CN112909570B - Three-dimensional broadband wave-absorbing metamaterial integrating multiple absorption mechanisms - Google Patents
Three-dimensional broadband wave-absorbing metamaterial integrating multiple absorption mechanisms Download PDFInfo
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- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
- H01Q15/0006—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices
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Abstract
The invention belongs to the technical field of electromagnetic functional materials, and particularly relates to a three-dimensional broadband wave-absorbing metamaterial integrating multiple absorption mechanisms; the three-dimensional broadband wave-absorbing metamaterial is an array of three-dimensional metamaterial units, each row at least comprises two three-dimensional metamaterial units, and each column at least comprises two three-dimensional metamaterial units; the three-dimensional metamaterial unit comprises an upper dielectric slab, a lower dielectric slab and a metal bottom plate which are sequentially arranged from top to bottom, wherein a high magnetic loss material plate is embedded in the midpoint of the inner part of the lower dielectric slab, and the lower surfaces of the upper dielectric slab and the lower dielectric slab are tightly attached to the upper surface of the metal bottom plate; the conductor core is embedded in the center of the upper dielectric plate, and the lower surfaces of the conductor core and the lower dielectric plate are tightly attached to the upper surface of the lower dielectric plate. By introducing the conductor core into the all-dielectric metamaterial and using materials with different loss capacities at different parts, the prepared wave-absorbing metamaterial has the loss mechanism of the traditional metamaterial and the step-type all-dielectric metamaterial, the effective absorption bandwidth is expanded, and the use of high-loss materials can be reduced.
Description
Technical Field
The invention belongs to the technical field of electromagnetic functional materials, and particularly relates to a three-dimensional broadband wave-absorbing metamaterial integrating multiple absorption mechanisms, which can be used for broadband microwave absorption.
Background
The traditional metamaterial wave absorber mainly absorbs waves through electromagnetic resonance of a metamaterial metal structure, when electromagnetic waves are incident on the surface of the metamaterial structure, an electric field enables a surface metal array to play a role of an electric resonator, and meanwhile, a magnetic field enables the surface metal array and a bottom metal substrate to play a role of a magnetic resonator. By adjusting the unit shape and the structural parameters of the metal array, the impedance of the metamaterial wave absorber at the resonance frequency and the free space can be matched, so as to minimize the reflection of the incident electromagnetic wave, such as the metamaterial wave absorber formed by the metal wires and the semiconductor wafers in patent CN 201110061836.9. However, the impedance of the conventional metamaterial wave absorber can only be matched with the free space in a very narrow range near the resonant frequency, so that the wave absorbing bandwidth is very narrow and is difficult to meet the practical application.
The step-type all-dielectric metamaterial mainly utilizes multiple lambda/4 resonance to achieve the purpose of phase cancellation, utilizes corner diffraction and coupling effect among units to concentrate electromagnetic waves, achieves good impedance matching, and further utilizes a loss medium to absorb, such as the step-type all-dielectric metamaterial provided by patent CN 201610989091.5. Although broadband absorption is easy to realize, the metamaterial has high requirement on the loss capacity of the dielectric material, and is not beneficial to industrial popularization and application.
Disclosure of Invention
The invention overcomes the defects of the prior art, provides the metamaterial for absorbing the electromagnetic waves based on multiple absorption mechanisms, leads the conductor core into the ladder-shaped all-dielectric metamaterial, uses materials with different loss capacities at different parts, ensures that the prepared wave-absorbing metamaterial has the loss mechanisms of the traditional metamaterial and the ladder-shaped all-dielectric metamaterial, only locally uses high-loss materials while expanding the effective absorption bandwidth, can effectively reduce the cost, and is beneficial to industrial popularization and application.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a three-dimensional broadband wave-absorbing metamaterial integrating multiple absorption mechanisms is characterized in that the three-dimensional broadband wave-absorbing metamaterial is an array of three-dimensional metamaterial units, each row at least comprises two three-dimensional metamaterial units, and each column at least comprises two three-dimensional metamaterial units; the three-dimensional metamaterial unit comprises an upper dielectric plate, a lower dielectric plate and a metal bottom plate which are sequentially arranged from top to bottom, wherein a high magnetic loss material plate is embedded in the center of the interior of the lower dielectric plate, and the lower surfaces of the upper dielectric plate and the lower dielectric plate are tightly attached to the upper surface of the metal bottom plate; a conductor core is embedded in the center of the upper dielectric plate, and the lower surfaces of the upper dielectric plate and the lower dielectric plate are tightly attached to the upper surface of the lower dielectric plate; all metal bottom plates are spliced together, and all lower dielectric slabs are respectively positioned on the same horizontal plane.
