CN113224547A - Hollowed-out Koch snowflake parting structure ultra-wideband terahertz wave absorber - Google Patents
Hollowed-out Koch snowflake parting structure ultra-wideband terahertz wave absorber Download PDFInfo
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- CN113224547A CN113224547A CN202110438767.2A CN202110438767A CN113224547A CN 113224547 A CN113224547 A CN 113224547A CN 202110438767 A CN202110438767 A CN 202110438767A CN 113224547 A CN113224547 A CN 113224547A
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- parting
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- koch snowflake
- terahertz wave
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q17/00—Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems
Abstract
The invention discloses a hollowed-out Koch snowflake parting medium structure ultra-wide band terahertz wave absorber, belongs to the technical field of wave absorbers, and aims to provide the hollowed-out Koch snowflake parting medium structure ultra-wide band terahertz wave absorber which solves the problems of few absorption frequency bands, poor wave absorbing rate and narrow absorption band width of the existing terahertz wave absorber. The Koch snowflake parting structure comprises a medium bottom layer and a parting medium structure top layer which are sequentially arranged from bottom to top, wherein the parting medium structure layer comprises a plurality of hollowed Koch snowflake parting structure units, the hollowed Koch snowflake parting structure units are designed based on gradient width modulation, and the higher the Koch snowflake parting iteration frequency is, the wider the gradient width section is. The terahertz wave absorber is suitable for terahertz wave absorbers.
Description
Technical Field
The invention belongs to the technical field of wave absorbers, and particularly relates to an ultra-wideband terahertz wave absorber with a hollow Koch snowflake parting medium structure.
Background
Terahertz waves refer to electromagnetic radiation in the frequency range of approximately 0.1-10 THz, with a corresponding wavelength range of approximately 0.03-3 mm between radio and light waves. Over the years, terahertz devices are continuously researched and developed, and comprise modulators, filters, optical lenses, wave absorbers, sensors and terahertz metamaterials. The high-performance terahertz device has important significance for the research and development and application of a terahertz system. The terahertz wave absorber can be applied to the fields of application and research of national economic development and national defense, such as stealth technology, energy collection, imaging, modulators, communication, sensing detection and the like, and therefore the design of the high-performance wave absorber in the terahertz frequency band has important value.
In recent years, terahertz wave absorbers with various structures, including metal resonance wave absorbers, patterned graphene wave absorbers, metal-loaded graphene wave absorbers and the like, have been widely researched. However, most of the conventional terahertz wave absorbers achieve single-frequency, narrow-band, discrete or continuous multi-band absorption. Most of the wave absorbers with the dielectric structures are based on patterned graphene structures, and the structures are complex to process and manufacture and have edge effects. Aiming at the problems, the invention provides a novel hollow medium parting structure, which is used for realizing a terahertz wave absorber with a terahertz frequency band, an ultra-wideband and high absorption rate, and has the characteristic of convenient structural parting design.
Doped silicon as a high-loss dielectric material is introduced into the field of terahertz devices in recent years. Firstly, complex patterns can be easily prepared on the doped silicon by utilizing the traditional photoetching technology, and the relative absorption bandwidth of more than 100 percent can be obtained by utilizing the zero-order diffraction and the first-order diffraction of the doped silicon wafer to carry out numerical simulation. Furthermore, the optical properties of doped silicon can be tuned by varying the doping concentration, so the design can be easily extended to higher frequencies. The novel terahertz wave absorbing device adopts a hollow Koch snowflake parting structure, and the snowflake Koch parting structure is designed based on gradient width modulation. The higher the number of Koch snowflake typing iterations, the wider the gradient width cross section. The second-order Koch snowflake type medium can be divided into infinite small trapezoids along the transverse direction, and each pair of transverse infinite facets are equivalent to two mirrors of a Fabry-Perot cavity, so that multi-frequency resonance can be obtained, and the absorption bandwidth is improved. The hollow structure design of the wave absorber further enhances the action effect of the electromagnetic wave and the structure, thereby achieving the purposes of improving the absorption rate of the wave absorber and widening the frequency band. Based on the mechanism, the novel terahertz wave absorber can realize ultra wide band and high absorption rate absorption. The method has important significance for the development of the terahertz technology.
Disclosure of Invention
The invention aims to: the ultra-wideband terahertz wave absorber with the hollowed-out Koch snowflake parting medium structure is provided, and the problems that an existing terahertz wave absorber is few in absorption frequency band, poor in wave absorbing rate, narrow in absorption bandwidth, complex in structure and the like are solved.
