Infrared and radar wave metamaterial

Abstract

The invention discloses an infrared and radar wave metamaterial which comprises a reflection layer located at the bottom, a radar wave absorption layer overlaid and covered on the reflection layer and a low infrared emission layer overlaid and covered on the radar wave absorption layer. By adopting the scheme, the infrared and radar wave flexible stealth camouflage material is realized, the flexible material can conveniently cover an irregular camouflage surface, and the camouflage material has the characteristics of light weight and good camouflage effect. The effect that the infrared emissivity is smaller than 0.3 can be achieved in the infrared band, and the effect that the infrared emissivity is larger than 6 Ghz and smaller than-20 dB can be achieved in the radar band.

Description

Technical Field

[0001] This application relates to the technology of metamaterials, and more specifically to an infrared and radar wave compatible metamaterial. Background Art

[0002] With the continuous development of science and technology and military reconnaissance technology, technologies such as infrared thermal imaging and radar are widely used in various detection equipment and weapon systems. In war preparations and modern high-tech wars, camouflage has become an important method for national defense projects, civil air defense projects, and military equipment to protect themselves. Functional materials with infrared compatibility and low radar detectability have become an important research direction. However, there are inherent contradictions in achieving radar and infrared compatible camouflage with the same material, which are difficult to overcome. Summary of the Invention

[0003] Aiming at the technical problem in the prior art that the compatible absorption of radar waves and infrared bands is poor and the stealth camouflage of the two bands cannot be achieved, the present invention provides a metamaterial that can achieve good absorption in both infrared and radar waves to overcome the above defects of the prior art.

[0004] To solve the above problems, the present invention provides an infrared and radar wave compatible metamaterial, which includes a reflection layer at the bottom, a radar wave absorption layer superimposed on the reflection layer, and a low infrared emission layer superimposed on the radar wave absorption layer.

[0005] Preferably, the low infrared emission layer includes an infrared matrix layer and an infrared resistance layer, and the infrared resistance layer covers the infrared matrix layer.

[0006] Preferably, the radar wave absorption layer includes a radar wave matrix layer and a radar wave resistance layer, and the radar wave resistance layer covers the radar wave matrix layer.

[0007] Preferably, the reflection layer includes an ITO-covered resistive film reflection surface.

[0008] Preferably, a first support layer is filled between the low infrared emission layer and the radar wave absorption layer.

[0009] Preferably, a second support layer is filled between the reflection layer and the radar wave absorption layer.

[0010] Preferably, the infrared matrix layer is made of PI or PET.

[0011] Preferably, the infrared resistance layer includes an array microstructure, and the impedance of the array microstructure of the infrared resistance layer is 5Ω / sq to 30Ω / sq.

[0012] Preferably, the array microstructure of the infrared resistance layer is a square ITO array block.

[0013] Preferably, the radar wave matrix layer is made of PI or PET.

[0014] Preferably, the radar resistance layer includes an array microstructure, and the impedance of the array microstructure of the radar resistance layer is 120 Ω / sq to 140 Ω / sq.

[0015] Preferably, the array microstructure of the radar resistance layer is a loop-shaped, cross-shaped, I-shaped, cross-snowflake-shaped or grid-shaped array microstructure.

[0016] Preferably, the reflective layer is a resistive film reflective surface covered with ITO, and the resistance value is 20 Ω / sq to 50 Ω / sq.

[0017] Preferably, the first support layer is PVC foam or polyurethane foam.

[0018] Preferably, the second support layer is PVC foam or polyurethane foam.

[0019] Implementing the infrared and radar wave metamaterial of the present invention can be conveniently covered on an irregular camouflage surface, and has the characteristics of light weight and good camouflage effect. In the infrared band, an infrared emissivity less than 0.3 can be obtained. When the frequency in the radar band is greater than 1 GHz, the absorption effect is rapidly improved, and an effect lower than -20 dB above 6 GHz can be obtained. Description of the Drawings

[0020] The drawings here are incorporated into the specification and constitute a part of this specification, showing embodiments consistent with this application, and are used together with the specification to explain the principles of this application.