Further, the upper and lower dielectric plates are in a regular quadrangular prism shape, wherein the side length a of the lower dielectric plate 315-25 mm in height h11-5.5 mm, the side length a of the upper dielectric plate 425-25 mm in height h2Is 1-5.5 mm, and a1＞a2The dielectric constants of the upper dielectric plate and the lower dielectric plate are both 4-8.
Further, the conductor core 5 is in the shape of a regular cross prism, which is a regular prism having a cross-shaped cross section, and has a length b11-5.5 mm, width b21-5.5 mm, height h41-5.5 mm, and b1＞b2，a2＞b1， h2≥h4(ii) a The conductor core 5 is made of a metal material or a carbon material.
Preferably, the metal material is copper, aluminum or silver; the carbon material is graphite or carbon black.
Furthermore, the high magnetic loss material plate 2 is in a regular quadrangular prism shape, and the side length b of the high magnetic loss material plate35-25 mm in thickness h3Is 1-5.5 mm, and a1＞b3，h1＞h3The dielectric constant of the high-magnetic-loss material plate 2 is 12-13, and the magnetic conductivity is 1-3.
Furthermore, the upper and lower dielectric plates and the high magnetic loss material plate 2 are all made of resin-based wave-absorbing composite materials.
Furthermore, the resin-based wave-absorbing composite material is composed of a resin matrix, a curing agent and a filled wave-absorbing agent.
Furthermore, the resin matrix is epoxy resin, the curing agent is amine or anhydride curing agent, and the filled wave absorbing agent is carbon material, magnetic material or composite multi-element particles of the carbon material and the magnetic material.
Preferably, the carbon material is graphene or carbon nanotubes; the magnetic material is ferroferric oxide, carbonyl iron or alpha-Fe.
Compared with the prior art, the invention has the following beneficial effects:
1) the conductor core is introduced into the periodic loss medium, so that the metamaterial-based resonant cavity has various absorption mechanisms such as traditional metamaterial electric resonance, magnetic resonance, ladder-type full-medium metamaterial lambda/4 resonance, edge diffraction and the like, and the filled conductor core is also beneficial to forming capacitors among units, strengthening the coupling effect among the units and improving the impedance matching effect. Therefore, the effective absorption bandwidth is as high as 13.57 GHz.
(2) According to the invention, because the part which generates magnetic resonance and concentrates a magnetic field is filled with the high-magnetic-loss material between the conductor core and the bottom metal substrate, the energy of the magnetic field can be accurately absorbed, the using amount of the high-magnetic-loss material can be reduced, the cost is effectively reduced, and the industrial popularization and application are facilitated.
(3) Due to the excellent symmetrical structure, the invention has certain polarization insensitivity and good large-angle incidence stability under TM polarization, and can keep the broadband absorption with the effective absorption bandwidth of 13.57 GHz within the range of 0-60 DEG incidence angle under the TM polarization mode.
The invention has the structural characteristics of the ladder-type all-dielectric metamaterial and introduces the conductor core, can concentrate incident electromagnetic waves by various absorption mechanisms and pertinently lose the incident electromagnetic waves, so that the broadband effective absorption in the range of 4.43-18 GHz is realized while only locally using a high-magnetic-loss material, and the ladder-type all-dielectric metamaterial has certain polarization insensitivity and incident angle stability; in addition, the method also has the advantages of low cost, contribution to industrial popularization and application and the like.
Drawings
FIG. 1 is a schematic view of an overall structure of a three-dimensional broadband wave-absorbing metamaterial integrating multiple absorption mechanisms.
