CN102904040B - Offset radar antenna - Google Patents

Abstract

The invention relates to an offset radar antenna which comprises a feed source, a metamaterial panel and a reflective plate. The feed source is positioned on the other side of the metamaterial and within a non-opposite area of the metamaterial panel. The metamaterial panel comprises a plurality of core layers with same refractive index distribution, each core layer comprises a plurality of metamaterial unit, and each metamaterial unit comprises a unit substrate provided with one or multiple micropores. Since the internal refractive index distribution conditions of the metamaterial panel of the offset radar antenna are changed, the far-field power of the antenna is strengthened greatly, propagation distance of the antenna is increased, front-to-rear ration of the antenna is increased, and the directivity of the antenna is improved. The offset radar antenna has the advantages radiation of electromagnetic waves is not shielded by the feed source any more, and affection of the radiatively electromagnetic waves to the feed source is avoided.

Description

A kind of offset-feed type radar antenna

Technical field

The present invention relates to radar antenna field, more particularly, relate to a kind of offset-feed type radar antenna using Meta Materials.

Background technology

The spherical wave of feed radiation is become plane wave by reflector by radar antenna, thus realizes directional reception or emitting electromagnetic wave, and the reflector used at present is parabolic shape, and feed is positioned at the near focal point of reflector.

The operation principle of radar antenna is similar to optical mirror, existing radar dish as shown in Figure 1, comprise routed source 1, paraboloidal reflector 2 and support 3, be placed with at the focus place of paraboloidal reflector 2 and launch or receive electromagnetic feed 1, utilize the focus characteristics of paraboloidal reflector 2, the spherical wave sent by feed 1 is transformed into plane wave after paraboloidal reflector 2 reflects, and is formed along the strongest narrow beam of parabola axial radiation.

Usually utilize die casting and molding to manufacture parabolic reflector or adopt Digit Control Machine Tool to carry out the method for processing.The technological process of first method comprises: make parabola mould, casting parabola and carry out the installation of parabolic reflector.Technics comparing is complicated, and cost is high, and paraboloidal shape more accurately will could realize the direction propagation of antenna, so also higher to the requirement of machining accuracy.Second method adopts large-size numerical control machine to carry out paraboloidal processing, by edit routine, and path that cutter is walked in domination number controlled machine, thus cut out required parabolic shape.This method cutting is very accurate, but it is more difficult to manufacture this large-size numerical control machine, and cost compare is high.

Meta Materials is a kind of artificial composite structure material with extraordinary physical property not available for natural material.Meta Materials, by the ordered arrangement to micro-structural, can change relative dielectric constant and the magnetic permeability of in Meta Materials often, realizes the heterogeneity of the refraction index profile of material thus controls electromagnetic wave propagation path in the material.

Summary of the invention

The object of the invention is to overcome in prior art the problem manufacturing parabolic antenna complex manufacturing, a kind of offset-feed type radar antenna is provided, this antenna proposes the radar antenna that a kind of structure simply has plane-reflector, the antenna of this planar structure has parabolic antenna can the advantage of directional reception or emitting electromagnetic wave, avoids complicated technology when producing parabolic antenna simultaneously.

In order to achieve the above object, the following technical scheme of the present invention's employing:

A kind of offset-feed type radar antenna, described antenna comprises: feed, for radiated electromagnetic wave, metamaterial panel, electromagnetic wave for being given off by described feed is converted into plane electromagnetic wave from spherical electromagnetic wave, described antenna also comprises the reflecting plate being close to described metamaterial panel side, for reflection of electromagnetic wave is carried out convergence refraction and distally radiation to metamaterial panel, described feed be positioned at described metamaterial panel opposite side and in the anon-normal of metamaterial panel to region, described metamaterial panel comprises multiple core layer with identical refraction index profile, each core layer described comprises multiple metamaterial unit, described metamaterial unit comprises the unit base material being provided with one or more aperture, the refractive index of each core layer of described metamaterial panel with the orthographic projection of described feed in each core layer for the distribution of center of circle semicircular in shape, along with the increase refractive index of radius reduces gradually, and the refractive index that radius exists together mutually is identical.

Further, described feed point in metamaterial panel orthographic projection in the base mid point of metamaterial panel.

Further, described metamaterial panel also comprises the multiple graded beddings being distributed in described core layer side, the air layer that each graded bedding described includes the substrate layer of sheet, the packed layer of sheet and is arranged between described substrate layer and packed layer.

