Microwave-millimeter wave compatible wave absorber based on multilayer super surface

Abstract

The application discloses a microwave-millimeter wave compatible wave absorber based on a multilayer super surface, which adopts a multilayer metal-dielectric composite structure; the composite structure is composed of a first metal layer (1), a first dielectric layer (2), a second metal layer (3), a second dielectric layer (4), a third dielectric layer (5), a fourth dielectric layer (6), a third metal layer (7), a fifth dielectric layer (8) and a fourth metal layer (9) from top to bottom; wherein the first metal layer (1) is a millimeter wave band wave absorbing layer, the second metal layer (3) is a millimeter wave metal ground, the third metal layer (7) is a microwave band wave absorbing unit, and the fourth metal layer (9) is a complete metal ground. Simulation and experimental results show that the wave absorber realizes a wave absorption rate of more than 90% in a 5.59 GHz-6.13 GHz microwave frequency band and a 139.1 GHz millimeter wave frequency band, has the advantages of compact structure, thin thickness, low cost, cross-band compatible wave absorption and the like, and is suitable for electromagnetic interference suppression and stealth application in a next-generation communication system.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic wave absorption and stealth technology, and in particular to a microwave-millimeter wave cross-band compatible absorption technology based on a multi-layer metasurface structure. It is suitable for electromagnetic interference suppression and target stealth applications in next-generation communication systems, and can also be used in the fields of electromagnetic compatibility and stealth protection in microwave and millimeter wave bands. Background Technology

[0002] Metamaterials, as an emerging type of wave-absorbing material, allow for more flexible electromagnetic parameter design by freely adjusting the effective dielectric constant and magnetic permeability of the medium to control the propagation direction of electromagnetic waves. This enables wider bandwidth, thinner and lighter volume, and stronger absorption and stealth effects.

[0003] In next-generation mobile communication technologies, operating frequency bands will cover the GHz to THz range. The diversity of application scenarios and the complexity of electromagnetic environments will continue to increase, leading to a growing demand for low-cost, thin absorbers compatible with both GHz and millimeter waves. However, in traditional absorber research, single-frequency absorbers typically operate within a very narrow frequency band, while multi-frequency or wide-band absorbers also have limited operating bands, making it difficult to span large frequency ranges and meet the demands. Therefore, there is an urgent need for a low-cost absorber capable of operating across a wide frequency band to cope with increasingly complex electromagnetic environments. Summary of the Invention

[0004] Technical Problem: The purpose of this invention is to provide a microwave-millimeter wave compatible absorber based on a multilayer metasurface to achieve microwave-millimeter wave cross-band compatible absorption, thereby solving the technical problem that existing technologies cannot adapt to complex electromagnetic environments and have limited applications.

[0005] Technical solution: The present invention provides a microwave-millimeter-wave compatible absorber based on a multilayer metasurface, which adopts a multilayer metal-dielectric composite structure. The composite structure consists of a first metal layer, a first dielectric layer, a second metal layer, a second dielectric layer, a third dielectric layer, a fourth dielectric layer, a third metal layer, a fifth dielectric layer, and a fourth metal layer from top to bottom. The first metal layer is a millimeter-wave absorbing layer, the second metal layer is a millimeter-wave metal ground, the third metal layer is a microwave absorbing unit, and the fourth metal layer is a complete metal ground.

[0006] The first metal layer comprises 6×6 millimeter-wave absorbing units arranged in a matrix, each absorbing unit employing a Jerusalem cross structure.

[0007] The millimeter-wave absorbing unit adopts a Jerusalem cross structure, which includes a central cross structure composed of two horizontal branches and a vertical branch of the same length, as well as an isosceles trapezoidal structure circumscribed around the cross structure. The geometric center distance between any two adjacent millimeter-wave absorbing units is 2.8-3.2 mm.

[0008] The material of the first dielectric layer is Rogers RT 5880, with a relative permittivity of 2.2 and a loss tangent of 0.0009.

[0009] The materials of the third and fifth dielectric layers are FR4, with a relative permittivity of 4.4 and a loss tangent of 0.025.

[0010] The second and fourth dielectric layers are made of Rogers 4450F, with a relative permittivity of 3.7 and a loss tangent of 0.004.

[0011] The second metal layer is divided into a checkerboard pattern by three longitudinal rectangular slots and three transverse rectangular slots; the metal ground, which serves as the millimeter-wave absorbing unit, generates strong resonance with the millimeter-wave absorbing unit during wave absorption.

[0012] The third metal layer is a microwave absorbing structure, consisting of four identical substructures that are symmetrical about the center of the third metal layer. Each substructure consists of two multi-order resonant structures that are mirror-symmetrical about the left and right sides.

