A wave absorbing unit and a wave absorbing metasurface

Abstract

The present application relates to the technical field of wave-absorbing materials, and in particular to a wave-absorbing unit and a wave-absorbing metasurface. The wave-absorbing unit of the present application includes a first layer, a second layer, a third layer and a fourth layer stacked in sequence in the vertical direction; wherein the side where the first layer is located is the side where the electromagnetic wave is incident, and the material of the first layer is polyvinyl chloride, which is used to absorb part of the incident electromagnetic wave; the second layer is provided with a pattern layer with gaps on the side close to the first layer, and the pattern layer is used to make the incident electromagnetic wave resonate; the material of the third layer is polyvinyl chloride, which is used to absorb part of the incident electromagnetic wave; the fourth layer is provided with a continuous floor layer on the side away from the third layer, and the floor layer is used to reflect the remaining electromagnetic waves out of the wave-absorbing unit. Since the gaps in the pattern layer can make the incident electromagnetic wave resonate, the bandwidth can be widened, so that the wave-absorbing unit proposed in the present application has a better wave-absorbing effect within a wider bandwidth range.

Description

Technical Field

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

[0002] The absorber can absorb electromagnetic waves incident on its surface. Its mechanism is to suppress the generation of reflected waves and convert the incident electromagnetic wave energy into internal energy dissipation.

[0003] Although the existing absorbers have good absorbing effects, their applicable bandwidth is narrow and their application range is limited. Therefore, there is an urgent need for an absorbing unit and an absorbing metasurface to solve the above technical problems. Summary of the invention

[0004] The present application provides an absorbing unit and an absorbing metasurface, which can have a high absorbing effect within a wider bandwidth.

[0005] In a first aspect, an embodiment of the present application provides an absorbing unit, comprising: a first layer, a second layer, a third layer, and a fourth layer stacked in sequence along a vertical direction; wherein:

[0006] The side where the first layer is located is the side where the electromagnetic wave is incident, and the material of the first layer is polyvinyl chloride, which is used to absorb part of the incident electromagnetic wave;

[0007] A pattern layer with gaps is provided on one side of the second layer close to the first layer, and the pattern layer is used to make the incident electromagnetic wave resonate;

[0008] The third layer is made of polyvinyl chloride, which is used to absorb part of the incident electromagnetic waves;

[0009] A continuous floor layer is provided on a side of the fourth layer away from the third layer, and the floor layer is used to reflect the remaining electromagnetic waves out of the wave absorbing unit.

[0010] In a possible design, the thickness of the first layer and the third layer is 2 mm, and the dielectric constant is 2.4C. 2 / (N·M 2 ).

[0011] In a possible design, the material of the second layer and the fourth layer includes at least one of polyethylene terephthalate and polyethylene naphthalate.

[0012] In a possible design, the thickness of the second layer and the fourth layer is 0.175 mm.

[0013] In a possible design, the pattern layer and the floor layer are made of indium tin oxide.

[0014] In a possible design, the pattern layer is a plum blossom-shaped pattern.

[0015] In a possible design, the sheet resistance of the pattern layer is 60Ω / sq.

[0016] In one possible design, the square resistance of the floor layer is 15Ω / sq.

[0017] In a possible design, the size of the absorbing unit is 12 mm×12 mm×4.35 mm.

[0018] In a second aspect, an embodiment of the present application provides an absorbing metasurface, which is composed of splicing any of the above-mentioned absorbing units.

[0019] The embodiments of the present application provide an absorbing unit and an absorbing metasurface, wherein the absorbing unit includes a first layer, a second layer, a third layer, and a fourth layer stacked in sequence along a vertical direction; a pattern layer with gaps is coated on one side of the second layer close to the first layer. Since the gaps in the pattern layer can cause incident electromagnetic waves to resonate, the bandwidth can be widened, so that the absorbing unit has a better absorbing effect within a wider bandwidth range. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 is a side cross-sectional view of a wave absorbing unit provided by one embodiment of the present invention;

[0022] Figure 2 is a schematic diagram of a plum blossom pattern provided by an embodiment of the present invention;

[0023] Figure 3 is a top view of a wave-absorbing metasurface provided by one embodiment of the present invention;

[0024] Figure 4 is an electromagnetic wave absorption characteristic curve of a test sample provided by an embodiment of the present invention;

[0025] Figure 5 is an oblique incidence angle stability curve of a test sample provided by an embodiment of the present invention;

[0026] Figure 6 is a light transmittance curve of a test sample provided by an embodiment of the present invention.

[0027] Reference numerals:

[0028] 1- First layer;

[0029] 2- Second layer;

[0030] 3- The third floor;

[0031] 4- the fourth floor;

[0032] 5- pattern layer;

[0033] 6- Floor layer. DETAILED DESCRIPTION

[0034] The present application is described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0035] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance; unless otherwise specified or explained, the term "multiple" refers to two or more; the terms "connected" and "fixed" should be understood in a broad sense, for example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0036] In the description of this specification, it should be understood that the directional words such as "upper" and "lower" described in the embodiments of the present application are described at the angles shown in the accompanying drawings and should not be understood as limiting the embodiments of the present application. In addition, in the context, it should also be understood that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to another element "upper" or "lower", but also indirectly connected to another element "upper" or "lower" through an intermediate element.