FIG. 2 is a schematic diagram of a unit structure of a three-dimensional broadband wave-absorbing metamaterial integrating multiple absorption mechanisms.
Fig. 3 is a perspective view of fig. 2.
Fig. 4 is a top view of fig. 2.
Fig. 5 is a side sectional view of fig. 2.
Fig. 6 is a graph showing the simulation result of the reflection loss in the TE polarization mode at an incident angle of 0 ° in the present invention.
Fig. 7 is a graph showing simulation results of reflection loss in the TM polarization mode at an incident angle of 0 ° in the present invention.
FIG. 8 is a graph showing the simulation results of reflection loss in the TM polarization mode at an incident angle of 0-60 deg. according to the present invention.
The figures are labeled as follows:
1-metal bottom plate, 2-high magnetic loss material plate, 3-lower dielectric plate, 4-upper dielectric plate and 5-conductor core.
Detailed Description
The present invention is further illustrated by the following examples.
Examples
As shown in FIG. 1, the present embodiment is formed by M × N three-dimensional metamaterial units with multiple absorption mechanisms periodically arranged, wherein M is greater than or equal to 2, N is greater than or equal to 2, and M and N are positive integers.
As shown in fig. 2 and 3, each three-dimensional metamaterial unit includes a metal base plate 1, a high-magnetic-loss material plate 2, a lower dielectric plate 3, an upper dielectric plate 4, and a conductor core 5.
The high magnetic loss material plate 2 is embedded in the center of the lower dielectric plate 3, and the lower surfaces of the high magnetic loss material plate and the lower dielectric plate are tightly attached to the upper surface of the metal bottom plate 1 with the thickness of 0.035 mm; the conductor core 5 is embedded in the center of the upper dielectric plate 4, and the lower surfaces of the two are tightly attached to the center of the upper surface of the lower dielectric plate 3.
As shown in FIGS. 4 and 5, the lower dielectric sheet 3 has a regular quadrangular prism shape with a side length a1Is 15 mm and has a height h12.5 mm, a relative dielectric constant of4-8。
As shown in fig. 5, the high magnetic loss material plate 2 has a regular quadrangular prism shape, and the bottom surface thereof is flush with the bottom surface of the lower dielectric plate 3 and is fitted in the center of the lower dielectric plate 3. Side length b thereof 3Is 13.2 mm and has a height h30.9mm, dielectric constant of 12-13 and magnetic permeability of 1-3.
The upper dielectric plate 4 is in the shape of a regular quadrangular prism with a side length a29.5mm, height h23.5mm and a relative dielectric constant of 4-8.
As shown in fig. 4, the upper surface of the conductor core 5 is flush with the upper surface of the upper dielectric plate 4 and is embedded in the center of the upper dielectric plate 4. It is in the shape of a regular cross prism and has a length of b1Is 5mm and has a width b2Is 1.5 mm and has a height h4Is 3.5 mm.
All of the metals mentioned above in this example are aluminum, but are not limited thereto.
The specific wave absorbing principle of the three-dimensional metamaterial integrating multiple absorption mechanisms in the embodiment is as follows:
when electromagnetic waves are incident to the metamaterial in the embodiment, the stepped structure formed by the lower dielectric plate 3 and the upper dielectric plate 4 can generate lambda/4 resonance with different frequencies at different thicknesses, so that the electromagnetic waves are subjected to coherence cancellation; the polygonal structure can generate edge diffraction effect, change the propagation direction of incident electromagnetic wave, make it enter the loss medium more easily, and propagate longer path. The side surfaces of the upper dielectric plate 4 and the conductor core 5 between different units can accumulate positive and negative charges under the action of an electromagnetic field, and can be equivalent to a series of capacitors, so that the electric field energy is concentrated between the units and is lost by a loss medium.
The conductor core 5 embedded in the upper dielectric plate 4 can generate electric resonance under the action of an electric field, and the electric field is concentrated around the metal and absorbed by a loss medium; the lower surface of the metal bottom plate and the metal bottom plate 1 can generate magnetic resonance under the action of a magnetic field, the magnetic field is concentrated between the lower surface of the metal bottom plate and the metal bottom plate, and the metal bottom plate is lost through a high-magnetic-loss material plate 2 embedded in the lower medium plate 3.
