A wave-absorbing / traveling wave suppression structure and its fabrication method

Abstract

This invention relates to a microwave absorbing / traveling wave suppression structure and its preparation method, belonging to the field of microwave absorbing materials technology. The method includes: compounding a first slurry containing flake-shaped carbonyl iron powder and epoxy resin, and a second slurry containing spherical carbonyl iron powder and epoxy resin, respectively, with fiber cloth, followed by drying to obtain a first adhesive film and a second adhesive film; coating a nano-silver slurry containing nano-silver powder and epoxy resin onto the surface of a base film, followed by drying and etching to obtain a nano-silver metamaterial film; the nano-silver metamaterial film includes multiple periodically arranged hexagonal ring units; layering the first adhesive film, the nano-silver metamaterial film, and the second adhesive film, followed by curing to obtain a microwave absorbing / traveling wave suppression structure; the microwave absorbing / traveling wave suppression structure includes a first adhesive film layer, a second adhesive film layer, and a nano-silver metamaterial film located between them. The microwave absorbing / traveling wave suppression structure prepared by this method has high strength, light weight, and broadband microwave absorption and traveling wave suppression functions.

Description

Technical Field

[0001] This invention relates to the field of microwave absorbing materials technology, and in particular to a microwave absorbing / traveling wave suppression structure and its preparation method. Background Technology

[0002] With the development of microwave technology, systems are placing increasingly higher demands on the weight, structural strength, and broadband absorption / traveling wave suppression performance of microwave absorbing materials. However, traditional absorbing materials suffer from drawbacks such as high weight, low structural strength, narrow absorption bandwidth, and insufficient traveling wave suppression capability, making them unable to meet the requirements of integrated broadband absorbing structures for typical components. Summary of the Invention

[0003] To address one or more technical problems existing in the prior art, this invention provides a microwave absorbing / traveling wave suppression structure and its preparation method. The microwave absorbing / traveling wave suppression structure prepared by this method has high strength, light weight, and broadband microwave absorption and traveling wave suppression functions. It can achieve microwave absorption and traveling wave suppression in the 2-18GHz band and can be used in airfoil structures, air intakes, low-scattering carriers, etc., with broad application prospects.

[0004] In a first aspect, this invention provides a method for fabricating a wave-absorbing / traveling-wave suppression structure, comprising: Preparation of adhesive film: A first slurry containing flake carbonyl iron powder and epoxy resin and a second slurry containing spherical carbonyl iron powder and epoxy resin are respectively compounded with fiber cloth and dried to obtain a first adhesive film and a second adhesive film. Preparation of nano-silver metamaterial thin film: A nano-silver paste containing nano-silver powder and epoxy resin is coated on the surface of a base film, and then dried and etched to obtain a nano-silver metamaterial thin film; the nano-silver metamaterial thin film includes multiple periodically arranged hexagonal ring units; Composite molding: A first adhesive film, a nano-silver metamaterial film, and a second adhesive film are laid up and cured to obtain a wave-absorbing / traveling wave suppression structure; the wave-absorbing / traveling wave suppression structure includes a first adhesive film layer, a second adhesive film layer, and a nano-silver metamaterial film located between the two.

[0005] Preferably, based on the total mass of flake carbonyl iron powder and epoxy resin, the flake carbonyl iron powder accounts for 70-90 wt%, and the epoxy resin accounts for 10-30 wt%; and / or, The viscosity of the first slurry is 10~30s.

[0006] Preferably, based on the total mass of spherical carbonyl iron powder and epoxy resin, the spherical carbonyl iron powder accounts for 70-90 wt%, and the epoxy resin accounts for 10-30 wt%; and / or, The viscosity of the second slurry is 10~30s.

[0007] Preferably, based on the total mass of the nano-silver powder and epoxy resin, the nano-silver powder accounts for 60-80 wt%, and the epoxy resin accounts for 20-40 wt%; and / or, The viscosity of the nano-silver paste is 10~30s.