[0013] The multi-order resonant structure is composed of multiple curved metal strips arranged in a gradient, with the multiple curved metal strips connected by a straight metal strip; the length of the curved metal strips decreases from the outermost edge to the inner edge.

[0014] The fourth metal layer is a complete metal ground, and has the same shape and size as the fifth dielectric.

[0015] Beneficial effects: Compared with the prior art, the technical solution of the present invention has the following advantages: 1. This invention achieves highly efficient and compatible absorption across a wide frequency band, from microwave to millimeter wave, through a layered design of a millimeter-wave absorbing layer and a microwave absorbing layer. The millimeter-wave absorbing layer employs a Jerusalem cross structure, achieving narrowband high-efficiency absorption in the 139.1 GHz millimeter-wave band. The microwave absorbing layer utilizes a multi-order resonant structure, forming broadband absorption through multiple adjacent resonant peaks, achieving stable absorption in the 5.59 GHz-6.13 GHz microwave band. Furthermore, the absorption rate in both bands exceeds 90%, effectively adapting to the complex electromagnetic environment of the GHz to THz frequency band in next-generation communication systems and meeting the core requirements of electromagnetic interference suppression and stealth applications.

[0016] 2. The two-layer absorbing structure designed in this invention is independent in electromagnetic response. The millimeter-wave metal ground does not affect the electromagnetic waves in the microwave band. Therefore, parameters can be adjusted separately for the absorption requirements of the microwave and millimeter-wave bands. Adjusting the absorption performance of one band does not affect the working effect of the other, significantly improving the adaptability of the absorber in different application scenarios and reducing the design difficulty for optimization of specific frequency bands.

[0017] 3. This invention adopts a multi-layer metal-dielectric composite integrated structure. The thickness of each metal layer is only 0.035mm, and the thickness of the dielectric layer is controlled within a reasonable range through optimized design. The overall structure has no redundant design, achieving compactness and thinness. It effectively solves the problems of complex structure and large size of traditional cross-band absorbers, and is more convenient to integrate into various equipment or scenarios with strict limitations on installation space.

[0018] 4. The metal and dielectric layer materials used in this invention (such as Rogers RT 5880, Rogers 4450F, FR4, etc.) are all mature, mass-produced materials available on the market, with convenient access. Furthermore, the processing technology for each layer conforms to the conventional manufacturing processes of existing microwave and millimeter-wave devices, requiring no special customized equipment or complex processing techniques, significantly reducing manufacturing costs and mass production difficulty. Simultaneously, its excellent absorption performance, thin and light structure, and low cost advantages make it widely applicable and valuable in multiple technical fields such as next-generation communication systems, electromagnetic compatibility protection, and target stealth. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the microwave-millimeter-wave compatible absorber based on a multilayer metasurface according to the present invention. Figure 2 This is a schematic diagram of the structure of the first metal layer 1 of a microwave-millimeter-wave compatible absorber based on a multilayer metasurface. Figure 3 This is a schematic diagram of the millimeter-wave absorbing unit 11 of a microwave-millimeter-wave compatible absorber based on a multilayer metasurface. Figure 4 This is a schematic diagram of the structure of the second metal layer 3 in a microwave-millimeter wave compatible absorber based on a multilayer metasurface. Figure 5 This is a schematic diagram of the third metal layer 7 in a microwave-millimeter wave compatible absorber based on a multilayer metasurface. Figure 6 To determine the microwave-to-millimeter wave reflectance and absorptivity of a microwave-to-millimeter wave compatible absorber based on a multilayer metasurface under X-polarized wave incidence, Figure 7 The reflection coefficient and absorption rate of a microwave-millimeter wave compatible absorber based on a multilayer metasurface under X-polarized wave incidence in the millimeter wave band are calculated.

[0020] It includes: a first metal layer 1, a first dielectric layer 2, a second metal layer 3, a second dielectric layer 4, a third dielectric layer 5, a fourth dielectric layer 6, a third metal layer 7, a fifth dielectric layer 8, and a fourth metal layer 9; a millimeter-wave absorbing unit 11, a transverse branch 12, a longitudinal branch 13, an isosceles trapezoidal structure 14; a longitudinal rectangular groove 21, a transverse rectangular groove 21, a substructure 31, a multi-order resonant structure 32, and six curved metal strips 33. Specific implementation methods

[0021] This invention proposes a microwave-millimeter-wave compatible absorber based on a multilayer metasurface. The absorber employs a multilayer metal-dielectric composite structure and achieves efficient compatible absorption across a wide frequency band by independently designing the microwave and millimeter-wave absorbing layers. Compared with existing technologies, this invention simplifies the absorber design process, allows for a greater difference in absorbing frequency bands, and reduces costs, providing a potential solution for reducing electromagnetic pollution across a wide frequency band in next-generation mobile communication technologies.