The technical effects of the invention are further explained by combining simulation experiments as follows:
1. simulation software:
business simulation software CST microwave studio 2018
2. Simulation content and results:
As can be seen from FIG. 6, when the TE polarization mode is adopted and the incident angle is equal to 0 °, the minimum reflection loss of the three-dimensional metamaterial integrating a plurality of absorption mechanisms in one body in the present example is-17.67 dB, and the effective absorption frequency band with the reflection loss less than-10 dB is from 4.43 GHz to 18 GHz.
As can be seen from FIG. 7, when the TM polarization mode is adopted and the incident angle is equal to 0 °, the minimum reflection loss of the three-dimensional metamaterial integrating multiple absorption mechanisms in one body in the example is-17.95 dB, and the absorption frequency band with the reflection loss smaller than-10 dB is from 4.43 GHz to 18 GHz. This is consistent with the results in the TE polarization mode, indicating that the present invention has polarization insensitive characteristics.
As can be seen from fig. 8, in the TM polarization mode, the effective absorption band range with a reflection loss of less than-10 dB remains substantially unchanged, and as the incident angle increases, the reflection loss value gradually decreases, and the minimum reflection loss reached at an incident angle of 60 ° is-25.23 dB. This shows that the present invention has incident angle stability in the TM polarization mode over the range of 0-60 ° incident angles.
While the foregoing description and examples have been given by way of illustration of preferred embodiments of the invention and are not intended to limit the invention, it will be apparent to those skilled in the art that various changes and modifications in form and detail may be made therein without departing from the spirit and scope of the invention, and it is intended to cover all modifications and variations of the invention as defined by the appended claims.
Claims (7)
1. A three-dimensional broadband wave-absorbing metamaterial integrating multiple absorption mechanisms is characterized in that the metamaterial is in a cross-shaped symmetrical structure; the three-dimensional broadband wave-absorbing metamaterial is an array of three-dimensional metamaterial units, each row at least comprises two three-dimensional metamaterial units, and each column at least comprises two three-dimensional metamaterial units; the three-dimensional metamaterial unit comprises an upper dielectric slab (4), a lower dielectric slab (3) and a metal bottom plate (1) which are sequentially arranged from top to bottom, wherein a high-magnetic-loss material plate (2) is embedded in the center of the interior of the lower dielectric slab (3), and the lower surfaces of the upper dielectric slab and the lower dielectric slab are tightly attached to the upper surface of the metal bottom plate (1); a conductor core (5) is embedded in the center of the upper dielectric plate (4), and the lower surfaces of the upper dielectric plate and the lower dielectric plate are tightly attached to the upper surface of the lower dielectric plate (3); all the metal bottom plates (1) are spliced together, and all the lower dielectric plates (3) are respectively positioned on the same horizontal plane;
the upper and lower dielectric plates are all in a regular quadrangular shape, wherein the side length a of the lower dielectric plate (3)15-25 mm in height h11-5.5 mm, the side length a of the upper dielectric plate (4)25-25 mm in height h2Is 1-5.5 mm, and a1＞a2The dielectric constants of the upper dielectric plate and the lower dielectric plate are both 4-8;
The conductor core (5) is in a regular cross prism shape, the regular cross prism is a regular prism with a cross-shaped section, and the length b of the regular cross prism is1Is 1-5.5 mm in width b21-5.5 mm, height h41-5.5 mm, and b1＞b2，a2＞b1，h2≥h4(ii) a The conductor core (5) is made of a metal material or a carbon material.
2. The three-dimensional broadband wave-absorbing metamaterial integrated with multiple absorption mechanisms according to claim 1, wherein the metal material is copper, aluminum or silver; the carbon material is graphite or carbon black.
3. The three-dimensional broadband wave-absorbing metamaterial integrating multiple absorption mechanisms as claimed in claim 1, wherein the high-magnetic-loss material plate (2) is in a regular quadrangular prism shape with a side length b35-25 mm in thickness h3Is 1-5.5 mm, and a1＞b3，h1＞h3The dielectric constant of the high-magnetic-loss material plate (2) is 12-13, and the magnetic conductivity is 1-3.
