A metasurface wave absorber based on square rectangular multi-nested structure

Abstract

The application discloses a square rectangle multi-nested structure based on a metasurface wave absorber, which is composed of a top metal resonant layer, a dielectric layer and a bottom metal layer. The proposed wave absorber is composed of a plurality of resonant unit periodic arrays, and the resonant layer is composed of a rectangular split ring and a square ring. The rectangular split ring is distributed on the outermost periphery of the dielectric layer, each rectangular split ring is composed of four rectangular connection structures, and the outer boundary of the rectangular split ring is coincided with the outer boundary of the dielectric layer, and the square ring is arranged at the inner center of the rectangular split ring and is kept a certain distance from the rectangular split ring. The proposed metasurface wave absorber has low manufacturing cost and simple structure, and the absorption rate at two frequency points of 6.46 GHz and 8.94 GHz reaches 99.4% and 99.8% respectively, and has very good double-band absorption characteristics.

Description

Technical Field

[0001] This invention pertains to electromagnetic wave absorption technology, and specifically relates to a metasurface absorber based on a rectangular multi-nested structure. Background Technology

[0002] Metasurfaces are artificial surfaces with subwavelength structures that allow for precise control of electromagnetic waves by manipulating their phase, amplitude, and polarization. By designing their geometry, material properties, and arrangement, metasurface absorbers can achieve absorption, reflection, and scattering of electromagnetic waves in ultra-thin forms. This overcomes the limitations of traditional absorbing materials, enabling strong absorption of specific frequency bands of electromagnetic waves in thinner structures, and even achieving multi-band and broadband absorption effects. This characteristic makes them highly promising for applications in electromagnetic stealth, radio wave interference suppression, and communication jamming.

[0003] When electromagnetic waves are incident on a metasurface absorber, three main phenomena occur: a portion of the electromagnetic waves are reflected, a portion is transmitted through the metasurface absorber, and the remaining portion is lost as energy in the dielectric layer. Due to the presence of the metal reflective layer, only a very small portion of the electromagnetic waves can penetrate. Therefore, by designing the structure of the metasurface absorber, it is possible to convert electromagnetic waves into other forms of energy in a specific frequency band, thereby achieving the absorption of electromagnetic waves. Summary of the Invention

[0004] To address existing technologies, this invention discloses a metasurface absorber based on a rectangular nested structure. The absorber comprises a top-layer metal resonant layer, a dielectric layer, and a bottom-layer metal reflective layer. The metal resonant layer is composed of a periodic array of multiple resonant units, each including a connecting rectangular split ring and a square ring. The dielectric layer has a square structure, with the center of the connecting rectangular split rings coinciding with the intersection of the diagonals of the dielectric layer, and its outer boundary coinciding with the boundary of the dielectric layer. The square rings are distributed around the inner center of the connecting rectangular split rings, maintaining a certain distance from them. This metasurface absorber is low in cost and simple in structure, achieving absorption rates of 99.4% and 99.8% at center frequencies of 6.44 GHz and 9.08 GHz, respectively, exhibiting excellent dual-band absorption characteristics.

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

[0006] A metasurface absorber based on a rectangular nested structure comprises, from top to bottom, a metal resonant layer, a dielectric layer, and a metal reflective layer. The proposed absorber's metal resonant layer is composed of a periodic array of multiple resonant units. Each resonant unit includes a connecting rectangular split ring and a square ring structure. Each connecting rectangular split ring consists of four rectangular connecting structures. Each resonant unit's rectangular connecting structure is formed by connecting a first rectangular structure and two second rectangular structures, with the length of the first rectangular structure greater than the length of the second rectangular structure. One side of the first rectangular structure along its length coincides with the boundary of the dielectric layer. The two second rectangular structures are connected side-by-side along their width to the other side of the first rectangular structure along its length, maintaining a 3mm distance between them. The center of the connecting rectangular split ring structure coincides with the intersection of the diagonals of the square of the dielectric layer. The connecting rectangular split rings are distributed around the perimeter of the dielectric layer, with their outer boundaries coinciding with the dielectric layer boundary. The square ring is located at the inner center of the connecting rectangular split rings, with its outer boundary maintaining a 4.9mm distance from the dielectric layer boundary. The metal resonant layer, dielectric layer, and metal reflective layer constitute an absorber unit structure, with the metal resonant layer attached to the top layer of the dielectric layer and the metal reflective layer attached to the bottom layer of the dielectric layer.

