Wave absorbing structure

Abstract

The utility model provides a wave-absorbing structure. The wave-absorbing structure comprises a wave-absorbing substrate and at least one wave-absorbing unit located on the wave-absorbing substrate, wherein the wave-absorbing unit comprises a wave-absorbing wall and a plurality of cavities enclosed by the wave-absorbing wall; the plurality of cavities comprise crossed first cavities and second cavities positioned at the end parts of the first cavities; wherein each second cavity is communicated with the corresponding first cavity, and the width of the cross section of the first cavity is smaller than that of the cross section of the second cavity. According to the technical scheme, the wave-absorbing units are adopted to form the cavities with different cross sectional areas, so that the absorption frequency ranges of the two cavities are different, the overall range of the absorbable frequency of the wave-absorbing structure is enlarged, and the wave-absorbing effect of the wave-absorbing structure is improved.

Description

Technical Field

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

[0002] Absorbing materials are often used in buildings or products to absorb waves in order to improve the electromagnetic protection effect of buildings or products. At present, most absorbing materials achieve electromagnetic wave energy loss by adding absorbers. At the same time, in order to reduce surface reflection, they are often supplemented with structural design so that electromagnetic waves can be incident into the material. Commonly used structures are porous, pyramidal or multi-layer structures. The frequency band of porous and multi-layer structures is generally narrow, and the low-frequency absorption effect of pyramidal structures is slightly worse. And when the electromagnetic wave is obliquely incident, the reflection is enhanced and the absorption effect becomes worse. Utility Model Content

[0003] The present application provides an absorbing structure, which increases the frequency bandwidth of the absorbing material, improves the absorbing performance of the absorbing material, and especially improves the absorbing effect of the absorbing material on electromagnetic waves when the electromagnetic waves are incident at an oblique angle.

[0004] The present application provides an absorbing structure, which comprises: an absorbing substrate and at least one absorbing unit located on the absorbing substrate; wherein the absorbing unit comprises an absorbing wall and a plurality of cavities surrounded by the absorbing wall; the plurality of cavities comprises a first cavity in a cross shape and a second cavity located at the end of each of the first cavities; wherein,

[0005] Each second cavity is communicated with the corresponding first cavity, and the cross-sectional width of the first cavity is smaller than the cross-sectional width of the second cavity.

[0006] In the above technical solution, cavities with different cross-sectional areas are formed by using absorbing units so that the two cavities absorb different frequency ranges, thereby increasing the overall range of frequencies that can be absorbed by the absorbing structure and improving the absorbing effect of the absorbing structure.

[0007] In a specific embodiment, the first cavity includes a first sub-cavity and a second sub-cavity that intersect, and the first sub-cavity and the second sub-cavity are perpendicular to each other; wherein,

[0008] A second cavity is disposed at each end of the first sub-cavity and the second sub-cavity.

[0009] In a specific possible implementation manner, there are a plurality of absorbing units, and a plurality of cavities are arranged in an array; wherein the cavities between adjacent absorbing units are connected.

[0010] In a specific possible implementation manner, adjacent second cavities in adjacent absorbing units are connected.

[0011] In a specific possible implementation manner, the absorbing unit and the absorbing substrate are integrally formed.

[0012] In a specific possible implementation manner, the wave-absorbing wall is a straight wall or the wave-absorbing wall as a whole is a structure that is pointed at the top and wide at the bottom.

[0013] In a specific possible implementation scheme, the wave absorbing wall includes a first wall and a second wall, the second wall encloses a plurality of the cavities; the first wall is nested outside the second wall and is spaced apart from the second wall; wherein,

[0014] The first wall includes a first straight wall and a first wavy wall arranged on the first straight wall; the propagation direction of the wavy shape of the first wavy wall is along the height direction of the first straight wall;

[0015] The second wall includes a second straight wall and a second wavy wall arranged on the second straight wall; the propagation direction of the wavy shape of the first wavy wall is along the height direction of the second straight wall.

[0016] In a specific possible implementation manner, the first wavy wall and the second wavy wall have the same shape; and the first straight wall is lower than the second straight wall.

[0017] In a specific embodiment, the straight-line distance between the crest and the trough of the first wavy wall is equal to the thickness of the first straight wall; and / or,

[0018] The straight-line distance between the crest and the trough of the second wavy wall is equal to the thickness of the second straight wall.

