CN116093632A - Design method of cross-band ultra-wideband absorber - Google Patents
Design method of cross-band ultra-wideband absorber Download PDFInfo
- Publication number
- CN116093632A CN116093632A CN202211725680.4A CN202211725680A CN116093632A CN 116093632 A CN116093632 A CN 116093632A CN 202211725680 A CN202211725680 A CN 202211725680A CN 116093632 A CN116093632 A CN 116093632A
- Authority
- CN
- China
- Prior art keywords
- surface metal
- ultra
- wideband
- layer
- equivalent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000013461 design Methods 0.000 title claims abstract description 56
- 238000000034 method Methods 0.000 title claims abstract description 39
- 239000006096 absorbing agent Substances 0.000 title claims abstract description 37
- 239000002184 metal Substances 0.000 claims abstract description 165
- 229910052751 metal Inorganic materials 0.000 claims abstract description 165
- 238000000926 separation method Methods 0.000 claims abstract description 60
- 238000005192 partition Methods 0.000 claims abstract description 46
- 238000010521 absorption reaction Methods 0.000 claims description 115
- 238000005457 optimization Methods 0.000 claims description 35
- 238000012545 processing Methods 0.000 claims description 10
- 230000009471 action Effects 0.000 claims description 8
- 230000002068 genetic effect Effects 0.000 claims description 8
- 238000005516 engineering process Methods 0.000 claims description 7
- 239000003990 capacitor Substances 0.000 claims description 6
- 239000006185 dispersion Substances 0.000 claims description 3
- 239000007769 metal material Substances 0.000 claims description 3
- 230000035699 permeability Effects 0.000 claims description 3
- 230000001105 regulatory effect Effects 0.000 claims description 3
- 238000012163 sequencing technique Methods 0.000 claims description 3
- 239000013598 vector Substances 0.000 claims description 3
- 238000001514 detection method Methods 0.000 abstract description 31
- 239000010410 layer Substances 0.000 description 156
- 230000003287 optical effect Effects 0.000 description 9
- 230000008569 process Effects 0.000 description 8
- 238000004364 calculation method Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 239000011358 absorbing material Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 230000005855 radiation Effects 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000000737 periodic effect Effects 0.000 description 3
- 239000002131 composite material Substances 0.000 description 2
- 238000012938 design process Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000005670 electromagnetic radiation Effects 0.000 description 2
- 238000009472 formulation Methods 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 230000002441 reversible effect Effects 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 230000008033 biological extinction Effects 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 230000001808 coupling effect Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000005622 photoelectricity Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000002829 reductive effect Effects 0.000 description 1
- 238000002310 reflectometry Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 238000000638 solvent extraction Methods 0.000 description 1
Images
Classifications
-
- 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
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
- G02B1/002—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of materials engineered to provide properties not available in nature, e.g. metamaterials
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/003—Light absorbing elements
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06N—COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS
- G06N3/00—Computing arrangements based on biological models
- G06N3/12—Computing arrangements based on biological models using genetic models
- G06N3/126—Evolutionary algorithms, e.g. genetic algorithms or genetic programming
-
- H—ELECTRICITY
- 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
- H01Q15/0086—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices having materials with a synthesized negative refractive index, e.g. metamaterials or left-handed materials
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biophysics (AREA)
- Theoretical Computer Science (AREA)
- Optics & Photonics (AREA)
- Bioinformatics & Cheminformatics (AREA)
- Bioinformatics & Computational Biology (AREA)
- Evolutionary Biology (AREA)
- Genetics & Genomics (AREA)
- General Health & Medical Sciences (AREA)
- Artificial Intelligence (AREA)
- Biomedical Technology (AREA)
- Computational Linguistics (AREA)
- Data Mining & Analysis (AREA)
- Evolutionary Computation (AREA)
- Physiology (AREA)
- Molecular Biology (AREA)
- Computing Systems (AREA)
- General Engineering & Computer Science (AREA)
- Mathematical Physics (AREA)
- Software Systems (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Aerials With Secondary Devices (AREA)
Abstract
The invention discloses a design method of a cross-band ultra-wideband wave absorber, which relates to the field of metamaterial wave absorber design and comprises the following steps: step S1: acquiring constraint conditions of a to-be-designed cross-band ultra-wideband absorber, and taking a sandwich structure of a surface metal layer/a medium layer/a surface metal layer/a bottom metal layer as a basic structural unit; step S2: dividing an ultra-wideband frequency range into 1-k sub-frequency ranges as partitions; step S3: independently designing a broadband wave-absorbing structure in a surface metal layer in each subarea sub-frequency range, and establishing a multi-separation layer structure; step S4: optimizing the wave absorbing efficiency at the boundary of each partition; the invention has wide application prospect in the fields of multi-band/broadband detection and ultra-wideband wave-absorbing stealth countermeasure.
Description
Technical Field
The invention relates to the field of metamaterial wave absorbers, in particular to a design method of a cross-band ultra-wideband wave absorber.
Background
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
The detection and stealth are a pair of contradicting communities which continuously evolve, and are mutually opposed and mutually promoted; the electromagnetic domain is developed and utilized most fully and effectively at present, and the traditional detection means in the whole electromagnetic wave band can be classified into active detection and passive detection; the active detection equipment is represented by radar and laser, wherein the radar is mainly and the laser is auxiliary; the passive detection equipment is typified by an electronic detection device and a visible light/infrared detector, wherein the electronic detection is mainly and the photoelectric detection is auxiliary. From the perspective of finding far and near targets, the detection finding of the long-distance targets is still mainly performed by active detection equipment such as radar, laser and the like, and the passive detection equipment is auxiliary; stealth materials are also evolving along the development direction of detection technology, and can be classified into wave-absorbing stealth and shielding stealth; the wave-absorbing stealth is mainly concentrated in two directions of radar and laser, and the shielding stealth is mainly concentrated in two directions of detection and photoelectricity.
The existing wave-absorbing stealth effects are mostly achieved only aiming at electromagnetic waves of specific wave bands, such as L, S, C, X, ka working frequency bands (2 GHz-100 GHz) of radars and near infrared wave bands (0.8 mu m-2 mu m) of lasers; the rapid progress of the terahertz technology makes the terahertz gap (0.1 THz-10 THz) gradually compensated, the remote terahertz radar plays an important role in the aspect of anti-stealth, the rapid progress of the laser technology makes the working wavelength of laser continuously progress towards the directions of ultraviolet (shorter wavelength) and far infrared (longer wavelength), and the development of single photon detection, quantum well detection, bicolor infrared, multi/high/hyperspectral detection and chip technology makes the broad spectrum/broadband detection gradually realistic; therefore, broadband stealth and even cross-band stealth are targets for continuous striving for stealth countermeasures; the existence of various active and passive distributed detection means with different spatial distributions, different geographic positions, different working wave bands, different detection mechanisms and different environmental backgrounds makes the perfect stealth of the active and passive almost impossible to realize, but the broadband stealth aiming at the same working mechanism is not far from reach, such as active detection equipment for acquiring target information by utilizing echo detection, such as traditional radar, laser and terahertz radar; particularly, in recent years, the artificial metamaterial is vigorously developed to be capable of absorbing wave in a broadband and hiding, so that the ultra-wide band or cross-band stealth of active detection equipment is hopefully realized through the flexible design of the artificial metamaterial.
