CN108400448A - Candy type Meta Materials wave absorbing device - Google Patents

Abstract

The invention discloses a candy-shaped metamaterial wave absorber, which includes a plurality of wave absorbing units arranged continuously along a plane, and each wave absorbing unit includes a first PET layer and an FR-4 layer of the same size from top to bottom. , PMMA layer, a square dielectric substrate formed by stacking the second PET layer medium, a square resistive film attached to the lower side of the dielectric layer and having the same size as the dielectric layer, and a candy-shaped resistive film attached to the upper side of the dielectric layer. Each part of the candy-shaped resistive film has the same width, and is located directly above the dielectric substrate, and the geometric centers of the two are coincident. The entire candy-shaped resistive film is an axisymmetric structure, which is composed of two equal-length circular arcs, four equal-length short arms connected to both ends of the arc, and two equal-length long arms connected and perpendicular to the four short arms. The invention has high absorptivity, wide working frequency band and stable absorptivity to obliquely incident electromagnetic waves.

Description

Candy-shaped metamaterial wave absorber

technical field

The invention belongs to the field of electromagnetic waves and novel artificial electromagnetic materials, and in particular relates to a candy-shaped metamaterial wave absorber.

Background technique

The absorbing technology is mainly a class of materials that use absorbing materials to effectively absorb incident electromagnetic waves and make them scatter and attenuate. It converts incident electromagnetic waves into heat energy or other energy through various loss mechanisms of materials to achieve the purpose of absorbing electromagnetic waves.

The metamaterial absorber is a structural absorber. The absorbing array is formed by periodic absorbing units. Each absorbing unit is generally a "sandwich" structure, consisting of a metal pattern on the top layer, a dielectric substrate in the middle layer, and a bottom layer. metal stub or ground plate. The performance of the metamaterial absorber depends largely on the geometric shape, size, arrangement, etc. Therefore, the design of the above parameters can realize the flexible regulation of the equivalent electromagnetic parameters of the metamaterial, and then meet the actual needs.

However, there is still a considerable gap between the absorption bandwidth of metamaterial absorbers and the bandwidth required by practical applications. Broadening the absorption frequency band is an urgent need in practical applications. In recent years, people have done a lot of research on the broadband metamaterial absorber. Commonly used methods include unit combination method, coherent and destructive method based on multi-layer media, and loss enhancement by loading lumped elements.

In the article "Design of P-band absorber based on metamaterials and magnetic materials", Yang Jingxian and others proposed a composite absorber made of metamaterials and magnetic materials, and realized the low-frequency absorption of the absorber through electromagnetic coupling technology. However, there are problems of low absorption peak and narrow working bandwidth.

According to the effective medium theory, the dielectric layer is an important part of the metamaterial structure, and its multilayer structure design is an effective means to improve its absorption bandwidth. Apply the multi-layer design theory of absorbing materials to the design of broadband metamaterials, use different structures of metamaterials in different layers according to the principle of impedance matching, and adjust the equivalent permittivity and equivalent permeability of each layer of metamaterial structure , so that the electromagnetic waves of different frequency bands resonate with the metamaterial structure of different layers, so as to realize the incident and absorption of electromagnetic waves layer by layer, and finally achieve the purpose of broadband absorption.

Contents of the invention

The purpose of the present invention is to provide a candy-shaped metamaterial wave absorber, which solves the problems of the existing metamaterial wave absorber such as low absorption rate, narrow working frequency band, and unstable absorption rate of obliquely incident electromagnetic waves.

The technical solution to realize the purpose of the present invention is: a candy-shaped metamaterial wave absorber, which adopts an infinite period structure, and includes N*M wave absorbing units connected in sequence, where N represents the number of columns, M represents the number of rows, and N ≥2, M≥1, the absorbing unit includes a candy-shaped resistive film, a square dielectric substrate, and a square resistive film arranged in sequence from top to bottom, and the square dielectric substrate includes a first PET layer arranged in sequence from top to bottom , FR-4 layer, PMMA layer, second PET layer, wherein the candy-shaped resistance film is sprayed on the top surface of the first PET layer, and the square resistance film is sprayed on the bottom surface of the second PET layer.

