Composite metamaterial wave absorber with tunable broadband

Abstract

The invention discloses a broadband tunable composite metamaterial wave absorber. A wave absorber unit is composed of a 3D printing structure on the upper layer, a PCB structure on the middle layer and a metal floor on the bottom layer. The 3D printing structure is a cuboid frame formed by 3D printing of a PLA material, and the frame is impregnated with carbon paste; metal wire patterns are etched on the upper surface and the lower surface of the PCB structure dielectric substrate, and the metal wire patterns on the upper surface are perpendicular to the metal wire patterns on the lower surface. The metal wire pattern is composed of a bending line of a trunk and parallel branches of branches; the overall structure of the wave absorber is formed by periodically extending units, and the PCB structure and the 3D printing structure are compounded through nylon screws to form the broadband tunable composite metamaterial wave absorber. The invention aims to realize dynamic tuning of wave absorption crest frequencies of P and L wave bands, and realize ultra-wideband wave absorption in S, C, X and Ku wave bands, so that the problem that high-frequency and low-frequency wave absorption of a traditional wave absorber is difficult to be compatible is solved.

Description

Technical Field

[0001] This invention belongs to the field of artificial electromagnetic materials, specifically relating to a broadband tunable composite metamaterial absorber. Background Technology

[0002] The rapid development of modern wireless communication, radar detection, and electronic equipment has led to an increasingly complex electromagnetic environment. Electromagnetic interference, information security, and equipment compatibility issues are becoming increasingly prominent. The widespread adoption of 5G technology and the advancement of 6G research have resulted in a surge in the number of wireless devices such as mobile phones, base stations, and satellites. Electromagnetic radiation issues may affect human health, interfere with the normal operation of electronic equipment, and cause electromagnetic energy waste. High-performance electromagnetic absorbers can absorb incident electromagnetic waves and convert them into heat energy, making them a key technology in electromagnetic protection and radar detection. Future applications of electromagnetic absorbers will primarily focus on: ultra-wideband and multi-band expansion, intelligent and dynamic control, and integrated functional structures.

[0003] Metamaterials are artificially designed materials that exhibit unique electromagnetic properties not found in natural materials. Metamaterial absorbers achieve highly efficient absorption of electromagnetic waves through specific structural designs, with the core mechanism being the synergistic effect of impedance matching and electromagnetic loss. When electromagnetic waves are incident on the surface of a metamaterial, the electromagnetic parameters of the structure are adjusted to match its wave impedance with the free-space impedance, minimizing reflection. Simultaneously, the resonant characteristics of the structure enhance the localization effect of the electromagnetic field, converting electromagnetic energy into heat or other forms of energy dissipation. In recent years, additive manufacturing (3D printing) technology has demonstrated unique advantages in the fabrication of complex metamaterial structures. However, in the practical application of metamaterial absorbers, challenges such as ultra-wide bandwidth, thinness, lightweight, extremely low frequency, and dynamic tunability remain difficult to simultaneously address.

[0004] Therefore, from an application perspective, there is an urgent need to explore an ultra-wideband electromagnetic absorber that also absorbs low-frequency waves and has dynamically adjustable performance, so as to expand the practical engineering application scenarios of electromagnetic absorbers. Summary of the Invention

[0005] The purpose of this invention is to provide a broadband tunable composite metamaterial absorber, which aims to achieve dynamic tunability of the absorption peak frequency in the P and L bands, and at the same time achieve ultra-wideband absorption in the S, C, X, and Ku bands, thereby improving the problem of incompatibility between high-frequency and low-frequency absorption in absorbers.

[0006] The technical solution to achieve the purpose of this invention is as follows: a broadband tunable composite metamaterial absorber, wherein the absorber unit consists of an upper 3D printed structure, a middle PCB structure, and a bottom metal floor; the 3D printed structure is a cuboid frame 3D printed from PLA material, and the four sides of the cuboid frame have gaps for the propagation of low-frequency electromagnetic waves in the P and L bands; the upper and lower surfaces of the dielectric substrate of the PCB structure are etched with metal line patterns, and the metal line patterns on the upper and lower surfaces are perpendicular to each other.

[0007] This invention provides a broadband tunable composite metamaterial absorber that solves the problem of incompatibility between high-frequency and low-frequency absorption in traditional absorbers, and has at least the following beneficial effects:

[0008] (1) The absorber unit designed in this invention has a working frequency band covering P, L, S, C, X and Ku bands, and achieves dynamic adjustable absorption in the frequency range of 0.55GHz-1.35GHz with a reflectivity of less than -10dB; and broadband absorption in the frequency range of 2GHz-18GHz with an average reflectivity of less than -15dB.