The metamaterial has the artificial design of supernormal electromagnetic characteristics, so that the metamaterial becomes an ideal material for absorbing electromagnetic waves once proposed; the advantages of the flexible design of the sub-wavelength structure, the ultra-thin thickness, the ultra-light weight, the ultra-strong wave absorbing performance and the like make the sub-wavelength structure, the ultra-thin thickness, the ultra-light weight, the ultra-strong wave absorbing performance and the like become optimal candidates for developing new generation stealth materials; the metamaterial wave-absorbing structure design is applied to the detection end, can realize good wave absorption and efficient utilization of electromagnetic waves, is beneficial to improving the sensitivity and responsivity of the detector, is applied to the target end, can realize efficient wave absorption of incident electromagnetic waves, reduces echo energy, can also shield electromagnetic radiation of the target, and reduces the radiation contrast of the target and the environment.
Therefore, the wave-absorbing structure of the cross-band ultra-wideband metamaterial can be a multiband compatible stealth countermeasure for multiband composite sensing detection, and an effective and feasible approach is provided; how to design a metamaterial absorber with high absorption efficiency and ultra-wide frequency range becomes the key of multi-band compatible stealth countermeasure; according to the impedance matching theory, most of metamaterial wave absorbing structures absorb near-perfect waves of narrowband electromagnetic waves in a single frequency band, and related reports are also available on dual-band, multi-band and broadband wave absorbers. In 2009, wen et al reported for the first time that the design of a dual-band absorber reached 99.99% absorption at both 0.50THz and 0.94 THz. Tao et al also propose a dual-band terahertz wave absorber, the theoretical absorption rate can reach 99.99%. In 2011, ma et al designed a terahertz dual-band absorber with absorption rates of 0.68 and 0.74 at 2.7THz and 5.2THz, respectively. Shen et al designed a three-band absorber structure with absorptances of 0.99,0.93 and 0.95 at 4.06GHz,6.73GHz and 9.22GHz, and in 2012, she et al realized three-band absorbers with terahertz bands with absorptances of 96.4%,96.3% and 96.7% at 0.5THz,1.03THz and 1.71 THz.
In practical radar stealth countermeasure application, the objective reality that the radar working frequency is unknown, the agile frequency and the modulation mode are uncertain, etc. make the narrow-band wave-absorbing structure not reach the ideal radar stealth countermeasure efficiency, and the ultra-wide-band metamaterial wave-absorbing structure is urgently needed.
Disclosure of Invention
The invention aims at:
aiming at the following defects in the prior art: 1. the existing metamaterial wave-absorbing structure mainly aims at broadband wave-absorbing in a wave band, mainly comprises radar wave-absorbing materials, has small wave-absorbing bandwidth, and does not have cross-band ultra-wideband wave-absorbing materials in the frequency range of 0.1GHz-1000THz of cross-band ultra-wideband wave-absorbing materials; 2. the design method of the cross-band metamaterial wave-absorbing structure is optimized by experience and man, the design process of the broadband wave-absorbing structure is complicated and complex, the design method of the reverse broadband metamaterial wave-absorbing structure is not more, and the cross-band ultra-broadband wave-absorbing structure is not related; 3. the broadband metamaterial wave-absorbing structure with the cross wave band has the advantages that the absorption efficiency is not ideal in a low-frequency wave band, and the wave-absorbing bandwidth with high absorption efficiency is low; the metamaterial wave-absorbing structure has the tailorability according to the requirement, can be arbitrarily tailored according to the requirement to achieve the wave-absorbing design of a specific wave band, and does not consider an atmospheric window; 4. the wave absorption bandwidth of the wave absorption structure of the cross-band broadband metamaterial is discontinuous, and the ultra-broadband continuous and efficient wave absorption can not be realized temporarily; the design method of the broadband ultra-wideband absorber is provided to realize the countermeasure and stealth of the ultra-wideband incident electromagnetic wave, cover the microwave/terahertz and terahertz/optical broadband, and the ultra-wideband absorber structure design in the microwave/terahertz/optical full-band and any frequency range.
The invention takes a metal/medium/metal three-layer structure as a basic structural unit to form a multi-layer metal/medium pair structure of metal/medium/metal (M/I/M/I/M), thereby achieving the purpose of effectively expanding the wave-absorbing bandwidth.
The invention adopts the reverse engineering design principle, is designed by demand guidance, optimizes the structural parameters by utilizing an intelligent optimization algorithm (genetic optimization algorithm) on the basis of initializing the structural parameters according to the frequency range and the absorption efficiency requirements, and simply and quickly determines the structural parameters of the metamaterial wave absorber.
The invention utilizes the sectional non-uniform sampling broadband wave-absorbing design method to effectively improve the wave-absorbing efficiency of the low-frequency wave band, expand the wave-absorbing bandwidth range and improve the high-efficiency wave-absorbing bandwidth ratio.
The invention defines the general design method and the basic design flow of the broadband metamaterial wave-absorbing structure, and is suitable for the structural design and the application of the ultra-wideband wave-absorbing device of microwave, terahertz, optical and other wave band cross-band ultra-wideband and any frequency range.
The invention defines the thickness limit of the wave-absorbing structure of the cross-band metamaterial and the cutting-on-demand principle of specific multiband frequency range, and realizes the wave-absorbing stealth countermeasure of the cross-band metamaterial with minimum structural complexity, minimum layer number and thickness as thin as possible.
The technical scheme of the invention is as follows:
a design method of a cross-band ultra-wideband absorber comprises the following steps:
step S1: acquiring constraint conditions of a to-be-designed cross-band ultra-wideband absorber, and taking a sandwich structure of a surface metal layer/a medium layer/a surface metal layer/a bottom metal layer as a basic structural unit; the constraint conditions include: ultra wideband frequency range and absorption efficiency;
step S2: dividing an ultra-wideband frequency range into 1-k sub-frequency ranges as partitions;
step S3: independently designing a broadband wave-absorbing structure in a surface metal layer in each subarea sub-frequency range, and establishing a multi-separation layer structure;
step S4: and optimizing the wave absorbing efficiency at the boundary between each two partitions.
Further, the step S1 includes:
based on the design requirements of the ultra-wideband frequency range and the high absorption efficiency of the cross-band ultra-wideband absorber, the mutual superposition of the high absorption peaks of a plurality of frequencies is utilized to achieve the purpose of effectively expanding the absorption bandwidth while keeping the high absorption efficiency, thereby achieving the purpose of consistent and efficient absorption in the ultra-wideband frequency range;
the ultra-wideband frequency range is represented by [ fmin, fmax ], wherein fmin is a lower frequency limit and fmax is an upper frequency limit.
Further, the step S2 includes:
[fmin，fmax]＝[fmin1，fmax1]∪[fmin2，fmax2]∪....∪[fmink，fmaxk]
wherein: k=floor (log) n (N)) +1; n=fmax/fmin; the value of n=fmaxk/fmink, n can be natural logarithm selected according to design requirement and processing technology constraint, and [2-10 ]]An integer of (a); fmink=fmaxk-1.
