Wave absorbing unit and wave absorbing structure

Abstract

The invention provides a wave absorbing unit and a wave absorbing structure, and relates to the technical field of electromagnetic wave absorbing materials. The wave absorbing unit comprises a first wave absorbing body and a second wave absorbing body. The first wave absorber is made of a dielectric material. The first wave absorbing body comprises a base and a wave absorbing main body, and the wave absorbing main body is conical or wedge-shaped; the wave absorbing body is arranged on the base, and a cavity is formed in the wave absorbing body. And the second wave absorbing body is made of a magnetic material. The second wave absorbing body is arranged on the side, away from the wave absorbing body, of the base, or the second wave absorbing body is arranged in the cavity. The wave absorbing structure provided by the invention adopts the wave absorbing unit. According to the wave-absorbing unit and the wave-absorbing structure provided by the invention, the problems of large overall weight, high cost and high installation difficulty of a wave-absorbing material caused by increase of manufacturing materials in order to improve the wave-absorbing performance in the prior art can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic wave absorbing materials, and in particular to a wave absorbing unit and a wave absorbing structure. Background Art

[0002] As the operating frequency band of microwave darkrooms expands, the absorbing materials used inside the darkrooms also need to cover a wider frequency band. Conventional microwave darkrooms start working at 300MHz. After the frequency band is widened, the operating frequency band is lowered to 100MHz, or even lower frequency 30MHz. This poses a great challenge to absorbing materials. Generally speaking, the height of absorbing materials is proportional to the bandwidth and absorption efficiency. The lower the operating frequency band, the higher the absorbing performance requirements, and the higher the size of the absorbing materials required. For this reason, the height of absorbing materials covering about 100MHz in the industry is usually close to 2 meters. Going to lower frequency bands, the material height is higher.

[0003] In order to improve the absorption performance of materials at low frequencies, it is difficult to meet the demand by relying on the resistance loss of dielectric materials. Therefore, one solution in the prior art is to increase the relaxation loss of magnetic materials to increase the absorption of electromagnetic waves.

[0004] However, when the absorbing material itself is relatively high in height and weight, adding magnetic material on this basis will result in a greater overall weight and height of the absorbing material, which will increase costs on the one hand and increase installation difficulty on the other. Summary of the invention

[0005] The technical problem solved by the present invention is how to improve the problem in the prior art that the overall weight of the absorbing material is large, the cost is high, and the installation difficulty is high due to the increase in manufacturing materials in order to improve the absorbing performance.

[0006] The embodiments of the present invention can be implemented as follows:

[0007] The present invention provides a wave absorbing unit, comprising:

[0008] The first wave absorbing body is made of a dielectric material; the first wave absorbing body comprises a base and a wave absorbing body, the wave absorbing body is in a cone or wedge shape; the wave absorbing body is arranged on the base, and a cavity is arranged in the wave absorbing body;

[0009] The second wave absorbing body is made of magnetic material; the second wave absorbing body is arranged on a side of the base away from the wave absorbing body, or the second wave absorbing body is arranged inside the cavity.

[0010] The beneficial effects of the wave absorbing unit provided by the present invention compared with the prior art include:

[0011] In the absorbing unit, since the absorbing body of the first absorbing body is designed in a hollow manner, on the one hand, the weight of the entire absorbing unit is reduced, the problem of engineering load-bearing is improved, and the amount and cost of the first absorbing body are reduced; on the other hand, the hollow absorbing body can make the electromagnetic waves incident into the cavity reflect multiple times in the cavity, which is beneficial to the improvement of low-frequency absorption performance to a certain extent. Furthermore, in the case of adding the second absorbing body, since the second absorbing body is made of magnetic material, it has very good loss for low-frequency (about 100MHz and lower) electromagnetic waves, which can further improve the loss of the absorbing unit for low-frequency electromagnetic waves, thereby improving the absorption capacity of low-frequency electromagnetic waves. Based on this, the absorbing unit can improve the problem of the existing technology that the amount of absorbing material is increased in order to improve the absorbing performance, resulting in a large overall weight of the absorbing material, high cost and high installation difficulty.