[0009] (2) The composite metamaterial absorber designed in this invention has a simple structure, thin thickness, and lightweight structure, and has great engineering application value;

[0010] (3) The composite metamaterial absorber designed in this invention has important application prospects in the fields of electromagnetic protection and radar detection. Attached Figure Description

[0011] Figure 1 This is a three-dimensional structural schematic diagram of the composite metamaterial absorber disclosed in the embodiments of the present invention.

[0012] Figure 2 This is a perspective view of the PCB structure of the middle layer of the composite metamaterial absorber disclosed in the embodiments of the present invention.

[0013] Figure 3 This is a schematic diagram of the 3D printed structure of the composite metamaterial absorber disclosed in the embodiments of the present invention.

[0014] Figure 4 This is a simulation of the dynamically adjustable reflectivity curves of the composite metamaterial absorber disclosed in the embodiments of the present invention in the P and L bands.

[0015] Figure 5 This is a broadband reflectivity curve of the composite metamaterial absorber disclosed in the embodiments of the present invention, simulated in the S, C, X, and Ku bands. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, it should be understood that the present invention can be implemented in various forms. The exemplary and non-limiting embodiments shown in the accompanying drawings and described below are not intended to limit the invention to the specific embodiments described.

[0017] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, this invention provides a broadband tunable composite metamaterial absorber in the microwave band, aiming to achieve dynamic tunability of the absorption peak frequency in the P and L bands, while simultaneously achieving ultra-wideband absorption in the S, C, X, and Ku bands, thereby improving the problem of incompatibility between high-frequency and low-frequency absorption in traditional absorbers. The absorber unit consists of an upper 3D-printed structure 1, a middle PCB structure 2, and a bottom metal ground plane 3. The 3D-printed structure 1 is a cuboid frame 3D-printed from PLA material, and the frame is impregnated with carbon paste. Metal line patterns 4 are etched on both the upper and lower surfaces of the PCB structure substrate, with the metal line patterns on the upper and lower surfaces perpendicular to each other. The metal line patterns consist of a bend in the main circuit 5 and parallel branches 6. A varactor diode 7 and a first surface mount resistor 8 are sequentially soldered onto the bend in the main circuit. A surface mount capacitor 9, a surface mount inductor 10, and a second surface mount resistor 11 are sequentially soldered onto the parallel branches, and a second feed line inductor 12 is soldered onto the edge feed line. The overall structure of the absorber is formed by periodically extending unit cells. 3D-printed structure 1 transmits waves in the P and L bands and absorbs waves in the S, C, X, and Ku bands; PCB structure 2 dynamically adjusts absorption in the P and L bands and reflects electromagnetic waves in the S, C, X, and Ku bands. PCB structure 2 and 3D-printed structure 1 are combined using nylon screws to form a composite metamaterial absorber with tunable absorption frequency in the P and L bands and broadband high absorption in the S, C, X, and Ku bands.

[0018] like Figure 1 As shown, in this embodiment, the dielectric substrate of the PCB structure 2 is FR4 board with a relative permittivity of 4.3; the relative permittivity of the PLA material is 2.6. The period P of the absorber unit is 18mm, the height h1 of the 3D printed structure 1 is 25mm, and the 3D printed structure 1 and the PCB structure 2 are joined by nylon screws, with an air layer of 0.5mm in height in between. The thickness of the dielectric substrate of the PCB structure 2 is h2=1mm, and the thickness of the air layer between the dielectric substrate and the bottom metal floor 3 is h3=11mm.

[0019] like Figure 2As shown, metal line patterns 4 are etched on both the upper and lower surfaces of the PCB structure 2, with the metal line patterns on the upper and lower surfaces perpendicular to each other. The metal line patterns consist of bends 5 in the main circuit and parallel links 6 in the branch circuits. The line width of the metal line pattern 4 is 0.5 mm, the width of the bends 5 in the main circuit is 0.8 mm, and the width of the parallel links 6 in the branch circuits is 0.5 mm. A varactor diode 7 and a first surface mount resistor 8 are sequentially soldered onto the bends 5 in the main circuit. The varactor diode 7 is model SMV2020-079LF, with a capacitance range of 0.35 pF-3.2 pF, and the first surface mount resistor 8 has a resistance of 30 Ω. A surface mount capacitor 9, a first surface mount inductor 10, and a second surface mount resistor 11 are sequentially soldered onto the parallel links in the branch circuits for impedance matching of electromagnetic waves of specific frequencies. A second surface mount inductor 12 is soldered onto the edge feed line to connect the feed line and isolate high-frequency signals. The metal wire pattern 4, the bend line 5 of the main road, and the parallel branch 6 of the branch road are all made of copper.

