CN112134025B

CN112134025B - Multi-frequency metamaterial wave absorber

Info

Publication number: CN112134025B
Application number: CN202011021578.7A
Authority: CN
Inventors: 邓光晟; 吕坤; 孙寒啸; 杨军; 尹治平
Original assignee: Hefei University of Technology
Current assignee: Hefei University of Technology
Priority date: 2020-09-25
Filing date: 2020-09-25
Publication date: 2022-06-10
Anticipated expiration: 2040-09-25
Also published as: CN112134025A

Abstract

The invention discloses a multi-frequency metamaterial wave absorber which sequentially comprises a metal thin film layer, a loss dielectric layer and a metal pattern layer from bottom to top; the metal pattern layer comprises an open square ring with an opening and a tooth-shaped structure which is positioned inside the open square ring and is provided with a plurality of 7-shaped teeth. The metal pattern layer is designed into a shape comprising the open square ring with the opening and a tooth-shaped structure with a plurality of 7-shaped teeth positioned inside the open square ring, so that the metal pattern layer has high symmetry and polarization insensitivity.

Description

Multi-frequency metamaterial wave absorber

Technical Field

The invention relates to the technical field of wave-absorbing materials, in particular to a multi-frequency metamaterial wave absorber.

Background

As a composite material with an artificially designed structure, the metamaterial draws high attention from the scientific community due to unique physical properties of the metamaterial, such as negative refraction materials, perfect lenses, invisible cloaks and the like. The metamaterial wave absorber is an important application field of the metamaterial, and has the advantages of flexible design, adjustable response, thin thickness and the like. In addition, the metamaterial wave absorber can realize ultra-wide band and extremely-narrow band through a well-designed structure, and is widely applied to the fields of stealth materials, frequency selective surfaces, terahertz imaging, intelligent communication, photoelectric detection and the like. In recent years, researchers have made a lot of researches in the direction of a multiband metamaterial wave absorber, but the main problem of the multiband metamaterial wave absorber is that the absorption rate under large-angle incident waves is very low, so that the practical application of the device is greatly limited.

Disclosure of Invention

The invention aims to provide a multi-frequency metamaterial wave absorber to improve the absorption rate of the wave absorber under large-angle incident waves.

In order to achieve the purpose, the invention provides the following scheme:

a multi-frequency metamaterial wave absorber comprises a metal thin film layer, a loss dielectric layer and a metal pattern layer from bottom to top in sequence;

the metal pattern layer comprises an open square ring with an opening and a tooth-shaped structure which is positioned inside the open square ring and is provided with a plurality of 7-shaped teeth.

Optionally, the number of the openings of the square opening ring is four, and the four openings respectively use the central points of the four sides of the square opening ring as the center.

Optionally, the absorption frequency of the wave absorber is adjusted by adjusting the size of the opening of the square ring.

Optionally, the middle part of the tooth-shaped structure is a cuboid;

a plurality of '7' shaped teeth are evenly distributed on the outer part of the cuboid.

Optionally, the 7-shaped teeth comprise long longitudinal rods, transverse rods and short longitudinal rods;

one end of the short longitudinal rod is vertically connected with one end of the transverse rod, and the other end of the transverse rod is vertically connected with one end of the long longitudinal rod;

the other end of the long vertical rod is connected with the cuboid.

Optionally, the number of the 7-shaped teeth is 8, and the included angle between two adjacent 7-shaped teeth is 45 °.

Optionally, the metal thin film layer and the metal pattern layer are made of metal copper.

Optionally, the material of the lossy dielectric layer is a photosensitive resin material.

According to the specific embodiment provided by the invention, the invention discloses the following technical effects:

the invention discloses a multi-frequency metamaterial wave absorber which sequentially comprises a metal film layer, a loss dielectric layer and a metal pattern layer from bottom to top; the metal pattern layer comprises an open square ring with an opening and a tooth-shaped structure which is positioned inside the open square ring and is provided with a plurality of 7-shaped teeth. The metal pattern layer is designed into a shape comprising the open square ring with the opening and a tooth-shaped structure with a plurality of 7-shaped teeth positioned inside the open square ring, so that the metal pattern layer has high symmetry and polarization insensitivity.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

FIG. 1 is a schematic structural diagram of a multi-frequency metamaterial wave absorber provided by the present invention;

FIG. 2 is a top view of a structure of a multi-frequency metamaterial wave absorber provided in the present invention;

FIG. 3 is a front view of a structure of a multi-frequency metamaterial wave absorber provided by the present invention;

FIG. 4 is a graph showing the results of a simulation of the absorption rate of the absorber at normal incidence according to the present invention;

FIG. 5 is a diagram showing the result of the absorption rate simulation of the wave absorber provided by the present invention under the condition of different polarization angles of TE polarized waves;

FIG. 6 is a graph showing the absorption rate simulation result of the wave absorber provided by the present invention under different incident angles of TE polarized waves;

FIG. 7 is a graph showing the results of the absorption rate simulation of TE polarized waves of the absorbers having different opening sizes according to the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