Further, the step S3 includes:
step S31: selecting and setting a plurality of characteristic absorption frequencies in each partition frequency range;
step S32: planning and designing a surface metal structure according to characteristic wavelengths corresponding to the characteristic absorption frequencies respectively, and determining the thickness of a medium layer in each partition; the surface metal structure comprises: surface metal structure size and surface metal structure shape;
step S33: calculating equivalent resonance circuit parameters of each surface metal structure under the action of surface plasmons by utilizing an equivalent impedance matching theory, and taking the equivalent resonance circuit parameters and the thickness of a dielectric layer as initialization parameters;
step S34: introducing an intelligent optimization algorithm to perform optimization design on the initialization parameters on the basis of constraint conditions so as to confirm that the requirements of wave absorption bandwidth and absorption efficiency can be met;
step S35: and inverting to obtain the optimized surface metal structure size and the optimized dielectric layer thickness based on the optimized equivalent resonant circuit parameters and the optimized dielectric layer thickness.
Further, the surface metal structure size in the step S32 includes: surface metal structure width and surface metal structure thickness;
the surface metal structure is in a ring shape.
Further, the equivalent resonant circuit parameters in the step S33 include: equivalent resistance, equivalent inductance, and equivalent capacitance.
Further, the step S33 includes:
C g ＝ε 0 h/(T-w) 2
wherein: c (C) g A gap capacitance between adjacent surface metal structures; epsilon 0 Is free space dielectric constant, i.e. vacuum conductivity; h is the thickness of the surface metal structure; t is the perimeter of the basic structural unit; w is the width of the surface metal structure;
C m ＝c 1 ε d ε 0 S/t
wherein: c (C) m The parallel plate capacitor is formed by the surface metal layer and the bottom metal layer; c 1 Is a regulatory factor; epsilon 0 Is the free space dielectric constant; epsilon d Is the dielectric constant of the dielectric layer; s is the area of the surface metal layer; t is the thickness of the dielectric layer;
L e ＝-S/(ω 2 δε 0 )·(ε'/(ε' 2 +ε” 2 ))
wherein: l (L) e Dynamic inductance caused by drifting electrons in the surface metal layer; omega is the angular frequency; delta is the metal skin depth of the surface metal layer; epsilon 'and epsilon' are the real part and the imaginary part of the dielectric constant of the metal material of the surface metal layer respectively;
L m ＝0.5μ 0 S·t
wherein: l (L) m Is the mutual inductance between the surface metal layer and the bottom metal layer; mu (mu) 0 Is vacuum magnetic permeability; s is the area of the surface metal layer; t is the thickness of the dielectric layer;
metal dispersion model of surface metal layer
Wherein: omega p The metal plasma frequency, ω is the angular frequency, i is the imaginary number, and K is the electron collision frequency;
equivalent impedance of the metal equivalent resonant circuit:
wherein: z is Z m Equivalent impedance of the metal equivalent resonant circuit; i is an imaginary number; omega is the angular frequency; l (L) m Is the mutual inductance between the surface metal layer and the bottom metal layer; l (L) e Dynamic inductance caused by drifting electrons in the surface metal layer; c (C) g C is the gap capacitance between adjacent surface metal structures m The parallel plate capacitor is formed by the surface metal layer and the bottom metal layer.
Further, the step S34 includes:
step A: calculating the average absorption rate of the multi-separation layer structure by using the initialization parameters;
and (B) step (B): calculating the average absorptivity of the multi-separation layer structure in the frequency range;
step C: and calling a genetic algorithm to obtain the equivalent resonant circuit parameters with optimal average absorption efficiency.
Further, the step a includes:
step A1: calculating wave vectors in horizontal and vertical directions;
step A2: judging whether the number of layers is multiple; if yes, the step A3 is carried out, if not, the step A3 is skipped, and the step A4 is carried out;
step A3: calculating the equivalent admittance of each separation layer;
step A4: the absorption rate of the separation layer is iteratively calculated.
Further, the step C includes:
step C1: adding a random value into the initialization parameter, and repeatedly calculating the average absorptivity for 1000 times;
step C2: sorting and selecting equivalent resonant circuit parameters with average absorptivity more than or equal to 80%;
step C3: performing average absorptivity interpolation on the selected equivalent resonant circuit parameters, recalculating the average absorptivity after interpolation, and sequencing the equivalent resonant circuit parameters with the front average absorptivity;
step C4: carrying out average absorptivity interpolation on the selected equivalent resonant circuit parameters, recalculating the average absorptivity after interpolation, and storing the average absorptivity and the corresponding equivalent resonant circuit parameters;
step C5: and sorting the saved equivalent resonant circuit parameters according to the average absorptivity, and selecting the equivalent resonant circuit parameter with the highest average absorptivity as an optimal output result.
Compared with the prior art, the invention has the beneficial effects that:
the invention has wide application prospect in the fields of multi-band/broadband detection and ultra-wideband wave-absorbing stealth countermeasure. In terms of detection, the ultra-wideband absorption structure is beneficial to the performance improvement of the multi-band or broadband detector, the efficient absorption of the incident signals can effectively improve the utilization efficiency of electromagnetic waves, the signal to noise ratio and the radiation contrast ratio, the design and the realization of the multi-band/broadband detector can be guided, the ultra-wideband absorption structure is applied to the field of passive detection of electromagnetic waves, and the high-precision direction finding is hopeful to be realized; in the aspect of countermeasure stealth, the ultra-wideband absorption structure can effectively reduce the energy of echo signals, achieves the aims of countermeasure and stealth of radar in a wideband, and is applied to the field of radar countermeasure stealth; in the electromagnetic shielding aspect, the ultra-wideband absorption structure can effectively shield electromagnetic radiation of a target, reduce the radiation contrast ratio of the target and the environment, improve the stealth performance of the target, and is hopeful to realize wideband stealth or cross-band ultra-wideband stealth.
Drawings
FIG. 1 is a flow chart of a design method of a cross-band ultra wideband absorber;
FIG. 2 is a flow chart for optimizing parameters of a multi-separation layer structure;
FIG. 3 is a schematic diagram of a surface cycle unit;
FIG. 4 is a schematic diagram of a metal equivalent resonant circuit of a surface plasmon effect;
FIG. 5 is a schematic illustration of a multiple separation layer structure;
FIG. 6 is a graph of reflection loss at each frequency point after structural parameter optimization of five separation layers in the range of 1-10 GHz;
FIG. 7 is a graph of reflection loss at each frequency point after structural parameter optimization of five separation layers in the range of 0.1-1 GHz;
FIG. 8 is a graph of reflection loss at each frequency point after structural parameter optimization of five separation layers in the range of 10-100 GHz;
FIG. 9 is a graph of reflection loss at each frequency point after optimization of five separation layer structural parameters in the range of 0.1-1 THz;
FIG. 10 is a graph of reflection loss at each frequency point after structural parameter optimization of five separation layers in the range of 1-10 THz;
FIG. 11 is a graph of reflection loss at each frequency point after optimization of five separation layer structural parameters in the range of 10-100 THz;
FIG. 12 is a graph of reflection loss at each frequency point after optimization of five separation layer structural parameters in the range of 100-1000 THz;
FIG. 13 is a graph of the overall absorption rate of a 0.1GHz-1000THz ultra-wideband metamaterial wave-absorbing structure;
FIG. 14a is a schematic diagram of five layers of structures in a full-band ultra wideband wave absorbing structure partition;
FIG. 14b is a schematic top view of five layers of structures within a full band ultra wideband wave absorbing structure partition;
FIG. 14c is a side view of a full band ultra wideband wave absorbing structure;
FIG. 15 is a graph of reflection loss at each frequency point of partition 1 after optimization of structural parameters of five separation layers of 1-100 GHz;
FIG. 16 is a graph of reflection loss at each frequency point of partition 2 after optimization of the structural parameters of five separation layers of 1-100 GHz;
FIG. 17 is a graph of reflection loss at each frequency point of partition 3 after optimization of the structural parameters of five separation layers of 1-100 GHz;
FIG. 18 is a graph of the overall absorption rate of a 1-100GHz ultra-wideband metamaterial wave-absorbing structure;
FIG. 19 is a graph of reflection loss at each frequency point of partition 1 after optimization of five separation layer structural parameters in the wavelength range of 0.2-20 μm;
FIG. 20 is a graph of reflection loss at each frequency point of partition 2 after optimization of five separation layer structural parameters in the wavelength range of 0.2-20 μm;
FIG. 21 is a graph of reflection loss at each frequency point of partition 3 after optimization of five separation layer structural parameters in the wavelength range of 0.2-20 μm;
FIG. 22 is a graph of the overall absorption rate of an ultra-wideband metamaterial wave-absorbing structure over a wavelength range of 0.2-20 μm.