[0007] Furthermore, the thickness of both the top metal resonant layer and the bottom metal reflective layer is 0.035 mm. In the rectangular connection structure of each unit structure metal resonant layer, the length l1 and width w1 of the long rectangle are 1 mm and 10 mm, respectively, the length l2 and width w2 of the short rectangle are 2 mm and 1.5 mm, respectively, the distance t between the two short rectangles is 3 mm, the inner side length l3 and outer side length l4 of the square ring are 3.8 mm and 6 mm, respectively, the dielectric layer and the metal reflective layer of the absorber are both squares with equal side lengths, and the side length L is 15.8 mm. The thickness X1 of the dielectric layer is 1.8 mm.

[0008] Furthermore, both the metal resonant layer and the metal reflective layer are made of copper with a thickness of 0.035 mm, and the dielectric layer is made of FR-4 epoxy resin, with a relative permittivity and loss tangent of 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 to two second rectangular structures. One side of the first rectangular structure along the length direction coincides with the boundary of the dielectric layer. The two second rectangular structures are connected side by side along the width direction to the other side of the first rectangular structure along the length direction, and a distance of 3mm is maintained between the two second rectangular structures.

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

[0011] 1. The resonant layer of this invention is composed of simple nested patterns. 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 6.38GHz-6.52GHz and 8.96GHz-9.18GHz, obvious resonance peaks are generated at two frequency points of 6.44GHz and 9.08GHz, respectively. The absorption rate of the absorber at these two center frequency points reaches 99.4% and 99.8%, respectively. Compared with similar metasurface absorbers, the absorption effect is better. Moreover, the structure of the absorber is a simple nested structure such as rectangles and square rings, which makes the manufacturing process simple.

[0012] 2. The absorber of this invention combines a simple resonant layer structure with excellent dual-band absorption performance. The absorber's unit structure comprises only three parts: a top-layer metal resonant layer, a dielectric layer, and a metal reflective layer. The metal resonant layer is composed of an array of multiple periodic units. The top-layer metal resonant unit includes nested rectangular split-ring structures and square ring structures. Furthermore, the absorption rates at 6.46 GHz and 8.94 GHz reach 99.4% and 99.8% respectively, exhibiting very high absorption rates compared to similar metamaterial absorbers. The absorber of this invention corresponds to a minimum resonant electromagnetic wave frequency band of 6.44 GHz, with a wavelength of 0.046 m. ​​However, in the design of traditional absorbers, the thickness is typically designed to be one-quarter of the wavelength of the absorbed electromagnetic wave. Therefore, the thickness of a traditional absorber designed to absorb 6.44 GHz electromagnetic waves is 0.0115 m, while the overall thickness of the absorber of this invention is 1.87 mm, significantly thinner than traditional metasurface absorbers. It's still smaller than twice.

[0013] The following will provide a detailed description with reference to the accompanying drawings and embodiments. Attached Figure Description

[0014] Figure 1 This is a structural diagram of a metasurface absorber based on a rectangular nested structure.

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

[0016] Figure 3 This is a structural diagram of the combination of the dielectric layer and the underlying metal reflective layer of the present invention;

[0017] Figure 4 This is a graph showing the absorption characteristics of the 4-10GHz frequency band of this invention.

[0018] Explanation of reference numerals in the attached figures:

[0019] In the diagram: 1. Metal resonant layer; 2. Dielectric layer; 3. Metal reflective layer; 4. Connecting rectangular split ring; 5. Square ring. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0021] like Figure 1 As shown, the present invention discloses a metasurface absorber based on a rectangular multi-nested structure, comprising, from top to bottom, a metal resonant layer 1, a dielectric layer 2, and a metal reflective layer 3. The proposed absorber's metal resonant layer 1 is composed of a periodic array of multiple resonant units, each resonant unit including a connecting rectangular split ring and a square ring, such as... Figure 1 As shown by the dashed lines and dotted lines, the connecting rectangular split rings are distributed around the dielectric layer. Each connecting rectangular split ring consists of four rectangular connecting structures, and the outer boundary of the connecting rectangular split ring coincides with the unit boundary. The rectangular connecting structure in each resonant unit is formed by connecting one 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 the two second rectangular structures are connected side by side along the width direction to the other side of the first rectangular structure along the length direction, and the two second rectangular structures maintain a distance of 3 mm between them. The square ring is located at the inner center of the connecting rectangular split ring and maintains a certain distance from it.

[0022] In this embodiment, the top metal resonant layer 1 and the bottom metal reflective 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] like Figure 2 As shown, in the rectangular connection structure of each metal resonant layer, the length and width of the first rectangular structure are l1 = 1 mm and w1 = 10 mm, respectively; the length and width of the second rectangular structure are l2 = 2 mm and w2 = 1.5 mm, respectively; the distance between the two second rectangular structures is t = 3 mm; and the inner and outer side lengths of the square ring are l3 = 3.8 mm and l4 = 6 mm, respectively.

[0024] like Figure 3 As shown, the dielectric layer 2 and the metal reflective layer 3 of the absorber of the present invention are both squares with equal side lengths, each with a side length of L = 15.8 mm. The thickness of the dielectric layer 2 is X1 = 1.8 mm, and the thickness of the metal reflective layer 3 is X2 = 0.035 mm.

[0025] like Figure 4As shown, the HFSS electromagnetic simulation software was used to simulate a metasurface absorber based on a rectangular nested structure according to this embodiment. A single-unit boundary condition was used in the horizontal direction, and an open boundary condition was used in the vertical direction. The electromagnetic wave was incident perpendicularly. Figure 4 The absorption characteristic curves of the periodic element array absorber in the 4-10 GHz frequency band are given by... Figure 4 It can be seen that the absorption rate of the absorber reaches more than 90% in the two frequency bands of 6.38GHz-6.52GHz and 8.96GHz-9.18GHz. In the two resonant frequency bands, obvious resonant peaks are generated near the two frequency points of 6.44GHz and 9.08GHz, respectively, and the absorption rates reach 99.4% and 99.8%, respectively, which meets the characteristics of dual frequency band and high absorption rate.

[0026] This invention also provides a method for fabricating a metasurface absorber based on a rectangular multi-nested structure: using PCB technology, the designed resonant structure is metal-printed on the dielectric layer 2 to obtain a metal resonant layer; the dielectric layer 2 and the metal reflective layer 3 are bonded and printed together to obtain a metasurface absorber based on a rectangular multi-nested structure.

[0027] The working principle of this 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, it achieves efficient absorption of electromagnetic waves. Its working principle lies in the resonant characteristics of the metasurface units. When an electromagnetic wave is incident on the metasurface, the structural units of the metal resonant layer 1 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 electromagnetic wave energy. When the electromagnetic wave enters the absorber, due to the presence of the metal reflective layer 3, the amount of electromagnetic wave reflected is almost zero. Therefore, most of the electromagnetic wave energy is consumed by the dielectric loss and resistive loss within the material when passing through the dielectric layer 2, thus achieving the absorption effect.

Claims

1. A metasurface absorber based on a rectangular multi-nested structure, characterized in that: include: A metal resonant layer, a dielectric layer, and a metal reflective layer; wherein the metal resonant layer is attached to the top layer of the dielectric layer, and the metal reflective layer is attached to the bottom layer of the dielectric layer; The metal resonant layer is composed of a periodic array of multiple resonant units, each of which includes a connecting rectangular split-ring structure and a square ring. The dielectric layer has a square structure, with the center of the connecting rectangular split-ring structure coinciding with the intersection of the diagonals of the dielectric layer. The square rings are distributed at the inner center of the connecting rectangular split-ring structure, and the outer boundary of the square rings 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 distributed around the dielectric layer. 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 its length coincides with the boundary of the dielectric layer, and two second rectangular structures are connected side by side along their width to the other side of the first rectangular structure along its length, with a distance of 3 mm between the two second rectangular structures.

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

3. The metasurface absorber based on a 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 both the metal resonant layer and the metal reflective layer is 0.035 mm.

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

5. A metasurface absorber based on a 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. A metasurface absorber based on a rectangular multi-nested structure according to claim 1, characterized in that: Both the metal resonant layer and the metal reflective layer are made of copper, and the dielectric layer is made of FR-4 epoxy resin, which has a relative permittivity of 4.4 and a loss tangent of 0.

02.

7. A metasurface absorber based on a rectangular multi-nested structure according to claim 1, characterized in that: Furthermore, 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 located below the long rectangular structure is 3mm.

8. A metasurface absorber based on a rectangular multi-nested structure according to claim 1, characterized in that: The metal resonant layer is deposited on the dielectric layer by metal printing, and the metal reflective layer is adhered and printed on the dielectric layer.

Images