4. The three-dimensional broadband wave-absorbing metamaterial integrating multiple absorption mechanisms according to claim 1 or 3, wherein the upper and lower dielectric plates and the high-magnetic-loss material plate (2) are made of resin-based wave-absorbing composite materials.
5. The three-dimensional broadband wave-absorbing metamaterial integrating multiple absorption mechanisms according to claim 4, wherein the resin-based wave-absorbing composite material is composed of a resin matrix, a curing agent and a filled wave-absorbing agent.
6. The three-dimensional broadband wave-absorbing metamaterial integrated with multiple absorption mechanisms according to claim 5, wherein the resin matrix is epoxy resin, the curing agent is amine or anhydride curing agent, and the filled wave-absorbing agent is carbon material, magnetic material or multi-element particles compounded by the carbon material and the magnetic material.
7. The three-dimensional broadband wave-absorbing metamaterial integrated with multiple absorption mechanisms according to claim 6, wherein the carbon material is graphene or carbon nanotubes; the magnetic material is ferroferric oxide, carbonyl iron or alpha-Fe.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH084147A (en) * | 1994-06-17 | 1996-01-09 | Mitsui Constr Co Ltd | Radiowave-absorptive concrete panel and radiowave-absorptive wall structure |
| CN106972278A (en) * | 2017-03-16 | 2017-07-21 | 浙江大学 | A kind of electromagnetism stealth material of the scattering particles of all dielectric zero and its composition |
| CN110635249A (en) * | 2019-09-05 | 2019-12-31 | 南京邮电大学 | Broadband transfer wave absorber based on mercury expansion with heat and contraction with cold regulation |
| CN110729532A (en) * | 2019-09-02 | 2020-01-24 | 杭州电子科技大学 | Dual polarization absorbing/transmitting frequency selection structure based on wave absorbing silicon rubber |
| CN110829012A (en) * | 2019-11-19 | 2020-02-21 | 中北大学 | Monopole antenna based on artificial electromagnetic material |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102723598B (en) * | 2012-05-30 | 2015-10-07 | 深圳光启创新技术有限公司 | Metamaterial microwave antenna cover and antenna system |
| JP5479540B2 (en) * | 2012-07-10 | 2014-04-23 | 株式会社リケン | Radio wave absorber |
| US10170831B2 (en) * | 2015-08-25 | 2019-01-01 | Elwha Llc | Systems, methods and devices for mechanically producing patterns of electromagnetic energy |
| CN107057135A (en) * | 2016-12-22 | 2017-08-18 | 中北大学 | A kind of High-performance graphene/FeNixThe preparation of/natural rubber electromagnetic wave absorbent material |
-
2021
- 2021-02-06 CN CN202110164786.0A patent/CN112909570B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH084147A (en) * | 1994-06-17 | 1996-01-09 | Mitsui Constr Co Ltd | Radiowave-absorptive concrete panel and radiowave-absorptive wall structure |
| CN106972278A (en) * | 2017-03-16 | 2017-07-21 | 浙江大学 | A kind of electromagnetism stealth material of the scattering particles of all dielectric zero and its composition |
| CN110729532A (en) * | 2019-09-02 | 2020-01-24 | 杭州电子科技大学 | Dual polarization absorbing/transmitting frequency selection structure based on wave absorbing silicon rubber |
| CN110635249A (en) * | 2019-09-05 | 2019-12-31 | 南京邮电大学 | Broadband transfer wave absorber based on mercury expansion with heat and contraction with cold regulation |
| CN110829012A (en) * | 2019-11-19 | 2020-02-21 | 中北大学 | Monopole antenna based on artificial electromagnetic material |
Non-Patent Citations (2)
| Title |
|---|
| "Design and evaluation of microwave absorber metamaterial approach";Arun Kumar Saha等;《SoutheastCon 2017》;20170511;全文 * |
| "基于2.5 维小型化设计的UHF频段高性能超材料吸波体";刘晓春等;《南京航空航天大学学报》;20191231;全文 * |
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