Detailed Description
It is noted that relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The features and capabilities of the present invention are described in further detail below in connection with examples.
Example 1
Referring to fig. 1, a design method of a cross-band ultra wideband absorber specifically includes the following steps:
step S1: acquiring constraint conditions of a to-be-designed cross-band ultra-wideband absorber, and taking a sandwich structure of a surface metal layer/a medium layer/a surface metal layer/a bottom metal layer as a basic structural unit; the constraint conditions include: ultra wideband frequency range and absorption efficiency; namely, the absorption efficiency is definitely achieved in the frequency range, and the absorption efficiency are always starting points of ultra-wideband wave-absorbing metamaterial design; the ultra-wideband frequency range is represented as [ fmin, fmax ], wherein fmin is a lower frequency limit and fmax is an upper frequency limit; in general, there is a contradiction between the absorption efficiency and the absorption bandwidth, that is, the higher the absorption efficiency is, the narrower the absorption bandwidth is, the wider the absorption bandwidth is, and the lower the absorption efficiency is, so the essence of the ultra-wideband wave-absorbing stealth design is that: based on the design requirements of the ultra-wideband frequency range and the high absorption efficiency of the cross-band ultra-wideband absorber, the mutual superposition of the high absorption peaks of a plurality of frequencies is utilized to achieve the purpose of effectively expanding the absorption bandwidth while keeping the high absorption efficiency, thereby achieving the purpose of consistent and efficient absorption in the ultra-wideband frequency range;
step S2: dividing an ultra-wideband frequency range into 1-k sub-frequency ranges as partitions; because the absorption bandwidth of most of the existing broadband metamaterial wave-absorbing structures is not large, fmax/fmin is less than or equal to 10, for the absorption bandwidth of the ultra-broadband metamaterial wave-absorbing structures is less than or equal to 10 and fmax/fmin=n is less than or equal to 1000, the wavelength span is very large, and the wave-absorbing coverage of all frequency points in the ultra-broadband frequency range is very difficult to realize by adopting the traditional metamaterial design method, so the embodiment divides the ultra-broadband frequency range, namely:
[fmin，fmax]＝[fmin1，fmax1]∪[fmin2，fmax2]∪....∪[fmink，fmaxk]
wherein: k=floor (log) n (N)) +1; n=fmax/fmin; the value of n=fmaxk/fmink, n can be natural logarithm selected according to design requirement and processing technology constraint, and [2-10 ]]An integer of (a); fmink=fmaxk-1; for example: if n=10000000, n=2, k=24, if n=10000000, n=10, k=7;
step S3: independently designing a broadband wave-absorbing structure in a surface metal layer in each subarea sub-frequency range, and establishing a multi-separation layer structure; the method can be carried out by adopting two modes of transverse multi-scale wave-absorbing design and longitudinal multi-separation layer wave-absorbing design, wherein the former is generally suitable for partitions with n being less than or equal to 3, and the latter has better effect when n being more than or equal to 3, and preferably, in the embodiment, the longitudinal five-separation layer wave-absorbing design is selected to realize the optimization of broadband wave-absorbing structures in the sub-frequency range of each partition;
step S4: optimizing the wave absorbing efficiency at the boundary of each partition; because the low frequency coverage is difficult in the design of the broadband wave-absorbing structure of each partition, if the low frequency edge part of each partition is not completely covered, the narrow-band perfect wave-absorbing layer structure can be utilized for blind compensation, thereby achieving the full coverage of the ultra-wideband frequency range.
In this embodiment, specifically, the step S3 includes:
step S31: selecting and setting a plurality of characteristic absorption frequencies in each partition frequency range; preferably, the number of the characteristic absorption frequencies is increased or decreased according to the bandwidth absorption frequency range, and 5-6 characteristic absorption frequencies are generally recommended to be proper, and the characteristic absorption frequencies are selected to realize multimodal absorption by using surface metal structures with different scales to expand the absorption bandwidth;
step S32: planning and designing a surface metal structure according to characteristic wavelengths corresponding to the characteristic absorption frequencies respectively, and determining the thickness of a medium layer in each partition; the surface metal structure comprises: surface metal structure size and surface metal structure shape; preferably, the surface metal structure size in the step S32 includes: surface metal structure width and surface metal structure thickness; wherein it is generally recommended that the shape of the surface metal structure is selected from regular geometric figures such as rectangle, square, circle, ring, etc., the structural dimension is of the order of sub-wavelength, typically between one third and one fourth of the characteristic wavelength, the thickness is smaller than the skin depth of the metal, it is generally recommended that one third of the skin depth is taken, preferably the shape of the surface metal structure is a ring structure; the thickness of the dielectric layer is about one tenth of the characteristic wavelength, and the thickness of the single-layer dielectric layer is about one tenth of the difference between the maximum wavelength and the minimum wavelength during broadband absorption;
step S33: calculating equivalent resonance circuit parameters of each surface metal structure under the action of surface plasmons by utilizing an equivalent impedance matching theory, and taking the equivalent resonance circuit parameters and the thickness of a dielectric layer as initialization parameters; it should be noted that, under the action of surface plasmon, the surface metal structure and the bottom metal layer (i.e. the bottom reflecting layer) form an equivalent resonant circuit, and the equivalent resonant circuit parameters of different scale metals/medium/metal (M/I/M) sandwich structures under the action of surface plasmon are calculated by using an equivalent impedance matching theory: equivalent impedance, equivalent inductance and equivalent capacitance, and the equivalent impedance, the equivalent inductance and the equivalent capacitance are used as initialization parameters for optimizing the multi-separation-layer structure together with the thickness of each dielectric layer; wherein, the equivalent resistance is related to the material and dielectric constant of the surface metal layer and the dielectric layer, the equivalent inductance is related to the area of the surface metal structure and the thickness of the dielectric layer, and the equivalent capacitance is related to the thickness of the dielectric layer;