[0012] In addition, the inventors have found that in the low frequency band, the strongest areas of interaction between electromagnetic waves and absorbing units are distributed in the middle and bottom of the first absorber, and at different frequency points, the specific positions of the strongest areas are different in the above range. Based on this, in order to improve the absorption performance of low-frequency electromagnetic waves, a second absorber is set in the cavity or at the bottom of the base. Furthermore, in practical applications, the setting position and laying area of ​​the second absorber can be adjusted at the bottom of the cavity and the base according to the use frequency band of the electromagnetic waves of focus, so as to improve the absorption performance of electromagnetic waves in the use frequency band.

[0013] Optionally, the cavity is in a cone or wedge shape.

[0014] Optionally, the absorbing unit further includes a third absorbing body, which is made of a magnetic material; and the third absorbing body is arranged inside the cavity.

[0015] Furthermore, by setting up the third absorber in combination with the second absorber, different laying methods can be selected based on actual conditions, thereby further optimizing the performance of specific frequency points of low-frequency electromagnetic waves to facilitate matching the application scenarios of the absorbing unit.

[0016] Optionally, the cavity has a bottom wall and side walls;

[0017] The second absorbing body is arranged on a side of the base away from the absorbing body, and the third absorbing body is arranged on the bottom wall and / or the side wall; or, the second absorbing body is arranged on the bottom wall, and the third absorbing body is arranged on the side wall.

[0018] Optionally, when the second wave absorbing body is arranged on the bottom wall, the second wave absorbing body covers the bottom wall;

[0019] When the third absorbing body is arranged on the side wall, the third absorbing body covers at least a portion of the side wall; when the third absorbing body is arranged on the bottom wall, the third absorbing body covers the bottom wall.

[0020] Optionally, when the second wave absorbing body is arranged on a side of the base away from the wave absorbing body, the second wave absorbing body covers the bottom surface of the base.

[0021] Optionally, the dielectric material uses at least one of the following absorbents: carbon black, carbon fiber, carbon tube, metal fiber or conductive polymer, and the substrate of the dielectric material is a foaming material;

[0022] The magnetic material uses at least one of the following absorbers: ferrite, carbonyl iron, magnetic fiber or silicon carbide.

[0023] Optionally, the base is a prism structure, and the top surface of the base coincides with the bottom surface of the absorbing body.

[0024] Optionally, the second absorber is a flat plate structure.

[0025] A wave absorbing structure comprises the above-mentioned wave absorbing unit.

[0026] The wave absorbing structure provided by the present invention adopts the above-mentioned wave absorbing unit. The beneficial effects of the wave absorbing structure relative to the prior art are the same as the beneficial effects of the above-mentioned wave absorbing unit relative to the prior art, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 This is one of the cross-sectional structural schematic diagrams of the absorbing unit provided in the embodiments of the present application;

[0029] Figure 2 This is a second schematic cross-sectional structural diagram of the wave absorbing unit provided in an embodiment of the present application;

[0030] Figure 3 This is a third schematic cross-sectional structural diagram of the wave absorbing unit provided in an embodiment of the present application;

[0031] Figure 4 This is a fourth schematic cross-sectional structural diagram of the absorbing unit provided in an embodiment of the present application;

[0032] Figure 5One of the electromagnetic parameter curves of two dielectric materials;

[0033] Figure 6 This is the second electromagnetic parameter curve graph of two dielectric materials.

[0034] Icon: 10 - absorbing unit; 100 - first absorbing body; 110 - base; 120 - absorbing body; 121 - cavity; 1211 - bottom wall; 1212 - side wall; 200 - second absorbing body; 300 - third absorbing body. DETAILED DESCRIPTION

[0035] In order to make the purpose, 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 in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0038] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0039] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0040] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0041] See also Figure 1In this embodiment, an absorbing unit 10 is provided, which can be used to make an absorbing structure, and the absorbing structure can be used in application scenarios such as an anechoic chamber to absorb electromagnetic waves. The absorbing unit 10 and the absorbing structure provided in this embodiment can improve the problem of the existing technology that the absorbing material is increased in order to improve the absorbing performance, resulting in a large overall weight, high cost and high installation difficulty of the absorbing material; and the absorbing unit 10 and the absorbing structure can improve the absorption performance of low-frequency electromagnetic waves.