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0022] Figure 1 It is a schematic structural diagram of an infrared and radar wave metamaterial according to an embodiment of the present invention;

[0023] Figure 2 It is a schematic diagram of the array microstructure on the infrared resistance layer according to an embodiment of the present invention;

[0024] Figure 3 It is a schematic diagram of the array microstructure on the radar wave resistance layer according to an embodiment of the present invention;

[0025] Figure 4 It is a schematic diagram of the I-shaped unit structure of the array microstructure on the radar wave resistance layer according to an embodiment of the present invention;

[0026] Figure 5 It is a schematic diagram of the cross-snowflake-shaped unit structure of the array microstructure on the radar wave resistance layer according to an embodiment of the present invention;

[0027] Figure 6 Schematic diagram of a grid-shaped unit structure with notches at the end corners of the array microstructure on the radar wave resistance layer in an embodiment of the present invention;

[0028] Figure 7 Numerical schematic diagram of the reflectivity corresponding to each frequency in the first embodiment of the present invention;

[0029] Figure 8 Numerical schematic diagram of the reflectivity corresponding to each frequency in the second embodiment of the present invention;

[0030] Figure 9 Numerical schematic diagram of the reflectivity corresponding to each frequency in the third embodiment of the present invention. Detailed implementation manners

[0031] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying 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 protection scope of the present application.

[0032] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes 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.

[0033] As Figure 1 shown is a schematic diagram of the structure of an infrared and radar wave stealth metamaterial in an embodiment of the present invention. The metamaterial in this embodiment includes a reflection layer 300 at the bottom, a radar wave absorption layer 200 superimposed on the reflection layer 300, and a low infrared emission layer 100 superimposed on the radar wave absorption layer 200. The low infrared emission layer 100 achieves a strong absorption effect for electromagnetic waves with a wavelength window greater than 300 GHz; the radar wave absorption layer 200 achieves a strong absorption effect for electromagnetic waves with a wavelength window greater than 1 GHz; the reflection layer 300 at the bottom is used to reflect the incident radar wave or infrared band for further absorption.

[0034] In an achievable embodiment, the low-infrared emission layer 100 includes an infrared matrix layer 102 and an infrared resistance layer 101, and the infrared resistance layer 101 covers the infrared matrix layer 102. The infrared resistance layer 101 is preferably made of materials such as AZO, FTO, and ITO. In terms of technology, a semiconductor etching process can be adopted to prepare array microstructures with different shapes and sizes to achieve different surface impedances. In this application, the resistance value of the infrared resistance layer 100 is 5 Ω / sq to 30 Ω / sq; the infrared matrix layer 102 is preferably made of materials such as PI and PET.

[0035] Taking PET as the infrared matrix layer 102 and ITO material as the infrared resistance layer 101 as an example for impedance matching design, ITO behaves like a metal in the infrared band, can adjust the resistance, and reduce its emissivity. Surface emissivity:

[0036] ε = ε I f I + ε p (1 - f I )

[0037] Where ε I is the emissivity of ITO, ε P is the emissivity of the PET substrate, and f I is the percentage of the ITO coverage area. Since the properties of ITO in the infrared band are approximately metallic, ε I is approximately 0.1.

[0038] Then for the infrared band, under the condition that the target emissivity is the design goal, the impedance design is:

[0039]

[0040] In an achievable embodiment, the radar wave absorption layer 200 includes a radar wave matrix layer 202 and a radar wave resistance layer 201 covering it. The radar wave resistance layer 201 is preferably made of materials such as AZO, FTO, and ITO. In terms of technology, a semiconductor etching process can be adopted to prepare array microstructures with different shapes and sizes to achieve different surface impedances, and the resistance value is 120 Ω / sq to 140 Ω / sq; in the present invention, the selectable array microstructure units can be in the shape of a square with a hole in the middle (as Figure 3 shown), cross-shaped, I-shaped (as Figure 4 shown), cross-snowflake-shaped (as Figure 5 shown), square-shaped, square-shaped with notches at the end corners (as Figure 6 shown), etc. The radar wave matrix layer 202 is preferably made of materials such as PI and PET.

[0041] For the design of radar wave absorption, we use the attenuation parameter α to represent the attenuation of electromagnetic wave energy per unit length:

[0042]

[0043] Electric loss tangent tanδ e = ε' / ε” and magnetic loss tangent tanδ m = μ' / μ” represent the degrees of electric loss and magnetic loss. When the imaginary parts of the permittivity and permeability are too large, they will cause changes in the characteristic impedance of the absorber, resulting in the inability to achieve impedance matching with free space. The electromagnetic waves entering the absorber are reduced, leading to a decrease in the absorption rate. According to the above formula, we can perform impedance design for the target absorption rate.

[0044] In a feasible embodiment, the reflective layer 300 includes a reflective matrix layer 302 and a reflective resistance layer 301. Preferably, the reflective layer 300 is a resistive film reflective surface completely covered by ITO, with a resistance value of 20Ω / sq to 50Ω / sq; it reflects the radar waves incident on the bottom of the metamaterial back to the dielectric layer for further absorption. Alternatively, the reflective layer is replaced with other conductive materials, such as suitable metals, conductive organic substances, etc.