step S34: introducing an intelligent optimization algorithm to perform optimization design on the initialization parameters on the basis of constraint conditions so as to confirm that the requirements of wave absorption bandwidth and absorption efficiency can be met; it should be noted that, when the broadband absorption wavelength difference is too large, the multi-scale surface metal structure cannot meet the requirement of continuous high absorption efficiency under the same thickness of the dielectric layer, and the design of the multiple separation layers aims at expanding the high absorption bandwidth of each characteristic absorption peak so as to ensure that the superposition absorption effect of multiple absorption peaks meets the requirement of broadband high absorption rate; however, strong coupling exists between the structures of the multiple separation layers and between the surface structures of the multiple separation layers, how to determine the thickness of each layer of the multiple separation layers and the metal structure of each layer of the surface to meet the requirement of broadband high absorptivity becomes the key of the design of the multiple separation layers, and the great increase of the degree of freedom of the design makes artificial adjustment of parameters of each layer become less feasible, so that an intelligent optimization algorithm is introduced to carry out optimization design on the structural parameters of the multiple separation layers under the constraint of absorption bandwidth and absorption efficiency so as to determine the structural parameters of the multiple separation layers which can meet the requirement of the absorption bandwidth and the absorption efficiency, the multi-objective optimization problem is essentially determined under the multi-constraint condition, the selection of the intelligent optimization algorithm depends on the complexity of the multi-constraint multi-objective optimization and the performance of the intelligent optimization algorithm, and generally genetic algorithm, evolutionary algorithm, immune algorithm, ant colony algorithm, particle swarm algorithm and the like; taking absorption efficiency as constraint, taking the equivalent resonant circuit parameters of the surface metal structure and the thickness of each dielectric layer as initialization parameters, optimizing the structural parameters of multiple separation layers of the equivalent resonant circuits of the surface metal structure by utilizing the equivalent impedance matching principle and the multilayer interference absorption principle, determining whether the primary optimization result of the multiple separation layer structure of each scale meets the absorption bandwidth requirement, searching a broadband absorption rule, properly cutting and selecting the structural scale to meet the absorption bandwidth requirement, and optimizing again to determine the equivalent resonant circuit parameters of each separation layer; preferably, in this embodiment, the intelligent optimization algorithm is a genetic algorithm;
step S35: inversion is carried out on the basis of the optimized equivalent resonant circuit parameters and the thickness of the dielectric layer to obtain the optimized surface metal structure size and the optimized thickness of the dielectric layer; it should be noted that, the parameters of the equivalent resonant circuit of each layer obtained after the multi-separation layer structure is optimized have certain difference with the initialization parameters, the surface metal structure of each layer needs to be inverted according to the equivalent resistance, the equivalent inductance and the equivalent capacitance, so that the subsequent process processing is facilitated, the multi-scale multi-separation layer structure also relates to the combined arrangement of the multi-separation layer structures with different scales to adapt to the processing process precision, if the processing process requirement is not met, the design is needed again, and the processing process constraint can be added when the parameters of the multi-separation layer structure are optimized, but the complexity of multi-constraint multi-objective optimization is increased, so that the optimal solution is possibly not obtained.
In this embodiment, specifically, the equivalent resonant circuit parameters in step S33 include: equivalent resistance, equivalent inductance and equivalent capacitance; specifically, the step S33 includes:
C g ＝ε 0 h/(T-w) 2
wherein: c (C) g The gap capacitance between the adjacent surface metal structures is equivalent capacitance; epsilon 0 Is free space dielectric constant, i.e. vacuum conductivity; h is the thickness of the surface metal structure; t is the perimeter of the basic structural unit; w is the width of the surface metal structure;
C m ＝c 1 ε d ε 0 S/t
wherein: c (C) m The parallel plate capacitor is formed by the surface metal layer and the bottom metal layer; c 1 Is a regulatory factor; epsilon 0 Is the free space dielectric constant; epsilon d Is the dielectric constant of the dielectric layer; s is the area of the surface metal layer; t is the thickness of the dielectric layer;
L e ＝-S/(ω 2 δε 0 )·(ε'/(ε' 2 +ε” 2 ))
wherein: l (L) e Dynamic inductance caused by drifting electrons in the surface metal layer; omega is the angular frequency; delta is the metal skin depth of the surface metal layer; epsilon 'and epsilon' are respectively the metal materials of the surface metal layersReal and imaginary parts of the dielectric constant;
L m ＝0.5μ 0 S·t
wherein: l (L) m The mutual inductance between the surface metal layer and the bottom metal layer is equivalent inductance; mu (mu) 0 Is vacuum magnetic permeability; s is the area of the surface metal layer; t is the thickness of the dielectric layer;
metal dispersion model of surface metal layer
Wherein: omega p The metal plasma frequency, ω is the angular frequency, i is the imaginary number, and K is the electron collision frequency;
equivalent impedance of the metal equivalent resonant circuit:
wherein: z is Z m The equivalent impedance of the metal equivalent resonant circuit is equivalent resistance; i is an imaginary number; omega is the angular frequency; l (L) m Is the mutual inductance between the surface metal layer and the bottom metal layer; l (L) e Dynamic inductance caused by drifting electrons in the surface metal layer; c (C) g C is the gap capacitance between adjacent surface metal structures m The parallel plate capacitor is formed by the surface metal layer and the bottom metal layer.
Referring to fig. 2, in this embodiment, specifically, the step S34 includes:
step A: calculating the average absorption rate of the multi-separation layer structure by using the initialization parameters; it should be noted that, the specific calculation formula and calculation method involved in the step a should be known to those skilled in the art, and will not be described in detail;
and (B) step (B): calculating the average absorptivity of the multi-separation layer structure in the frequency range; it should be noted that, the specific calculation formula and calculation method involved in the step B should be known to those skilled in the art, and will not be described in detail;
step C: calling a genetic algorithm to obtain equivalent resonant circuit parameters with optimal average absorption efficiency; it should be noted that, the calculation formula in the genetic algorithm in the step C should be known to those skilled in the art, and will not be described in detail.
In this embodiment, specifically, the step a includes:
step A1: calculating wave vectors in horizontal and vertical directions;
step A2: judging whether the number of layers is multiple; if yes, the step A3 is carried out, if not, the step A3 is skipped, and the step A4 is carried out;
step A3: calculating the equivalent admittance of each separation layer;
step A4: the absorption rate of the separation layer is iteratively calculated.
In this embodiment, specifically, the step C includes:
step C1: adding a random value into the initialization parameter, and repeatedly calculating the average absorptivity for 1000 times;
step C2: sorting and selecting equivalent resonant circuit parameters with average absorptivity more than or equal to 80%;
step C3: performing average absorptivity interpolation on the selected equivalent resonant circuit parameters, recalculating the average absorptivity after interpolation, and sequencing the equivalent resonant circuit parameters with the front average absorptivity; for example: top 100 or 200 may be selected;
step C4: carrying out average absorptivity interpolation on the selected equivalent resonant circuit parameters, recalculating the average absorptivity after interpolation, and storing the average absorptivity and the corresponding equivalent resonant circuit parameters;
step C5: and sorting the saved equivalent resonant circuit parameters according to the average absorptivity, and selecting the equivalent resonant circuit parameter with the highest average absorptivity as an optimal output result.
Example two
Aiming at a 0.1GHz-1000THz microwave/terahertz/optical full-band ultra-wideband metamaterial wave absorbing structure, the design method of the cross-band ultra-wideband wave absorber provided by the first embodiment is adopted for design, and the specific design process is as follows.