[0019] In a specific implementation manner, the height difference between the first wavy wall and the second wavy wall is between 0.5 and 2 wavelengths. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of the wave absorbing structure provided in the embodiment of the present application;

[0021] Figure 2 A schematic diagram of the simulation of the electric field strength of the wave absorbing structure provided in the embodiment of the present application;

[0022] Figure 3 A schematic diagram of the simulation of the electric field vector intensity of the wave absorbing structure provided in an embodiment of the present application;

[0023] Figure 4 for Figure 1 The simulation schematic diagram of the wave absorbing structure shown;

[0024] Figure 5 It is a simulation schematic diagram of a flat plate-shaped wave absorbing structure in the prior art;

[0025] Figure 6 A schematic structural diagram of another wave absorbing structure provided in an embodiment of the present application;

[0026] Figure 7 A schematic structural diagram of a wave-absorbing wall of a wave-absorbing structure provided in an embodiment of the present application;

[0027] Figure 8 A schematic diagram of the vertical division of the wave-absorbing wall provided in an embodiment of the present application;

[0028] Fig. 9 and Fig.10 The electromagnetic wave is incident obliquely and normally to Figure 6 Simulation diagram of the absorbing structure shown. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings.

[0030] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in one or more embodiments of this specification should be understood by people with ordinary skills in the field to which this disclosure belongs. The "first", "second" and similar words used in one or more embodiments of this specification do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0031] To facilitate understanding of the wave-absorbing structure provided in the embodiment of the present application, its application scenario is first described. The wave-absorbing structure provided in the embodiment of the present application can be applied to different wave-absorbing buildings or wave-absorbing products. When the current wave-absorbing structure realizes wave absorption, on the one hand, it absorbs waves through materials, and on the other hand, it realizes wave absorption through the structure of the wave-absorbing structure. However, no matter which one is adopted, the current wave-absorbing structure can absorb a narrow frequency range, which affects the wave-absorbing effect, and usually at oblique incidence, the surface reflection is enhanced and the wave-absorbing effect is weakened. To this end, the embodiment of the present application provides a wave-absorbing structure to improve the wave-absorbing effect of the wave-absorbing structure. The wave-absorbing structure provided in the embodiment of the present application is described in detail below in conjunction with specific drawings.

[0032] When absorbing waves, the absorbing performance of the material depends on the amount of electromagnetic waves entering the material and the amount of electromagnetic wave energy consumed by the material. The electromagnetic waves entering the material are determined by the impedance of the material. Electromagnetic waves of materials with matched impedance can enter in large quantities. Therefore, gradient design of the impedance of the material can effectively increase the amount of electromagnetic waves entering, thereby achieving a good absorbing effect. The absorbing structure provided by the embodiment of the present application is described in detail below in conjunction with the accompanying drawings.

[0033] refer to Figure 1 As shown in , the absorbing structure provided by the embodiment of the present application includes an absorbing substrate 100 and an absorbing unit 200 disposed on the absorbing substrate 100. It should be understood that the number of the absorbing unit 200 may be one or more, and when the number of the absorbing unit 200 is more than one, the plurality of absorbing units 200 may be arranged in an array. When absorbing waves, both the absorbing substrate 100 and the absorbing unit 200 can be used for absorbing waves, wherein the absorbing substrate 100 absorbs waves through its material, and the absorbing unit 200 absorbs waves through its own material on the one hand, and reflects the waves through its internal cavity structure on the other hand, so that the waves are offset in the cavity to achieve wave absorption.

[0034] Continue to refer Figure 1 As shown in , the absorbing unit 200 provided in the embodiment of the present application includes an absorbing wall 210 and a plurality of cavities surrounded by the absorbing wall 210; wherein, the opening direction of the cavity is away from the absorbing substrate 100. In order to absorb units of different frequencies, the cavity is set in different ways. Specifically, the multiple cavities include a first cavity 230 in a cross shape, and a second cavity 220 located at the end of each first cavity 230; wherein, each second cavity 220 is connected to the corresponding first cavity 230, the cross-sectional width of the first cavity 230 is smaller than the cross-sectional width of the second cavity 220, and the first cavity 230 and the second cavity 220 have different corresponding absorbing frequency bands.

[0035] In a specific example, the width of the cross section of the first cavity 230 is smaller than the width of the cross section of the second cavity 220. Exemplarily, the width of the cross section of the first cavity 230 is D1, and the width of the cross section of the second cavity 220 is D2, then D1<D2 is satisfied. In addition, the size of D1 satisfies: the path difference formed by the electromagnetic wave after reflection in the first cavity 230 is n+1 / 2 of the wavelength of the corresponding frequency, so that the wave reflected back through the side wall of the first cavity 230 can offset the incident wave to achieve the purpose of absorption. Similarly, the size of D2 is also designed in the same way, so that the wave reflected back through the side wall of the second cavity 220 can offset the incident wave to achieve the purpose of absorption.

