Electromagnetic metamaterial wave absorber periodic unit

Abstract

The invention provides an electromagnetic metamaterial wave absorber periodic unit which comprises M * N metamaterial wave absorbing units in periodic arrangement, each metamaterial wave absorbing unit comprises an absorbing layer, an air layer and a reflecting layer which are sequentially arranged from top to bottom, each absorbing layer comprises a first dielectric substrate and an absorbing unit, each absorbing unit comprises a first metal patch and a resistor patch, the first metal patch is arranged on the upper surface of the first dielectric substrate, and the resistor patch is welded on the surface of the first metal patch; the reflecting layer comprises a second dielectric substrate and a reflecting unit, the reflecting unit comprises a second metal patch, and the second metal patch is arranged on the upper surface of the second dielectric substrate. The absorbing layer can absorb electromagnetic waves of a single frequency point, the reflecting layer can reflect low-frequency-band electromagnetic waves back to the absorbing layer, and the air layer has the functions of impedance matching and bandwidth expanding. The ultra-wide wave-absorbing band wave-absorbing material is simple in structure, easy to process and low in cost, has the advantages of ultra-wide wave-absorbing band and good in-band absorbing effect, and has wide application prospects in the aspects of electromagnetic protection and radar stealth.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic wave metamaterials, and in particular relates to a periodic unit of an electromagnetic metamaterial absorber. Background Art

[0002] Electromagnetic metamaterials are artificial materials whose properties are determined by the properties of the periodic units that make up the metamaterials. Frequency Selective Surface (FSS) is a type of electromagnetic metamaterial, which is a planar structure with one or more layers of the same unit structure arranged periodically. By changing the unit structure, FSS can present different response characteristics to electromagnetic waves in space. FSS has the characteristics of bandpass or bandstop for incident electromagnetic waves, that is, it has the function of frequency selection.

[0003] With the development of FSS technology, the electromagnetic wave absorption function can also be realized through FSS. In the case of multi-station radar detection, the electromagnetic metamaterial absorber based on FSS can make the detected target have the stealth capability against radar. At present, most electromagnetic metamaterial absorbers based on FSS can only achieve high absorption rate of electromagnetic waves in a narrow frequency band. Therefore, designing an electromagnetic metamaterial absorber with ultra-wideband absorption characteristics has practical significance and engineering application value in the field of electromagnetic protection and radar stealth. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide an electromagnetic metamaterial absorber periodic unit that can achieve ultra-wideband absorbing characteristics, with the absorbing frequency band covering the C band and most of the S band.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0006] The present invention provides an electromagnetic metamaterial absorber periodic unit, comprising M×N metamaterial absorber units arranged in a periodic manner; the metamaterial absorber unit comprises an absorption layer, an air layer and a reflection layer which are sequentially arranged from top to bottom; the absorption layer comprises a first dielectric substrate and an absorption unit, the absorption unit comprises a first metal patch and a resistor patch, the first metal patch is arranged on the upper surface of the first dielectric substrate, and the resistor patch is welded on the surface of the first metal patch; the reflection layer comprises a second dielectric substrate and a reflection unit, the reflection unit comprises a second metal patch, and the second metal patch is arranged on the upper surface of the second dielectric substrate.

[0007] Furthermore, the first metal patch includes an outer ring rectangular patch, an inner ring rectangular patch, two first T-shaped patches and two second T-shaped patches; the outer ring rectangular patch is arranged on the upper surface of the first dielectric substrate, the inner ring rectangular patch is nested inside the outer ring rectangular patch, and the four sides of the outer ring rectangular patch are respectively parallel to the four sides of the inner ring rectangular patch; the two first T-shaped patches are symmetrically distributed on the outside of the two opposite first side edges of the outer ring rectangular patch, and the vertical edges of the two first T-shaped patches are respectively connected to the two first side edges of the outer ring rectangular patch; the two The second T-shaped patches are symmetrically distributed on the outside of the two second side edges opposite to the outer rectangular patch, and the vertical edges of the two second T-shaped patches are respectively connected to the two second side edges of the outer rectangular patch; the first rectangular patches are respectively arranged between the two second side edges of the outer rectangular patch and the inner rectangular patch, and two second rectangular patches are symmetrically connected inside the inner rectangular patch; the vertical edge of the second T-shaped patch, the first rectangular patch and the second rectangular patch have the same width, and the vertical edge of the second T-shaped patch, the first rectangular patch and the second rectangular patch coincide with the central axis.

[0008] Furthermore, there are four resistor patches, which are respectively arranged on the upper surfaces of the four sides of the outer ring rectangular patch; the four resistor patches are rotationally symmetric along the center normal of the outer ring rectangular patch.