The technical scheme adopted by the invention is as follows:
the ultra-wideband high-efficiency wide-angle terahertz wave absorber with the gradient structure loaded with the graphene medium comprises a medium bottom layer and a parting medium structure top layer which are sequentially arranged from bottom to top, wherein the parting medium structure layer comprises a plurality of hollowed-out Koch snowflake parting structure units, the hollowed-out Koch snowflake parting structure units are designed based on gradient width modulation, the higher the Koch snowflake parting iteration frequency is, and the wider the gradient width section is.
Furthermore, the material of the medium substrate layer is doped silicon.
Furthermore, the material of the medium parting structural layer is doped silicon.
In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:
1. the terahertz wave absorber is simple in structure and easy to process and manufacture, and the hollow structure design of the terahertz wave absorber further enhances the effect of electromagnetic waves and the structure, so that the purposes of improving the absorption rate of the wave absorber and widening the frequency band are achieved. The medium structure layer is a plurality of hollow Koch snowflake parting medium structures, and the structure is designed based on gradient width modulation. The higher the number of Koch snowflake typing iterations, the wider the gradient width cross section. The second order Koch snowflake-patterned medium is laterally separable into infinitely small trapezoids, each pair of laterally infinite facets corresponding to two mirrors of a Fabry-Perot cavity, so that multi-frequency resonance can be obtained. The structural absorber can realize high absorption rate and ultra wide band absorption in the whole terahertz frequency band. The absorber of the invention has good angular stability under a large angle of 50 degrees, has polarization insensitive characteristic, can realize ultra wide band absorption effect, has an absorption bandwidth (average absorption rate 95.33 percent) of 9.4THz and a relative absorption bandwidth of 177 percent from 0.6THz to 10THz in a terahertz frequency band range, and effectively solves the problems of few absorption frequency bands, poor wave absorbing rate, narrow absorption bandwidth, complex structure and edge effect in the prior art.
Drawings
FIG. 1 is a three-dimensional schematic diagram of a unit structure of a wave absorber based on a medium parting structure;
FIG. 2 is a top view of a wave absorber based on a dielectric parting structure;
FIG. 3 is an absorption spectrum of a dielectric fractal structure wave absorber in a terahertz frequency range under the condition of vertical incidence of a TE polarized wave;
FIGS. 4(a) - (c) are graphs of electric field distribution corresponding to three typical absorption peak frequencies within a frequency band in an absorption spectrum;
FIG. 5 is a comparison graph of absorption curves of a medium-parting-structure wave absorber in a terahertz frequency range under different parting orders;
FIG. 6 is an absorption spectrum of a TE polarized wave incident at an incident angle varying continuously from 0 to 80;
FIG. 7 is a graph showing a comparison of absorption curves at the time of TE polarized wave incidence and TM polarized wave incidence;
FIG. 8 is an absorption spectrum of a wave absorber with a medium parting structure under different hollow sizes;
the labels in the figure are: 1-medium substrate layer and 2-parting medium structure layer.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The ultra-wideband terahertz wave absorber with the hollow Koch snowflake parting medium structure comprises a medium bottom layer and a parting medium structure top layer which are sequentially arranged from bottom to top, wherein the parting medium structure layer comprises a plurality of hollow Koch snowflake parting structure units, the hollow Koch snowflake parting structure units are designed based on gradient width modulation, the higher the frequency of Koch snowflake parting iteration is, the wider the gradient width section is.
Furthermore, the material of the medium substrate layer is doped silicon.
Furthermore, the material of the medium parting structural layer is doped silicon.
Wherein, the working frequency range: 0.6THz-10 THz;
relative absorption bandwidth: 177%;
absorption bandwidth: 9.4 THz.
Fig. 1 is a three-dimensional schematic diagram of a unit structure of a wave absorber based on a medium parting structure. The absorber unit structure is composed of a medium substrate layer and a hollow Koch snowflake parting medium layer. The two layers of dielectric materials are doped silicon, the thickness of the top layer dielectric structure is 250 micrometers, and the side length is 210 micrometers. The thickness of the parting structure medium layer is 75 μm.
FIG. 2 is a top view of a wave absorber based on a medium parting structure, wherein the side length of the outer side of the Koch snowflake parting structure is 160 μm, and the side length of the inner side of the hollow Koch snowflake parting structure is 120 μm.
Fig. 3 is an absorption spectrum of the dielectric-fractal-structure wave absorber in the terahertz frequency range under the condition of vertical incidence of the TE polarized wave, and the absorption bandwidth can be from 0.6THz to 10THz, and the relative absorption bandwidth is up to 177%. FIGS. 4(a) - (c) are graphs of electric field distribution corresponding to three typical absorption peak frequencies in frequency bands of an absorption spectrum, such as 1.0THz (b)4.0THz (c)8.0 THz (4 a). It can be clearly seen that, as the frequency increases, the electric field energy is initially between the typing unit structures and then gathered at the hollowed-out grooves, and finally the electromagnetic wave energy permeates into the substrate to be consumed.