[0036] It can be seen from the above description that in the embodiment of the present application, during the design, the cross-sectional dimensions of the first cavity 230 and the second cavity 220 can be set corresponding to the range of frequencies to be absorbed, so that the first cavity 230 and the second cavity 220 can absorb waves in different frequency ranges, thereby enhancing the ability of the absorbing unit 200 to absorb waves in more frequency ranges and improving the absorbing effect of the absorbing unit 200. That is, in the solution provided in the embodiment of the present application, cavities with different cross-sectional areas are formed by using the absorbing unit 200, so that the two cavities absorb different frequency ranges, thereby increasing the overall range of frequencies that can be absorbed by the absorbing structure and improving the absorbing effect of the absorbing structure.

[0037] When the first cavity 230 is formed, the first cavity 230 is a cross cavity. Specifically, it includes two sub-cavities, which are named the first sub-cavity 231 and the second sub-cavity 232 for convenience of description, and the first sub-cavity 231 and the second sub-cavity 232 cross to form an X-shaped structure. When this arrangement is adopted, when the electromagnetic waves are reflected on the side walls of the two cavities, the path difference is different, resulting in different frequencies of the electromagnetic waves that interfere with each other, broadening the absorption frequency band and improving the wave absorption effect.

[0038] In addition, when the second cavity 220 is provided, the second cavity 220 is connected with the first cavity 230, and the specific connection mode is that a second cavity 220 is provided at the end of each first cavity 230, and each second cavity 220 is connected with the corresponding first cavity 230. Specifically, the number of the second cavities 220 is four, wherein two second cavities 220 are provided at both ends of the first sub-cavity 231, and the other two second cavities 220 are provided at both ends of the second sub-cavity 232. When the above arrangement is adopted, in the formed absorbing unit 200, the four second cavities 220 are located on the outside and form a ring, while the first cavity 230 is located in the central area, and the four second cavities 220 are connected through an X-shaped structure.

[0039] In an optional solution, the first sub-cavity 231 and the second sub-cavity 232 are perpendicular to each other, and a second cavity 220 is disposed at each end of the first sub-cavity 231 and the second sub-cavity 232, so that the wave absorbing unit 200 forms a self-symmetrical structure. Therefore, no matter from which direction or in which polarization direction the wave is incident on the wave absorbing unit 200, the first cavity 230 and the second cavity 220 can correspond to the incident wave, thereby improving the wave absorbing effect.

[0040] In an optional solution, the second cavity 220 may be a square cavity, and the first sub-cavity 231 or the second sub-cavity 232 is connected to a corner of the second cavity 220. For example, the length direction of the first sub-cavity 231 or the second sub-cavity 232 is parallel to a diagonal line of the second cavity 220.

[0041] In the embodiment of the present application, when there are multiple absorbing units 200, multiple cavities are arranged in an array. In the specific arrangement, the cavities between adjacent absorbing units 200 are connected. This allows the cavities in the multiple absorbing units 200 to be connected, thereby increasing the coverage of the cavities, so that more waves can be absorbed.

[0042] When a plurality of absorbing units 200 are connected, the adjacent second cavities 220 in the adjacent absorbing units 200 are connected. In an exemplary solution, the adjacent absorbing units 200 may share a second cavity 220. Exemplarily, in two adjacent absorbing units 200, the length directions of the two first sub-cavities 231 are the same, and when connected, there is a second cavity 220 between the two first sub-cavities 231, and the two first sub-cavities 231 are arranged on both sides of the diagonal of the second cavity 220.

[0043] When absorbing waves, the side walls of the first cavity 230 and the second cavity 220 are the above-mentioned wave absorbing walls 210, and the incident waves are irradiated to the wave absorbing walls 210 and reflected by the wave absorbing walls 210. In an operative solution, the wave absorbing walls 210 are straight walls or the wave absorbing walls 210 are generally of a structure with a pointed top and a wide bottom. Figure 1 As shown in Figure 1 The absorbing wall 210 in the example is a wall with a triangular cross section, and of course, in addition to the triangular cross section, it can also be a trapezoidal cross section. When the absorbing wall 210 adopts a structure that is narrow at the top and wide at the bottom, the absorbing effect of the absorbing structure on obliquely incident electromagnetic waves can be increased.

