cover the low-frequency radar detection requirements, the present invention provides a negative conical absorbing honeycomb to overcome the above problems.

[0005] The solution of the present invention to the above problems is as follows: Provide a negative conical absorbing honeycomb, including a negative conical impedance matching layer, an absorption layer, and a reflection layer, wherein the negative conical impedance matching layer, the absorption layer, and the reflection layer each include at least one honeycomb layer, and the honeycomb pore diameters of the negative conical impedance matching layer, the absorption layer, and the reflection layer decrease in sequence; the surface of the negative conical impedance matching layer includes at least one negative conical cut groove.

[0006] Preferably, the negative conical impedance matching layer, the absorption layer, and the reflection layer are added with an absorber.

[0007] Preferably, the concentrations of the absorbers added to the negative conical impedance matching layer, the absorption layer, and the reflection layer increase in sequence.

[0008] Preferably, the absorber concentration of the negative conical impedance matching layer is 10% - 15%; the absorber concentration of the absorption layer is 20% - 25%; the absorber concentration of the reflection layer is 30% - 35%.

[0009] Preferably, the side length of the honeycomb cell of the negative conical impedance matching layer is 3.67 mm ± 10%.

[0010] Preferably, the side length of the honeycomb cell of the absorption layer is 2.75 mm ± 10%.

[0011] Preferably, the side length of the honeycomb cell of the reflection layer is 1.83 mm ± 10%.

[0012] Preferably, the thickness of the negative conical impedance matching layer is greater than or equal to the thickness of the absorption layer, and the thickness of the absorption layer is greater than or equal to the thickness of the reflection layer.

[0013] Preferably, the thickness of the negative conical impedance matching layer is 30 mm - 40 mm, the thickness of the absorption layer is 10 mm - 20 mm, and the thickness of the reflection layer is 8 mm - 10 mm.

[0014] Preferably, the negative conical groove is a triangular groove, the opening width of the negative conical groove is 18 - 22 mm, and the depth is 18 - 22 mm.

[0015] Preferably, the preparation of the negative conical absorbing honeycomb includes: adding a carbon-based absorber to a resin solution, grinding to prepare an absorbing slurry; impregnating an aramid paper honeycomb into the absorbing slurry, and baking and curing.

[0016] Preferably, the carbon-based absorber is acetylene black or conductive carbon black.

[0017] Preferably, the resin solution is prepared by mixing resin and solvent at a ratio of 1:1.5 - 1:3.0.

[0018] Preferably, the resin is phenolic resin or epoxy resin.

[0019] Preferably, the solvent can be an alcohol solvent or a strongly polar solvent.

[0020] When implementing the solution of the present invention, when electromagnetic waves are incident on the honeycomb, the negative conical shape design ensures that there are always two surfaces in the state of oblique incidence in the polarization direction, enhancing the scattering of electromagnetic waves, reducing reflection, strengthening the impedance matching with the air wave impedance, allowing electromagnetic waves to enter the material interior to the greatest extent, increasing the multiple reflections and refractions of electromagnetic waves in the negative conical structure, effectively reducing the energy of the radiated electromagnetic waves, and achieving efficient broadband absorption of electromagnetic waves. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 Isometric schematic diagram of a preferred embodiment of the present invention;

[0024] Figure 2 Cross-sectional schematic diagram of a preferred embodiment of the present invention;

[0025] Figure 3 Enlarged schematic diagram of the honeycomb structure of a preferred embodiment of the present invention;

[0026] Figure 4 Cross-sectional dimension schematic diagram of the negative conical groove;

[0027] Figure 5 Schematic diagram of the electromagnetic characteristic curve of Experimental Example 1;

[0028] Figure 6 Schematic diagram of the electromagnetic characteristic curve of Experimental Example 2;

[0029] Figure 7 Schematic diagram of the electromagnetic characteristic curve of Experimental Example 3. Detailed implementation manners

[0030] In order to enable those skilled in the art of the present technology to better understand the solution of the present application, the following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present application.

[0031] It should be noted that the terms "first", "second", etc. in the description, claims and the above-mentioned drawings of this application are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0032] As Figure 1 shown is a three-dimensional schematic diagram of a negative conical wave-absorbing honeycomb structure according to a preferred embodiment of the present invention. The negative conical wave-absorbing honeycomb includes a matrix, the matrix is composed of multiple stacked honeycomb layers, and the upper surface of the matrix is provided with a plurality of negative conical cut grooves; the cell sizes of the multiple honeycomb layers decrease from the upper surface to the bottom surface.