[0045] In a feasible embodiment, a first support layer 401 is filled between the low-infrared emission layer and the radar wave absorption layer. The support layer material is a flexible foaming material, preferably selected from PVC foam and polyurethane foam.

[0046] In a feasible embodiment, a second support layer 402 is filled between the reflective layer and the radar wave absorption layer. The support layer material is a flexible foaming material, preferably selected from PVC foam and polyurethane foam.

[0047] Embodiment 1

[0048] The following are the material parameters of a preferred embodiment according to the present invention and the corresponding infrared absorption and radar wave absorption effects:

[0049] Low-infrared emission layer 100: The infrared matrix layer 101 is made of transparent PET material with a thickness of 0.18mm; the planar structure of the infrared resistance layer 102 is as Figure 2 shown. Square array blocks with a side length a = 1mm are prepared from ITO material with a thickness of 0.05mm, and the square array spacing is b = 0.1mm. The equivalent resistance of the entire infrared resistance layer is 5Ω / sq.

[0050] Radar wave absorption layer 200: The radar wave matrix layer 201 is made of transparent PET material with a thickness of 0.18 mm. On this transparent PET material, a semiconductor etching process is used to prepare a meandering shape composed of a square ring and a square patch ITO resistive film line. The equivalent resistance generated by the array microstructure is 120 Ω / sq.

[0051] Reflection layer 300: The reflection layer 300 is a resistive film reflection surface completely covered by ITO. It reflects the radar waves incident on the bottom of the metamaterial for further absorption. The reflection resistance layer 301 is ITO with a thickness of 0.05 mm and an equivalent resistance of 20 Ω / sq. The PET substrate has a thickness of 0.18 mm.

[0052] First support layer 401: Polyvinyl chloride is selected with a filling thickness of 1 mm.

[0053] Second support layer 402: Polyvinyl chloride is selected with a filling thickness of 1.5 mm.

[0054] In Example 1 with the above parameters, the overall structural size is 300 mm * 300 mm. The measured infrared absorption rate is 0.27, and its radar wave absorption rate is as Figure 7 shown. When the frequency is greater than 1 GHz, the absorption effect increases rapidly, and a reflectivity lower than -20 dB is obtained at frequencies above 5 GHz. At multiple sensitive bands, such as 8 GHz, 12 GHz, etc., an absorption rate lower than -30 dB is obtained.

[0055] Example 2

[0056] The following are the material parameters of another preferred embodiment according to the present invention and the corresponding infrared absorption and radar wave absorption effects:

[0057] Low infrared emission layer 100: The infrared matrix layer 101 is made of transparent PET material with a thickness of 0.18 mm; the infrared resistive layer 102 is made of ITO material with a thickness of 0.05 mm to prepare a square array block with side length a = 1.5 mm, and the square array pitch b = 0.1 mm. The equivalent resistance of the entire infrared resistive layer is 30 Ω / sq.

[0058] Radar wave absorption layer 200: Transparent PET material is selected with a thickness of 0.18 mm. On this transparent PET material, a semiconductor etching process is used to prepare a meandering array microstructure composed of a square ring and a square patch ITO resistive film line. The equivalent resistance generated by the array microstructure is 140 Ω / sq.

[0059] Reflection layer 300: The reflection layer is a resistive film reflection surface completely covered by ITO. It reflects the radar waves incident on the bottom of the metamaterial for further absorption. The thickness of ITO is 0.05 mm, and the equivalent resistance is 50 Ω / sq. The thickness of the PET substrate is 0.18 mm.

[0060] The first support layer 401: The flexible material PVC is selected, and the filling thickness is 1 mm.

[0061] The second support layer 402: The flexible material PVC is selected, and the filling thickness is 1.5 mm.

[0062] The overall structural size is 300 mm * 300 mm. In the infrared band, the infrared emissivity of this embodiment is 0.24, and the radar wave reflectivity is referenced as Figure 8 shown. When the frequency is greater than 1 GHz, the absorption effect increases rapidly. In the frequency band where the frequency is greater than 6 GHz, the overall reflectivity is lower than -20 dB, and peak absorption rates are obtained near the frequencies of 8 GHz and 12 GHz, and the absorption effect exceeds -40 dB.

[0063] Embodiment 3

[0064] The following are the material parameters of the third embodiment according to the present invention and the corresponding infrared absorption and radar wave absorption effects:

[0065] Low infrared emission layer 100: The infrared matrix layer 101 is made of transparent PET material with a thickness of 0.18 mm; the infrared resistive layer 102 is made of ITO material with a thickness of 0.05 mm to prepare square array blocks with a side length of 1 mm, and the square array spacing is 0.1 mm. The equivalent resistance of the entire infrared resistive layer 102 is 20 Ω / sq.

