Ultra-light wide-angle wave-absorbing metamaterial based on 2-18 ghz full-frequency absorption of low-price and easily-available carbon-based conductive films and easy to manufacture, and manufacturing method therefor

Abstract

The present invention relates to the technical field of functional composite materials, and provides an ultra-light wide-angle wave-absorbing metamaterial based on 2-18 GHz full-frequency absorption of low-price and easily-available carbon-based conductive films and easy to manufacture, and a manufacturing method therefor. The metamaterial comprises a first dielectric substrate, a first carbon-based conductive thin film structure array layer, a second dielectric substrate, a second carbon-based conductive thin film structure array layer, a third dielectric substrate, and a third carbon-based conductive thin film structure array layer which are sequentially stacked from bottom to top. The first, second and third carbon-based conductive thin film structure array layers are all formed by periodically arranging discrete carbon-based conductive thin film patches. According to the present invention, by means of coupling of multilayer carbon-based conductive thin film periodic unit arrays, a wave-absorbing metamaterial having the characteristics of low price, easy formation processing, ultra-lightness, ultra-wideband, stable large incident angle, high absorptivity, and the like is obtained; the metamaterial weighs 0.4-0.5 kg per square meter, which is only 1 / 100 of that of a traditional absorber of the same size. The metamaterial has an absorption rate of 90% or more in a full frequency range of 2-18 GHz.

Description

Ultra-light, wide-angle absorbing metamaterial based on inexpensive and readily available carbon-based conductive film for full-frequency absorption from 2 to 18 GHz and easy to manufacture, and its manufacturing method

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application number 202410083767.9, filed with the Patent Office of China on January 19, 2024, entitled "Ultra-light, wide-angle absorbing metamaterial with 2-18 GHz full-frequency absorption and easy-to-manufacture based on inexpensive and readily available carbon-based conductive film and its manufacturing method", the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present invention relates to the technical field of functional composite materials, and in particular to an ultra-light, wide-angle absorbing metamaterial based on an inexpensive and readily available carbon-based conductive film that absorbs the full frequency range of 2-18 GHz and is easy to manufacture, and a manufacturing method thereof. Background Art

[0004] The ubiquitous presence of electromagnetic wave (EMW) radiation in the environment not only interferes with the normal operation of sensitive equipment such as civil aircraft radios, radars, and aerospace data transceivers, but has also drawn public attention to its potential harm to human health. With the advent of artificial intelligence and 5G communications, this situation is expected to become increasingly serious. Therefore, when designing and manufacturing products, it is crucial to convert most EMW radiation into heat energy while minimizing secondary pollution, and to dissipate any EMW that intrudes into the medium. Materials with this capability, known as absorbers, are currently a hot topic of research and development both domestically and internationally. Carbon-based thin films, as a typical dielectric material, have emerged as a promising class of EMW absorbers due to their low density, excellent environmental stability, adjustable electron mobility, and designable structural configurations.

[0005] EMW absorbing materials not only have important applications in the military but also play a significant role in practical civil engineering. Practical requirements require not only high EMW absorption rates but also a wide frequency range. Furthermore, strict requirements are placed on the mechanical strength, specific gravity, temperature and moisture resistance, radiation resistance, and corrosion resistance of the absorbing materials. Currently, the most widely used materials are Ni-Zn ferrite and hexagonal ferrite, primarily used in aircraft engine fairings. These materials suffer from narrow absorption bandwidths, fixed polarization, complex three-dimensional structures, and heavy weight. Therefore, the development of highly absorptive, broadband, and lightweight absorbing materials is essential.

[0006] Metamaterials are a new type of material with extraordinary physical properties. They are composed of artificially arranged units. Compared with traditional materials, they can more precisely control the operating frequency band and performance strength, and have advantages such as light weight and thinness. Metamaterials can exhibit properties such as negative dielectric constant, negative magnetic permeability, negative refractive index, and zero refractive index, and therefore have important application value in many fields. Metamaterial absorbers are one of the application branches of metamaterials. They are materials that can absorb, scatter, or change the propagation direction of electromagnetic waves. They can be used to reduce electromagnetic interference, enhance stealth performance, and improve the efficiency of solar cells. The research on metamaterial absorbers involves multiple disciplines such as physics, materials science, and electronic engineering, and is a challenging and promising research field.

[0007] The unit cell structure of a conventional metamaterial consists of an electrically resonant ring at the top, a dielectric substrate in the middle, and a metal backplate at the bottom, forming a classic metal / dielectric / metal structure. Currently, most metamaterial absorbers, both single-layer and multi-layer, employ this structure. By optimizing the structural parameters, strong electromagnetic resonance is generated between the resonant unit and the metal backplate at the bottom, matching the input impedance of the metamaterial absorber with that of free space, thereby absorbing incident radar waves with virtually no reflection. This metamaterial absorber, which nearly completely absorbs radar wave energy, is also known as a perfect metamaterial absorber. However, this classic structure is polarization-sensitive, has a narrow absorption bandwidth, and requires strict alignment of the metal backplate at the bottom and the metal patch at the top to achieve ideal absorption, placing high demands on the manufacturing process.