[0044] When the absorbing unit 200 and the absorbing substrate 100 are specifically prepared, the absorbing unit 200 and the absorbing substrate 100 are integrally formed, so as to facilitate the preparation of the absorbing structure. Of course, the absorbing unit 200 and the absorbing substrate 100 can also adopt a separate structure, such as the absorbing unit 200 and the absorbing substrate 100 are fixedly connected by bonding.

[0045] It should be understood that no matter whether the absorbing unit 200 and the absorbing substrate 100 adopt an integrated or split structure. The absorbing substrate 100 and the absorbing unit 200 provided in the embodiment of the present application are made of absorbing materials. The absorbing material refers to a type of material that can absorb and attenuate electromagnetic waves incident into the material and convert them into energy of other properties. It is mainly composed of an absorbent and a matrix material. The absorbent is a substance that absorbs and reflects electromagnetic waves. Commonly used ones include ferrite, carbonyl iron, conductive polymers, metal oxides, carbon black, graphite, etc. The matrix material is a carrier of the absorbent, which can carry and disperse the absorbent, and has certain mechanical properties itself, such as rubber, soft polyurethane foam, hard styrene foam, etc.

[0046] The loss mechanism can be divided into electrical loss type, magnetic loss type and dielectric loss type absorbers. Electrical loss type absorbers mainly include conductive polymers, carbon materials, etc. They usually have a high dielectric constant and use electron transition and migration to form current to convert electromagnetic energy into electrical energy. Dielectric loss type absorbers include materials such as zinc oxide, barium titanate, silicon carbide, titanium nitride, manganese dioxide, etc., which mainly use electric dipole polarization and relaxation, interface polarization and other mechanisms to attenuate electromagnetic waves in the microwave frequency band; magnetic loss type absorbers mainly include materials such as iron, cobalt, nickel, ferrite, ferroferric oxide, etc., which mainly rely on hysteresis loss, interface loss, domain wall resonance loss, natural resonance loss and eddy current loss to lose electromagnetic waves.

[0047] To facilitate understanding of the effect of the wave absorbing structure provided in the embodiment of the present application, Figure 1 The structure in which the absorbing wall is a straight wall in the absorbing structure shown in the figure is simulated as an example, and the simulation results are as follows Figure 2-3 shown.

[0048] The electric field strength simulation is as follows Figure 2 , the electric field vector simulation is as follows Figure 3 .like Figure 2 As shown, in this frequency band, the electromagnetic wave energy of the cross structure (i.e., the first cavity 230) in the figure is significantly reduced, and the electromagnetic wave energy is being lost here. The electromagnetic wave loss is also gradually reduced as the wave-facing surface of the absorbing wall 210 expands inward, while the corresponding substrate 100 part in the second cavity 220 has a lower loss. When the electromagnetic wave is incident on the absorbing wall 210 part, it is reflected and refracted on the surface of the structure. The electromagnetic field intensity incident on the absorbing substrate 100 is lower than that of the surrounding free space. The electromagnetic wave intensity in the second cavity 220 is lower than that of the surrounding free space. Figure 3 ,Since electromagnetic waves are reflected and refracted between walls, there is also some scattering, which causes the direction of the electric field vector to change and the intensity of the electric field vector to weaken in some locations.

[0049] In order to facilitate understanding of the wave absorbing effect of the wave absorbing structure provided in the embodiment of the present application, Figure 1 The absorbing structure shown is simulated with the existing absorbing structure to verify its absorbing effect. Among them, the existing absorbing structure adopts a flat plate absorbing structure. Figure 1 The parameters of the absorbing structure are: A=17, h=40, b=10, t=45, l=180, the size of the absorbing unit is 175, and the size of the absorbing substrate is 180*180mm. Among them, the height of the absorbing unit is h, the thickness of the absorbing substrate is b, the cross-section of the absorbing wall is a triangle, the bottom width of the absorbing wall is t, and the height is h. The materials used for the absorbing wall and the absorbing substrate are both paraffin-based materials mixed with 8% by weight of carbon black. Similarly, the material of the comparative flat-plate absorbing structure also uses a paraffin-based material mixed with 8% by weight of carbon black.