[0009] Furthermore, the outer ring rectangular patch, the inner ring rectangular patch, the two first T-shaped patches, the two second T-shaped patches, the two first rectangular patches and the two second rectangular patches are an integrated structure.

[0010] Furthermore, the second metal patch is a square metal patch etched with a cross groove and four square grooves; the four square grooves are distributed on the four sides of the cross groove, and the four square grooves are rotationally symmetrical along the center normal of the cross groove, and the four square grooves and the cross groove form a cross-shaped structure.

[0011] Furthermore, the center of the cross-shaped groove coincides with the center of the second metal patch.

[0012] Furthermore, the center of the outer ring rectangular patch, the center of the inner ring rectangular patch and the center of the first dielectric substrate coincide with each other.

[0013] Furthermore, the ratio of the period lengths of the absorption unit and the reflection unit is 2:1.

[0014] Furthermore, the first dielectric substrate and the second dielectric substrate are both made of square plates with a relative dielectric constant of 4.4 and a loss tangent value of 0.02.

[0015] Furthermore, in the M×N periodically arranged metamaterial absorbing units, M and N are natural numbers greater than or equal to 5.

[0016] Beneficial Effects

[0017] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0018] The present invention proposes an electromagnetic metamaterial absorber periodic unit, in which an absorption unit is arranged on the upper surface of a first dielectric substrate, and a reflection unit is arranged on the upper surface of a second dielectric substrate. The absorption layer can absorb electromagnetic waves of a single frequency point, the reflection layer can reflect low-frequency electromagnetic waves back to the absorption layer, and the air layer can achieve impedance matching and bandwidth expansion functions. The present invention increases the bandwidth of the absorbing frequency band and improves the absorption effect of the absorbing frequency band by cascading the absorption layer, the air layer and the reflection layer, and can effectively achieve the effect of ultra-wide absorbing frequency band and high absorption rate of the metamaterial absorber. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a side view of a periodic unit of the electromagnetic metamaterial absorber of the present invention.

[0020] Figure 2 It is a schematic diagram of the three-dimensional structure of the periodic unit of the electromagnetic metamaterial absorber of the present invention.

[0021] Figure 3 It is a schematic diagram of the structure of the absorption unit in the periodic unit of the electromagnetic metamaterial absorber of the present invention.

[0022] Figure 4 It is a schematic diagram of the structure of the reflection unit in the periodic unit of the electromagnetic metamaterial absorber of the present invention.

[0023] Figure 5 This is a simulation result diagram of the periodic unit absorptivity of the electromagnetic metamaterial absorber of the present invention.

[0024] The symbols in the accompanying drawings are:

[0025] 1. Absorption unit; 2. First dielectric substrate; 3. Air layer; 4. Reflection unit; 5. Second dielectric substrate; 6. Resistor patch; 7. Outer ring rectangular patch; 8. Inner ring rectangular patch; 9. First T-shaped patch; 10. Second T-shaped patch; 11. First rectangular patch; 12. Second rectangular patch; 13. Cross-shaped slot; 14. Square slot. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] An embodiment of the present invention provides an electromagnetic metamaterial absorber periodic unit, comprising M×N periodically arranged metamaterial absorber units, wherein M and N are natural numbers greater than or equal to 5. Specifically, in this embodiment, M=5, N=5.

[0028] like Figure 1 As shown, the metamaterial absorbing unit includes an absorption layer, an air layer and a reflection layer arranged in sequence from top to bottom.

[0029] The absorption layer includes a first dielectric substrate 2 and an absorption unit 1. The absorption unit 1 includes a first metal patch and a resistor patch 6. The first metal patch is arranged on the upper surface of the first dielectric substrate 2. The resistor patch 6 is welded on the surface of the first metal patch.

[0030] like Figure 2 As shown, the first metal patch (resonant metal patch) includes an outer ring rectangular patch 7, an inner ring rectangular patch 8, two first T-shaped patches 9 and two second T-shaped patches 10. The outer ring rectangular patch 7 (square structure) is arranged on the upper surface of the first dielectric substrate 2, the long side length of the inner ring rectangular patch 8 is less than the side length of the outer ring rectangular patch 7, the inner ring rectangular patch 8 is nested inside the outer ring rectangular patch 7, and the four sides of the outer ring rectangular patch 7 are respectively parallel to the four sides of the inner ring rectangular patch 8, and the center of the outer ring rectangular patch 7, the center of the inner ring rectangular patch 8 and the center of the first dielectric substrate 2 coincide.

[0031] Specifically, in this embodiment, the outer side length a of the outer rectangular patch 7 is 9.5 mm, the width w of the outer rectangular patch 7 is 0.8 mm, the long side length a3 of the inner rectangular patch 8 is 5.6 mm, the short side length is 2.8 mm, and the width w2 of the inner rectangular patch 8 is 1.3 mm. Figure 3 shown.