[0008] To expand the absorption bandwidth of metamaterials, researchers at home and abroad have explored various approaches. However, the absorption bandwidth of metamaterial absorbers remains unsatisfactory, and reports of metamaterial absorbers that fully cover multiple wavelengths across multiple bands are rare. Furthermore, the absorption bands of existing broadband metamaterial absorbers are not stable, and radar reflection issues may still exist within the bands. Furthermore, polarization stability and performance stability at wide oblique incidence angles are less than ideal. Only materials with stable absorption performance at wide incidence angles are likely to find practical application.

[0009] Therefore, against the above background, the present invention combines ultra-light polystyrene foam with carbon-based conductive film to obtain an ultra-wideband wide-angle metamaterial absorber with a three-layer composite structure having multi-resonance and excellent impedance matching performance.

[0010] Summary of the Invention

[0011] The present invention overcomes the shortcomings of the existing technology by combining ultra-light polystyrene foam plastic with a carbon-based conductive film to provide an ultra-light, wide-angle absorbing metamaterial based on a cheap and readily available carbon-based conductive film that can absorb the entire frequency range of 2-18 GHz and is easy to manufacture, as well as a manufacturing method thereof. The metamaterial is an ultra-wideband, wide-angle metamaterial absorber with a three-layer composite structure that has multiple resonances and excellent impedance matching performance.

[0012] To solve the above technical problems, the technical solution adopted by the present invention is: an ultra-light, wide-angle absorbing metamaterial based on inexpensive and readily available carbon-based conductive film that absorbs the full frequency range of 2-18 GHz and is easy to manufacture, comprising a first dielectric substrate, a first carbon-based conductive film structure array layer, a second dielectric substrate, a second carbon-based conductive film structure array layer, a third dielectric substrate, and a third carbon-based conductive film structure array layer, which are stacked in sequence from bottom to top (the top is the incident direction of the electromagnetic wave);

[0013] The first carbon-based conductive film structure array layer, the second carbon-based conductive film structure array layer and the third carbon-based conductive film structure array layer are all formed by periodically arranging discrete carbon-based conductive film patches;

[0014] The carbon-based conductive film constituting the first carbon-based conductive film structure array layer has a resistivity of 1-3 Ω·cm, a conductivity of 0.6-1 S / cm, and a sheet resistance of 200-220 Ω / sq; the carbon-based conductive film constituting the second carbon-based conductive film structure array layer and the third carbon-based conductive film structure array layer has a resistivity of 1-3 Ω·cm, a conductivity of 0.4-1 S / cm, and a sheet resistance of 220-260 Ω / sq;

[0015] The first carbon-based conductive thin film structure array layer, the second carbon-based conductive thin film structure array layer, and the third carbon-based conductive thin film structure array layer are each arranged in an array of m×n unit structures, and the side length P of each unit structure is 50 mm, where m ≥ 4 and is an even integer, and n ≥ 4 and is an even integer;

[0016] The unit structure of the first carbon-based conductive film structure array layer is a square patch; the unit structure of the second carbon-based conductive film structure array layer is a square ring patch; the unit structure of the third carbon-based conductive film structure array layer is a combination pattern consisting of four square patches.

[0017] As a further improvement of the technical solution of the present invention, the first dielectric substrate, the second dielectric substrate and the third dielectric substrate are all polystyrene foam boards; the relative dielectric constant of the polystyrene foam board is 1-1.1, the loss tangent value is 0.018, and the density is 19-21 kg / m 3 .

[0018] As a further improvement of the technical solution of the present invention, the thickness H1 of the first dielectric substrate is 5-7 mm; the thickness H2 of the second dielectric substrate is 9-11 mm; and the thickness H3 of the third dielectric substrate is 4-6 mm.

[0019] As a further improvement of the technical solution of the present invention, the side length L1 of the square patch of the unit structure of the first carbon-based conductive thin film structure array layer is 45-49 mm; the inner ring width L2 of the square ring patch of the unit structure of the second carbon-based conductive thin film structure array layer is 10-13 mm, and the outer ring width L3 is 11-13 mm; the side length L4 of the four square patches of the unit structure of the third carbon-based conductive thin film structure array layer is 14-17 mm.

[0020] As a further improvement to the technical solution of the present invention, the unit structures of the first carbon-based conductive thin film structure array layer, the second carbon-based conductive thin film structure array layer and the third carbon-based conductive thin film structure array layer are all centrosymmetric patterns.