[0050] refer to Figure 4 and Figure 5 , Figure 4 A simulation schematic diagram of the wave absorbing structure provided in the embodiment of the present application, Figure 5 It is a simulation schematic diagram in the prior art. Figure 4 It can be seen that the reflectivity of the wave absorbing structure provided in the embodiment of the present application is greatly reduced compared with the prior art, and the reflectivity of 2 to 18 GHz is below -10 dB, the minimum reflectivity reaches -38 dB, and the bandwidth is increased. Figure 5 It can be seen that the absorbing structure in the prior art has a high surface reflectivity, and the frequency band width below -10dB is only 0.4GHz. It can be seen that this structure can greatly enhance the absorbing performance of the material.

[0051] For reference Figure 6 and Figure 7 , Figure 6 A deformation structure of the wave absorbing structure is shown. Figure 7 The absorbing wall 210 provided in the embodiment of the present application is not limited to Figure 1 The straight wall shown in the figure may also adopt other forms of walls. In a specific embodiment, the absorbing wall 210 includes a first wall 212 and a second wall 211, and the second wall 211 encloses the above-mentioned multiple cavities (the first cavity 230 and the second cavity 220); the first wall 212 is nested outside the second wall 211 and is spaced apart from the second wall 211, that is, a cavity is also formed between the first wall 212 and the second wall 211. When the first wall 212 and the second wall 211 are specifically arranged, the first wall 212 and the second wall 211 each include a straight wall and a wavy wall. Specifically, the straight wall is fixedly connected to the absorbing substrate 100, and the absorbing wall 210 is located above the straight wall.

[0052] Specifically, the first wall 212 includes a first straight wall 2121 and a first wavy wall 2122 disposed on the first straight wall 2121, and the wavy propagation direction of the first wavy wall 2122 is along the height direction of the first straight wall 2121. The second wall 211 includes a second straight wall 2111 and a second wavy wall 2112 disposed on the second straight wall 2111; the wavy propagation direction of the first wavy wall 2122 is along the height direction of the second straight wall 2111. Figure 7It can be seen that the height direction of the first straight wall 2121 and the second straight wall 2111 is along the vertical direction, and the first wavy wall 2122 and the second wavy wall 2112 extend along the height direction of the first straight wall 2121 and the second straight wall 2111, thereby forming a curved wavy shape at the top of the first wall 212 and the second wall 211. The wavy top (the first wavy wall 2122 and the second wavy wall 2112) can also be formed by arcs or trigonometric functions as the side surfaces.

[0053] When the first wall 212 and the second wall 211 are arranged in the above manner, a straight surface (straight wall) and a folded surface (wavy wall) are formed in the height direction, so as to form different impedance matching areas in the height direction. Specifically, an impedance area of ​​the overlapping area of ​​the first straight wall 2121 and the second straight wall 2111 and another impedance area composed of the first wavy wall 2122 and the second wavy wall 2112 can be formed.

[0054] Continue to refer Figure 7 , the first wavy wall 2122 and the second wavy wall 2112 have the same shape; and the first straight wall 2121 is lower than the height of the second straight wall 2111. Figure 7 In the embodiment, the first wavy wall 2122 and the second wavy wall 2112 both include a crest and a trough, and the first wavy wall 2122 and the second wavy wall 2112 have the same trend. When the height of the first straight wall 2121 is lower than the height of the second straight wall 2111, the height of the first wavy wall 2122 is also lower than the height of the second wavy wall 2112. In a specific embodiment, the height difference between the first straight wall 2121 and the second straight wall 2111 is between 0.5 and 2 wavelengths. That is, the first wavy wall 2122 and the second wavy wall 2112 have a height difference between 0.5 and 2 wavelengths. Therefore, the first wavy wall 2122 and the second wavy wall 2112 have the same inclination direction in the overlapping portion.

[0055] In a specific possible implementation, the straight-line distance between the crest and trough of the first wavy wall 2122 is equal to the thickness of the first straight wall 2121; and / or, the straight-line distance between the crest and trough of the second wavy wall 2112 is equal to the thickness of the second straight wall 2111. That is, the thickness of the first wavy wall 2122 is less than the thickness of the first straight wall 2121. Similarly, the thickness of the second wavy wall 2112 is less than the thickness of the second straight wall 2111, so that the portion where the first straight wall 2121 overlaps with the first straight wall 2121 forms a fourth region, and the portion where the second straight wall 2111 overlaps with the first wavy wall 2122 forms a third region; the portion where the second wavy wall 2112 overlaps with the first wavy wall 2122 forms a second region, and the portion where the second wavy wall 2112 is higher than the first wavy wall 2122 forms a first region. In combination Figure 7 and Figure 8 It can be seen that the filling rate of the absorbing matrix gradually increases along the partition from top to bottom of the absorbing wall 210, in order to make the electromagnetic wave more easily enter the material and be lost due to the step-shaped arrangement and the difference in the filling rate of the upper and lower parts when the electromagnetic wave is obliquely incident. Multiple reflections are more likely to occur in the air cavity formed by the structure, thereby absorbing frequencies in a wider frequency range. The role of the wavy top is that when the electromagnetic wave is obliquely incident on the surface, the electromagnetic wave will be incident on the wavy position. At this time, the side spikes of the wavy surface also play the role of impedance matching and multiple reflections. The electromagnetic wave is lost at the wavy top, and the surface reflection is weakened, thereby playing a good absorbing role for oblique incidence.

[0056] refer to Fig. 9 as well as Fig.10 ,in, Fig. 9 The following example shows a simulation diagram of an electromagnetic wave obliquely incident on an absorbing structure. Fig.10 The example shows a simulation schematic diagram of an electromagnetic wave incident on an absorbing structure. Among them, H = 38b = 10l = 180; among them, H is the height of the structure layer, b is the thickness of the substrate, and l is the width of the absorbing unit. Fig. 9 In the figure, the incident direction of the electromagnetic wave is oblique incidence at 45 degrees; Fig.10 In the process, the electromagnetic wave is incident perpendicular to the plate surface. When the electromagnetic wave is incident at a certain angle, the frequency range below -10dB is 3 to 18GHz. When the electromagnetic wave is incident normally, the frequency range with reflectivity below -10dB is 1.5 to 2.6GHz and 4 to 18GHz. Although the absorption effect of low frequency is slightly lower at oblique incidence, the same bandwidth can still be maintained, which significantly improves the absorption performance at oblique incidence.

[0057] One or more embodiments of this specification are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of this specification should be included in the scope of protection of this disclosure.

[0058] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A wave absorbing structure, characterized in that: include: An absorbing substrate and at least one absorbing unit located on the absorbing substrate; wherein the absorbing unit comprises an absorbing wall and a plurality of cavities surrounded by the absorbing wall; the plurality of cavities comprises a first cavity in a cross shape and a second cavity located at the end of each of the first cavities; wherein, Each second cavity is communicated with the corresponding first cavity, and the cross-sectional width of the first cavity is smaller than the cross-sectional width of the second cavity.

2. The wave absorbing structure according to claim 1, characterized in that: The first cavity includes a first sub-cavity and a second sub-cavity that intersect each other, and the first sub-cavity and the second sub-cavity are perpendicular to each other; wherein, A second cavity is disposed at each end of the first sub-cavity and the second sub-cavity.

3. The wave absorbing structure according to claim 1, characterized in that: There are multiple wave absorbing units, and multiple cavities are arranged in an array; wherein the cavities between adjacent wave absorbing units are connected.

4. The wave absorbing structure according to claim 3, characterized in that: Adjacent second cavities in adjacent wave absorbing units are connected.

5. The wave absorbing structure according to claim 1, characterized in that: The wave absorbing unit and the wave absorbing substrate are integrally formed.

6. The wave absorbing structure according to any one of claims 1 to 5, characterized in that: The wave-absorbing wall is a straight wall or the wave-absorbing wall as a whole has a structure that is pointed at the top and wide at the bottom.

7. The wave absorbing structure according to any one of claims 1 to 5, characterized in that: The wave-absorbing wall includes a first wall and a second wall, wherein the second wall encloses a plurality of the cavities; the first wall is nested outside the second wall and is spaced apart from the second wall; wherein, The first wall includes a first straight wall and a first wavy wall arranged on the first straight wall; the propagation direction of the wavy shape of the first wavy wall is along the height direction of the first straight wall; The second wall includes a second straight wall and a second wavy wall arranged on the second straight wall; the propagation direction of the wavy shape of the first wavy wall is along the height direction of the second straight wall.

8. The wave absorbing structure according to claim 7, characterized in that: The first wavy wall and the second wavy wall have the same shape; and the first straight wall is lower than the second straight wall.

9. The wave absorbing structure according to claim 8, characterized in that: The straight-line distance between the crest and the trough of the first wavy wall is equal to the thickness of the first straight wall; and / or, The straight-line distance between the crest and the trough of the second wavy wall is equal to the thickness of the second straight wall.

10. The wave absorbing structure according to claim 8, characterized in that: The height difference between the first wavy wall and the second wavy wall is between 0.5 and 2 wavelengths.

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