Fig. 5 is a comparison graph of absorption curves of the wave absorber under different fractional orders, and it can be clearly seen that the absorption performance is better as the fractional order is higher. The hollow snowflake Koch fractal structure wave absorber is also designed based on gradient width modulation, and the higher the Koch snowflake fractal iteration frequency is, the wider the gradient width section is. Therefore, more resonance can be obtained, thereby improving the absorption performance.
Fig. 6 is an absorption spectrum diagram when the incident angle is continuously changed from 0 ° to 80 ° under the incident condition of the TE polarized wave, and it can be seen that, in the range of the incident angle less than 50 °, the absorption rate is integrally maintained high, and the wave absorber can still maintain good absorption performance and bandwidth, and as the incident angle continues to increase, the overall absorption rate starts to decrease after 50 °. Therefore, the absorber of the invention shows good wave-absorbing stability under a large angle of 50 degrees, has wide-angle wave-absorbing characteristics, is easy to realize, operate and compatible in practical application, and is beneficial to being applied to various terahertz practical application scenes.
FIG. 7 is a graph showing the absorption curves of TE polarized waves and TM polarized waves. It can be seen that the two curves have almost the same trend and maintain high-performance absorption, that is, the absorption performance of the wave absorber does not change with the difference of polarization modes, indicating that the structure has the characteristic of polarization insensitivity.
Fig. 8 is a comparison graph of absorption curves of the wave absorber with the medium parting structure under different hollow sizes. The larger the hollowed-out size is, the better the absorption performance is, which fully shows that the design of the hollowed-out structure greatly improves the absorption performance of the wave absorber.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (3)
1. The ultra-wideband terahertz wave absorber with the hollowed-out Koch snowflake parting medium structure is characterized by comprising a medium substrate layer (1) and a medium parting structure layer (2) which are sequentially arranged from bottom to top, wherein the medium structure layer (2) comprises a plurality of hollowed-out Koch snowflake parting structure units, the hollowed-out Koch snowflake parting structure units are designed based on gradient width modulation, the higher the Koch snowflake parting iteration frequency is, and the wider the gradient width section is.
2. The ultra-wideband terahertz wave absorber with the hollowed-out Koch snowflake parting dielectric structure as claimed in claim 1, wherein the dielectric substrate layer (1) is made of doped silicon.
3. The ultra-wideband terahertz wave absorber with the hollowed-out Koch snowflake parting dielectric structure as claimed in claim 1, wherein the top layer (2) of the dielectric parting structure is made of doped silicon.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002001668A2 (en) * | 2000-06-28 | 2002-01-03 | The Penn State Research Foundation | Miniaturized conformal wideband fractal antennas on high dielectric substrates and chiral layers |
| CN103539401A (en) * | 2012-07-10 | 2014-01-29 | 株式会社理研 | Electromagnetic wave absorber |
| CN106972277A (en) * | 2016-01-14 | 2017-07-21 | 武汉碧海云天科技股份有限公司 | Electromagnetism Meta Materials |
| CN112582802A (en) * | 2020-10-12 | 2021-03-30 | 中国计量大学 | Perfect wave absorber of all-dielectric metamaterial multifrequency section based on 3D prints |
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2021
- 2021-04-22 CN CN202110438767.2A patent/CN113224547A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002001668A2 (en) * | 2000-06-28 | 2002-01-03 | The Penn State Research Foundation | Miniaturized conformal wideband fractal antennas on high dielectric substrates and chiral layers |
| CN103539401A (en) * | 2012-07-10 | 2014-01-29 | 株式会社理研 | Electromagnetic wave absorber |
| CN106972277A (en) * | 2016-01-14 | 2017-07-21 | 武汉碧海云天科技股份有限公司 | Electromagnetism Meta Materials |
| CN112582802A (en) * | 2020-10-12 | 2021-03-30 | 中国计量大学 | Perfect wave absorber of all-dielectric metamaterial multifrequency section based on 3D prints |
Non-Patent Citations (2)
| Title |
|---|
| HUAFENG LIU: "An Ultra-Wideband THz/IR Metamaterial Absorber Based on Doped Silicon", 《MATERIALS》 * |
| 夏少旭: "Koch分形结构活性碳纤维电路屏复合材料的研制及其吸波性能研究", 《中国优秀硕士论文电子期刊网》 * |
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Application publication date: 20210806 |