[0021] The present invention also provides a method for manufacturing the aforementioned ultra-light, wide-angle absorbing metamaterial that is easy to manufacture and has full-band absorption of 2-18 GHz based on a cheap and readily available carbon-based conductive film, comprising the following steps:

[0022] (1) According to the designed length*width*thickness of the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate, a polystyrene foam board product is cut into the designed size using a heated foam cutting machine, thereby obtaining the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate;

[0023] (2) Drawing the shape of the designed unit structure of the first carbon-based conductive thin film structure array layer, the shape of the unit structure of the second carbon-based conductive thin film structure array layer, and the shape of the unit structure of the third carbon-based conductive thin film structure array layer on a computer, and then printing and using the printed hard sheet as a template to cut the purchased carbon-based conductive thin film product into the designed unit structure shape, thereby obtaining the unit structure of the first carbon-based conductive thin film structure array layer, the unit structure of the second carbon-based conductive thin film structure array layer, and the unit structure of the third carbon-based conductive thin film structure array layer respectively;

[0024] (3) Using a computer to draw the position of each unit structure in the third carbon-based conductive film structure array layer on the third dielectric substrate obtained in step (1), and then gluing the structural unit of the third carbon-based conductive film obtained in step (2) to the surface of the third dielectric substrate according to the printed pattern; after gluing, gluing the second dielectric substrate on which the pattern of each unit structure in the second carbon-based conductive film structure array layer is printed by computer, and then gluing the structural unit of the second carbon-based conductive film obtained in step (2) to the surface of the second dielectric substrate according to the printed pattern; after gluing, gluing the first dielectric substrate on which the pattern of each unit structure in the first carbon-based conductive film structure array layer is printed by computer, and then gluing the structural unit of the first carbon-based conductive film obtained in step (2) to the surface of the first dielectric substrate according to the printed pattern; after gluing, an ultra-light wide-angle absorbing metamaterial with full-frequency absorption of 2-18 GHz based on a cheap and readily available carbon-based conductive film and easy to manufacture is obtained.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The ultra-light, wide-angle absorbing metamaterial of the present invention exhibits both excellent incident wave polarization and stability at wide incident angles. Due to the miniaturized design of the structural unit, the metamaterial of the present invention can achieve oblique incident responses of up to 45° for transverse electric (TE) polarization and 60° for transverse magnetic (TM) polarization. Even at TM wave incident angles of up to 60°, it still maintains an 80% EMW energy absorption rate.

[0027] (2) The present invention uses a lossy layer based on a carbon-based conductive film to replace the metal pattern superstructure currently widely used at home and abroad, and uses ultra-light polystyrene foam plastic to make the entire superstructure light in weight, with a density of only 20kg / m 3 , weighing 0.4-0.5 kg per square meter, which is only 1 / 100 of the traditional absorber of the same size.

[0028] (3) The present invention can change the electrical performance parameters of the metamaterial by adjusting specific structural parameters to obtain the required electromagnetic wave transmission and absorption frequency bands; in addition, effective absorption of the entire band can be achieved simultaneously within the frequency range of 2-18 GHz (RL≤-10 dB). BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic structural diagram of an ultra-light, wide-angle absorbing metamaterial that is easy to manufacture and has full-frequency absorption of 2-18 GHz based on an inexpensive and readily available carbon-based conductive film, manufactured in Example 1 of the present invention, wherein Figure 1(a) is a schematic structural diagram of the entire structure, Figure 1(b) is a schematic structural diagram of a unit of a first carbon-based conductive film array layer, Figure 1(c) is a schematic structural diagram of a unit of a second carbon-based conductive film array layer, and Figure 1(d) is a schematic structural diagram of a unit of a fourth carbon-based conductive film array layer.

[0030] FIG2 is a schematic diagram of an ultra-light, wide-angle absorbing metamaterial that is easy to manufacture and has full-band absorption capability of 2-18 GHz based on a cheap and readily available carbon-based conductive film, manufactured in Example 1 of the present invention.

[0031] FIG3 is a schematic diagram of a first carbon-based conductive film array layer formed by an array of 4×4 unit structures of an ultra-light, wide-angle absorbing metamaterial that is easy to manufacture and has full-frequency absorption of 2-18 GHz based on inexpensive and readily available carbon-based conductive films, manufactured in Example 1 of the present invention.

[0032] FIG4 is a schematic diagram of a second carbon-based conductive film array layer formed by an array of 4×4 unit structures of an ultra-light, wide-angle absorbing metamaterial based on a cheap and readily available carbon-based conductive film with full-frequency absorption of 2-18 GHz and easy to manufacture, manufactured in Example 1 of the present invention.

[0033] FIG5 is a schematic diagram of a third carbon-based conductive film array layer formed by an array of 4×4 unit structures of an ultra-light, wide-angle absorbing metamaterial that is easy to manufacture and has full-frequency absorption of 2-18 GHz based on inexpensive and readily available carbon-based conductive films, manufactured in Example 1 of the present invention.

[0034] Figure 6 is a physical photograph of the ultra-light, wide-angle absorbing metamaterial with 2-18 GHz full-band absorption and easy-to-manufacture based on inexpensive and readily available carbon-based conductive film, manufactured in Example 1 of the present invention. Figure 6(a) is the first carbon-based conductive film structure array layer, Figure 6(b) is the second carbon-based conductive film structure array layer, Figure 6(c) is the third carbon-based conductive film structure array layer, and Figure 6(d) is the overall structure of the metamaterial.

[0035] FIG7 is a simulation curve of radar wave reflection loss (RL) in the 2-18 GHz electromagnetic wave frequency range for the ultra-light, wide-angle absorbing metamaterials based on inexpensive and readily available carbon-based conductive films for full-frequency absorption in the 2-18 GHz range, manufactured in Examples 1, 2, 3, and 4 of the present invention.