The candy-shaped resistive film has an axisymmetric structure, and its geometric center coincides with that of the dielectric substrate.

The candy-shaped resistive film includes two equal-length arcs, four equal-length short arms, and two equal-length long arms. The openings of the two arcs are opposite and symmetrically spaced. It is connected with one end of two short arms of equal length, and two long arms of equal length are respectively connected with two short arms located at the same end and on different arcs, and the widths of the arcs, short arms and long arms are the same.

The length of the long arm is greater than the distance between two short arms at the same end and on different arcs.

Compared with the prior art, the present invention has the following remarkable advantages: (1) high absorption rate; (2) wide operating frequency range; (3) stable absorption rate for obliquely incident electromagnetic waves; (4) simple structure and easy manufacture.

Description of drawings

Fig. 1 is a structural schematic diagram of the absorbing unit of the candy-shaped metamaterial wave absorber of the present invention.

Fig. 2 is a top view of the structure of the wave absorbing unit of the candy-shaped metamaterial wave absorber of the present invention.

Fig. 3 is a side view of the wave absorbing unit of the candy-shaped metamaterial wave absorber of the present invention.

Fig. 4 is a simulation result diagram of the absorption rate of the candy-shaped metamaterial wave absorber of the present invention when the electromagnetic wave is perpendicularly incident.

Fig. 5 is a simulation result diagram of the absorption rate of the candy-shaped metamaterial wave absorber of the present invention for TM waves under different incident angles.

Fig. 6 is a simulation result diagram of the absorption rate of the candy-shaped metamaterial wave absorber of the present invention for TE waves under different incident angles.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

The candy-shaped metamaterial wave absorber of the present invention has an infinite period structure, including N*M wave absorbing units connected in sequence, where N represents the number of columns, M represents the number of rows, N≥2, M≥1.

As shown in Figure 1, Figure 2 and Figure 3, each absorbing unit includes a candy-shaped resistive film 1, a square dielectric substrate 2 and a square resistive film 3 arranged in sequence from top to bottom, and the square dielectric substrate 2 includes The first PET layer 21, FR-4 layer 22, PMMA layer 23, and second PET layer 24 are arranged in sequence from top to bottom, wherein the candy-shaped resistance film 1 is sprayed on the top surface of the first PET layer 21, and the square resistance film 3 is sprayed. on the bottom surface of the second PET layer 24 .

The candy-shaped resistive film 1 has an axisymmetric structure, and its geometric center coincides with the geometric center of the dielectric substrate 2 . The candy-shaped resistive film 1 includes two equal-length circular arcs 1-1, four equal-length short arms 1-2 and two equal-length long arms 1-3, and the openings of the two equal-length arcs 1-1 are opposite to each other. , arranged symmetrically at intervals, the two ends of the circular arc 1-1 are respectively connected to one end of two equal-length short arms 1-2, and the two equal-length long arms 1-3 are respectively connected to the same end and have different circular arcs The two short arms 1-2 on 1-1, the above-mentioned circular arc 1-1, short arm 1-2 and long arm 1-3 have the same width.

The length of the long arm 1-3 is greater than the distance between two short arms 1-2 located at the same end and on different arcs 1-1.

The dielectric constant of the first PET layer 21 and the second PET layer 24 in the dielectric substrate 2 is ε _r1 =3.0, and the loss tangent is t _d1 =0.06. The dielectric constant of the FR-4 layer 22 in the dielectric substrate 2 is ε _r2 =4.4, and the loss tangent is t _d2 =0.02. The dielectric constant of the PMMA layer 23 in the dielectric substrate 2 is ε _r3 =2.25, and the loss tangent is t _d3 =0.001.