[0066] Radar wave absorption layer 200: Transparent PET material is selected with a thickness of 0.18 mm. On this transparent PET material, a cross-shaped array microstructure composed of a square ring and a square patch ITO resistive film line is prepared by semiconductor etching process. The equivalent resistance generated by the array microstructure is 130 Ω / sq.

[0067] Reflection layer 300: The reflection layer is a resistive film reflection surface completely covered by ITO. It reflects the radar waves incident on the bottom of the metamaterial for further absorption. The thickness of ITO is 0.05 mm, and the equivalent resistance is 40 Ω / sq. The thickness of the PET substrate is 0.18 mm.

[0068] The first support layer 401: Polyurethane absorber is selected, and the filling thickness is 1 mm.

[0069] The second support layer 402: Polyurethane absorber is selected, and the filling thickness is 1.5 mm.

[0070] The overall structural size is 300mm * 300mm. In the infrared band, the infrared emissivity of this embodiment is 0.26, and the radar wave reflectivity reference Figure 9 is shown. When it is greater than 1 GHz, the absorption effect rapidly improves, and in the band above 6 GHz, a reflectivity of more than -20 dB is obtained, and a strong absorption effect is obtained near 8 GHz, with the reflectivity exceeding -45 dB.

[0071] Adopting the solution of the present invention to realize an infrared and radar wave flexible stealth camouflage material, the flexible material can be conveniently covered on an irregular camouflage surface, and has the characteristics of light weight and good camouflage effect. In the infrared band, an effect with an infrared emissivity less than 0.3 can be obtained, and when it is greater than 1 GHz in the radar band, the absorption effect rapidly improves, and an effect below -20 dB above 6 GHz can be obtained.

[0072] For specific examples in this embodiment, reference can be made to the examples described in the above embodiments and exemplary embodiments, and details thereof are not elaborated herein.

[0073] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. 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. An infrared and radar wave metamaterial, characterized in that It includes a reflective layer (300) located at the bottom, a radar wave absorption layer (200) superimposed and covering the reflective layer (300), and a low infrared emission layer (100) superimposed and covering the radar wave absorption layer (200).

2. The infrared and radar wave metamaterial according to claim 1, wherein The low infrared emission layer (100) includes an infrared matrix layer (102) and an infrared resistance layer (101), and the infrared resistance layer (101) covers the infrared matrix layer (102).

3. The infrared and radar wave metamaterial according to claim 1, wherein The radar wave absorption layer (200) includes a radar wave matrix layer (202) and a radar wave resistance layer (201), and the radar wave resistance layer (201) covers the radar wave matrix layer (202).

4. The infrared and radar wave metamaterial according to claim 1, wherein The reflective layer (300) includes a reflective matrix layer (302) and a reflective resistance layer (301), and the reflective matrix layer (302) covers the reflective resistance layer (301).

5. The infrared and radar wave metamaterial according to claim 1, wherein A first support layer (401) is filled between the low infrared emission layer (100) and the radar wave absorption layer (200).

6. The infrared and radar wave metamaterial according to claim 1, wherein A second support layer (402) is filled between the reflective layer (300) and the radar wave absorption layer (200).

7. The infrared and radar wave metamaterial according to claim 2, wherein The infrared matrix layer (102) is made of PI or PET.

8. The infrared and radar wave metamaterial according to claim 2, wherein The infrared resistance layer (101) includes an array microstructure, and the impedance of the array microstructure of the infrared resistance layer is 5Ω / sq to 30Ω / sq.

9. The infrared and radar wave metamaterial according to claim 8, wherein The array microstructure of the infrared resistance layer is a square ITO array block.

10. The infrared and radar wave metamaterial according to claim 3, wherein The radar wave matrix layer (202) is made of PI or PET.

11. The infrared and radar wave metamaterial according to claim 3, characterized in that, The radar resistance layer (201) includes an array microstructure, and the impedance of the array microstructure of the radar resistance layer is 120Ω / sq to 140Ω / sq.

12. The infrared and radar wave metamaterial according to claim 11, wherein The array microstructure of the radar resistance layer is an array microstructure in the shape of a meander, a cross, an I-shape, a cross snowflake, or a grid.

13. The infrared and radar wave metamaterial according to claim 4, wherein The reflective layer (300) is a resistive film reflective surface covered with ITO, and the resistance value is 20Ω / sq to 50Ω / sq.

14. The infrared and radar wave metamaterial according to claim 6, wherein The first support layer (401) is PVC foam or polyurethane foam.

15. The infrared and radar wave metamaterial according to claim 7, wherein The second support layer (402) is PVC foam or polyurethane foam.

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