[0036] FIG8 is a simulation curve of the normalized absorption rate in the 2-18 GHz electromagnetic wave frequency range of the ultra-light, wide-angle absorbing metamaterials manufactured in Examples 1, 2, 3, and 4 of the present invention, which are based on inexpensive and readily available carbon-based conductive films and are easy to manufacture.

[0037] FIG9 is a measured curve of radar wave reflection loss (RL) in the 2-18 GHz electromagnetic wave frequency range of an ultra-light, wide-angle absorbing metamaterial manufactured in Example 1 of the present invention, which is based on an inexpensive and readily available carbon-based conductive film and is easy to manufacture, and is manufactured.

[0038] FIG10 is a measured curve of the normalized absorption rate of the easy-to-manufacture ultra-light, wide-angle absorbing metamaterial with full-frequency absorption of 2-18 GHz based on an inexpensive and readily available carbon-based conductive film, manufactured in Example 1 of the present invention, in the electromagnetic wave frequency range of 2-18 GHz.

[0039] FIG11 shows the RL simulation results of the ultra-light, wide-angle absorbing metamaterial with full-band absorption of 2-18 GHz and easy-to-manufacture based on inexpensive and readily available carbon-based conductive film, manufactured in Example 1 of the present invention, at different incident angles of TE and TM waves. FIG11( a ) shows the case of TE wave incidence, and FIG11( b ) shows the case of TM wave incidence. DETAILED DESCRIPTION

[0040] The present invention will be further described below with reference to specific embodiments.

[0041] Example 1

[0042] An ultra-light, wide-angle absorbing metamaterial based on inexpensive and readily available carbon-based conductive film that absorbs the entire 2-18 GHz frequency band and is easy to manufacture. The specific structure is shown in Figure 1 , comprising a first dielectric substrate, a first carbon-based conductive film structure array layer, a second dielectric substrate, a second carbon-based conductive film structure array layer, a third dielectric substrate, and a third carbon-based conductive film structure array layer, stacked in sequence from bottom to top (the top is the direction of electromagnetic wave incidence).

[0043] The first dielectric substrate is a polystyrene foam board with a relative dielectric constant of 1.1, a loss tangent of 0.018, and a density of 20 kg / m 3 ;Thickness H1 is 6.1mm.

[0044] The second dielectric substrate is a polystyrene foam board with a relative dielectric constant of 1.1, a loss tangent of 0.018, and a density of 20 kg / m 3 ;Thickness H2 is 10.3mm.

[0045] The third dielectric substrate is a polystyrene foam board with a relative dielectric constant of 1.1, a loss tangent of 0.018, and a density of 20 kg / m 3 ;Thickness H3 is 4.65mm.

[0046] The first carbon-based conductive film array layer is composed of periodically arranged square carbon-based conductive film patches. The structure, as shown in Figure 3, consists of a 4×4 unit structure array. The unit structure side lengths are P (referring to the outer frame dimensions of the first carbon-based conductive film array layer) = 50 mm, and L1 = 48.7 mm. The carbon-based conductive film is a commercially available product made from carbon black and carbon nanotubes, with a resistivity of 1.366 Ω·cm, a conductivity of 0.7325 S / cm, and a sheet resistance of 210 Ω / sq.

[0047] The second carbon-based conductive film array layer is composed of a periodic arrangement of square ring-shaped carbon-based conductive film patches. The structure, as shown in Figure 4, consists of a 4×4 unit structure array. The unit structure side lengths are P (referring to the outer frame dimensions of the second carbon-based conductive film array layer) = 50 mm, L2 = 12.8 mm, and L3 = 12.9 mm. The carbon-based conductive film is a commercially available product made from carbon black and carbon nanotubes, with a resistivity of 2.17 Ω·cm, a conductivity of 0.4610 S / cm, and a sheet resistance of 220 Ω / sq.

[0048] The third carbon-based conductive film structure array layer consists of four periodically arranged square carbon-based conductive film patches. The structure, as shown in Figure 5, is arranged in a 4×4 unit structure array. The unit structure side lengths are P (referring to the outer frame dimensions of the third carbon-based conductive film structure array layer) = 50 mm, and L4 = 15.9 mm. The carbon-based conductive film is a commercially available product made from carbon black and carbon nanotubes, with a resistivity of 2.17 Ω·cm, a conductivity of 0.4610 S / cm, and a sheet resistance of 220 Ω / sq.

[0049] Its manufacturing process is:

[0050] (1) A heated foam cutting machine was used to cut the foam board produced by Shanxi Sihai Youcheng Company using high-density polystyrene resin into a board with a size of 200 mm × 200 mm × 4.6 mm (third dielectric substrate), a board with a size of 200 mm × 200 mm × 6.1 mm (first dielectric substrate), and a board with a size of 200 mm × 200 mm × 10.3 mm (first dielectric substrate).