[0008] Preferably, the drying temperature is 60~80℃; and / or, The drying temperature is 120~140℃.

[0009] Preferably, the thickness of the first adhesive film is 0.23~0.5mm; The thickness of the second adhesive film is 0.23~0.5mm; and / or, The thickness of the nano-silver metamaterial film is 0.05~0.1mm.

[0010] Preferably, the thickness of the first adhesive film layer is 0.3~0.7 mm; and / or, The thickness of the second adhesive film is 0.7~1.1mm.

[0011] Preferably, the inner side length of the hexagonal annular unit is 1.70~2.70mm; The outer side length of the hexagonal annular unit is 1.75~2.75mm; and / or, The hexagonal annular units have an arrangement period of 4.50~5.50 mm.

[0012] Preferably, the curing process includes: placing the laid-up material under vacuum conditions, first holding it at 50~60℃ for 40~60 min, then holding it at 80~90℃ for 20~30 min, then holding it at 110~120℃ for 100~150 min, and finally cooling it to below 40~60℃ to obtain a wave-absorbing / traveling wave suppression structure.

[0013] In a second aspect, the present invention provides a wave-absorbing / traveling wave suppression structure, which is prepared using the method described in the first aspect.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects: This invention involves mixing flake-shaped carbonyl iron powder as a low-frequency absorber with epoxy resin to form a first slurry, and mixing spherical carbonyl iron powder as a high-frequency absorber with epoxy resin to form a second slurry, which are then composited with quartz fiber cloth to form a first film with low-frequency absorption properties and a second film with high-frequency absorption properties. Nano-silver powder is then used as a filler and composited with epoxy resin to form a nano-silver metamaterial film with a specific structure. The first film, the nano-silver metamaterial film, and the second film are then layered and cured to obtain an absorption / traveling wave suppression structure. The absorption / traveling wave suppression structure obtained by this method has high strength, light weight, and broadband absorption and traveling wave suppression functions, achieving absorption and traveling wave suppression in the 4-18 GHz band. This effectively solves the problems of previous absorption materials, such as large weight, poor traveling wave suppression performance, narrow absorption bandwidth, and low structural strength. It can be used in airfoil structures, air intakes, low-scattering carriers, etc., and has broad application prospects. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the hexagonal ring unit in a wave-absorbing / traveling wave suppression structure provided by the present invention; Figure 2 This is a schematic diagram of a wave-absorbing / traveling wave suppression structure provided by the present invention; Figure 3 This is a comparison of the RCS of the wave-absorbing / traveling wave suppression structure in Example 1 with that of the metal traveling wave plate; Figure 4 This is the reflectivity curve of the absorbing / traveling wave suppression structure in Example 1; Figure 5 This is a comparison of the RCS of the wave-absorbing / traveling wave suppression structure in Example 2 with that of the metal traveling wave plate; Figure 6 This is the reflectivity curve of the absorbing / traveling wave suppression structure in Example 2; Figure 7 The comparison shows the RCS of the wave-absorbing / traveling wave suppression structure in Comparative Example 1 and the metal traveling wave plate. Figure 8 The reflectivity curve of the absorbing / traveling wave suppression structure in Comparative Example 1 is shown. Figure 9 The comparison shows the RCS of the absorbing / traveling wave suppression structure in Comparative Example 2 and the metal traveling wave plate. Figure 10This is the reflectivity curve of the wave-absorbing / traveling wave suppression structure in Comparative Example 2.