[0032] like Figure 2 As shown, two first T-shaped patches 9 are symmetrically distributed outside the two opposite first sides of the outer rectangular patch 7, and the vertical sides of the two first T-shaped patches 9 are respectively vertically connected to the two first sides of the outer rectangular patch 7. Two second T-shaped patches 10 are symmetrically distributed outside the two opposite second sides of the outer rectangular patch 7, and the vertical sides of the two second T-shaped patches 10 are respectively vertically connected to the two second sides of the outer rectangular patch 7. First rectangular patches 11 are respectively arranged between the two second sides of the outer rectangular patch 7 and the inner rectangular patch 8, and two second rectangular patches 12 are symmetrically connected inside the inner rectangular patch 8, and the vertical sides of the second T-shaped patch 10, the first rectangular patch 11, and the second rectangular patch 12 have the same width, and the vertical sides of the second T-shaped patch 10, the first rectangular patch 11, and the second rectangular patch 12 have the same central axis.

[0033] As a preferred embodiment of the present invention, the outer rectangular patch 7, the inner rectangular patch 8, the two first T-shaped patches 9, the two second T-shaped patches 10, the two first rectangular patches 11 and the two second rectangular patches 12 are an integrated structure.

[0034] Specifically, in this embodiment, the vertical side length of the first T-shaped patch 9 is a2=2mm, and the distance between the inner edge of the horizontal side of the second T-shaped patch 10 and the inner end of the second rectangular patch 12 is b=5.5mm; the horizontal side length of the first T-shaped patch 9 is the same as the horizontal side length of the second T-shaped patch 10, both are a1=9mm, and the vertical side width of the first T-shaped patch 9 is the same as the vertical side width of the second T-shaped patch 10, both are w1=0.8mm. Figure 3 shown.

[0035] like Figure 2 As shown, there are four resistor patches 6, which are respectively welded on the upper surfaces of the four sides of the outer rectangular patch 7, and the four resistor patches 6 are rotationally symmetrical along the center normal of the outer rectangular patch 7. Specifically, in this embodiment, the resistance values ​​of the four resistor patches 6 are 80 ohms respectively.

[0036] like Figures 1-2 As shown, the reflection layer includes a second dielectric substrate 5 and reflection units 4, and each second dielectric substrate 5 corresponds to four reflection units 4. The reflection unit 4 includes a second metal patch, and the second metal patch is printed on the upper surface of the second dielectric substrate 5.

[0037] The second metal patch is a square metal patch etched with a cross-shaped groove 13 and four square grooves 14 of the same specifications. The center of the cross-shaped groove 13 coincides with the center of the second metal patch. One side of the cross-shaped groove 13 is parallel to the two opposite sides of the second metal patch, and the other side of the cross-shaped groove 13 is parallel to the other two opposite sides of the second metal patch. The four square grooves 14 are distributed on the four sides of the cross-shaped groove 13, and the four square grooves 14 are rotationally symmetrical along the center normal of the cross-shaped groove 13. The four square grooves 14 and the cross-shaped groove 13 form a cross-shaped structure.

[0038] Specifically, in this embodiment, the length d of the cross-shaped groove 13 is 8 mm, the width w3 is 0.5 mm, and the side length a4 of the square groove 14 is 3.5 mm. Figure 4 shown.

[0039] As a further preferred embodiment of the present invention, the ratio of the period length of the absorption unit 1 to the period length of the reflection unit 4 is 2: 1. In this embodiment, the period of the absorption unit 1 is p=18 mm, and the period of the reflection unit 4 is 9 mm.

[0040] As a further preferred embodiment of the present invention, the first dielectric substrate 2 and the second dielectric substrate 5 are both made of square plates with a relative dielectric constant of 4.4 and a loss tangent of 0.02. The side length p of the first dielectric substrate 2 and the second dielectric substrate 5 is 18 mm, the thickness t is 0.76 mm, and the air layer thickness h is 8 mm. Figure 1 and 3 shown.

[0041] The absorptivity of the periodic unit of the electromagnetic metamaterial absorber is simulated using commercial simulation software. The results are as follows: Figure 5 As shown. Figure 5 It can be seen that the absorption rate of the periodic unit of the electromagnetic metamaterial absorber proposed in the present invention is greater than 90% in the frequency band of 2.69-8.22 GHz, and the relative bandwidth is 101.4%. The absorption band can cover the C band and most of the S band, and can achieve good absorption effect of electromagnetic waves in an ultra-wide band.

[0042] In summary, the electromagnetic metamaterial absorber periodic unit proposed by the present invention has a simple structure, is easy to process, and has low cost. The absorption layer is used to absorb electromagnetic waves of a single frequency point, and the absorption rate of electromagnetic waves can be effectively improved by adding a resistor patch. The absorption layer, the air layer, and the reflection layer are cascaded to effectively achieve impedance matching and expand the absorption bandwidth, so that the electromagnetic metamaterial absorber periodic unit provided by the present invention has ultra-wideband and high absorption rate effects on electromagnetic waves.

[0043] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. An electromagnetic metamaterial absorber periodic unit, characterized in that: It includes M×N periodically arranged metamaterial absorbing units; The metamaterial absorbing unit comprises an absorbing layer, an air layer and a reflecting layer arranged in sequence from top to bottom; The absorption layer comprises a first dielectric substrate (2) and an absorption unit (1), the absorption unit (1) comprises a first metal patch and a resistor patch (6), the first metal patch is arranged on the upper surface of the first dielectric substrate (2), and the resistor patch (6) is welded on the surface of the first metal patch; The reflective layer comprises a second dielectric substrate (5) and a reflective unit (4); the reflective unit (4) comprises a second metal patch, and the second metal patch is arranged on the upper surface of the second dielectric substrate (5).

2. The electromagnetic metamaterial absorber periodic unit according to claim 1, characterized in that: The first metal patch comprises an outer ring rectangular patch (7), an inner ring rectangular patch (8), two first T-shaped patches (9) and two second T-shaped patches (10); The outer ring rectangular patch (7) is arranged on the upper surface of the first dielectric substrate (2), the inner ring rectangular patch (8) is nested inside the outer ring rectangular patch (7), and the four sides of the outer ring rectangular patch (7) are respectively parallel to the four sides of the inner ring rectangular patch (8); The two first T-shaped patches (9) are symmetrically distributed outside two opposite first side edges of the outer ring rectangular patch (7), and the vertical edges of the two first T-shaped patches (9) are respectively connected to the two first side edges of the outer ring rectangular patch (7); The two second T-shaped patches (10) are symmetrically distributed outside two opposite second side edges of the outer ring rectangular patch (7), and the vertical edges of the two second T-shaped patches (10) are respectively connected to the two second side edges of the outer ring rectangular patch (7); A first rectangular patch (11) is respectively arranged between the two second side edges of the outer rectangular patch (7) and the inner rectangular patch (8), and two second rectangular patches (12) are symmetrically connected inside the inner rectangular patch (8); the vertical edge of the second T-shaped patch (10), the first rectangular patch (11) and the second rectangular patch (12) have the same width, and the vertical edge of the second T-shaped patch (10), the first rectangular patch (11) and the second rectangular patch (12) have coincident central axes.

3. The electromagnetic metamaterial absorber periodic unit according to claim 2, characterized in that: The number of the resistor patches (6) is four, and they are respectively arranged on the upper surfaces of the four sides of the outer ring rectangular patch (7); The four resistor patches (6) are rotationally symmetric along the center normal of the outer ring rectangular patch (7).

4. The electromagnetic metamaterial absorber periodic unit according to claim 2, characterized in that: The outer ring rectangular patch (7), the inner ring rectangular patch (8), the two first T-shaped patches (9), the two second T-shaped patches (10), the two first rectangular patches (11) and the two second rectangular patches (12) are an integrated structure.

5. The electromagnetic metamaterial absorber periodic unit according to claim 3, characterized in that: The second metal patch is a square metal patch etched with a cross-shaped groove (13) and four square grooves (14); the four square grooves (14) are distributed on the four sides of the cross-shaped groove (13), and the four square grooves (14) are rotationally symmetrical along the center normal of the cross-shaped groove (13).

6. The electromagnetic metamaterial absorber periodic unit according to claim 5, characterized in that: The center of the cross-shaped groove (13) coincides with the center of the second metal patch.

7. The electromagnetic metamaterial absorber periodic unit according to claim 2, characterized in that: The center of the outer ring rectangular patch (7), the center of the inner ring rectangular patch (8) and the center of the first dielectric substrate (2) coincide with each other.

8. The electromagnetic metamaterial absorber periodic unit according to claim 1, characterized in that: The ratio of the period lengths of the absorption unit (1) and the reflection unit (4) is 2:

1.

9. The electromagnetic metamaterial absorber periodic unit according to claim 1, characterized in that: The first dielectric substrate (2) and the second dielectric substrate (5) are both made of square plates with a relative dielectric constant of 4.4 and a loss tangent value of 0.

02.

10. The electromagnetic metamaterial absorber periodic unit according to claim 1, characterized in that: In the M×N periodically arranged metamaterial absorbing units, M and N are natural numbers greater than or equal to 5.

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