[0051] (2) drawing the shape of the designed unit structure of the first carbon-based conductive thin film structure array layer, the shape of the unit structure of the second carbon-based conductive thin film structure array layer, and the shape of the unit structure of the third carbon-based conductive thin film structure array layer on a computer, and then printing and using the printed hard sheet as a template to manually cut the purchased carbon-based conductive thin film product into the shape of the designed unit structure, thereby obtaining the unit structure of the first carbon-based conductive thin film structure array layer, the unit structure of the second carbon-based conductive thin film structure array layer, and the unit structure of the third carbon-based conductive thin film structure array layer respectively;

[0052] (3) Using a computer to draw the position of each unit structure in the third carbon-based conductive film structure array layer on the third dielectric substrate obtained in step (1), and then gluing the structural unit of the third carbon-based conductive film obtained in step (2) to the surface of the third dielectric substrate according to the printed pattern; after gluing, gluing the second dielectric substrate on which the pattern of each unit structure in the second carbon-based conductive film structure array layer is printed by computer, and then gluing the structural unit of the second carbon-based conductive film obtained in step (2) to the surface of the second dielectric substrate according to the printed pattern; after gluing, gluing the first dielectric substrate on which the pattern of each unit structure in the first carbon-based conductive film structure array layer is printed by computer, and then gluing the structural unit of the first carbon-based conductive film obtained in step (2) to the surface of the first dielectric substrate according to the printed pattern; after gluing, an ultra-light wide-angle absorbing metamaterial with a size of 200 mm × 200 mm × 21 mm based on a cheap and readily available carbon-based conductive film with full-frequency absorption of 2-18 GHz and easy to manufacture is obtained.

[0053] As shown in Figures 7 and 9, the minimum RL of the ultra-light, wide-angle absorbing metamaterial obtained in Example 1, which absorbs the entire frequency range of 2-18 GHz and is easy to manufacture based on a cheap and readily available carbon-based conductive film, occurs at 13.28 GHz, resulting in a strong absorption of -40.57 dB; the effective absorption bandwidth (RL ≤ -10 dB) in the ultra-wide frequency band of 2-18 GHz is 18 GHz.

[0054] As shown in Figures 8 and 10, the normalized absorption rate of the metamaterial obtained in Example 1 is above 90% (RL≤-10dB) in the ultra-wide frequency band of 2-18 GHz, and is close to 100% at 2.79 GHz and 13.28 GHz, achieving efficient absorption.

[0055] As shown in Figure 11, in the TE polarization mode, the strong absorption performance of the metamaterial obtained in Example 1 remains stable (absorption rate greater than 90%) when the incident angle increases from 0° to 45°. In the TM polarization mode, when the incident angle increases from 0° to 60°, the metamaterial's absorption rate only slightly decreases in the low-frequency range, while the overall absorption rate remains stable, with good angular stability. This demonstrates that the metamaterial absorber of the present invention has excellent polarization stability and angular insensitivity. This is due to the strong symmetry and miniaturization of the designed unit structure. The oblique incidence responses of the TE mode and TM mode can reach 45° and 60°, respectively, under different polarization conditions.

[0056] Example 2

[0057] An ultra-light, wide-angle absorbing metamaterial based on inexpensive and readily available carbon-based conductive film that absorbs the entire frequency range of 2-18 GHz and is easy to manufacture. The specific structure is shown in Figure 1, comprising a first dielectric substrate, a first carbon-based conductive film structure array layer, a second dielectric substrate, a second carbon-based conductive film structure array layer, a third dielectric substrate, and a third carbon-based conductive film structure array layer, which are stacked in sequence from bottom to top (the top is the incident direction of the electromagnetic wave).

[0058] The first dielectric substrate is a polystyrene foam board with a relative dielectric constant of 1.1, a loss tangent of 0.018, and a density of 20 kg / m 3 ;Thickness H1 is 6.1mm.

[0059] The second dielectric substrate is a polystyrene foam board with a relative dielectric constant of 1.1, a loss tangent of 0.018, and a density of 20 kg / m 3 ;Thickness H2 is 9.8mm.

[0060] The third dielectric substrate is a polystyrene foam board with a relative dielectric constant of 1.1, a loss tangent of 0.018, and a density of 20 kg / m 3 ;Thickness H3 is 5.1mm.

[0061] The first carbon-based conductive film array layer is composed of periodically arranged square carbon-based conductive film patches. The structure, as shown in Figure 3, consists of a 4×4 unit structure array. The side length of the array unit structure is P (referring to the outer frame dimension of the first carbon-based conductive film array layer) = 50 mm, and L1 = 48.7 mm. The carbon-based conductive film is a commercially available carbon-based conductive film made from carbon black and carbon nanotubes, with a resistivity of 1.4 Ω·cm, a conductivity of 0.8 S / cm, and a sheet resistance of 210 Ω / sq.