Example 1

A candy-shaped metamaterial wave absorber is an infinite periodic structure, including N*M wave absorbing units connected in sequence, and the structural size parameters of each layer of each wave absorbing unit are as follows: the side length p of the wave absorbing unit = 13 mm, the thickness h ₁ of the candy-shaped resistive film 1 = 0.175 mm, and the square resistance value R of the candy-shaped resistive film 1 = 100Ω. The line width of the candy-shaped resistive film 1 is s=0.5mm, the outer diameter of the arc 1-1 is r=3.9mm, the length of the short arm 1-2 is n=1.3mm, and the length of the long arm 1-3 is m=5mm. The first PET layer 21 and the second PET layer 24 have the same thickness, h ₂ =0.175 mm, the thickness h ₃ of the FR-4 layer 22 =0.85 mm, and the thickness h ₄ of the PMMA layer 23 =2.25 mm.

The simulation results are shown in Fig. 4, Fig. 5 and Fig. 6. The advantages of the candy-shaped metamaterial wave absorber of the present invention are as follows:

1. High absorption rate: the peak absorption rate of the present invention is 100.0% at 11.42GHz, and the absorption rate of the absorber is above 90% in the 7.31GHz-15.20GHz frequency band; in the 10.24GHz-12.57GHz frequency band, the absorption The rate is above 99%. It has the characteristics of "perfect wave absorption".

2. Working frequency bandwidth: the absorption rate of the present invention exceeds 90%, and the relative absorption bandwidth can reach 69.1%, and the working frequency bandwidth is wide.

3. The absorption rate of obliquely incident electromagnetic waves is stable: when the incident angle gradually increases, the frequency corresponding to the absorption peak of the absorber shifts to the right, but the bandwidth with an absorption rate above 99% can guarantee More than 2GHz, the relative bandwidth of the absorption rate above 90% is guaranteed to exceed 60%, with good stability.

4. The structure is simple and easy to manufacture.

In summary, the working frequency band of the candy-shaped metamaterial wave absorber of the present invention completely covers the X-band and partially covers the Ku-band, and can perfectly absorb electromagnetic waves of a specific band, and has great advantages in the detection and stealth of X-band radars. application value.

Claims (4)

1. a kind of candy type Meta Materials wave absorbing device using infinite period structure, including is sequentially connected N*M suction wave list of arrangement Member, wherein N indicate that columns, M indicate line number, N >=2, M >=1, it is characterised in that：The suction wave unit includes from up to down successively The candy type resistive film of setting（1）, square medium substrate（2）With square resistance film（3）, the square medium substrate （2）Including the first pet layer set gradually from top to bottom（21）, FR-4 layers（22）, PMMA layers（23）, the second pet layer（24）, Middle candy type resistive film（1）It is sprayed on the first pet layer（21）Top surface, square resistance film（3）It is sprayed on the second pet layer（24）Bottom Face.

2. candy type Meta Materials wave absorbing device according to claim 1, it is characterised in that：The candy type resistive film（1）It is in Axially symmetric structure, geometric center and medium substrate（2）Geometric center overlap.

3. candy type Meta Materials wave absorbing device according to claim 1 or 2, it is characterised in that：The candy type resistive film（1） Including two sections of isometric circular arcs（1-1）, four sections of isometric galianconism（1-2）It is isometric long-armed with two（1-3）, two sections of circular arcs（1- 1）Opening is opposite, interval is symmetrical arranged, the circular arc（1-1）Both ends respectively with two sections of isometric galianconism（1-2）One end phase Even, two it is isometric long-armed（1-3）It is separately connected positioned at the same end and different circular arcs（1-1）On two galianconism（1-2）, above-mentioned Circular arc（1-1）, galianconism（1-2）With it is long-armed（1-3）Width all same.

4. candy type Meta Materials wave absorbing device according to claim 3, it is characterised in that：It is described long-armed（1-3）Length it is big In positioned at the same end and different circular arcs（1-1）On two galianconism（1-2）Spacing.