[0020] like Figure 3 As shown, the 3D-printed structure 1 is a cuboid frame 3D printed from PLA material, with a height h1 = 25 mm. Each of its four sides has a slit with a width w = 0.4 mm for the propagation of low-frequency electromagnetic waves in the P and L bands. The slit depth h4 = 21 mm. The surface of the 3D-printed structure 1 is impregnated with carbon paste, and its surface sheet resistance ranges from 300 Ω to 500 Ω. This is used for impedance matching and loss absorption of electromagnetic waves at specific frequencies.

[0021] Figure 4 This is a simulation of the dynamic adjustable reflectivity curves of the composite metamaterial absorber disclosed in the embodiments of the present invention in the P and L bands, which realizes dynamic adjustable absorption in the frequency range of 0.55GHz-1.35GHz, with a reflectivity of less than -10dB. Figure 5 This is a simulation of the broadband reflectivity curves of the composite metamaterial absorber disclosed in the embodiments of the present invention in the S, C, X, and Ku bands. It achieves broadband absorption in the frequency range of 2GHz-18GHz, with an average reflectivity of less than -15dB. The composite metamaterial absorber designed in this invention has a simple structure, thin thickness, and lightweight structure, and has significant engineering application value.

[0022] The above description is merely a preferred embodiment of the present invention. The same structure can be directly extended to the millimeter-wave band, infrared, terahertz, and visible light bands by scaling the size. This should not be construed as limiting the scope of the present invention; all simple equivalent changes and modifications made in accordance with the claims and description of the present invention should still fall within the scope of the patent coverage of this invention.

Claims

1. A broadband tunable composite metamaterial absorber, characterized in that, The absorber unit consists of an upper 3D printed structure (1), a middle PCB structure (2), and a bottom metal floor (3). The 3D printed structure (1) is a cuboid frame 3D printed from PLA material. There are gaps on the four sides of the cuboid frame for the propagation of low-frequency electromagnetic waves in the P and L bands. The upper and lower surfaces of the dielectric substrate of the PCB structure (2) are etched with metal line patterns (4), and the metal line patterns on the upper and lower surfaces are perpendicular to each other.

2. The broadband tunable composite metamaterial absorber according to claim 1, characterized in that, The 3D printed structure (1) has a surface impregnated with carbon paste, and the surface sheet resistance range is 300Ω-500Ω, which is used for impedance matching and loss absorption of high-frequency electromagnetic waves.

3. A broadband tunable composite metamaterial absorber according to claim 1 or 2, characterized in that, The 3D printed structure (1) has a height of 25mm, a gap width of 0.4mm, and a gap depth of 21mm.

4. The broadband tunable composite metamaterial absorber according to claim 1, characterized in that, The metal wire pattern (4) is composed of the bent line (5) of the main line and the parallel branch (6) of the branch; the bent line of the main line is welded with a varactor diode (7) and a first chip resistor (8) in sequence; the parallel branch is welded with a chip capacitor (9), a first chip inductor (10) and a second chip resistor (11) in sequence for impedance matching of electromagnetic waves of a specific frequency; the edge feed line is welded with a second chip inductor (12) for connecting the feed line and isolating high-frequency signals.

5. A broadband tunable composite metamaterial absorber according to claim 4, characterized in that, The varactor diode (7) is model SMV2020-079LF, with a capacitance range of 0.35pF-3.2pF, and the first chip resistor (8) has a resistance of 30Ω.

6. A broadband tunable composite metamaterial absorber according to claim 4, characterized in that, The metal wire pattern (4), the bend line of the main road (5), and the parallel branch of the branch road (6) are all made of copper.

7. A broadband tunable composite metamaterial absorber according to claim 1, characterized in that, The overall structure of the absorber is formed by periodic extension of units. The PCB structure and the 3D printed structure are combined with nylon screws, with an air layer of 0.5mm in height in between, forming a broadband tunable composite metamaterial absorber.

8. A broadband tunable composite metamaterial absorber according to claim 1, characterized in that, The relative permittivity of the PLA material is 2.

6.

9. A broadband tunable composite metamaterial absorber according to claim 1, characterized in that, The dielectric substrate of the PCB structure (2) is FR4 board with a relative permittivity of 4.

3.

10. A broadband tunable composite metamaterial absorber according to claim 1, characterized in that, The 3D printed structure (1) transmits waves in the P and L bands and absorbs waves in the S, C, X, and Ku bands; the PCB structure (2) absorbs waves dynamically and adjustable in the P and L bands and reflects electromagnetic waves in the S, C, X, and Ku bands.

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