[0062] The second carbon-based conductive film structure array layer is composed of a periodic arrangement of square-ring carbon-based conductive film patches, as shown in Figure 4. This arrangement consists of a 4×4 unit structure array, with a side length of P (referring to the outer frame dimension of the second carbon-based conductive film structure array layer) = 50 mm, L2 = 12.8 mm, and L3 = 12.9 mm. The carbon-based conductive film is a commercially available product made from carbon black and carbon nanotubes, with a resistivity of 2.3 Ω·cm, a conductivity of 0.6 S / cm, and a sheet resistance of 220 Ω / sq.

[0063] The third carbon-based conductive film structure array layer is composed of four periodically arranged square carbon-based conductive film patches. The structure is shown in Figure 5 and is composed of a 4×4 unit structure array. The side length of the array unit structure is P (referring to the outer frame size of the third carbon-based conductive film structure array layer) = 50 mm, L4 = 15.9 mm; the carbon-based conductive film is a commercial carbon-based conductive film prepared from carbon black and carbon nanotubes, with a resistivity of 2.3Ω·cm, a conductivity of 0.6S / cm, and a square resistance of 220Ω / sq.

[0064] The manufacturing process is the same as that of Example 1, except for the different materials and structural parameters.

[0065] As shown in Figure 7, the minimum RL of the ultra-light, wide-angle absorbing metamaterial obtained in Example 2, which has a full-band absorption of 2-18 GHz using a cheap and readily available carbon-based conductive film and is easy to manufacture, occurs at 2.96 GHz, resulting in a strong absorption of -41.12 dB; the effective absorption bandwidth (RL ≤ -10 dB) in the ultra-wide frequency band of 2-18 GHz is 18 GHz.

[0066] As shown in Figure 8, the normalized absorption rate of the metamaterial in the ultra-wide frequency band of 2-18 GHz is above 90% (RL≤-10dB), and the normalized absorption rate at 2.96 GHz and 15.22 GHz is close to 100%, achieving efficient absorption.

[0067] Example 3

[0068] An ultra-light, wide-angle absorbing metamaterial based on inexpensive and readily available carbon-based conductive film that absorbs the entire 2-18 GHz frequency band and is easy to manufacture. The specific structure is shown in Figure 1 , comprising a first dielectric substrate, a first carbon-based conductive film structure array layer, a second dielectric substrate, a second carbon-based conductive film structure array layer, a third dielectric substrate, and a third carbon-based conductive film structure array layer, stacked in sequence from bottom to top (the top is the direction of electromagnetic wave incidence).

[0069] The first dielectric substrate is a polystyrene foam board with a relative dielectric constant of 1, a loss tangent of 0.018, and a density of 19 kg / m 3 ;Thickness H1 is 5mm.

[0070] The second dielectric substrate is a polystyrene foam board with a relative dielectric constant of 1, a loss tangent of 0.018, and a density of 19 kg / m 3 ;Thickness H2 is 9mm.

[0071] The third dielectric substrate is a polystyrene foam board with a relative dielectric constant of 1, a loss tangent of 0.018, and a density of 19 kg / m 3 ;Thickness H3 is 4mm.

[0072] The first carbon-based conductive film array layer is composed of periodically arranged square carbon-based conductive film patches. The structure, as shown in Figure 3, consists of a 4×4 unit structure array. The unit structure side lengths are P (referring to the outer frame dimensions of the first carbon-based conductive film array layer) = 50 mm, and L1 = 45 mm. The carbon-based conductive film is a commercially available product made from carbon black and carbon nanotubes, with a resistivity of 1.2 Ω·cm, a conductivity of 0.6 S / cm, and a sheet resistance of 200 Ω / sq.

[0073] The second carbon-based conductive film structure array layer is composed of a periodic arrangement of square-ring carbon-based conductive film patches, as shown in Figure 4. This arrangement consists of a 4×4 unit structure array, with a side length of P (referring to the outer frame dimension of the second carbon-based conductive film structure array layer) = 50 mm, L2 = 10 mm, and L3 = 11 mm. The carbon-based conductive film is a commercially available product made from carbon black and carbon nanotubes, with a resistivity of 2.3 Ω·cm, a conductivity of 0.5 S / cm, and a sheet resistance of 230 Ω / sq.

[0074] The third carbon-based conductive film structure array layer is composed of four periodically arranged square carbon-based conductive film patches. The structure is shown in Figure 5 and is composed of a 4×4 unit structure array. The side length of the array unit structure is P (referring to the outer frame size of the third carbon-based conductive film structure array layer) = 50 mm, L4 = 14 mm; the carbon-based conductive film is a commercial carbon-based conductive film prepared from carbon black and carbon nanotubes, with a resistivity of 2.3Ω·cm, a conductivity of 0.5S / cm, and a square resistance of 230Ω / sq.

[0075] The manufacturing process is the same as that of Example 1, except for the different materials and structural parameters.

[0076] As shown in Figure 7, the minimum RL of the ultra-light, wide-angle absorbing metamaterial obtained in Example 3, which is based on a cheap and readily available carbon-based conductive film and has full-band absorption of 2-18 GHz and is easy to manufacture, appears at 15.98 GHz, resulting in a strong absorption of -45.63 dB; the effective absorption bandwidth (RL ≤ -10 dB) in the ultra-wide frequency band of 2-18 GHz is 18 GHz.