Further, the medium of filling in described packed layer comprises air and the medium with described substrate layer same material.

Further, each metamaterial unit described is formed with an aperture, the medium that refractive index is less than unit base material refractive index is filled with in described aperture, and the aperture in all metamaterial unit all fills the medium of same material, the described arrangement rule of small pore volume in each core layer be arranged in metamaterial unit is: the small pore volume that described metamaterial unit is formed with the orthographic projection of described feed in each core layer for the distribution of center of circle semicircular in shape, along with the small pore volume that the increase metamaterial unit of radius is formed also increases, and it is identical to have the small pore volume that the metamaterial unit at same radius place is formed.

Further, each metamaterial unit described is formed with an aperture, the medium that refractive index is greater than unit base material refractive index is filled with in described aperture, and the aperture in all metamaterial unit all fills the medium of same material, the described arrangement rule of small pore volume in each core layer be arranged in metamaterial unit is: the small pore volume that described metamaterial unit is formed with the orthographic projection of described feed in each core layer for the distribution of center of circle semicircular in shape, along with the small pore volume that the increase metamaterial unit of radius is formed reduces gradually, and it is identical to have the small pore volume that the metamaterial unit at same radius place is formed.

Further, described metamaterial unit is formed with quantity difference, the aperture that volume is identical, the medium that refractive index is less than unit base material refractive index is filled with in described aperture, and the aperture in all metamaterial unit all fills the medium of same material, the described arrangement rule of little hole number in each core layer be arranged in metamaterial unit is: the little hole number that described metamaterial unit is formed with the orthographic projection of described feed in each core layer for the distribution of center of circle semicircular in shape, along with the little hole number that the increase metamaterial unit of radius is formed also increases gradually, and it is identical to have the little hole number that the metamaterial unit at same radius place is formed.

Further, described metamaterial unit is formed with quantity difference, the aperture that volume is identical, the medium that refractive index is greater than unit base material refractive index is filled with in described aperture, and the aperture in all metamaterial unit all fills the medium of same material, the described arrangement rule of little hole number in each core layer be arranged in metamaterial unit is: the little hole number that described metamaterial unit is formed with the orthographic projection of described feed in each core layer for the distribution of center of circle semicircular in shape, along with the little hole number that the increase metamaterial unit of radius is formed reduces gradually, and it is identical to have the little hole number that the metamaterial unit at same radius place is formed.

Further, the refractive index of each core layer of described metamaterial panel with the orthographic projection of described feed in each core layer for the center of circle, along with the Changing Pattern of radius r is as following formula:

$n\left(r\right)=n_{\max }-\frac{\sqrt{{\mathrm{ss}}^2+r^2}-\mathrm{ss}}{2d};$

N in formula _maxrepresent the largest refractive index value in each core layer described, d represents the gross thickness of all core layers, and ss represents the distance of described feed to the core layer near feed location, and n (r) represents each core layer inside radius r place refractive index value described.

Further, the distribution of refractive index homogeneity in each graded bedding of described metamaterial panel, and between multiple graded bedding the Changing Pattern of refraction index profile as following formula:

$n_i={\left(\frac{n_{\max }+n_{\min }}{2}\right)}^{\frac{i}{m}},i=1,\mathrm{2,3},...,m,$

Wherein n _irepresent the refractive index value of i-th layer of graded bedding, m represents the number of plies of graded bedding, n _minrepresent the minimum refractive index value in each core layer described, n _maxrepresent the largest refractive index value in each core layer described, wherein m layer graded bedding and core layer close, diminish gradually away from core layer along with m value, ground floor graded bedding is outermost layer graded bedding.

The present invention is relative to prior art, there is following beneficial effect: a kind of offset-feed type radar antenna, the structure of flat plane antenna is simple, by the characteristic utilizing Meta Materials to converge electromagnetic wave, radar antenna is made not rely on the shape of electromagnetic wave convergence equipment, eliminate the complex fabrication process of processing traditional parabolic antenna, the advantage of traditional parabolic antenna directional reception or emitting electromagnetic wave can be realized again simultaneously.Present invention employs offset-feed type radar antenna in addition, feed is no longer blocked electromagnetic radiation, it also avoid the impact of electromagnetic wave on feed of radiation simultaneously.