[0033] Functionally divided, the matrix includes a negative conical impedance matching layer, an absorption layer and a reflection layer stacked in sequence.

[0034] With such a negative conical structure, when electromagnetic waves are incident on the honeycomb, the negative conical shape design ensures that there are always two surfaces in an oblique incidence state in the polarization direction, enhancing the scattering of electromagnetic waves, reducing reflection, strengthening the impedance matching with air waves, and allowing electromagnetic waves to enter the material interior to the greatest extent. It increases the multiple reflections and refractions of electromagnetic waves in the negative conical structure, effectively reducing the energy of the electromagnetic waves radiated out, and realizing the high-efficiency broadband absorption of electromagnetic waves.

[0035] For the scheme of using large-sized cells transitioning to small-sized cells, when incident electromagnetic waves first pass through the wave-absorbing honeycomb structure with large cell sizes, electromagnetic waves with longer wavelengths are lost due to multiple reflections within the cells, which is beneficial for the loss of low-frequency electromagnetic waves with larger wavelengths; similarly, when electromagnetic waves with shorter wavelengths enter the absorption layer, more multiple reflections occur in the smaller honeycomb cells, resulting in enhanced loss of high-frequency electromagnetic waves in the structure with smaller honeycomb cells. When electromagnetic waves enter the reflection layer, more multiple reflections occur in the smallest honeycomb cells and are affected by the conductivity of this layer, forming strong electromagnetic loss. Compared with the conventional multi-layer honeycomb structure with the same cell size, the structure of this embodiment effectively utilizes the differences in wavelengths of each frequency band and efficiently introduces electromagnetic waves into the honeycomb structure.

[0036] As Figure 2 shown is Figure 1Schematic cross-sectional view of the structure of the stacked honeycomb layers. In this embodiment, the stacked honeycomb layers include a first honeycomb layer, a second honeycomb layer, and a third honeycomb layer stacked along the incident direction from the incident surface. The first honeycomb layer is a negative conical impedance matching layer, the second honeycomb layer is an absorption layer, and the third honeycomb layer is a reflection layer. All three honeycombs are closely connected hexagonal wave-absorbing honeycombs, where the honeycomb aperture sizes are: first honeycomb layer > second honeycomb layer > third honeycomb layer; the amount of wave-absorbing agent added is: first honeycomb layer < second honeycomb layer < third honeycomb layer.

[0037] In Figure 2 the embodiment, the structure with each functional layer being a single honeycomb layer is given. According to the principle of the present invention, each functional layer can also be implemented using multiple honeycomb layers.

[0038] In Figure 2 the embodiment, it is given that the three-layer honeycomb structure can select honeycomb materials with different dielectric constants to achieve the design of impedance gradient distribution.

[0039] As Figure 3 shown is Figure 1 , Figure 2 the enlarged schematic view of the honeycomb structure in Figure 4 . In this embodiment, 3 layers of honeycombs are stacked, which are, from top to bottom, a negative conical impedance matching layer 100, an absorption layer 200, and a reflection layer 300. First, the top negative conical impedance matching layer 100 is cut to form a negative cone, and then all 3 layers of honeycombs are stacked. The dimensions of the negative conical groove are as

[0040] shown, where a is the opening half-width and b is the groove depth. In an achievable example, a is 10 mm and b is 20 mm. The opening width can also be other values. For example, the opening width of the negative conical cut groove is 2a = 18 - 22 mm, and the depth is b = 18 - 22 mm

[0041] According to the above size requirements and process, by adding wave-absorbing agents with different concentrations, different wave-absorbing characteristics can be achieved, as shown in the following experimental examples.

[0042] Experimental Example 1

[0043] (1) Slurry preparation: After dispersing epoxy resin into DMF at a ratio of 1:1.5, acetylene black is added at 10%, 20%, and 30% according to the resin content, and then ground to obtain microwave-absorbing slurries respectively used for preparing the honeycombs of the negative conical impedance matching layer, the absorption layer, and the reflection layer.

[0044] (2) Honeycomb preparation:

[0045] The following honeycombs are respectively impregnated once to obtain the microwave-absorbing honeycomb cores of each layer required:

[0046] Dimensions of the honeycomb of the negative conical impedance matching layer: 300 mm (L) * 300 mm (W) * 40 mm (T), the range of the side length d1 of the cell lattice: 3.67 mm ± 10%; the addition amount of the microwave absorber is 10%; where L and W are the length and width of the honeycomb projection, and T is the thickness. The same meaning applies to the following dimensions and will not be elaborated further.