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0023] like Figure 1 As shown, this invention proposes a microwave-millimeter wave compatible absorber based on a multilayer metasurface. The structure includes a millimeter wave absorbing layer, a millimeter wave metal ground, a microwave band absorbing layer, a dielectric layer, and a complete metal backplate.

[0024] The microwave-millimeter-wave compatible absorber structure based on a multilayer metasurface of the present invention comprises four metal layers and five dielectric layers. The layered structure, from top to bottom, includes: The first layer is the first metal layer 1.

[0025] The second layer is the first dielectric layer 2.

[0026] The third layer is the second metal layer 3.

[0027] The fourth layer is the second dielectric layer 4.

[0028] The fifth layer is the third dielectric layer 5.

[0029] The sixth layer is the fourth dielectric layer 6.

[0030] The seventh layer is the third metal layer 7.

[0031] The eighth layer is the fifth dielectric layer 8.

[0032] The ninth layer is the fourth metal layer 9.

[0033] The first dielectric layer 2 is Rogers RT 5880, with a relative permittivity of 2.2 and a loss tangent of 0.0009.

[0034] The first dielectric layer 2 has a square dielectric structure with a side length of 18 mm and a thickness of 0.254 mm.

[0035] The second dielectric layer 4 and the fourth dielectric layer 6 are Rogers 4450F, with a relative permittivity of 3.7 and a loss tangent of 0.004.

[0036] The dielectric structure of the second dielectric layer 4 and the fourth dielectric layer 6 is square, with a side length of 18 mm and a thickness of 0.101 mm.

[0037] The third dielectric layer 5 and the fifth dielectric layer 8 are FR4 with a relative permittivity of 4.4 and a loss tangent of 0.025.

[0038] The dielectric structure of the third dielectric layer 5 and the fifth dielectric layer 8 is square with a side length of 18mm. The thickness of the third dielectric layer 5 is 0.4mm, and the thickness of the fifth dielectric layer 8 is 2mm.

[0039] The first metal layer comprises 6×6 millimeter-wave absorbing units, each of which adopts a Jerusalem cross structure.

[0040] The millimeter-wave absorbing unit adopts a Jerusalem cross structure, which includes a central cross structure composed of two horizontal branches of the same length and a vertical branch, as well as an isosceles trapezoidal structure circumscribed around it. Each branch of the central cross structure is 1.45 mm long and 0.15 mm wide. The upper base of the isosceles trapezoid is 0.8 mm, the lower base is 1.3 mm, and the height is 0.25 mm.

[0041] The first metal layer comprises 6×6 millimeter-wave absorbing units, with a geometric center spacing of 3 mm between each adjacent millimeter-wave absorbing unit and a thickness of 0.035 mm.

[0042] The thickness of the first metal layer is 0.035 mm.

[0043] The second metal layer has a checkerboard structure and serves as the metal ground of the millimeter-wave absorbing unit, generating strong resonance with the millimeter-wave absorbing unit during wave absorption.

[0044] The second metal layer has a checkerboard structure, with a square outer contour, divided into a checkerboard pattern by three vertical rectangular cutouts and three horizontal rectangular cutouts.

[0045] The longitudinal rectangular cutouts of the second metal layer are spaced 5.6 mm apart, and the distance between the longitudinal rectangular cutouts and the outer boundaries of the left and right sides is 2.8 mm.

[0046] The horizontal rectangular cutouts of the second metal layer are spaced 5.6 mm apart, and the distance between the horizontal rectangular cutouts and the outer boundaries of the upper and lower sides is 2.8 mm.

[0047] The second metal layer has a square metal structure with a side length of 18 mm and a thickness of 0.035 mm.

[0048] The third metal layer is a microwave absorbing structure, which consists of four identical substructures, and each substructure consists of two mirror-symmetric multi-order resonant structures.

[0049] The multi-stage resonant structure consists of gradient-arranged curved metal strips, with six curved metal strips connected by a straight metal strip. The outermost curved metal strip has a length of 3.6 mm, and the distance from the lower zigzag structure to the straight metal strip is 0.2 mm. The length of the curved metal strips decreases from the outermost edge. The length difference between the first five metal strips is 0.21 mm. To prevent the four substructures from overlapping, the length difference between the shortest metal strip and the fifth metal strip is set to 0.3 mm.

[0050] The third metal layer adopts a curved metal strip structure mainly to increase the current path when the microwave segment unit absorbs waves within the smallest possible area, and to reduce the size difference between the millimeter wave absorbing structure and the microwave segment absorbing structure.