The microwave/terahertz and terahertz/optical cross-band frequency ranges are subsets of the full-band ultra-wideband frequency ranges, full-band coverage from microwaves to optical bands is targeted, the full-band ultra-wideband wave absorption frequency ranges of 0.1GHz-1000THz are used as constraint conditions, and the absorption efficiency is 80%, so that the full-band ultra-wideband metamaterial wave absorption structure is designed.
According to design constraints, fmax=1000thz, fmin=0.1 ghz, fmax/fmin=n=10000000, and preliminary partition division is performed with n=2, e,3,4,5,6,7,8,9, respectively, the number of partitions is k=24, 17, 15, 12, 12,9,9,8,8, and when n=10, k=7.
In the embodiment, n=10 and k=7 are selected for designing the broadband wave-absorbing structure in the subarea; the specific partitioning results are as follows: fmm1=0.1 GHz and fmax1=1 GHz in partition 1; fmin 2=1 GHz, fmax2=10 GHz in partition 2; fmin3 = 10GHz, fmax3 = 100GHz in partition 3; fmin4 = 0.1THz, fmax4 = 1THz in partition 4; fmin5 = 1THz, fmax5 = 10THz in partition 5; fmin6 = 10THz, fmax6 = 100THz; fmin7 = 100THz, fmax7 = 1000THz.
Taking partition 2 as an example, the design of broadband wave-absorbing structure in the partition is described.
Determining characteristic absorption frequencies in the subareas; the broadband wave absorption principle is that a plurality of absorption peaks are overlapped, a plurality of characteristic absorption frequencies are selected in a partition as the central frequency of the absorption peaks, the number of the characteristic absorption frequencies is not particularly limited, generally 4-5, but the central frequencies are close to low frequencies because of difficult low frequency coverage, and four characteristic absorption frequencies of 1GHz, 2GHz, 4GHz, 8GHz and 16GHz are selected, so that a surface metal structure is primarily designed according to characteristic wavelengths corresponding to the characteristic absorption frequencies.
Wherein the width of the surface metal structure is set to be about one quarter of the characteristic wavelength, and the thickness of the surface metal structure is 15nm; each surface metal structure and the bottom metal reflecting layer form an equivalent resonant circuit under the surface plasmon principle, and the incident electromagnetic wave is consumed in the equivalent resonant circuit, so that the efficient wave absorption of specific frequency is realized; specifically, the calculation formula of the surface metal structure size is as follows:
wherein:
w is the width of the surface metal structure; lambda is the characteristic wavelength; h is the thickness of the surface metal structure; delta is the metal skin depth; c is the vacuum electromagnetic wave speed; f is the characteristic absorption frequency; k (k) a Is the extinction coefficient of the metal.
Determining the shape of a surface metal structure; the characteristic absorption frequency is 5, and the corresponding surface metal structure has 5 sizes; the arrangement modes of the surface metal structures with different sizes are different, the structures of the surface periodic units can be generally divided into horizontal arrangement, vertical arrangement and nested arrangement, the annular structure is more suitable for nested arrangement, other shapes suggest horizontal arrangement, and the vertical arrangement is suitable for multi-layer design; therefore, in the embodiment, the surface periodic unit size of the preliminary design is mainly selected to be 100mm, the nested annular structure sizes are 80/60, 40/30, 20/15, 10/7.5 and 5/3.75mm, and the air gap size between the annular structures is 20/10/5/2.5mm, and the specific structure is shown in fig. 3; it should be noted that, in the actual preparation process, the surface metal structures of each layer are not concentric as shown in fig. 3, and specifically, the number of the surface metal structures on different surface metal layers can be determined according to the actual situation.
When the thickness of the dielectric layer is d=3mm, the equivalent resistance Z m ＝[212,454,675,1306,1812]Omega (ohm), equivalent inductance L m ＝[1.53e-16,1.22e-16,5.91e-17,6.21e-17,2.30e-16]H (henry), equivalent capacitance C g ＝[4.42e-13,5.28e-13,6.35e-14,8.19e-14,4.99e-15]F (method), the absorption bandwidths of the metal structures with different dimensions on the same dielectric layer thickness are different; the metal equivalent resonant circuit of the surface plasmon effect is shown in fig. 4.
The aim of the optimization of the multi-separation-layer structure parameters is to define the coupling effect among the surface metal structure, the thickness and the periodic structure of each layer so as to meet the requirement of broadband efficient absorption, and to determine the multi-separation-layer structure parameters; from the standpoint of complexity of the structural processing process, it is desirable to achieve efficient broadband absorption with a small number of layers and a simpler structure with the lowest processing difficulty, the number of layers being temporarily set to 5 layers, and the multiple separation layer structure being as shown in fig. 5.
Before starting the optimization of the parameters of the multi-separation-layer structure, the initialization parameters of each separation layer are determined firstly, and the determination method is as follows:
the thickness of each dielectric layer is set to be 1/10 of the minimum wavelength, namely d=3 mm (10 GHz corresponds to 1/10 of the wavelength);
the initialization parameters consist of equivalent resistance, equivalent inductance, equivalent capacitance and dielectric layer thickness of each layer, namely:
para＝[Z 1 ,Z 2 ,Z 3 ,Z 4 ,Z 5 ,L 1 ,L 2 ,L 3 ,L 4 ,L 5 ,C 1 ,C 2 ,C 3 ,C 4 ,C 5 ,d 1 ,d 2 ,d 3 ,d 4 ,d 5 ]
substituting the equivalent resonant circuit parameters into the following steps: para= [212,454,675,1306,1812,1.53e -16 ,1.22e -16 ,5.91e -17 ,6.21e -17 ,2.30e -16 ,4.42e -13 ,5.28e -13 ,6.35e -14 ,8.19e -14 ,4.99e -15 ,3e -3 ,3e -3 ,3e -3 ,3e -3 ]。
Optimizing by adopting a graph genetic algorithm; the absorption of radar absorbing materials is generally measured by using reflection Loss, loss=20log (r), r is the reflectivity, and the reflection Loss of each frequency point after the structural parameters of five separation layers of zone 2 (1-10 GHz) are optimized is shown in fig. 6.
The method is adopted to respectively design wideband wave absorbing structures in the subareas 1 (0.1-1 GHz), 3 (10-100 GHz), 4 (0.1-1 THz), 5 (1-10 THz), 6 (10-100 THz) and 7 (100-1000 THz); the reflection loss of each frequency point after the structural parameters of each partition five separation layers are optimized is shown in figures 7-12.
The parameters of the equivalent resonant circuit after optimization of the partitions 1 to 7 are shown in table 1.
TABLE 1 equivalent resonant Circuit parameters after optimization of partition 1 to partition 7
The absorption rate of the ultra-wideband metamaterial wave-absorbing structure is shown in figure 13.
Inverting and combining the sizes of the metal structures on the surfaces of all layers; inverting the size of the metal structure on the surface of each layer according to the optimized equivalent resonant circuit parameters of each layer; because the wavelength scale spans greatly, the surface metal structure size and the thickness of the multiple separation layers of the partition 1 are the largest, the surface metal structure size and the thickness of the multiple separation layers of the partition 2-partition 6 are sequentially reduced, and the surface metal structure size and the thickness of the multiple separation layers of the partition 7 are the smallest, therefore, when the multiple ultra-wideband wave absorbing structure is combined and arranged, the multiple separation layers are sequentially overlapped according to the sequence of the partition 7-partition 1, the annular size is periodically arranged on each layer, and finally the designed full-band ultra-wideband wave absorbing structure is shown as shown in fig. 14a, 14b and 14c, wherein the number of the surface metal structures of each surface metal layer in the figure is determined by the ratio of the maximum structure size to the structure size of each surface metal layer.