As shown in fig. 1-3, the wave absorber of the present invention comprises a bottom metal thin film layer, a middle lossy dielectric layer, and a top metal pattern layer, which are sequentially arranged from bottom to top. The metal pattern layer on the top layer consists of a square ring with 4 openings and 8 7-shaped structures which are rotated by 45 degrees. The bottom metal film is an all-metal film. In the specific implementation process, the corresponding structural arrangement comprises:

the dielectric substrate (loss dielectric layer) is of a cubic structure with the side length of a and the thickness of h, and the thicknesses of the metal pattern layer on the top layer and the metal film layer on the bottom layer are both t. The outer side length of the square open ring is b, the ring width is w1, and the opening distance (opening size) is b 1. The height of the 7-shaped teeth is h1, the side length of the upper part (transverse rod) is L, the height of the left part (short longitudinal rod) is h2, the ring width is w2, and the ring widths of all the positions are equal. The middle parts of 8 7-shaped teeth are filled with cuboids with the side length of w, and the rotating angle of the adjacent seven-shaped structures is 45 degrees.

In a specific application, the following are set:

22mm for a, 1mm for h, 0.02mm for t, 20mm for b, 1.5mm for w1, 3mm for b1, 7mm for h1, 3.7mm for L, 2.2mm for h2, 1mm for w2, 3mm for w, and 45 ° for θ. The dielectric layer material is photosensitive resin material, the dielectric constant is 2.9, and the loss tangent is 0.02.

Fig. 4 is a graph of a simulation result of the normal incidence absorptance of the absorber obtained by the simulation software. It can be seen from fig. 4 that the absorption rate for normal incidence is also high.

Fig. 5 is a diagram of the result of the absorption rate simulation of the absorber under different polarization angles of the TE polarized wave, which is obtained by simulation software. The wave absorption rate curves under different polarization angles are consistent, so that the wave absorber has polarization insensitivity.

Fig. 6 is a graph showing the results of the absorption rate simulation by simulation software for different oblique incident angles of the TE polarized wave. When the angle of incidence reaches 45 deg., the absorption is higher than 0.9. When the angle of incidence reaches 60 deg., the absorption is also higher than 0.8. Therefore, the wave absorber has good absorption performance under the condition of large-angle oblique incidence.

Fig. 7 is a graph of the results of absorptance simulation at different opening pitches obtained by simulation software. As the opening pitch increases, the second and third absorption peaks shift to the right.

The wave absorber is a multi-frequency metamaterial wave absorber working in a C-K wave band, and incident waves of multiple frequency points are perfectly absorbed by utilizing the mutually coupled resonance units. Compared with the traditional multi-frequency metamaterial wave absorber, the multi-frequency metamaterial wave absorber is thinner in structure thickness, smaller in volume and easy to machine. The absorption frequency of the wave absorber can be changed by changing the opening distance of the square opening ring. The absorption rate is high under the condition of large-angle incident waves, and the polarization insensitivity of the incident waves is realized.

Compared with the prior art, the invention has the following advantages:

1. for the multi-frequency metamaterial wave absorber, the absorption rate of the multi-frequency metamaterial wave absorber at 3 working frequency points of the multi-frequency metamaterial wave absorber reaches over 98 percent for vertically incident electromagnetic waves.

2. The multi-frequency metamaterial wave absorber has high symmetry, so that the multi-frequency metamaterial wave absorber has the polarization insensitivity.

3. The multi-frequency metamaterial wave absorber can change the position of an absorption peak by changing the opening distance of the opening square ring.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The principle and the implementation manner of the present invention are explained by applying specific examples, the above description of the embodiments is only used to help understanding the method of the present invention and the core idea thereof, the described embodiments are only a part of the embodiments of the present invention, not all embodiments, and all other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the protection scope of the present invention.

Claims

1. The multi-frequency metamaterial wave absorber is characterized by comprising a metal thin film layer, a loss dielectric layer and a metal pattern layer from bottom to top in sequence;

the metal pattern layer comprises an open square ring with an opening and a tooth-shaped structure which is positioned in the open square ring and is provided with a plurality of 7-shaped teeth;

the number of the openings of the opening square ring is four, and the four openings respectively use the center points of four edges of the opening square ring as centers;

the middle part of the tooth-shaped structure is a cuboid;

a plurality of 7-shaped teeth are uniformly distributed outside the cuboid;

the 7-shaped teeth comprise long longitudinal rods, transverse rods and short longitudinal rods;

the other end of the long longitudinal rod is connected with the cuboid;

the number of the 7-shaped teeth is 8, and the included angle between every two adjacent 7-shaped teeth is 45 degrees.

2. The multi-frequency metamaterial wave absorber of claim 1, wherein the absorption frequency of the wave absorber is adjusted by adjusting the size of the openings of the square ring of openings.

3. The multi-frequency metamaterial wave absorber of claim 1, wherein the material of the metal thin film layer and the metal pattern layer is copper.

4. The multi-frequency metamaterial wave absorber of claim 1, wherein the material of the lossy dielectric layer is a photosensitive resin material.