[0037] As mentioned above, the applicable bandwidth range of the absorbing metasurface in the prior art is relatively narrow, and therefore the scope of application is limited. To address this problem, the inventors propose that a pattern layer with gaps can be coated on the upper surface of the second layer of the absorption unit, and the gaps in the pattern layer can be used to make the incident electromagnetic waves resonate, thereby widening the bandwidth.

[0038] like Figure 1 As shown, it is a side cross-sectional view of the wave absorbing unit provided in the embodiment of the present application. As can be seen from the figure, the wave absorbing unit includes a first layer 1, a second layer 2, a third layer 3 and a fourth layer 4 stacked in sequence along the vertical direction; wherein,

[0039] The side where the first layer 1 is located is the side where the electromagnetic wave is incident. The material of the first layer 1 is polyvinyl chloride PVC, which is used to absorb part of the incident electromagnetic wave;

[0040] A pattern layer 5 with gaps is coated on one side of the second layer 2 close to the first layer 1, and the pattern layer 5 is used to make the incident electromagnetic wave resonate;

[0041] The third layer 3 is made of polyvinyl chloride (PVC), which is used to absorb part of the incident electromagnetic waves;

[0042] A continuous floor layer 6 is coated on one side of the fourth layer 4 away from the third layer 3 , and the floor layer 6 is used to reflect the remaining electromagnetic waves out of the absorbing unit.

[0043] The absorbing unit provided in the present application is achieved by coating a pattern layer with gaps on one side of the second layer close to the first layer, and utilizing the gaps in the pattern layer to cause the incident electromagnetic waves to resonate, thereby widening the bandwidth, so that the absorbing unit has a better absorbing effect within a wider bandwidth range.

[0044] In some embodiments, each layer of the medium is bonded using an optically transparent adhesive (OCA) to ensure light transmittance.

[0045] In some embodiments, the thickness of the first layer 1 and the third layer 3 is 2 mm, and the dielectric constant is 2.4C. 2 / (N·M 2 ).

[0046] In this embodiment, by optimizing the dielectric constants of the first layer 1 and the third layer 3, not only the wave absorption rate of the wave absorbing unit can be improved, but also the bandwidth can be widened and the incident angle of the electromagnetic wave can be improved, so that the electromagnetic wave incident angle has a good wave absorption effect in the range of 0 to 45 degrees. In addition, the thickness of the first layer 1 and the third layer 3 is 2 mm, which can ensure the flexibility and light transmittance of the wave absorbing unit while ensuring the wave absorption effect.

[0047] In some embodiments, the material of the second layer 2 and the fourth layer 4 includes at least one of polyethylene terephthalate and polyethylene naphthalate.

[0048] In this embodiment, polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) are both materials with high light transmittance and low refractive index. The use of these two materials will not affect people's visual judgment. Since polyethylene terephthalate (PET) is relatively low in cost, it can be used as a preferred material. Of course, users can also choose other materials with high light transmittance and low refractive index. This application does not specifically limit the materials.

[0049] In addition, in some embodiments, the thickness of the second layer 2 and the fourth layer 4 is 0.175 mm. This is because if the thickness of these two layers is too large, the light transmittance will be poor, and if the thickness is too thin, it will be unfavorable to coat the pattern layer 5 and the floor layer 6. In addition, since the thickness of the second layer 2 is small, it cannot meet the transmission phase condition. Therefore, the present application stacks the two materials in the second layer 2 and the fourth layer 4 to form a dielectric layer together.

[0050] In some embodiments, the material of the pattern layer 5 and the floor layer 6 is indium tin oxide, which is because indium tin oxide has good light transmittance and conductivity. In some embodiments, indium tin oxide can be coated on the second layer 2 and the fourth layer 4 by magnetron sputtering.

[0051] In addition, through broadband electromagnetic loss analysis, it can be seen that the larger the square resistance of the pattern layer 5, the better the electromagnetic absorption effect, but since the square resistance and transmittance of indium tin oxide are in an antagonistic relationship, the transmittance will deteriorate, and the transmittance is mainly related to the sputtering thickness. Therefore, through simulation methods, parameter scanning optimization can be performed multiple times to achieve a balance between the electromagnetic loss capacity and the transmittance of the pattern layer 5.

[0052] In some embodiments, the square resistance of the pattern layer 5 is 60Ω / sq. Under this resistance, the electromagnetic loss effect of the absorbing unit is the best, the electromagnetic wave absorption rate is higher than 90%, and the sputtering thickness of indium tin oxide is low, and the transmittance in the visible light band is high. In addition, since the pattern layer 5 has a high absorbency, the thickness of the first layer 1 and the third layer 2 can be reduced, so that the cross-sectional height of the entire absorbing unit can be reduced, and the transmittance and flexibility can be further improved, and the applicable scope of the absorbing unit is increased, such as special-shaped glass, solar panels, and transparent RF identification systems.

[0053] In some embodiments, the square resistance of the floor layer 6 is 15Ω / sq. This is because the absorbing unit is of a transmitting type, and under this resistance, the floor layer 6 can reflect the electromagnetic waves that are not absorbed to the free space outside the absorbing unit.

[0054] like Figure 2 As shown, in some embodiments, after indium tin oxide is coated on the second layer 2, the pattern layer 5 can be etched into a plum blossom pattern using a laser etching method. The gap structure in the plum blossom pattern can increase the equivalent capacitance value of the absorbing unit, achieve impedance matching between the absorbing unit and the free space, make the incident electromagnetic wave generate multiple resonances, and maximize the bandwidth.

[0055] In some embodiments, the size of the wave absorbing unit is 12 mm×12 mm×4.35 mm. Figure 2As shown, the geometric parameters of the plum blossom pattern are: unit period P = 12mm, outer arm length L1 = 11mm, outer protrusion length L2 = 3mm, plum blossom pattern width w1 = 6.6mm, outer protrusion width w2 = 1.2mm, outer arm width d = 0.6mm. After using the plum blossom pattern, the present application can achieve an absorption rate of more than 90% in the operating frequency band of 7.88-33.53GHz, and can still ensure an absorption rate of more than 80% when the oblique incident angle is 45°.

[0056] like Figure 3 As shown, it is a schematic diagram of an absorbing metasurface provided in an embodiment of the present application. The absorbing metasurface is composed of the absorbing units provided in any of the above embodiments, and has all the characteristics of the absorbing units, which will not be described one by one in this embodiment.

[0057] In order to verify that the absorbing unit has a high electromagnetic wave absorption rate and oblique incident angle stability, the inventor used an absorbing metasurface with a size of 300mm×300mm×4.35mm as a test sample, and verified the electromagnetic wave absorption characteristics and oblique incident angle stability of the test sample through the "arch frame + broadband dual horn antenna" test system.

[0058] like Figure 4 As shown, it is the electromagnetic wave absorption characteristic curve of the test sample. It can be seen from the figure that the test sample has an absorption rate of more than 90% in the working frequency band of 7.88 to 33.53 GHz.

[0059] like Figure 5 As shown, it is the oblique incident angle stability curve of the test sample. It can be seen from the figure that the electromagnetic wave absorption rate of the absorbing unit proposed in the present application is maintained above 90% within the oblique incident angle range of 0 to 45°, that is, the test sample has good incident angle stability.

[0060] In addition, the inventors tested the transmittance of the test samples using a Perkin & Elmer Lambda-950 UV / VIS spectrometer. The test results are as follows: Figure 6 As shown in the figure, it can be seen that within the visible light band (380nm-780nm), the average transmittance of the test sample is about 69.7%, that is, the test sample has a good transmittance.

[0061] In summary, since the test sample is composed of absorbing units, it can be determined based on the test results of the test sample that the absorbing unit and absorbing metasurface provided in the present application have an absorption rate of more than 90% in the working frequency band of 7.88 to 33.53 GHz, good incident angle stability in the range of 0 to 45° (that is, the absorption rate is greater than 90%) and an average light transmittance of approximately 69.7%.

[0062] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical factors in the process, method, article or device including the elements.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wave absorbing unit, characterized in that: It comprises a first layer (1), a second layer (2), a third layer (3) and a fourth layer (4) which are stacked in sequence in a vertical direction; wherein: The side where the first layer (1) is located is the side where the electromagnetic wave is incident, and the material of the first layer (1) is polyvinyl chloride, which is used to absorb part of the incident electromagnetic wave; A pattern layer (5) with gaps is coated on one side of the second layer (2) close to the first layer (1), and the pattern layer (5) is used to cause incident electromagnetic waves to resonate; The third layer (3) is made of polyvinyl chloride and is used to absorb part of the incident electromagnetic waves; A continuous floor layer (6) is coated on a side of the fourth layer (4) away from the third layer (3), and the floor layer (6) is used to reflect the remaining electromagnetic waves out of the absorbing unit; The thickness of the first layer (1) and the third layer (3) is 2 mm, and the dielectric constant is 2.4C2 / (N·M2); The pattern layer (5) is a plum blossom pattern; The square resistance of the pattern layer (5) is 60Ω / sq; The size of the absorbing unit is 12 mm×12 mm×4.35 mm, and the geometric parameters of the quincunx pattern are: unit period P=12 mm, outer arm length L1=11 mm, outer protrusion length L2=3 mm, quincunx pattern width w1=6.6 mm, outer protrusion width w2=1.2 mm, and outer arm width d=0.6 mm; The material of the second layer (2) and the fourth layer (4) includes at least one of polyethylene terephthalate and polyethylene naphthalate; The thickness of the second layer (2) and the fourth layer (4) is 0.175 mm; The square resistance of the floor layer (6) is 15Ω / sq.

2. The absorbing unit according to claim 1, characterized in that: The material of the pattern layer (5) and the floor layer (6) is indium tin oxide.

3. A wave-absorbing metasurface, characterized in that: It is composed of the wave absorbing units described in any one of claims 1 to 2.

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