The structural parameters of the multiple separation layers of the wave absorbing structure of the full-band ultra-wideband metamaterial with the frequency ranging from 0.1GHz to 1000TGHz are shown in the table 2.
TABLE 2 structural parameters of 0.1GHz-1000THz ultra wideband metamaterial multiple separation layers
The microwave/terahertz and terahertz/optical cross-band ultra-wideband wave absorbing structure design can be optimized again according to the frequency range, and can also be realized by selecting a proper layer structure in the structural parameters; considering the working band of the detector, the working band of a typical radar is 2-40GHz, the terahertz radar is not mature, the working band is 0.1-2THz, the infrared atmospheric window is 3-5 mu m, 8-14 mu m and the ultraviolet to near infrared is 0.2-2 mu m, therefore, in order to simplify the complexity and processing difficulty of the full-band ultra-wideband wave-absorbing structure, the design of the corresponding cross-band ultra-wideband metamaterial wave-absorbing structure can be developed according to the frequency range or the band range as required, and the application of the terahertz radar has a certain difficulty because the millimeter wave radar has a limited working distance, and the stealth countermeasure requirements of the existing vast majority of composite sensing detection can be met by respectively designing the two ultra-wideband wave-absorbing structures of the frequency range of 1-100GHz and 0.2-20 mu m (fmax/fmin=100); here, it is proposed to divide n=100, n=5 into 3 regions, and to perform non-uniform sampling in the regions to optimize the metamaterial structure parameters in the regions.
The wave absorbing performance of the ultra-wideband metamaterial wave absorbing structure in the frequency range of 1-100GHz is shown in figures 15-18.
The structural parameters of the multi-separation layer of the 1-100GHz ultra-wideband metamaterial wave-absorbing structure are shown in Table 3.
Table 3 1-100GHz ultra-wideband metamaterial multi-separation-layer structure parameters
The wave absorbing performance of the ultra-wideband metamaterial wave absorbing structure in the wavelength range of 0.2-20 μm (15-1500 THz) is shown in figures 15-18.
The parameters of the multi-separation layer structure of the ultra-wideband metamaterial wave-absorbing structure in the wavelength range of 0.2-20 μm are shown in Table 4.
TABLE 4 structural parameters of ultra-wideband metamaterial multiple separation layers in the wavelength range 0.2-20 μm
On one hand, the optical wave band wave absorption is used for realizing stealth countermeasure to active detection type laser equipment by high-efficiency wave absorption of laser incident signals, and on the other hand, the optical wave band wave absorption is used for reducing infrared and visible light radiation energy by high-efficiency wave absorption of natural light infrared and visible light.
The foregoing examples merely represent specific embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the present application. It should be noted that, for those skilled in the art, several variations and modifications can be made without departing from the technical solution of the present application, which fall within the protection scope of the present application.
This background section is provided to generally present the context of the present invention and the work of the presently named inventors, to the extent it is described in this background section, as well as the description of the present section as not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present invention.
Claims (10)
1. The design method of the cross-band ultra-wideband absorber is characterized by comprising the following steps of:
step S1: acquiring constraint conditions of a to-be-designed cross-band ultra-wideband absorber, and taking a sandwich structure of a surface metal layer/a medium layer/a surface metal layer/a bottom metal layer as a basic structural unit; the constraint conditions include: ultra wideband frequency range and absorption efficiency;
step S2: dividing an ultra-wideband frequency range into 1-k sub-frequency ranges as partitions;
step S3: independently designing a broadband wave-absorbing structure in a surface metal layer in each subarea sub-frequency range, and establishing a multi-separation layer structure;
step S4: and optimizing the wave absorbing efficiency at the boundary between each two partitions.
2. The method for designing a broadband ultra-wideband absorber according to claim 1, wherein the step S1 comprises:
based on the design requirements of the ultra-wideband frequency range and the high absorption efficiency of the cross-band ultra-wideband absorber, the mutual superposition of the high absorption peaks of a plurality of frequencies is utilized to achieve the purpose of effectively expanding the absorption bandwidth while keeping the high absorption efficiency, thereby achieving the purpose of consistent and efficient absorption in the ultra-wideband frequency range;
the ultra-wideband frequency range is represented by [ fmin, fmax ], wherein fmin is a lower frequency limit and fmax is an upper frequency limit.
3. The method for designing a broadband ultra-wideband absorber according to claim 2, wherein the step S2 includes:
[fmin，fmax]＝[fmin1，fmax1]∪[fmin2，fmax2]∪....∪[fmink，fmaxk]
wherein: k=floor (log) n (N)) +1; n=fmax/fmin; the value of n=fmaxk/fmink, n can be natural logarithm selected according to design requirement and processing technology constraint, and [2-10 ]]An integer of (a); fmink=fmaxk-1.
4. The method for designing a broadband ultra-wideband absorber according to claim 1, wherein the step S3 includes:
step S31: selecting and setting a plurality of characteristic absorption frequencies in each partition frequency range;
step S32: planning and designing a surface metal structure according to characteristic wavelengths corresponding to the characteristic absorption frequencies respectively, and determining the thickness of a medium layer in each partition; the surface metal structure comprises: surface metal structure size and surface metal structure shape;
step S33: calculating equivalent resonance circuit parameters of each surface metal structure under the action of surface plasmons by utilizing an equivalent impedance matching theory, and taking the equivalent resonance circuit parameters and the thickness of a dielectric layer as initialization parameters;
step S34: introducing an intelligent optimization algorithm to perform optimization design on the initialization parameters on the basis of constraint conditions so as to confirm that the requirements of wave absorption bandwidth and absorption efficiency can be met;
step S35: and inverting to obtain the optimized surface metal structure size and the optimized dielectric layer thickness based on the optimized equivalent resonant circuit parameters and the optimized dielectric layer thickness.
5. The method for designing a broadband ultra-wideband absorber according to claim 4, wherein the surface metal structure in step S32 comprises: surface metal structure width and surface metal structure thickness;
the surface metal structure is in a ring shape.
6. The method for designing a broadband ultra-wideband absorber according to claim 5, wherein the equivalent resonant circuit parameters in step S33 include: equivalent resistance, equivalent inductance, and equivalent capacitance.