[0077] As shown in Figure 8, the normalized absorption rate of the metamaterial in the ultra-wide frequency band of 2-18 GHz is above 90% (RL≤-10dB), and the normalized absorption rate at 2.98 GHz and 15.98 GHz is close to 100%, achieving efficient absorption.

[0078] Example 4

[0079] An ultra-light, wide-angle absorbing metamaterial based on inexpensive and readily available carbon-based conductive film that absorbs the entire frequency range of 2-18 GHz and is easy to manufacture. The specific structure is shown in Figure 1, comprising a first dielectric substrate, a first carbon-based conductive film structure array layer, a second dielectric substrate, a second carbon-based conductive film structure array layer, a third dielectric substrate, and a third carbon-based conductive film structure array layer, which are stacked in sequence from bottom to top (the top is the incident direction of the electromagnetic wave).

[0080] The first dielectric substrate is a polystyrene foam board with a relative dielectric constant of 1, a loss tangent of 0.018, and a density of 21 kg / m 3 ;Thickness H1 is 7mm.

[0081] The second dielectric substrate is a polystyrene foam board with a relative dielectric constant of 1, a loss tangent of 0.018, and a density of 21 kg / m 3 ;Thickness H2 is 11mm.

[0082] The third dielectric substrate is a polystyrene foam board with a relative dielectric constant of 1, a loss tangent of 0.018, and a density of 21 kg / m 3 ;Thickness H3 is 6mm.

[0083] The first carbon-based conductive film array layer consists of periodically arranged square carbon-based conductive film patches. The structure, as shown in Figure 3, is composed of a 4×4 unit structure array. The unit structure side lengths are P (referring to the outer frame dimensions of the first carbon-based conductive film array layer) = 50 mm, and L1 = 49 mm. The carbon-based conductive film is a commercially available product made from carbon black and carbon nanotubes, with a resistivity of 1.5 Ω·cm, a conductivity of 1.0 S / cm, and a sheet resistance of 220 Ω / sq.

[0084] The second carbon-based conductive film structure array layer is composed of a periodic arrangement of square-ring carbon-based conductive film patches, as shown in Figure 4. This arrangement consists of a 4×4 unit structure array, with a side length of P (referring to the outer frame dimension of the second carbon-based conductive film structure array layer) = 50 mm, L2 = 13 mm, and L3 = 13 mm. The carbon-based conductive film is a commercially available product made from carbon black and carbon nanotubes, with a resistivity of 3.0 Ω·cm, a conductivity of 1.0 S / cm, and a sheet resistance of 260 Ω / sq.

[0085] The third carbon-based conductive film structure array layer is composed of four periodically arranged square carbon-based conductive film patches. The structure is shown in Figure 5 and is composed of a 4×4 unit structure array. The side length of the array unit structure is P (referring to the outer frame size of the third carbon-based conductive film structure array layer) = 50 mm, L4 = 17 mm; the carbon-based conductive film is a commercial carbon-based conductive film prepared from carbon black and carbon nanotubes, with a resistivity of 3.0 Ω·cm, a conductivity of 1.0 S / cm, and a square resistance of 260 Ω / sq.

[0086] The manufacturing process is the same as that of Example 1, except for the different materials and structural parameters.

[0087] As shown in Figure 7, the minimum RL of the ultra-light, wide-angle absorbing metamaterial prepared in Example 4, which has full-band absorption of 2-18 GHz and is easy to manufacture based on a cheap and readily available carbon-based conductive film, occurs at 3.01 GHz, resulting in strong absorption of -55.38 dB; the effective absorption bandwidth (RL ≤ -10 dB) in the ultra-wide frequency band of 2-18 GHz is 18 GHz.

[0088] As shown in Figure 8, the normalized absorption rate of the metamaterial in the ultra-wide frequency band of 2-18 GHz is above 90% (RL≤-10dB), and the normalized absorption rate at 3.01 GHz and 14.83 GHz is close to 100%, achieving efficient absorption.

[0089] It should be understood that the above structural dimensions are only one embodiment and are provided for illustrative purposes. The specific dimensional changes are determined according to actual conditions and are not limited in the present invention.

[0090] The above-described embodiments are only preferred specific implementation methods of the present invention, and the protection scope of the present invention is not limited thereto. Any simple changes or equivalent replacements of the technical solutions that can be obviously obtained by any technician familiar with the field within the technical scope disclosed in the present invention fall within the protection scope of the present invention.

Claims

1. An ultra-light wide-angle wave-absorbing metamaterial based on a carbon-based conductive film that is inexpensive and easily available, with full-frequency absorption in the range of 2 - 18 GHz and is easy to manufacture, characterized in that, It includes a first dielectric substrate, a first carbon-based conductive thin film structure array layer, a second dielectric substrate, a second carbon-based conductive thin film structure array layer, a third dielectric substrate, and a third carbon-based conductive thin film structure array layer that are stacked in sequence from bottom to top; The first carbon-based conductive thin film structure array layer, the second carbon-based conductive thin film structure array layer, and the third carbon-based conductive thin film structure array layer are all formed by periodically arranging discrete carbon-based conductive thin film patches; The resistivity of the carbon-based conductive thin film constituting the first carbon-based conductive thin film structure array layer is 1 - 3 Ω·cm, the conductivity is 0.6 - 1 S / cm, and the sheet resistance is 200 - 220 Ω / sq; the resistivity of the carbon-based conductive thin film constituting the second carbon-based conductive thin film structure array layer and the third carbon-based conductive thin film structure array layer is 1 - 3 Ω·cm, the conductivity is 0.4 - 1 S / cm, and the sheet resistance is 220 - 260 Ω / sq; The first carbon-based conductive thin film structure array layer, the second carbon-based conductive thin film structure array layer, and the third carbon-based conductive thin film structure array layer are all arranged in an array of m×n unit structures, and the side length P of each unit structure is 50 mm, where m≥4 and is an even integer, and n≥4 and is an even integer; The unit structure of the first carbon-based conductive thin film structure array layer is a square patch; the unit structure of the second carbon-based conductive thin film structure array layer is a square ring patch; the unit structure of the third carbon-based conductive thin film structure array layer is a combined pattern composed of four square patches.

2. The ultra-light wide-angle wave-absorbing metamaterial based on a carbon-based conductive film that is inexpensive and easily available and has full-frequency absorption in the range of 2-18 GHz and is easy to manufacture, as described in claim 1, is characterized in that The first dielectric substrate, the second dielectric substrate, and the third dielectric substrate are all polystyrene foam boards; the relative dielectric constant of the polystyrene foam board is 1 - 1.1, the loss tangent value is 0.018, and the density is 19 - 21 kg / m 3 .

3. A super-light wide-angle wave-absorbing metamaterial based on a carbon-based conductive film that is inexpensive and readily available, with full-frequency absorption in the 2-18 GHz band and easy to manufacture, characterized in that, The thickness H1 of the first dielectric substrate is 5 - 7 mm; the thickness H2 of the second dielectric substrate is 9 - 11 mm; the thickness H3 of the third dielectric substrate is 4 - 6 mm.

4. A super-light wide-angle wave-absorbing metamaterial based on a carbon-based conductive film that is inexpensive and readily available and has 2-18 GHz full-frequency absorption and is easy to manufacture, characterized in that The side length L1 of the square patch of the unit structure of the first carbon-based conductive thin film structure array layer is 45 - 49 mm; the inner ring width L2 of the square ring patch of the unit structure of the second carbon-based conductive thin film structure array layer is 10 - 13 mm, and the outer ring width L3 is 11 - 13 mm; the side length L4 of the four square patches of the unit structure of the third carbon-based conductive thin film structure array layer is 14 - 17 mm.

5. A super-light wide-angle wave-absorbing metamaterial based on a carbon-based conductive film that is inexpensive and readily available, with full-frequency absorption in the 2 - 18 GHz band and is easy to manufacture, characterized in that, The unit structures of the first carbon-based conductive thin film structure array layer, the second carbon-based conductive thin film structure array layer, and the third carbon-based conductive thin film structure array layer are all centrosymmetric figures.

6. A manufacturing method of an ultra-light wide-angle wave-absorbing metamaterial based on a carbon-based conductive film that is inexpensive and easily available and has full-frequency absorption in the range of 2-18 GHz and is easy to manufacture, characterized in that, It includes the following steps: (1) According to the designed length * width * thickness of the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate, use a heated foam cutter to cut a polystyrene foam board product into the designed size, then the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate are obtained; (2) Draw the shapes of the unit structures of the first carbon-based conductive thin film structure array layer, the second carbon-based conductive thin film structure array layer, and the third carbon-based conductive thin film structure array layer designed on the computer, then print and use the printed hard sheet as a template to cut the purchased carbon-based conductive thin film product into the designed unit structure shapes, then the unit structures of the first carbon-based conductive thin film structure array layer, the unit structures of the second carbon-based conductive thin film structure array layer, and the unit structures of the third carbon-based conductive thin film structure array layer are respectively obtained; (3) Use a computer to draw the positions of each unit structure in the third carbon-based conductive thin film structure array layer on the third dielectric substrate obtained in step (1), and then paste the structural units of the third carbon-based conductive thin film obtained in step (2) onto the surface of the third dielectric substrate according to the printed pattern; after pasting, paste the second dielectric substrate with the pattern of each unit structure in the second carbon-based conductive thin film structure array layer printed by the computer on it with glue, and then paste the structural units of the second carbon-based conductive thin film obtained in step (2) onto the surface of the second dielectric substrate according to the printed pattern with glue on it; After pasting, paste the first dielectric substrate with the pattern of each unit structure in the first carbon-based conductive thin film structure array layer printed by the computer on it with glue, and then paste the structural units of the first carbon-based conductive thin film obtained in step (2) onto the surface of the first dielectric substrate according to the printed pattern with glue on it; After pasting, a super-light wide-angle absorbing metamaterial based on a carbon-based conductive film with 2-18 GHz full-frequency absorption that is inexpensive and easy to obtain and is easy to manufacture is obtained.

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