[0017] Figure reference numerals: 11-first adhesive film layer; 12-nano silver metamaterial thin film; 121-hexagonal ring unit; 13-second adhesive film layer. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0019] In a first aspect, this invention provides a method for fabricating a wave-absorbing / traveling-wave suppression structure, comprising: Preparation of adhesive film: A first slurry containing flake carbonyl iron powder and epoxy resin and a second slurry containing spherical carbonyl iron powder and epoxy resin are respectively compounded with fiber cloth and dried to obtain a first adhesive film and a second adhesive film. Preparation of nano-silver metamaterial thin films: A nano-silver paste containing nano-silver powder and epoxy resin is coated onto the surface of a base film, followed by drying and etching to obtain the nano-silver metamaterial thin film; for example... Figure 1 As shown, the nanosilver metamaterial film 12 includes multiple periodically arranged hexagonal ring units 121; Composite molding: A first adhesive film, a nano-silver metamaterial film, and a second adhesive film are layered and cured to obtain a wave-absorbing / traveling-wave-suppressing structure; such as Figure 2 As shown, the wave-absorbing / traveling wave suppression structure includes a first film layer 11, a second film layer 13, and a nano-silver metamaterial thin film 12 located between the two.

[0020] This invention involves mixing flake-shaped carbonyl iron powder as a low-frequency absorber with epoxy resin to form a first slurry, and mixing spherical carbonyl iron powder as a high-frequency absorber with epoxy resin to form a second slurry, which are then composited with quartz fiber cloth to form a first film with low-frequency absorption properties and a second film with high-frequency absorption properties. Nano-silver powder is then used as a filler and composited with epoxy resin to form a nano-silver metamaterial film with a specific structure. The first film, the nano-silver metamaterial film, and the second film are then layered and cured to obtain an absorption / traveling wave suppression structure. The absorption / traveling wave suppression structure obtained by this method has high strength, light weight, and broadband absorption and traveling wave suppression functions, achieving absorption and traveling wave suppression in the 4-18 GHz band. This effectively solves the problems of previous absorption materials, such as large weight, poor traveling wave suppression performance, narrow absorption bandwidth, and low structural strength. It can be used in airfoil structures, air intakes, low-scattering carriers, etc., and has broad application prospects.

[0021] In some specific embodiments, the preparation of the first slurry includes: mixing flake carbonyl iron powder with an epoxy resin solution, then adding an anti-settling agent and a solvent, dispersing, grinding, and adjusting the viscosity to obtain the first slurry; wherein the solid content of the epoxy resin solution is 50-53%; dispersion is achieved using a high-speed disperser at a speed of 800-1400 r / min for a dispersion time of 5-15 min; during grinding, the spacing between the grinders is 0.1-1 mm, the grinding speed is 400-800 r / min, and the grinding time is 30-90 min; the viscosity of the first slurry is 10-30 s. The preparation method of the second slurry is basically the same as that of the first slurry, except that the flake carbonyl iron powder is replaced with spherical carbonyl iron powder.

[0022] In some specific embodiments, the preparation of the first adhesive film includes: firstly, using a laminating machine to laminate a fiber cloth prepreg with a thickness of 0.03~0.2mm to release paper; then, using a laminating machine to coat a first slurry onto the quartz fiber cloth prepreg laminated with release paper, controlling the gap between the machine and the quartz fiber cloth prepreg to be 0.2~0.3mm, the machine angle to be 30~60°, and the machine speed to be 1~5m / min, and holding the film in an environment of 60~80℃ for 10~20min to form a first adhesive film with a thickness of 0.23~0.5mm. The preparation method of the second adhesive film is basically the same as that of the first adhesive film, except that the first slurry is replaced with a second slurry. To better laminate the slurry and fiber cloth, the fiber cloth is first laminated with resin to form a fiber cloth prepreg. The resin in the fiber cloth prepreg is preferably the resin in the slurry, which is beneficial for obtaining an adhesive film with high structural strength. The type of fiber cloth in this invention is not specifically limited; in some specific embodiments, the fiber cloth is preferably quartz fiber cloth.