[0047] Dimensions of the honeycomb of the absorption layer: 300 mm (L) * 300 mm (W) * 20 mm (T), the range of the side length d2 of the cell lattice: 2.75 mm ± 10%; the addition amount of the microwave absorber is 20%;

[0048] Thickness dimensions of the honeycomb of the reflection layer: 300 mm (L) * 300 mm (W) * 10 mm (T), the range of the side length d3 of the cell lattice: 1.83 mm ± 10%; the addition amount of the microwave absorber is 30%;

[0049] (3) Stacked honeycomb preparation:

[0050] The honeycomb of the negative conical impedance matching layer is cut and grooved with a being 10 mm and b being 20 mm, that is, the opening width is 20 mm; and the three layers are bonded respectively using an adhesive.

[0051] The electromagnetic characteristic curve of this experimental example is as Figure 5 shown. Among them Figure 5 The left side is the characteristic diagram of HH polarization (both transmission and reception are horizontal polarization), and the right side is the characteristic diagram of VV polarization (both transmission and reception are vertical polarization).

[0052] Experimental example two

[0053] (1) Slurry preparation: After dispersing epoxy resin into DMF at a ratio of 1:1.5, acetylene black is added at 10%, 20%, and 35% according to the resin content, and then ground to obtain microwave-absorbing slurries respectively used for preparing the honeycombs of the negative conical impedance matching layer, the absorption layer, and the reflection layer.

[0054] (2) Honeycomb preparation:

[0055] The following honeycombs are respectively impregnated once to obtain the microwave-absorbing honeycomb cores of each layer required:

[0056] Negative conical impedance matching layer honeycomb size: 300 mm (L) * 300 mm (W) * 30 mm (T), pore grid side length d1 range: 3.67 mm ± 10%; absorbent additive amount 10%;

[0057] Absorbing layer honeycomb size: 300 mm (L) * 300 mm (W) * 20 mm (T), pore grid side length d2 range: 2.75 mm ± 10%; absorbent additive amount 20%;

[0058] Reflection layer honeycomb thickness size: 300 mm (L) * 300 mm (W) * 10 mm (T), pore grid side length d3 range: 1.83 mm ± 10%; absorbent additive amount 35%;

[0059] (3) Laminated honeycomb preparation:

[0060] The negative conical impedance matching layer honeycomb is cut and grooved with a being 10 mm and b being 20 mm, that is, the opening width is 20 mm; the three layers are bonded respectively using an adhesive.

[0061] The electromagnetic characteristic curve of this experimental example is as Figure 6 shown, with the characteristic diagram of HH polarization on the left and the characteristic diagram of VV polarization on the right.

[0062] Experimental example three

[0063] (1) Slurry preparation: After dispersing epoxy resin in DMF at a ratio of 1:3.0, acetylene black is added at 15%, 25%, and 35% according to the resin parts, and ground to obtain absorbent slurries respectively used for preparing the negative conical impedance matching layer honeycomb, the absorbing layer honeycomb, and the reflection layer honeycomb;

[0064] (2) Honeycomb preparation:

[0065] The following honeycombs are impregnated once respectively to obtain the required absorbent honeycomb cores of each layer:

[0066] Negative conical impedance matching layer honeycomb size: 300 mm (L) * 300 mm (W) * 30 mm (T), pore grid side length d1 range: 3.67 mm ± 10%; absorbent additive amount 15%;

[0067] Absorbing layer honeycomb size: 300 mm (L) * 300 mm (W) * 10 mm (T), pore grid side length d2 range: 2.75 mm ± 10%; absorbent additive amount 25%;

[0068] Reflection layer honeycomb thickness size: 300 mm (L) * 300 mm (W) * 10 mm (T), pore grid side length d3 range: 1.83 mm ± 10%; absorbent additive amount 35%;

[0069] (3) Laminated honeycomb preparation:

[0070] The negative conical impedance matching layer honeycomb is cut and grooved with a being 20 mm and b being 20 mm, that is, the opening width is 40 mm; the three layers are bonded respectively using an adhesive.

[0071] The electromagnetic characteristic curve of this experimental example is as Figure 7 shown. The left side is the characteristic diagram of HH polarization, and the right side is the characteristic diagram of VV polarization.