Accompanying drawing explanation

Fig. 1 is the structural representation of parabola radar antenna in prior art;

Fig. 2 is a kind of offset-feed type radar antenna schematic diagram of the present invention;

Fig. 3 is a kind of offset-feed type radar antenna schematic diagram of the present invention;

Fig. 4 is the structural representation of metamaterial panel of the present invention;

Fig. 5 is the structural representation of core layer of the present invention;

Fig. 6 is metamaterial modular construction schematic diagram of the present invention;

Fig. 7 is graded bedding structural representation of the present invention;

Fig. 8 is core layer variations in refractive index schematic diagram of the present invention;

Fig. 9 is core layer variations in refractive index schematic diagram of the present invention.

Embodiment

Below in conjunction with embodiment and accompanying drawing, the present invention is described in further detail, but embodiments of the present invention are not limited thereto.

Fig. 2 and Fig. 3 is the structural representation of offset-feed type radar antenna of the present invention, this antenna comprises feed 10, metamaterial panel 20 and reflecting plate 30, described feed 10 and expelling plate 30 lay respectively at the both sides of described metamaterial panel 20, reflecting plate 30 is close to metamaterial panel 20 and is connected, and the orthographic projection of feed 10 point in described metamaterial panel 20 is the mid point of metamaterial panel 20 bottom.

Usually from the electromagnetic wave of feed 10 radiation be spherical electromagnetic wave, but the far field directional performance of spherical electromagnetic wave is bad, for remote be that the Signal transmissions of carrier has significant limitation with spherical electromagnetic wave, and decay is fast, the present invention has the metamaterial panel 20 of electromagnetic wave convergence function by design one, most of electromagnetic wave that feed 10 radiates by this metamaterial panel 20 is converted to plane electromagnetic wave from spherical electromagnetic wave, and at the electromagnetic wave by metamaterial panel 20 again converge by metamaterial panel 20 refraction and radiate after reflecting plate 30 reflects, make the directivity of radar antenna better, antenna main lobe energy density is higher, energy is larger, and then being carrier with this plane electromagnetic wave, signal transmission distance is farther.

Shown in Fig. 4, described metamaterial panel 20 comprises multiple core layer 210 with identical refraction index profile and the multiple graded beddings 220 be distributed near feed 10 side, the functional layer of described core layer 210 namely metamaterial panel 10, be made up of multiple metamaterial unit, because metamaterial panel 20 need produce continuous response to electromagnetic wave, therefore metamaterial unit size should be less than 1/5th of required response electromagnetic wavelength, and the present embodiment is preferably 1/10th of electromagnetic wavelength.As shown in Figure 6, described metamaterial unit comprises the unit base material 211 being provided with one or more aperture 212.Each core layer 210 being provided with aperture 212 is like this superimposed and just forms the functional layer of metamaterial panel 20, as shown in Figure 5.

Multiple core layers 210 of described metamaterial panel 20 are by changing the refraction index profile of its inside to realize by the electromagnetic wave equiphase radiation after described metamaterial panel 20, and the spherical electromagnetic wave namely realizing giving off from described feed 10 is converted to plane electromagnetic wave.In the present invention, the refraction index profile of each core layer 210 is all identical, is only described in detail the refraction index profile rule of a Meta Materials core layer 210 here.The refraction index profile of each core layer 210 is made as shown in Figure 9 by the design of the medium of filling and the density of aperture 212 in the volume to aperture 212, aperture 212.Each core layer 210 of metamaterial panel 20 comprises the territory, semicircle face that is the center of circle with the orthographic projection of feed 10 in each core layer 210, and the circle centre position refractive index in territory, semicircle face is n to the maximum _max, have same radius place refractive index identical, radius is larger, and refractive index is less.Provide variations in refractive index figure in Fig. 8, but should know that variations in refractive index of the present invention is not as limit.Purpose of design of the present invention is: make electromagnetic wave when each core layer 210, and electromagnetic wave deflection angle is changed and final parallel radiation gradually.By formula S in θ=q Δ n, wherein θ is the electromagnetic angle of required deviation, Δ n is front and back variations in refractive index differences, and q is the thickness of Meta Materials functional layer and can determines desired parameters value by Computer Simulation and reach purpose of design of the present invention.