[0051] The third metal layer has a side length of 13.4 mm and a thickness of 0.035 mm.

[0052] The fourth metal layer is a complete metal ground layer, with the same shape and size as the fifth dielectric layer. The thickness of the fourth metal layer is 0.035 mm.

[0053] like Figure 6 As shown, under X-polarized wave incident light, the metasurface absorber of this invention exhibits excellent absorption performance in the microwave band. Within the frequency range of 5.59 GHz to 6.13 GHz, the metasurface has a reflection coefficient less than or equal to -10 dB and an absorption rate greater than or equal to 90%.

[0054] like Figure 7 As shown, under X-polarized wave incident light, the metasurface absorber of this invention exhibits excellent absorption performance in the millimeter-wave band. At approximately 139.1 GHz, the reflection coefficient is less than or equal to -10 dB, demonstrating narrowband absorption, with an absorption rate greater than or equal to 90%.

[0055] It should be further noted that the absorber provided in this embodiment operates at center frequencies of 5.85 GHz and 139.1 GHz. By adjusting the unit size, its operating frequency band can be flexibly adjusted while still achieving good multi-functional electromagnetic control performance.

[0056] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A microwave-millimeter-wave compatible absorber based on a multilayer metasurface, characterized in that: The absorber adopts a multi-layer metal-dielectric composite structure; the composite structure consists of a first metal layer (1), a first dielectric layer (2), a second metal layer (3), a second dielectric layer (4), a third dielectric layer (5), a fourth dielectric layer (6), a third metal layer (7), a fifth dielectric layer (8), and a fourth metal layer (9) from top to bottom; wherein the first metal layer (1) is a millimeter-wave absorbing layer, the second metal layer (3) is a millimeter-wave metal ground, the third metal layer (7) is a microwave absorbing unit, and the fourth metal layer (9) is a complete metal ground.

2. The microwave-millimeter-wave compatible absorber based on a multilayer metasurface according to claim 1, characterized in that: The first metal layer (1) includes 6×6 millimeter-wave absorbing units (11) arranged in a matrix, each absorbing unit adopting a Jerusalem cross structure.

3. The microwave-millimeter-wave compatible absorber based on a multilayer metasurface according to claim 2, characterized in that: The millimeter-wave absorbing unit (11) adopts a Jerusalem cross structure, including a central cross structure composed of two horizontal branches (12) and a vertical branch (13) of the same length, and an isosceles trapezoidal structure (14) circumscribed around the cross structure. The geometric center distance between any two adjacent millimeter-wave absorbing units (11) is 2.8-3.2 mm.

4. The microwave-millimeter-wave compatible absorber based on a multilayer metasurface according to claim 1, characterized in that: The material of the first dielectric layer (2) is Rogers RT 5880, with a relative permittivity of 2.2 and a loss tangent of 0.0009.

5. The microwave-millimeter-wave compatible absorber based on a multilayer metasurface according to claim 1, characterized in that: The materials of the third dielectric layer (5) and the fifth dielectric layer (8) are FR4, with a relative permittivity of 4.4 and a loss tangent of 0.

025.

6. The microwave-millimeter-wave compatible absorber based on a multilayer metasurface according to claim 1, characterized in that: The materials of the second dielectric layer (4) and the fourth dielectric layer (6) are Rogers 4450F, with a relative permittivity of 3.7 and a loss tangent of 0.

004.

7. The microwave-millimeter-wave compatible absorber based on a multilayer metasurface according to claim 1, characterized in that: The second metal layer (3) is divided into a checkerboard pattern by three longitudinal rectangular slots (21) and three transverse rectangular slots (21); the metal ground, which serves as the millimeter wave absorbing unit, generates strong resonance with the millimeter wave absorbing unit during wave absorption.

8. The microwave-millimeter-wave compatible absorber based on a multilayer metasurface according to claim 1, characterized in that: The third metal layer (7) is a microwave absorbing structure, consisting of four identical substructures (31) that are symmetrical about the center of the third metal layer (7), and each substructure consists of two multi-order resonant structures (32) that are mirror-symmetrical about the left and right sides.

9. The microwave-millimeter-wave compatible absorber based on a multilayer metasurface according to claim 8, characterized in that: The multi-order resonant structure (32) is composed of multiple curved metal strips (33) arranged in a gradient, and the multiple curved metal strips (33) are connected by a straight metal strip (34); the length of the curved metal strips decreases from the outermost edge to the inner edge.

10. The microwave-millimeter-wave compatible absorber based on a multilayer metasurface according to claim 1, characterized in that: The fourth metal layer (9) is a complete metal ground, and has the same shape and size as the fifth dielectric layer (8).

Images