[0072] It can be seen from the above three experimental examples that for the wave-absorbing honeycomb prepared according to the present invention, when electromagnetic waves are incident on the wave-absorbing honeycomb, at least two surfaces are in the state of oblique incidence in the polarization direction, increasing the multiple reflections and refractions of electromagnetic waves in the negative conical structure, effectively reducing the energy of the radiated electromagnetic waves, and achieving efficient broadband absorption of electromagnetic waves.

[0073] The specific examples in this embodiment can refer to the examples described in the above embodiments and exemplary embodiments, and will not be repeated here.

[0074] Obviously, those skilled in the art should understand that the above-mentioned modules or steps of the present invention can be implemented by a general-purpose computing device. They can be concentrated on a single computing device or distributed on a network composed of multiple computing devices. They can be implemented by program codes executable by the computing device. Thus, they can be stored in a storage device and executed by the computing device. And in some cases, the steps shown or described can be executed in a different order from here, or they can be separately fabricated into individual integrated circuit modules, or multiple modules or steps among them can be fabricated into a single integrated circuit module to implement. In this way, the present invention is not limited to any specific combination of hardware and software.

[0075] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A negative cone absorbing honeycomb, characterized in that: The invention comprises a negative tapered impedance matching layer (100), an absorption layer (200) and a reflection layer (300), wherein the negative tapered impedance matching layer (100), the absorption layer (200) and the reflection layer (300) respectively comprise at least one honeycomb layer, and the honeycomb cell side lengths of the negative tapered impedance matching layer (100), the absorption layer (200) and the reflection layer (300) decrease in sequence; and the surface of the negative tapered impedance matching layer (100) comprises at least one negative tapered groove.

2. The negative cone absorbing honeycomb according to claim 1, characterized in that: The negative tapered impedance matching layer (100), the absorption layer (200) and the reflection layer (300) are added with a wave absorbing agent.

3. The negative cone absorbing honeycomb according to claim 2, characterized in that: The concentrations of the wave absorbing agent added to the negative tapered impedance matching layer (100), the absorption layer (200) and the reflection layer (300) increase in sequence.

4. The negative cone absorbing honeycomb according to claim 3, characterized in that: The concentration of the wave absorbing agent in the negative tapered impedance matching layer (100) is 10% to 15%; the concentration of the wave absorbing agent in the absorption layer (200) is 20% to 25%; and the concentration of the wave absorbing agent in the reflection layer (300) is 30% to 35%.

5. The negative cone absorbing honeycomb according to claim 1, characterized in that: The side length of the honeycomb cells of the negative tapered impedance matching layer (100) is 3.67 mm±10%.

6. The negative cone absorbing honeycomb according to claim 1, characterized in that: The side length of the honeycomb cells of the absorption layer (200) is 2.75 mm±10%.

7. The negative cone absorbing honeycomb according to claim 1, characterized in that: The side length of the honeycomb cells of the reflective layer (300) is 1.83 mm±10%.

8. The negative cone absorbing honeycomb according to claim 1, characterized in that: The thickness of the negative tapered impedance matching layer (100) is greater than or equal to the thickness of the absorption layer (200), and the thickness of the absorption layer (200) is greater than or equal to the thickness of the reflection layer (300).

9. The negative cone absorbing honeycomb according to claim 8, characterized in that: The thickness of the negative tapered impedance matching layer (100) is 30 mm to 40 mm, the thickness of the absorption layer (200) is 10 mm to 20 mm, and the thickness of the reflection layer (300) is 8 mm to 10 mm.

10. The negative cone absorbing honeycomb according to claim 1, characterized in that: The negative tapered groove is a triangular groove, and the opening width of the negative tapered groove is 18 to 22 mm and the depth is 18 to 22 mm.

11. The negative cone absorbing honeycomb according to claim 1, characterized in that: The preparation of the negative cone absorbing honeycomb includes: adding a carbon-based absorbing agent into a resin solution, grinding and preparing an absorbing slurry; dipping the aramid paper honeycomb into the absorbing slurry, and baking and curing.

12. The negative cone absorbing honeycomb according to claim 11, characterized in that: The carbon-based wave absorbing agent is acetylene black or conductive carbon black.

13. The negative cone absorbing honeycomb according to claim 11, characterized in that: The resin solution is prepared by mixing the resin and the solvent at a ratio of 1:1.5 to 1:3.

0.

14. The negative cone absorbing honeycomb according to claim 13, characterized in that: The resin is phenolic resin or epoxy resin.

15. The negative cone absorbing honeycomb according to claim 13, characterized in that: The solvent is an alcohol solvent or a strong polar solvent.

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