[0023] In some specific embodiments, the preparation of a nano-silver metamaterial thin film includes: mixing nano-silver powder, solvent, and dispersant, adding epoxy resin and mixing again, and then ball milling to form a nano-silver slurry; wherein, mixing is achieved using a dual planetary mixer for 10-30 min; and ball milling is achieved using a ball mill for 10-20 min. The nano-silver slurry is uniformly coated onto a base film (e.g., a polyimide film) with a thickness of 50-100 μm, and then baked in an oven at 120-140 °C for 5-20 min to obtain a nano-silver conductive thin film with a thickness of 100-150 μm. The nano-silver conductive thin film is placed on a laser etching stage for vacuum adsorption, and the designed metamaterial structure model (including multiple periodically arranged hexagonal ring units) is imported, and etched for 10 cycles to obtain the nano-silver metamaterial thin film. The hexagonal ring units and their periodic arrangement are as follows: Figure 1As shown, the white area represents the area where the silver nanofilm is retained, and the black area represents the area where the silver nanofilm is etched. The dimensions are a=2.20mm, b=2.25mm, and c=5.00mm.

[0024] According to some preferred embodiments, the flake carbonyl iron powder accounts for 70-90 wt% and the epoxy resin accounts for 10-30 wt% based on the total mass of the flake carbonyl iron powder and epoxy resin.

[0025] According to some preferred embodiments, the viscosity of the first slurry is 10~30s.

[0026] According to some preferred embodiments, the spherical carbonyl iron powder accounts for 70-90 wt% and the epoxy resin accounts for 10-30 wt% of the total mass of the spherical carbonyl iron powder and epoxy resin.

[0027] According to some preferred embodiments, the viscosity of the second slurry is 10~30s.

[0028] According to some preferred embodiments, the total mass of the nano-silver powder and epoxy resin is 60-80 wt% and 20-40 wt% respectively.

[0029] It should be noted that the aforementioned percentage of epoxy resin mass refers to the percentage of epoxy resin in the total mass of flake carbonyl iron powder and epoxy resin, the total mass of spherical carbonyl iron powder and epoxy resin, and the total mass of nano silver powder and epoxy resin in the epoxy resin solution. Taking 850g of flake carbonyl iron powder and 300g of epoxy resin solution with a solid content of 50% (epoxy resin mass is 150g) as an example, based on the total mass of flake carbonyl iron powder and epoxy resin, the flake carbonyl iron powder accounts for 85wt%, and the epoxy resin accounts for 15wt%.

[0030] According to some preferred embodiments, the viscosity of the nano-silver paste is 10~30s.

[0031] According to some preferred embodiments, the drying temperature is 60~80°C.

[0032] According to some preferred embodiments, the drying temperature is 120~140°C.

[0033] According to some preferred embodiments, the thickness of the first adhesive film is 0.23~0.5mm.

[0034] According to some preferred embodiments, the thickness of the second adhesive film is 0.23~0.5mm.

[0035] According to some preferred embodiments, the thickness of the nanosilver metamaterial film is 0.05~0.1 mm.

[0036] According to some preferred embodiments, the thickness of the first film layer is 0.3~0.7 mm.

[0037] According to some preferred embodiments, the thickness of the second film layer is 0.7~1.1 mm.

[0038] By controlling the layup thickness of the first and second adhesive films within the above-mentioned range while keeping other conditions unchanged, this invention ensures the production of a wave-absorbing / traveling-wave-suppressing structure with high structural strength, light weight, and broadband wave absorption and traveling-wave suppression functions.

[0039] According to some preferred embodiments, the inner side length 'a' of the hexagonal annular unit is 1.70~2.70 mm; The outer side length b of the hexagonal annular unit is 1.75~2.75mm; and / or, The arrangement period c of the hexagonal ring unit is 4.50~5.50mm.

[0040] By controlling the size and arrangement period of the hexagonal ring units within the aforementioned range while keeping other conditions unchanged, this invention ensures the fabrication of a wave-absorbing / traveling-wave-suppressing structure with high structural strength, light weight, and broadband wave absorption and traveling-wave suppression functions. If the size and arrangement period of the hexagonal ring units are too large or too small, it will negatively impact the wave absorption and traveling-wave suppression functions.

[0041] According to some preferred embodiments, the curing process includes: placing the laid-up material under vacuum conditions, first holding it at 50~60℃ for 40~60 min, then holding it at 80~90℃ for 20~30 min, then holding it at 110~120℃ for 100~150 min, and finally cooling it to below 40~60℃ to obtain a wave-absorbing / traveling wave suppression structure.

[0042] In some specific implementation methods, according to such Figure 2 As shown, a first adhesive film, a nano-silver metamaterial film, and a second adhesive film are laid in layers to a thickness of 1-1.8 mm. The thickness of the first adhesive film is 0.3-0.7 mm, and the thickness of the second adhesive film is 0.7-1.1 mm. After the layers are laid, the film is placed in an autoclave and vacuumed. It is then heated at 50-60°C for 40-60 min, 80-90°C for 20-30 min, and 110-120°C for 100-150 min. After cooling to below 40-60°C, the film is demolded to form a wave-absorbing / traveling wave suppression structure.

[0043] In a second aspect, the present invention provides a wave-absorbing / traveling wave suppression structure, which is prepared using the method described in the first aspect.

[0044] To more clearly illustrate the technical solution and advantages of the present invention, the present invention will be further described below with reference to the embodiments. However, the scope of protection of the present invention is not limited to the following embodiments. The present invention does not specifically limit the source of the reagents used in the following embodiments and comparative examples, which can be directly purchased or synthesized by the individual.

[0045] Example 1 A method for fabricating a wave-absorbing / traveling wave suppression structure, comprising: Preparation of the first film: First, put 850g of flake carbonyl iron powder into a beaker or stirring tank, then add 300g of epoxy resin solution with a solid content of 50%, 0.1g of 118 anti-settling agent and 400g of acetone solvent, and disperse using a high-speed disperser at a dispersion speed of 800r / min for 8min to form a dispersion solution with a mass concentration of 85%. The dispersion solution was placed in a three-roll mill, the mill spacing was adjusted to 0.1 mm, the milling speed was 500 r / min, and the milling time was 60 min. During the milling process, acetone solvent was added to adjust the viscosity of the dispersion to 15 s to obtain the first slurry. A laminating machine was used to laminate a 0.05 mm thick quartz fiber cloth prepreg with release paper. Then, the first slurry was laminated onto the quartz fiber cloth prepreg with release paper using a laminating machine. The gap between the machine and the quartz fiber cloth prepreg was set to 0.2 mm, the machine angle was set to 45°, and the machine speed was set to 5 m / min. The mixture was kept in an 80°C environment for 15 min to form a first film with a thickness of 0.25 mm.

[0046] Preparation of the second film: First, put 820g of spherical carbonyl iron powder into a beaker or stirring tank, then add 340g of epoxy resin solution with a solid content of 53%, 0.1g of 118 anti-settling agent and 400g of acetone solvent, and disperse using a high-speed disperser at a dispersion speed of 800r / min for 8min to form a dispersion solution with a mass concentration of 82%. The dispersion solution was placed in a three-roll mill, the mill spacing was adjusted to 0.1 mm, the milling speed was 500 r / min, and the milling time was 60 min. During the milling process, acetone solvent was added to adjust the viscosity of the dispersion to 15 s to obtain a second slurry. A 0.05 mm thick quartz fiber cloth prepreg was laminated with release paper using a laminating machine. Then, the second slurry was laminated onto the quartz fiber cloth prepreg with release paper using a laminating machine. The gap between the machine and the quartz fiber cloth prepreg was set to 0.225 mm, the machine angle was set to 45°, and the machine speed was set to 5 m / min. The mixture was kept in an 80°C environment for 15 min to form a second film with a thickness of 0.275 mm.

[0047] Preparation of nano-silver metamaterial thin films: 700g of nano-silver powder was placed in a beaker, along with 400g of ethyl acetate and 0.4g of dispersant. The mixture was stirred in a double planetary mixer for 30 min. 600g of epoxy resin solution with a solid content of 50% was added to the uniformly stirred nano-silver powder dispersion. The mixture was stirred in a double planetary mixer for 30 min, then ball-milled for 20 min until the slurry was uniformly dispersed, forming a nano-silver slurry. 1000g of the nano-silver slurry was weighed and uniformly coated onto a 50μm thick polyimide film using a doctor blade. The film was then baked in a 120℃ oven for 10 min to obtain a 100μm thick nano-silver conductive film. The nano-silver conductive film was placed on the stage of a laser etching instrument for vacuum adsorption. The designed metamaterial structure model (including multiple periodically arranged hexagonal ring units) was imported, and etched for 10 cycles to obtain the nano-silver metamaterial thin film. The hexagonal ring units and their periodic arrangement are shown below. Figure 1 As shown, the white area represents the area where the silver nanofilm is retained, and the black area represents the area where the silver nanofilm is etched. The dimensions are a=2.20mm, b=2.25mm, and c=5.00mm.

[0048] Fabrication of wave-absorbing / traveling-wave suppression structure: The first adhesive film, the second adhesive film, and the nano-silver metamaterial thin film are prepared according to... Figure 2 The layering sequence shown is applied sequentially to the mold up to 1.7 mm thick. The first adhesive film has a thickness of 0.5 mm, forming the first adhesive film layer; the second adhesive film has a thickness of 1.1 mm, forming the second adhesive film layer. Then, the mold is placed in an autoclave and vacuumed. The mold is then processed according to the following procedure: first, it is heated at 60°C for 60 min, then at 85°C for 30 min, then at 115°C for 100 min, and finally cooled to below 40°C to demold, forming a wave-absorbing / traveling wave suppression structure.

[0049] Depend on Figure 3 and Figure 4 It can be seen that the absorbing / traveling wave suppression structure prepared in this embodiment has a reflectivity of no more than -6dB in the 4-18GHz frequency band and a traveling wave attenuation rate of no less than 25dB / m. It has the excellent characteristics of thin thickness, strong traveling wave suppression capability and wide absorbing bandwidth, and can be used for absorbing and suppressing traveling waves in structural components such as low scattering carriers.

[0050] Example 2 A method for fabricating a wave-absorbing / traveling wave suppression structure, comprising: Preparation of the first film: First, put 820g of flake carbonyl iron powder into a beaker or stirring tank, then add 340g of epoxy resin solution with a solid content of 53%, 0.1g of 118 anti-settling agent and 400g of acetone solvent, and disperse using a high-speed disperser at a dispersion speed of 800r / min for 8min to form a dispersion solution with a mass concentration of 82%. The dispersion solution was placed in a three-roll mill, the mill spacing was adjusted to 0.1 mm, the milling speed was 500 r / min, and the milling time was 60 min. During the milling process, acetone solvent was added to adjust the viscosity of the dispersion to 15 s to obtain the first slurry. A laminating machine was used to laminate a 0.05 mm thick quartz fiber cloth prepreg with release paper. Then, the first slurry was laminated onto the quartz fiber cloth prepreg with release paper using a laminating machine. The gap between the machine and the quartz fiber cloth prepreg was set to 0.2 mm, the machine angle was set to 45°, and the machine speed was set to 5 m / min. The mixture was kept in an 80°C environment for 15 min to form a first film with a thickness of 0.25 mm.

[0051] Preparation of the second film: First, put 850g of spherical carbonyl iron powder into a beaker or stirring tank, then add 300g of epoxy resin solution with a solid content of 50%, 0.1g of 118 anti-settling agent and 400g of acetone solvent, and disperse using a high-speed disperser at a dispersion speed of 800r / min for 8min to form a dispersion solution with a mass concentration of 85%. The dispersion solution was placed in a three-roll mill, the mill spacing was adjusted to 0.1 mm, the milling speed was 500 r / min, and the milling time was 60 min. During the milling process, an appropriate amount of acetone solvent could be added to adjust the viscosity of the dispersion to 15 s to obtain the second slurry. A 0.05 mm thick quartz fiber cloth prepreg was laminated with release paper using a laminating machine. Then, the second slurry was laminated onto the quartz fiber cloth prepreg with release paper using another laminating machine. The gap between the machine and the quartz fiber cloth prepreg was set to 0.225 mm, the machine angle was set to 45°, and the machine speed was set to 5 m / min. The mixture was kept in an 80°C environment for 15 min to form a second film with a thickness of 0.275 mm.

[0052] Preparation of nano-silver metamaterial thin films: 700g of nano-silver powder was placed in a beaker, along with 400g of ethyl acetate and 0.4g of dispersant. The mixture was stirred in a double planetary mixer for 30 min. 600g of epoxy resin solution with a solid content of 50% was added to the uniformly stirred nano-silver powder dispersion. The mixture was stirred in a double planetary mixer for 30 min, then ball-milled for 20 min until the slurry was uniformly dispersed, forming a nano-silver slurry. 1000g of the nano-silver slurry was weighed and uniformly coated onto a 50μm thick polyimide film using a doctor blade. The film was then baked in a 120℃ oven for 10 min to obtain a 100μm thick nano-silver conductive film. The nano-silver conductive film was placed on a laser etching stage for vacuum adsorption. The designed metamaterial structure model (including multiple periodically arranged hexagonal ring units) was imported, and etched for 10 cycles to obtain the nano-silver metamaterial thin film. The hexagonal ring units and their periodic arrangement are shown below. Figure 1 As shown, the white area represents the area where the silver nanofilm is retained, and the black area represents the area where the silver nanofilm is etched. The dimensions are a=2.20mm, b=2.25mm, and c=5.00mm.

[0053] Fabrication of wave-absorbing / traveling-wave suppression structure: The first adhesive film, the second adhesive film, and the nano-silver metamaterial thin film are prepared according to... Figure 2 The layup sequence shown is applied sequentially on the mold to a thickness of 1.7 mm. The thickness of the first adhesive film is 0.5 mm, forming the first adhesive film layer; the thickness of the nano-silver metamaterial film is 0.1 mm; and the thickness of the second adhesive film is 1.1 mm, forming the second adhesive film layer. The mold is then placed in an autoclave and vacuumed. The mold is then processed according to the following procedure: first, it is heated at 60°C for 60 min, then at 85°C for 30 min, then at 115°C for 100 min, and finally cooled to below 40°C to demold, forming a wave-absorbing / traveling wave suppression structure.

[0054] Depend on Figure 5 and Figure 6 It can be seen that the absorbing / traveling wave suppression structure prepared in this embodiment has a reflectivity of no more than -6dB in the 4-18GHz frequency band and a traveling wave attenuation rate of no less than 25dB / m. It has the excellent characteristics of thin thickness, strong traveling wave suppression capability and wide absorbing bandwidth, and can be used for absorbing and suppressing traveling waves in structural components such as low scattering carriers.

[0055] Comparative Example 1 The process is essentially the same as in Example 1, except that the thicknesses of the first and second films are 0.15 mm and 0.275 mm, respectively. Preparation of the wave-absorbing / traveling-wave suppression structure: The first film, the second film, and the nano-silver metamaterial film are prepared according to... Figure 2The layup sequence shown is applied sequentially on the mold to a thickness of 1.35 mm. The thickness of the first adhesive film is 0.15 mm, forming the first adhesive film layer; the thickness of the nano-silver metamaterial film is 0.1 mm; and the thickness of the second adhesive film is 1.1 mm, forming the second adhesive film layer.

[0056] Depend on Figure 7 and Figure 8 It can be seen that the absorption / traveling wave suppression structure prepared in this comparative example has deteriorated absorption performance and traveling wave attenuation performance in the 4-18GHz frequency band. The bandwidth with reflectivity less than -6dB is only 11GHz, and the bandwidth with attenuation rate greater than 25dB / m is only 11GHz.

[0057] Comparative Example 2 It is basically the same as Example 1, except that in the nano-silver metamaterial film, a=1.20mm, b=1.25mm, and c=1.00mm.

[0058] Depend on Figure 9 and Figure 10 It can be seen that the absorption / traveling wave suppression structure prepared in this comparative example has deteriorated absorption performance and traveling wave attenuation performance in the 4-18GHz frequency band. The bandwidth with reflectivity less than -6dB is only 13GHz, and the bandwidth with attenuation rate greater than 25dB / m is only 13GHz.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for fabricating a wave-absorbing / traveling wave suppression structure, characterized in that, include: Preparation of adhesive film: A first slurry containing flake carbonyl iron powder and epoxy resin and a second slurry containing spherical carbonyl iron powder and epoxy resin are respectively compounded with fiber cloth and dried to obtain a first adhesive film and a second adhesive film. Preparation of nano-silver metamaterial thin film: A nano-silver paste containing nano-silver powder and epoxy resin is coated on the surface of a base film, and then dried and etched to obtain a nano-silver metamaterial thin film; the nano-silver metamaterial thin film includes multiple periodically arranged hexagonal ring units; Composite molding: A first adhesive film, a nano-silver metamaterial film, and a second adhesive film are laid up and cured to obtain a wave-absorbing / traveling wave suppression structure; the wave-absorbing / traveling wave suppression structure includes a first adhesive film layer, a second adhesive film layer, and a nano-silver metamaterial film located between the two.

2. The preparation method according to claim 1, characterized in that, Based on the total mass of flake carbonyl iron powder and epoxy resin, the flake carbonyl iron powder accounts for 70-90 wt%, and the epoxy resin accounts for 10-30 wt%; and / or, The viscosity of the first slurry is 10~30s.

3. The preparation method according to claim 1, characterized in that, Based on the total mass of spherical carbonyl iron powder and epoxy resin, the spherical carbonyl iron powder accounts for 70-90 wt%, and the epoxy resin accounts for 10-30 wt%; and / or, The viscosity of the second slurry is 10~30s.

4. The preparation method according to claim 1, characterized in that, Based on the total mass of nano-silver powder and epoxy resin, nano-silver powder accounts for 60-80 wt%, and epoxy resin accounts for 20-40 wt%; and / or, The viscosity of the nano-silver paste is 10~30s.

5. The preparation method according to claim 1, wherein the drying temperature is 60~80℃; and / or, The drying temperature is 120~140℃.

6. The preparation method according to claim 1, characterized in that, The thickness of the first adhesive film is 0.23~0.5mm; The thickness of the second adhesive film is 0.23~0.5mm; and / or, The thickness of the nano-silver metamaterial film is 0.05~0.1mm.

7. The preparation method according to claim 1, characterized in that, The thickness of the first adhesive film is 0.3~0.7 mm; and / or, The thickness of the second adhesive film is 0.7~1.1mm.

8. The preparation method according to claim 1, characterized in that, The inner side length of the hexagonal annular unit is 1.70~2.70mm; The outer side length of the hexagonal annular unit is 1.75~2.75mm; and / or, The hexagonal annular units have an arrangement period of 4.50~5.50 mm.

9. The preparation method according to claim 1, characterized in that, The curing process includes: placing the laid-up material under vacuum conditions, first holding it at 50~60℃ for 40~60 min, then holding it at 80~90℃ for 20~30 min, then holding it at 110~120℃ for 100~150 min, and finally cooling it down to below 40~60℃ to obtain a wave-absorbing / traveling wave suppression structure.

10. A wave-absorbing / traveling-wave suppression structure, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.

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