Fig. 8 is the view of the core layer of Meta Materials shown in Fig. 9 refraction index profile on r direction.As common practise, we are known, electromagnetic refractive index with proportional, wherein μ is magnetic permeability, ε is dielectric constant, when a branch of electromagnetic wave by a kind of Medium Propagation to another medium time, electromagnetic wave can reflect, when the refraction index profile of material inside is non-homogeneous, electromagnetic wave will to the larger position deviation of refractive index ratio, therefore, the refractive index of design metamaterial panel 20 each point makes it meet above-mentioned variations in refractive index rule, it should be noted that, because in fact metamaterial unit is a cube but not a point, therefore territory, above-mentioned semicircle face is approximate description, the metamaterial unit that actual refractive index is identical or substantially identical distributes in a zigzag semi-circumference.The programming mode (such as OpenGL) of described point is carried out when its specific design is similar to the smoothed curves such as computer square pixels point-rendering semicircle, half elliptic, when pixel is very little relative to curve, curve is shown as smooth, and curve shows sawtooth when pixel is larger relative to curve.

For the change making functional layer realize refractive index shown in Fig. 8 and Fig. 9, can the medium of filling in the volume of aperture 212, aperture 212 be designed.Discuss two kinds of better embodiment in detail below.

As shown in Figure 5, each core layer 210 of metamaterial panel 20 is made up of multiple metamaterial unit, and each metamaterial unit comprises the unit base material 211 being provided with an aperture 212.Unit base material 211 can select high molecular polymer, ceramic material, ferroelectric material, ferrite material etc.Wherein preferred FR-4 or the F4B material of high molecular polymer.Corresponding different unit base material 211 can adopt different technique to form aperture 212 on unit base material 211, such as when high molecular polymer selected by unit base material 211, form aperture 212 by modes such as drilling machine boring, punch forming or injection mo(u)ldings, then form aperture 212 by modes such as drilling machine boring, punch forming or high temperature sinterings when unit base material 211 Ceramics.

Can filled media in aperture 212, in this better embodiment, the medium of filling in aperture 212 is air, and the refractive index of air must be less than the refractive index of unit base material 211, when aperture 212 volume is larger, the refractive index of the metamaterial unit at aperture 212 place is then less.In this better embodiment, the arrangement rule of aperture 212 in each core layer 210 be arranged in metamaterial unit is: aperture 212 volume that described metamaterial unit is formed with the orthographic projection of feed 10 in each core layer 210 for the distribution of center of circle semicircular in shape, the volume of the aperture 212 that the metamaterial unit of wherein circle centre position is formed is minimum, along with aperture 212 volume that the increase metamaterial unit of radius is formed also increases, and it is identical to have aperture 212 volume that the metamaterial unit at same radius place is formed.Ground can be imagined, when being filled with refractive index in aperture 212 and being greater than the same media of unit base material 211, then now aperture 212 volume is larger, the refractive index of the metamaterial unit occupied by aperture 212 is also larger, is therefore now arranged on aperture 212 in the metamaterial unit arrangement rule in each core layer 210 by completely contrary with the arrangement rule being filled to air in aperture 212.

Another embodiment of the present invention, is with the difference of the first better embodiment, there is the identical aperture of multiple volume 212, can be reduced at technology difficulty unit base material 211 being arranged aperture 212 like this in each metamaterial unit.The place identical with the first better embodiment is, in this better embodiment in each metamaterial unit all apertures to account for the regularity of distribution of the volume of metamaterial unit identical with the first better embodiment, namely two kinds of situations are divided into: when the medium refraction index of filling in (1) all apertures is less than unit base material refractive index, each core layer 210 comprises one with the orthographic projection of feed 10 in each core layer 210 territory, semicircle face that is the center of circle and the minimum number of the aperture 212 that the metamaterial unit of circle centre position is formed, the quantity with the aperture 212 that the metamaterial unit of same radius is formed is identical, along with the increase of radius, the quantity of the aperture 212 that the metamaterial unit everywhere of respective radius is formed also increases.This better embodiment is namely this kind of situation and in all apertures 2, filled media is air; (2) when the medium refraction index of filling in all apertures 212 is greater than substrate index, each core layer 210 comprises one with the orthographic projection of feed 10 in each core layer 210 territory, semicircle face that is the center of circle and the quantity of the aperture 212 that the metamaterial unit of circle centre position is formed is maximum, the quantity with the aperture 212 that the metamaterial unit everywhere of same radius is formed is identical, and the quantity of the aperture 212 that the metamaterial unit everywhere along with the increase of radius, respective radius is formed reduces.