[0042] In this embodiment, please refer to Figure 1 and Figure 2 The absorbing unit 10 includes a first absorbing body 100 and a second absorbing body 200. The first absorbing body 100 is made of a dielectric material; and the first absorbing body 100 includes a base 110 and an absorbing body 120, the absorbing body 120 is conical or wedge-shaped; the absorbing body 120 is disposed on the base 110, and a cavity 121 is disposed in the absorbing body 120. The second absorbing body 200 is made of a magnetic material; the second absorbing body 200 is disposed on a side of the base 110 away from the absorbing body 120, or the second absorbing body 200 is disposed inside the cavity 121.

[0043] In the absorbing unit 10, since the absorbing body 120 of the first absorbing body 100 is designed in a hollow manner, on the one hand, the weight of the entire absorbing unit 10 is reduced, the problem of engineering load-bearing is improved, and the amount and cost of the first absorbing body 100 are reduced; on the other hand, the hollow absorbing body 120 can make the electromagnetic waves incident into the cavity 121 reflect multiple times in the cavity 121, which is beneficial to the improvement of low-frequency absorption performance to a certain extent. Further, in the case of adding the second absorbing body 200, since the second absorbing body 200 is made of magnetic material, it has very good loss for low-frequency electromagnetic waves, which can further improve the loss of low-frequency electromagnetic waves of the absorbing unit 10, thereby improving the absorption capacity of low-frequency electromagnetic waves. Based on this, the absorbing unit 10 can improve the problem of the existing technology that the overall weight of the absorbing material is large, the cost is high, and the installation difficulty is high due to the increase in manufacturing materials in order to improve the absorbing performance.

[0044] In addition, generally, in the low frequency band, the strongest areas of interaction between electromagnetic waves and the absorbing unit 10 are distributed in the middle and bottom of the absorbing body 120, and at different frequency points, the specific positions of the strongest areas are different in the above positions. Based on this, in order to improve the absorption performance of low-frequency electromagnetic waves, a second absorber 200 is set in the cavity 121 or at the bottom of the base 110. Further, in practical applications, the setting position and laying area of ​​the magnetic material at the bottom of the cavity 121 and the base 110 can be adjusted according to the use frequency band of the electromagnetic waves to be focused on, so as to improve the absorption performance of the electromagnetic waves in the use frequency band.

[0045] In this embodiment, the dielectric material refers to an absorbing material with dielectric loss as the main feature, and carbon black, carbon fiber, carbon tube, metal fiber or conductive polymer can be used as the absorbent; and the base material of the dielectric material can be a foam material, such as expanded polyethylene (EPE), expanded polystyrene (EPS) or expanded polypropylene (EPP).

[0046] In addition, the magnetic material refers to an absorbing material with magnetic loss as the main factor, and ferrite, carbonyl iron, magnetic fiber or silicon carbide can be used as an absorber. Optionally, the magnetic material is ferrite.

[0047] Optionally, in this embodiment, the shape of the cavity 121 is conical or wedge-shaped. It is worth noting that, generally, the shape of the cavity 121 is similar to the overall shape of the absorbing body 120, that is, when the absorbing body 120 is conical, the cavity 121 is set to be conical; and when the absorbing body 120 is wedge-shaped, the cavity 121 is set to be wedge-shaped.

[0048] It should be understood that in other embodiments, the shape of the cavity 121 may also be set according to actual conditions, that is, the shape of the cavity 121 may also be different from the shape of the absorbing body 120 .

[0049] In addition, the shape of the cavity 121 can also be a frustum, that is, a shape formed by removing the top of a cone, and the top of the shape also has a plane; based on this, when the cavity 121 is formed into a cone and the top is removed to form a plane, the plane of the top can also be non-parallel to the bottom of the cone, that is, an irregular frustum-like shape is formed. Similarly, the cavity 121 can also be formed by removing the top structure on the basis of the wedge shape, and the shape can be regarded as an inverted prism.

[0050] For further information, please refer to Figure 3 and Figure 4 In order to further improve the absorption performance of low-frequency electromagnetic waves, the absorbing unit 10 further includes a third absorbing body 300, which is made of magnetic material; the third absorbing body 300 is arranged inside the cavity 121. Through the arrangement of the third absorbing body 300, in combination with the second absorbing body 200, different laying methods can be selected based on actual conditions, thereby further optimizing the performance of specific frequency points of low-frequency electromagnetic waves, so as to match the application scenario of the absorbing unit 10.

[0051] Among them, in this embodiment, the third absorber 300 is made of magnetic material, which can be made of the same material as the second absorber 200. In other words, the third absorber 300 can also be made of an absorber material with magnetic loss as the main component, such as ferrite, carbonyl iron, magnetic fiber or silicon carbide as an absorbent. Further, in some embodiments, considering the convenience of installation / laying of the third absorber 300, the third absorber 300 uses a magnetic absorber material with a flexible substrate, such as a rubber-based magnetic absorber material.

[0052] Optionally, the cavity 121 has a bottom wall 1211 and a side wall 1212 ; when the cavity 121 is conical or wedge-shaped, the inner wall of the cavity 121 close to the base 110 is the bottom wall 1211 , and the other inner wall is the side wall 1212 .

[0053] In one embodiment, the second absorbing body 200 is disposed on a side of the base 110 away from the absorbing body 120, and the third absorbing body 300 is disposed on the bottom wall 1211 and / or the side wall 1212. Here, "and / or" means that the third absorbing body 300 can be disposed only on the bottom wall 1211, the third absorbing body 300 can also be disposed only on the side wall 1212, or the third absorbing body 300 is disposed on both the bottom wall 1211 and the side wall 1212.

[0054] In another embodiment, the second absorbing body 200 is disposed on the bottom wall 1211 , and the third absorbing body 300 is disposed on the side wall 1212 .

[0055] Among them, when the second absorbing body 200 is arranged inside the cavity 121, compared with arranging the second absorbing body 200 at the bottom of the base 110, less material is used, which reduces the production cost to a certain extent. Moreover, compared with the method of laying magnetic material at the bottom of the solid cone in the prior art, the absorbing unit 10 provided in this embodiment can better absorb low-frequency electromagnetic waves and improve the absorption performance in the low-frequency band.

[0056] It should be noted that, when targeting electromagnetic waves of different frequency bands, the laying method of the second absorber 200 and the third absorber 300 can be adjusted according to actual conditions to complete the setting of the absorbing unit 10 in a targeted manner, which is beneficial to improve the absorption performance of electromagnetic waves in a specified frequency band, so as to match the current application scenario.

[0057] In this embodiment, when the second absorbing body 200 is disposed on the bottom wall 1211, the second absorbing body 200 completely covers the bottom wall 1211. When the third absorbing body 300 is disposed on the side wall 1212, the third absorbing body 300 covers at least a portion of the side wall 1212; in other words, the third absorbing body 300 can completely cover the side wall 1212 or can cover a portion of the side wall 1212. When the third absorbing body 300 is disposed on the bottom wall 1211, the third absorbing body 300 completely covers the bottom wall 1211.

[0058] Since the space at the top of the cavity 121 is relatively narrow, in order to reduce the difficulty of laying, only part of the side wall 1212 may be laid. By completely covering the bottom wall 1211 with the second absorber 200 or completely covering the bottom wall 1211 with the third absorber 300, the area for receiving electromagnetic waves can be increased, which is beneficial to improving the absorbing performance.

[0059] In addition, in this embodiment, when the second absorber 200 is disposed on the side of the base 110 away from the absorber body 120, the second absorber 200 completely covers the bottom surface of the base 110. This can increase the area for receiving electromagnetic waves and improve the absorption performance for low-frequency electromagnetic waves.

[0060] In this embodiment, the base 110 is a prism, and the top surface of the base 110 coincides with the top surface of the absorbing body 120, that is, the cross section of the base 110 and the cross section of the absorbing body 120 are similar or identical; for example, the base 110 is a quadrangular prism, and the absorbing body 120 is a quadrangular pyramid; for another example, the base 110 is a hexagonal prism, and the absorbing body 120 is a hexagonal pyramid. In addition, the second absorbing body 200 is a flat plate structure, and the second absorbing body 200 is attached to the bottom surface of the base 110.

[0061] The following provides control examples and experimental examples for conducting electromagnetic wave absorption tests.

[0062] Among them, the control examples include control examples 1 and control examples 2, and the experimental examples include experimental examples 1, experimental examples 2, experimental examples 3, and experimental examples 4. The overall appearance and size of control example 1, control example 2, experimental example 1, experimental example 2, experimental example 3, and experimental example 4 are the same; and the control example and the experimental example both use dielectric materials and magnetic materials. Specifically, the control example and the experimental example both use a pyramidal main structure and a prismatic base structure.

[0063] The center of the bottom surface of the main structure coincides with the center of the upper surface of the base structure. The total height of the structures used in the control example and the experimental example is 2.18m, the height of the main structure is 2.02m, the width of the base structure is 0.35m, and the height of the base structure is 0.16m.

[0064] The difference is that the control example adopts a main structure of a solid structure, while the experimental example adopts a main structure of a hollow structure (that is, the absorbing body 120 with a cavity 121 provided above); in addition, there are differences in the setting materials of the first absorber 100, the setting method of the second absorber 200, and the setting method of the third absorber 300 in Control Example 1, Control Example 2, Experimental Example 1, Experimental Example 2, Experimental Example 3, and Experimental Example 4.

[0065] The details are as follows: Comparative Example 1 includes a base in the shape of a quadrangular prism and a solid absorbing member in the shape of a regular quadrangular pyramid disposed on the base, the solid absorbing member is made of material 1; an absorbing body is disposed at the bottom of the base; the absorbing body uses ferrite as an absorbent. Comparative Example 2 includes a base in the shape of a quadrangular prism and a solid absorbing member in the shape of a regular quadrangular pyramid disposed on the base, the solid absorbing member is made of material 2; and an absorbing body is disposed at the bottom of the base; the absorbing body uses ferrite as an absorbent. Both material 1 and material 2 are dielectric materials, that is, both material 1 and material 2 can use carbon black, carbon fiber, carbon tube, metal fiber or conductive polymer as absorbent, but material 1 and material 2 have different electromagnetic parameters.

[0066] In Experimental Example 1, the base 110 is in the shape of a quadrangular prism, the absorbing body 120 is in the shape of a quadrangular pyramid, and the absorbing body 120 is made of material 1, the second absorbing body 200 is arranged on the bottom surface of the base 110, and the third absorbing body 300 is not arranged. In Experimental Example 2, the base 110 is in the shape of a quadrangular prism, the absorbing body 120 is in the shape of a quadrangular pyramid, and the absorbing body 120 is made of material 2, the second absorbing body 200 is arranged on the bottom wall 1211 of the cavity 121, and the third absorbing body 300 is not arranged. In Experimental Example 3, the base 110 is in the shape of a quadrangular prism, the absorbing body 120 is in the shape of a quadrangular pyramid, and the absorbing body 120 is made of material 2, the second absorbing body 200 is arranged on the bottom surface of the base 110; the third absorbing body 300 is arranged on the side wall 1212 of the cavity 121, and is arranged on the side wall 1212 at a height area of ​​200mm-800mm. In Experimental Example 4, the base 110 is in the shape of a quadrangular prism, the absorbing body 120 is in the shape of a quadrangular pyramid, and the absorbing body 120 is made of material 2, the second absorbing body 200 is arranged on the bottom wall 1211 of the cavity 121, and the third absorbing body 300 is arranged on the side wall 1212 of the cavity 121, and is arranged in a height area of ​​200 mm-800 mm on the side wall 1212. Among them, the second absorbing body 200 uses ferrite as an absorbent; and the third absorbing body 300 uses a magnetic rubber sheet.

[0067] In the experimental example, the height of the cavity 121 is 1 m, and the size of the bottom wall 1211 of the hollow structure is 0.2 m*0.2 m.

[0068] Figure 5 The dielectric real part ε' of material 1 and material 2 is shown in the figure, where the abscissa represents the frequency and the ordinate represents the dielectric real part ε'; Figure 6 The dielectric loss tangent tan of material 1 and material 2 is shown, where the horizontal axis represents the frequency and the vertical axis represents the dielectric loss tangent tan. It can be understood that in the technical field, the complex dielectric constant includes a real part and an imaginary part, wherein the real part ε' of the dielectric constant represents the response ability of the medium to the electric field. The loss tangent tan is the ratio of the imaginary part (loss factor) and the real part (dielectric constant) of the dielectric constant, which represents the coupling ability of the material with electromagnetic waves. These two parameters are important parameters that affect the electromagnetic absorption performance of dielectric materials.

[0069] Further, referring to the table below, the comparison results of the absorption rates of the control example and the experimental example in the low frequency band are as follows.

[0070] frequency 0.03-0.05GHz 0.05-0.1GHz 0.1~0.15GHz Comparative Example 1 <-10dB <-15dB <-30dB Comparative Example 2 <-20dB <h2 style=";text-align:left;direction:ltr"><-25dB<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr"><-35dB<h2 style=";text-align:left;direction:ltr"> Example 1 <-10dB <-15dB <-40dB Example 2 <h2 style=";text-align:left;direction:ltr"><-25dB<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr"><-25dB<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr"><-35dB<h2 style=";text-align:left;direction:ltr"> Example 3 <-20dB <-30dB <-40dB Example 4 <h2 style=";text-align:left;direction:ltr"><-25dB<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr"><-25dB<h2 style=";text-align:left;direction:ltr"> <-40dB

[0071] In addition, comparison is made between Control Example 1 and Experimental Example 1 using the same dielectric material (Material 1), and comparison is made between Control Example 2 and Experimental Examples 2-4 using the same dielectric material (Material 2).

[0072] It can be seen that, by comparing Experimental Example 1 with Control Example 1, the absorption performance of electromagnetic waves in the range of 0.1 GHz-0.15 GHz is optimized and improved by about 10 dB by setting the absorbing body 120 to have a cavity structure.

[0073] Similarly, it can be seen that in the comparison between Experimental Example 2 and Control Example 2, by setting the absorber body 120 to have a cavity structure and laying the second absorber 200 on the bottom wall 1211 of the cavity 121, the absorption rate in the 0.03GHz-0.05GHz frequency band is optimized, and the performance is improved by about 10dB. It is worth noting that the performance difference between Control Example 1 and Control Example 2 is caused by the use of dielectric materials with different electromagnetic parameters, and the performance difference between Experimental Example 1 and Experimental Example 2 is the same.

[0074] In addition, by comparing Experimental Example 3 with Control Example 2, by setting the absorbing body 120 to be hollow and laying the third absorbing body 300 on part of the side wall 1212 of the cavity 121, the absorption rate in the frequency band range of 0.05GHz-0.1GHz and the frequency band range of 0.1GHz-0.15GHz can be improved at the same time, so that the performance is improved by about 5dB.

[0075] In addition, by comparing Experimental Example 4 with Control Example 2, by setting the absorbing body 120 to be hollow, setting the second absorbing body 200 on the bottom wall 1211 of the cavity 121, and laying the third absorbing body 300 on part of the side wall 1212 of the cavity 121, the absorption rate in the frequency band range of 0.03GHz-0.05GHz and the frequency band range of 0.1GHz-0.15GHz can be improved at the same time, so that the performance is improved by about 5dB.

[0076] Based on the above-mentioned absorbing unit 10 , this embodiment further provides a absorbing structure, which adopts the above-mentioned absorbing unit 10 .

[0077] In summary, in the absorbing unit 10 and the absorbing structure provided in the present embodiment, since the absorbing body 120 of the first absorbing body 100 is designed in a hollow manner, on the one hand, the weight of the entire absorbing unit 10 is reduced, the problem of engineering load-bearing is improved, and the amount and cost of the first absorbing body 100 are reduced; on the other hand, the hollow absorbing body 120 can make the electromagnetic waves incident into the cavity 121 reflect multiple times in the cavity 121, which is beneficial to the improvement of low-frequency absorption performance to a certain extent. Further, in the case of adding the second absorbing body 200, since the second absorbing body 200 is made of magnetic material, it has very good loss for low-frequency electromagnetic waves, which can further improve the loss of low-frequency electromagnetic waves of the absorbing unit 10, thereby improving the absorption capacity of low-frequency electromagnetic waves. Based on this, the absorbing unit 10 can improve the problem of the overall weight of the absorbing material, high cost and high installation difficulty caused by increasing the manufacturing materials in order to improve the absorbing performance in the prior art. In addition, generally, in the low frequency band, the strongest areas of interaction between electromagnetic waves and the absorbing unit 10 are distributed in the middle and bottom of the absorbing body 120, and at different frequency points, the specific positions of the strongest areas are different within the above positions. Based on this, in order to improve the absorption performance of low-frequency electromagnetic waves, a second absorbing body 200 is set in the cavity 121 or at the bottom of the base 110. Further, in practical applications, the setting position and laying area of ​​the magnetic material at the bottom of the cavity 121 and the base 110 can be adjusted according to the use frequency band of the electromagnetic waves to be focused on, so as to improve the absorption performance of the electromagnetic waves in the use frequency band. Furthermore, by setting the third absorbing body 300 and using it in combination with the second absorbing body 200, different laying methods can be selected based on actual conditions, so as to further optimize the performance of the specific frequency points of the low-frequency electromagnetic waves, so as to match the application scenario of the absorbing unit 10.

[0078] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A wave absorbing unit (10), characterized in that: include: A first wave absorbing body (100) is made of a dielectric material; the first wave absorbing body (100) comprises a base (110) and a wave absorbing body (120); the wave absorbing body (120) is in a cone or wedge shape; the wave absorbing body (120) is arranged on the base (110), and a cavity (121) is arranged in the wave absorbing body (120); The second wave absorbing body (200) is made of a magnetic material; the second wave absorbing body (200) is arranged on a side of the base (110) away from the wave absorbing body (120), or the second wave absorbing body (200) is arranged inside the cavity (121).

2. The absorbing unit (10) according to claim 1, characterized in that: The cavity (121) is in a cone or wedge shape.

3. The absorbing unit (10) according to claim 2, characterized in that: The wave absorbing unit (10) further comprises a third wave absorbing body (300), wherein the third wave absorbing body (300) is made of a magnetic material; and the third wave absorbing body (300) is arranged inside the cavity (121).

4. The absorbing unit (10) according to claim 3, characterized in that: The cavity (121) has a bottom wall (1211) and a side wall (1212); The second wave absorbing body (200) is arranged on a side of the base (110) away from the wave absorbing body (120), and the third wave absorbing body (300) is arranged on the bottom wall (1211) and / or the side wall (1212); or, the second wave absorbing body (200) is arranged on the bottom wall (1211), and the third wave absorbing body (300) is arranged on the side wall (1212).

5. The absorbing unit (10) according to claim 4, characterized in that: When the second wave absorbing body (200) is arranged on the bottom wall (1211), the second wave absorbing body (200) covers the bottom wall (1211); When the third wave absorbing body (300) is arranged on the side wall (1212), the third wave absorbing body (300) covers at least a portion of the side wall (1212); when the third wave absorbing body (300) is arranged on the bottom wall (1211), the third wave absorbing body (300) covers the bottom wall (1211).

6. The absorbing unit (10) according to claim 1, characterized in that: When the second wave absorbing body (200) is arranged on a side of the base (110) away from the wave absorbing body (120), the second wave absorbing body (200) covers the bottom surface of the base (110).

7. The absorbing unit (10) according to claim 1, characterized in that: The dielectric material uses at least one of the following absorbents: carbon black, carbon fiber, carbon tube, metal fiber or conductive polymer, and the substrate of the dielectric material is a foaming material; The magnetic material uses at least one of the following absorbers: ferrite, carbonyl iron, magnetic fiber or silicon carbide.

8. The absorbing unit (10) according to claim 1, characterized in that: The base (110) is a prism structure, and the top surface of the base (110) and the bottom surface of the wave absorbing body (120) overlap.

9. The absorbing unit (10) according to claim 1, characterized in that: The second wave absorbing body (200) is a flat plate structure.

10. A wave absorbing structure, characterized in that: It comprises the wave absorbing unit (10) as claimed in any one of claims 1 to 9.

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