7. The method for designing a broadband ultra-wideband absorber according to claim 6, wherein the step S33 includes:
C g ＝ε 0 h/(T-w) 2
wherein: c (C) g A gap capacitance between adjacent surface metal structures; epsilon 0 Is free space dielectric constant, i.e. vacuum conductivity; h is the thickness of the surface metal structure; t is the perimeter of the basic structural unit; w is the width of the surface metal structure;
C m ＝c 1 ε d ε 0 S/t
wherein: c (C) m The parallel plate capacitor is formed by the surface metal layer and the bottom metal layer; c 1 Is a regulatory factor; epsilon 0 Is the free space dielectric constant; epsilon d Is the dielectric constant of the dielectric layer; s is the area of the surface metal layer; t is the thickness of the dielectric layer;
L e ＝-S/(ω 2 δε 0 )·(ε'/(ε' 2 +ε” 2 ))
wherein: l (L) e For drifting electrons in a surface metal layerThe resulting dynamic inductance; omega is the angular frequency; delta is the metal skin depth of the surface metal layer; epsilon 'and epsilon' are the real part and the imaginary part of the dielectric constant of the metal material of the surface metal layer respectively;
L m ＝0.5μ 0 S·t
wherein: l (L) m Is the mutual inductance between the surface metal layer and the bottom metal layer; mu (mu) 0 Is vacuum magnetic permeability; s is the area of the surface metal layer; t is the thickness of the dielectric layer;
metal dispersion model of surface metal layer
Wherein: omega p The metal plasma frequency, ω is the angular frequency, i is the imaginary number, and K is the electron collision frequency;
equivalent impedance of the metal equivalent resonant circuit:
wherein: z is Z m Equivalent impedance of the metal equivalent resonant circuit; i is an imaginary number; omega is the angular frequency; l (L) m Is the mutual inductance between the surface metal layer and the bottom metal layer; l (L) e Dynamic inductance caused by drifting electrons in the surface metal layer; c (C) g C is the gap capacitance between adjacent surface metal structures m The parallel plate capacitor is formed by the surface metal layer and the bottom metal layer.
8. The method for designing a broadband ultra-wideband absorber according to claim 4, wherein the step S34 includes:
step A: calculating the average absorption rate of the multi-separation layer structure by using the initialization parameters;
and (B) step (B): calculating the average absorptivity of the multi-separation layer structure in the frequency range;
step C: and calling a genetic algorithm to obtain the equivalent resonant circuit parameters with optimal average absorption efficiency.
9. The method for designing a broadband ultra-wideband absorber according to claim 8, wherein said step a comprises:
step A1: calculating wave vectors in horizontal and vertical directions;
step A2: judging whether the number of layers is multiple; if yes, the step A3 is carried out, if not, the step A3 is skipped, and the step A4 is carried out;
step A3: calculating the equivalent admittance of each separation layer;
step A4: the absorption rate of the separation layer is iteratively calculated.
10. The method for designing a broadband ultra-wideband absorber according to claim 8, wherein said step C comprises:
step C1: adding a random value into the initialization parameter, and repeatedly calculating the average absorptivity for 1000 times;
step C2: sorting and selecting equivalent resonant circuit parameters with average absorptivity more than or equal to 80%;
step C3: performing average absorptivity interpolation on the selected equivalent resonant circuit parameters, recalculating the average absorptivity after interpolation, and sequencing the equivalent resonant circuit parameters with the front average absorptivity;
step C4: carrying out average absorptivity interpolation on the selected equivalent resonant circuit parameters, recalculating the average absorptivity after interpolation, and storing the average absorptivity and the corresponding equivalent resonant circuit parameters;
step C5: and sorting the saved equivalent resonant circuit parameters according to the average absorptivity, and selecting the equivalent resonant circuit parameter with the highest average absorptivity as an optimal output result.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211725680.4A CN116093632A (en) | 2022-12-30 | 2022-12-30 | Design method of cross-band ultra-wideband absorber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211725680.4A CN116093632A (en) | 2022-12-30 | 2022-12-30 | Design method of cross-band ultra-wideband absorber |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116093632A true CN116093632A (en) | 2023-05-09 |
Family
ID=86200396
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211725680.4A Pending CN116093632A (en) | 2022-12-30 | 2022-12-30 | Design method of cross-band ultra-wideband absorber |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116093632A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116387849A (en) * | 2023-06-05 | 2023-07-04 | 四川九洲电器集团有限责任公司 | Wave absorber periodic unit and ultra-wideband wave absorber based on resistance surface |
| CN117457123A (en) * | 2023-11-02 | 2024-01-26 | 中国矿业大学 | Method for extracting equivalent permeability of cross-band metamaterial based on average method |
-
2022
- 2022-12-30 CN CN202211725680.4A patent/CN116093632A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116387849A (en) * | 2023-06-05 | 2023-07-04 | 四川九洲电器集团有限责任公司 | Wave absorber periodic unit and ultra-wideband wave absorber based on resistance surface |
| CN116387849B (en) * | 2023-06-05 | 2023-08-04 | 四川九洲电器集团有限责任公司 | Wave absorber periodic unit and ultra-wideband wave absorber based on resistance surface |
| CN117457123A (en) * | 2023-11-02 | 2024-01-26 | 中国矿业大学 | Method for extracting equivalent permeability of cross-band metamaterial based on average method |
| CN117457123B (en) * | 2023-11-02 | 2024-06-11 | 中国矿业大学 | Method for extracting equivalent permeability of cross-band metamaterial based on average method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN116093632A (en) | Design method of cross-band ultra-wideband absorber | |
| Tahir et al. | A novel FSS for gain enhancement of printed antennas in UWB frequency spectrum | |
| Mishra et al. | Cascaded graphene frequency selective surface integrated tunable broadband terahertz metamaterial absorber | |
| US9912069B2 (en) | Dual-polarized, broadband metasurface cloaks for antenna applications | |
| Noor et al. | Metamaterial dual polarised resistive Hilbert curve array radar absorber | |
| CN111129784A (en) | High-light-transmittance ultra-wideband low-scattering super surface suitable for solar cell array | |
| CN109309286B (en) | Polarization-insensitive ultra-wideband terahertz wave absorber with multilayer structure | |
| Hakim et al. | Polarization-independent fractal square splits ring resonator (FSSRR) multiband metamaterial absorber/artificial magnetic conductor/sensor for Ku/K/Ka/5G (mm-Wave) band applications | |
| Singh et al. | A triple band polarization insensitive ultrathin metamaterial absorber for S-C-and X-bands | |
| Abdulkarim et al. | A polarization-insensitive triple-band perfect metamaterial absorber incorporating ZnSe for terahertz sensing | |
| Baskey et al. | Design of metamaterial based structure for the radar cross section reduction of a microstrip antenna | |
| Sood et al. | A wideband wide-angle ultra-thin metamaterial microwave absorber | |
| Ruppin | Bragg reflectors containing left‐handed materials | |
| Akarsu et al. | A novel ultra-wideband metamaterial-based perfect absorber for 5G millimeter-wave applications | |
| CN104701629B (en) | A kind of method for frequency scanning reflecting grating antenna and its suppressing mirror reflection ripple | |
| Ramachandran et al. | Impact of compact and novel 1-Bit coding based metamaterial design for microwave absorption applications | |
| Parameswaran et al. | Bandwidth enhancement of microstrip patch antenna using metamaterials | |
| Viji et al. | A Review on Electromagnetic Metamaterial Absorbers | |
| Wang et al. | Design of dual-band frequency selective surface for antenna RCS reduction | |
| Wang et al. | Beam Scanning Antenna with Unfixed/Fixed Frequency Based on Spoof Surface Plasmon Polaritons | |
| Duan et al. | A composite electromagnetic absorber for anechoic chambers | |
| Gharat et al. | Dualband and Tripleband Metamaterial absorber in WR1 band and Lower TeraHertz frequencies | |
| Nilotpal et al. | Metamaterial-based High-Performance Radar Absorbing Structure | |
| Jain et al. | DESIGN AND ANALYSIS OF RING MULTIBAND METAMATERIAL ABSORBER | |
| Kanjanasit et al. | Study of Multiband Resonant Absorbers Based on Modified Electric LC Resonators |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |