Super-surface wave absorber based on rectangular multi-nested structure

Abstract

The invention discloses a metasurface wave absorber based on a rectangular multi-nested structure. The structure is composed of a top metal resonance layer, a dielectric layer and a bottom metal layer. The wave absorber is composed of a plurality of resonant unit periodic arrays, and a resonant layer of the wave absorber is composed of a rectangular split ring and a square ring which are connected. The connecting rectangular split rings are distributed on the outermost periphery of the dielectric layer, each connecting rectangular split ring is composed of four rectangular connecting structures, the outer boundary of each connecting rectangular split ring coincides with the outer boundary of the dielectric layer, and the square rings are located at the centers of the inner sides of the connecting rectangular split rings and keep a certain distance from the connecting rectangular split rings. The metasurface wave absorber is low in manufacturing cost and simple in structure, the absorption rates of the metasurface wave absorber at the two frequency points of 6.46 GHz and 8.94 GHz reach 99.4% and 99.8% respectively, and the metasurface wave absorber has the very good dual-band absorption characteristic.

Description

Technical Field

[0001] The present invention belongs to the field of electromagnetic wave absorption technology, and particularly relates to a metasurface absorber based on a square-rectangular multi-nested structure. Background Art

[0002] A metasurface is an artificial surface with sub-wavelength structures, which can precisely control electromagnetic waves by controlling their phase, amplitude, and polarization. By designing its geometric shape, material properties, and arrangement, a metasurface absorber can achieve functions such as absorption, reflection, and scattering of electromagnetic waves in an ultra-thin form. It breaks through the limitations of traditional absorbing materials and can achieve strong absorption of electromagnetic waves in a specific frequency band in a thinner structure, and even achieve multi-band and wide-band absorption effects. This feature gives it great application potential in the fields of electromagnetic stealth, radio waves, and communication interference suppression.

[0003] When electromagnetic waves enter a metasurface absorber, mainly three phenomena occur: a part of the electromagnetic waves are reflected, a part of the electromagnetic waves are transmitted through the metasurface absorber, and another part is dissipated in the dielectric layer in the form of energy. Due to the presence of the metal reflection layer, only a very small part of the electromagnetic waves can penetrate. Therefore, by designing the structure of the metasurface absorber, electromagnetic waves can be converted into other forms of energy in a specific frequency band, thereby achieving the absorption of electromagnetic waves. Summary of the Invention

[0004] In view of the prior art, the present invention discloses a metasurface absorber based on a square-rectangular multi-nested structure. The absorber includes a top metal resonant layer, a dielectric layer, and a bottom metal reflection layer; the metal resonant layer is composed of a periodic array of multiple resonant units, and the resonant unit includes a connected rectangular split ring and a square ring; the dielectric layer is a square structure, the center of the connected rectangular split ring structure coincides with the intersection point of the diagonal of the dielectric layer, and its outer boundary coincides with the boundary of the dielectric layer; the square rings are distributed at the centers of the inner sides of the connected rectangular split rings around and maintain a certain distance from them. The metasurface absorber has low manufacturing cost and simple structure, and the absorption rates at the center frequencies of 6.44 GHz and 9.08 GHz reach 99.4% and 99.8% respectively, having very good dual-band absorption characteristics.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A metasurface absorber based on a square-rectangular multi-nested structure includes a metal resonant layer, a dielectric layer, and a metal reflection layer from top to bottom in sequence; the proposed metal resonant layer of the absorber consists of a periodic array of multiple resonant units, and each resonant unit includes an interconnected rectangular split ring and a square ring structure, and each interconnected rectangular split ring is composed of four rectangular connection structures; each rectangular connection structure in each resonant unit is formed by connecting a first rectangular structure and two second rectangular structures, and the length of the first rectangular structure is greater than the length of the second rectangular structure; one side of the first rectangular structure along the length direction coincides with the boundary of the dielectric layer, and one side of the two second rectangular structures along the width direction is juxtaposed and connected to the other side of the first rectangular structure along the length direction, and a distance of 3 mm is maintained between the two second rectangular structures. The center of the interconnected rectangular split ring structure coincides with the intersection of the diagonals of the square of the dielectric layer. The interconnected rectangular split rings are distributed around the dielectric layer and the outer boundary coincides with the boundary of the dielectric layer. The square ring is located at the inner center of the interconnected rectangular split ring and the outer boundary is 4.9 mm away from the boundary of the dielectric layer. The metal resonant layer, the dielectric layer, and the metal reflection layer form the absorber unit structure. The metal resonant layer is attached to the top layer of the dielectric layer, and the metal reflection layer is attached to the bottom layer of the dielectric layer.

[0007] Further, the thicknesses of both the top metal resonant layer and the bottom metal reflection layer are 0.035 mm. In the rectangular connection structure of the metal resonant layer of each unit structure, the length l 1 and width w 1 of the long rectangular structure are 1 mm and 10 mm respectively, and the length l 2 and width w 2 of the short rectangular structure are 2 mm and 1.5 mm respectively. The distance t between the two short rectangular structures is 3 mm. The inner side length l 3 and outer side length l 4 of the square ring are 3.8 mm and 6 mm respectively. The dielectric layer and the metal reflection layer of the absorber are both squares with equal side lengths, and the side length L is 15.8 mm. The thickness X 1 of the dielectric layer is 1.8 mm.

[0008] Further, both the metal resonant layer and the metal reflection layer are made of copper with a thickness of 0.035 mm, and the dielectric layer is made of FR-4 epoxy resin. The relative permittivity and loss tangent of FR-4 epoxy resin are 4.4 and 0.02 respectively.

[0009] Furthermore, the connecting rectangular split ring is composed of four rectangular connecting structures. In each rectangular connecting structure, the first rectangular structure is seamlessly connected with two second rectangular structures. One side of the first rectangular structure along the length direction coincides with the boundary of the dielectric layer. One side of the two second rectangular structures along the width direction is juxtaposed and connected to the other side of the first rectangular structure along the length direction, and a distance of 3 mm is maintained between the two second rectangular structures.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0011] 1. The structure of the resonant layer of the present invention is composed of simple pattern nesting. When electromagnetic waves are incident on the metasurface absorber, the absorber has a perfect impedance effect with the external medium. In the two frequency bands of 6.38 GHz - 6.52 GHz and 8.96 GHz - 9.18 GHz, obvious resonant peaks are generated at the two frequency points of 6.44 GHz and 9.08 GHz respectively, and the absorption rates of the absorber at these two center frequency points reach 99.4% and 99.8% respectively. Compared with the same type of metasurface absorber, the absorption effect is better, and the structure of the absorber is the nesting of simple structures such as rectangles and square rings, and the manufacturing process is simple.

[0012] 2. The absorber of the present invention takes into account the simple structure of the resonant layer and the good performance of dual-band absorption. The unit structure of the absorber only includes three parts, namely the top metal resonant layer, the dielectric layer and the metal reflection layer; the metal resonant layer is composed of the structure of multiple periodic unit arrays. The top metal resonant unit includes a nested rectangular split ring structure and a square ring structure, and the absorption rates at the two frequency points of 6.46 GHz and 8.94 GHz reach 99.4% and 99.8% respectively, and it has a very high absorption rate compared with the same type of metamaterial absorber; the lowest resonant point electromagnetic wave frequency band corresponding to the absorber of the present invention is 6.44 GHz, and the wavelength of the electromagnetic wave in this frequency band is 0.046 m. However, when designing a traditional absorber, the thickness is usually designed to be one-fourth of the wavelength of the electromagnetic wave corresponding to the absorbed frequency band. Therefore, the thickness of the absorber designed to absorb the electromagnetic wave of 6.44 GHz in the traditional absorber is 0.0115 m, while the overall thickness of the absorber of the present invention is 1.87 mm, which is smaller than times that of the traditional metasurface absorber.

[0013] The following will be described in detail with reference to the embodiments and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is the overall structure diagram of a metasurface absorber based on a square-rectangle multi-nested structure of the invention;

[0015] Figure 2 It is the schematic diagram of the top metal resonant layer of the present invention;

[0016] Figure 3 Combined structural diagram of the dielectric layer and the bottom metal reflection layer of the present invention;

[0017] Figure 4 Absorption characteristic curve of the 4 - 10 GHz frequency band of the present invention;

[0018] Explanation of reference numerals:

[0019] In the figure: 1, metal resonance layer; 2, dielectric layer; 3, metal reflection layer; 4, connecting rectangular split ring; 5, square ring. Detailed implementation manner

[0020] The present invention will be further described below in conjunction with the accompanying drawings and the detailed implementation manner.

[0021] As Figure 1 shown, a metasurface absorber based on a square - rectangle multi - nested structure of the present invention includes, from top to bottom, a metal resonance layer 1, a dielectric layer 2, and a metal reflection layer 3 in sequence; the proposed metal resonance layer 1 of the absorber is composed of a periodic array of multiple resonance units, and the resonance unit includes a connecting rectangular split ring and a square ring, as Figure 1 shown by the dashed line and the dotted - dashed line in; the connecting rectangular split rings are distributed around the dielectric layer, each connecting rectangular split ring is composed of four rectangular connecting structures, and the outer boundary of the connecting rectangular split ring coincides with the unit boundary. Each rectangular connecting structure in each resonance unit is formed by connecting a first rectangular structure and two second rectangular structures, and the length of the first rectangular structure is greater than the length of the second rectangular structure; one side of the first rectangular structure along the length direction coincides with the boundary of the dielectric layer, and one side of the two second rectangular structures along the width direction is juxtaposed and connected to the other side of the first rectangular structure along the length direction, and a distance of 3 mm is maintained between the two second rectangular structures; the square ring is located at the inner center of the connecting rectangular split ring and is kept at a certain distance from it.

[0022] In this embodiment, the top metal resonance layer 1 and the bottom metal reflection layer 3 of the absorber are both made of copper with a thickness of 0.035 mm, and the dielectric layer 2 is made of FR - 4 epoxy resin with a dielectric constant and a loss tangent of 4.4 and 0.02 respectively.

[0023] As Figure 2 shown, in the rectangular connecting structure of each metal resonance layer, the length and width of the first rectangular structure are l 1 = 1 mm and w 1 = 10 mm respectively, and the length and width of the second rectangular structure are l 2 = 2 mm and w 2= 1.5 mm, the distance between the two second rectangular structures is t = 3 mm, and the inner and outer side lengths of the square ring are l 3 = 3.8 mm and l 4 = 6 mm.

[0024] As Figure 3 shown, the dielectric layer 2 and the metal reflection layer 3 of the absorber of the present invention are both squares with equal side lengths, and the side lengths are both L = 15.8 mm. The thickness X of the dielectric layer 2 1 = 1.8 mm, and the thickness X of the metal reflection layer 3 2 = 0.035 mm.

[0025] As Figure 4 shown, the HFSS electromagnetic simulation software is used to perform simulation operations on a metasurface absorber based on a square-rectangle multi-nested structure of the present embodiment. The boundary conditions of the unit structure are adopted in the horizontal direction, and the open boundary conditions are adopted in the vertical direction. The electromagnetic wave is incident vertically. Figure 4 is the absorption characteristic curve of the periodic unit array absorber in the 4 - 10 GHz frequency band. It can be seen from Figure 4 this that the absorption rate of the absorber reaches more than 90% in the two frequency bands of 6.38 GHz - 6.52 GHz and 8.96 GHz - 9.18 GHz. Obvious resonance peaks are generated near the two frequency points of 6.44 GHz and 9.08 GHz respectively in the two resonance frequency bands, and the absorption rates reach 99.4% and 99.8% respectively, meeting the characteristics of dual-band and high absorption rate.

[0026] The present invention also provides a manufacturing method of a metasurface absorber based on a square-rectangle multi-nested structure: using the PCB process, metal printing is performed on the dielectric layer 2 for the designed resonant structure to obtain a metal resonant layer; the dielectric layer 2 and the metal reflection layer 3 are adhesively printed to obtain a metasurface absorber based on a square-rectangle multi-nested structure.

[0027] The working principle of the present invention: The metasurface absorber utilizes the electromagnetic resonance effect. By designing the geometric structure of the metal resonant layer 1 and selecting specific material parameters, efficient absorption of electromagnetic waves is achieved. Its working principle lies in the resonance characteristics of the metasurface unit. When an electromagnetic wave is incident on the metasurface, the structural unit of the metal resonant layer 1 will generate electromagnetic resonance, causing the energy of the electromagnetic wave to be locally concentrated and absorbed. This local resonance effect greatly improves the response to electromagnetic waves of a specific frequency, enabling the absorber to effectively capture and dissipate the electromagnetic wave energy. When the electromagnetic wave enters the absorber, due to the presence of the metal reflection layer 3, the amount of the reflected electromagnetic wave is almost zero. Therefore, most of the electromagnetic wave energy is consumed in the form of dielectric loss and resistance loss inside the material when passing through the dielectric layer 2, thereby achieving the absorption effect.

Claims

1. A metasurface absorber based on a square-rectangular multi-nested structure, characterized in that: include: A metal resonance layer, a dielectric layer and a metal reflection layer; wherein the metal resonance layer is attached to the top layer of the dielectric layer, and the metal reflection layer is attached to the bottom layer of the dielectric layer; The metal resonance layer is composed of a periodic array of multiple resonance units, and the resonance units include: a connected rectangular split ring structure and a square ring; the dielectric layer is a square structure, the center of the connected rectangular split ring structure coincides with the intersection of the diagonal of the dielectric layer, the square rings are distributed at the inner center of the connected rectangular split ring structure, and the outer boundary of the square ring maintains a distance of 4.9 mm from the boundary of the dielectric layer; The connecting rectangular split ring is composed of four rectangular connecting structures, which are respectively distributed around the dielectric layer, and each rectangular connecting structure is formed by connecting a first rectangular structure and two second rectangular structures, and the length of the first rectangular structure is greater than the length of the second rectangular structure; One side of the first rectangular structure along the length direction coincides with the boundary of the dielectric layer, one side of two second rectangular structures along the width direction is connected in parallel to the other side of the first rectangular structure along the length direction, and a distance of 3 mm is maintained between the two second rectangular structures.

2. The metasurface absorber based on a square-rectangular multi-nested structure according to claim 1, characterized in that: The dielectric layer and the metal reflective layer are both square, and the side lengths of the squares are both 15.8 mm.

3. The metasurface absorber based on a square-rectangular multi-nested structure according to claim 1, characterized in that: The thickness of the dielectric layer is 1.8 mm, and the thickness of the metal resonance layer and the metal reflection layer are both 0.035 mm.

4. The metasurface absorber based on a square-rectangular multi-nested structure according to claim 1, characterized in that: The length and width of the first rectangular structure in the rectangular connection structure are 1 mm and 10 mm respectively, and the length and width of the second rectangular structure are 2 mm and 1.5 mm respectively.

5. The metasurface absorber based on a square-rectangular multi-nested structure according to claim 1, characterized in that: The inner side length of the square ring is 3.8 mm, and the outer side length of the square ring is 6 mm.

6. The metasurface absorber based on a square-rectangular multi-nested structure according to claim 1, characterized in that: The metal resonance layer and the metal reflection layer are both made of copper, and the dielectric layer is made of FR-4 epoxy resin. The relative dielectric constant of the FR-4 epoxy resin is 4.4, and the loss tangent is 0.

02.

7. The metasurface absorber based on a square-rectangular multi-nested structure according to claim 1, characterized in that: The longer side of the short rectangular structure is perpendicular to the longer side of the long rectangular structure, and the distance between the two short rectangular structures below the long rectangular structure is 3 mm.

8. The metasurface absorber based on a square-rectangular multi-nested structure according to claim 1, characterized in that: The metal resonance layer is arranged on the dielectric layer by metal printing, and the metal reflection layer is adhesively printed on the dielectric layer.

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