In the embodiment of the present invention, the refractive index of each core layer 210 of described metamaterial panel 20 with the orthographic projection of feed 10 in each core layer 210 for the center of circle, along with the Changing Pattern of radius r is as following formula:

$n\left(r\right)=n_{\max }-\frac{\sqrt{{\mathrm{ss}}^2+r^2}-\mathrm{ss}}{2d};$

N in formula _maxrepresent the largest refractive index value in each core layer 210 described, d represents the gross thickness of all core layers 210, ss represents that described feed 10 is to the distance near the core layer 210 of feed location, and n (r) represents described each core layer 210 inside radius r place refractive index value.

Usually when electromagnetic wave is from a kind of medium transmission to another kind of medium time, due to the problem of impedance mismatch, there will be a part of reflection of electromagnetic wave, the electromagnetic transmission performance of such impact, in the present invention, when the electromagnetic wave incident radiated from feed 10 can produce reflection equally to during metamaterial panel 20, in order to reduce the impact of reflection on radar antenna, we pile in core layer 210 side of metamaterial panel 20 and arrange multiple Meta Materials graded bedding 220, as shown in Figure 4.

As shown in Figure 7, each Meta Materials graded bedding 220 air layer 222 of including the substrate layer 221 of sheet, the packed layer 223 of sheet and being arranged between described substrate layer 221 and packed layer 223.Substrate layer 221 can select high molecular polymer, ceramic material, ferroelectric material, ferrite material etc.Wherein preferred FR-4 or the F4B material of high molecular polymer.Refraction index profile in each graded bedding 220 is uniform, refractive index between multiple graded bedding is different, in order to mate the impedance of air and core layer 210, Distance geometry normally by adjusting described air layer 222 realizes impedance matching by the medium of filling containing different refractivity in packed layer 223, this medium also can be the material identical with substrate layer 221 also can be air, wherein increases gradually towards core layer 210 direction refractive index closest to air near the refractive index of the Meta Materials graded bedding 220 of air.

In the present invention in embodiment, the refractive index homogeneity distribution in each graded bedding 220 of described metamaterial panel 20, and the Changing Pattern of multiple graded bedding 220 refraction index profile is as following formula:

$n_i={\left(\frac{n_{\max }+n_{\min }}{2}\right)}^{\frac{i}{m}},i=1,\mathrm{2,3},...,m,$

Wherein n _irepresent the refractive index value of i-th layer of graded bedding, m represents the number of plies of graded bedding, n _minrepresent the minimum refractive index value in each core layer described, n _maxrepresent the largest refractive index value in each core layer described, wherein m layer graded bedding and core layer close, diminish gradually away from core layer along with m value, ground floor graded bedding is outermost layer graded bedding.

In sum, a kind of offset-feed type radar antenna of the present invention, by changing the refraction index profile situation of metamaterial panel 20 inside, makes Antenna Far Field power greatly enhance, and then improves the distance of antenna propagation, add the front and back ratio of antenna simultaneously, make antenna have more directivity; Present invention employs offset-feed type radar antenna, feed 10 is no longer blocked electromagnetic radiation, it also avoid the electromagnetic wave of radiation to the impact of feed 10 simultaneously.

Above-described embodiment is the present invention's preferably execution mode; but embodiments of the present invention are not restricted to the described embodiments; change, the modification done under other any does not run counter to Spirit Essence of the present invention and principle, substitute, combine, simplify; all should be the substitute mode of equivalence, be included within protection scope of the present invention.

Claims (9)

1. an offset-feed type radar antenna, described antenna comprises: feed, for radiated electromagnetic wave, metamaterial panel, electromagnetic wave for being given off by described feed is converted into plane electromagnetic wave from spherical electromagnetic wave, it is characterized in that, described antenna also comprises the reflecting plate being close to described metamaterial panel side, for reflection of electromagnetic wave is carried out convergence refraction and distally radiation to metamaterial panel, described feed be positioned at described metamaterial panel opposite side and in the anon-normal of metamaterial panel to region, described metamaterial panel comprises multiple core layer with identical refraction index profile, each core layer described comprises multiple metamaterial unit, described metamaterial unit comprises the unit base material being provided with one or more aperture, the refractive index of each core layer of described metamaterial panel with the orthographic projection of described feed in each core layer for the distribution of center of circle semicircular in shape, along with the increase refractive index of radius reduces gradually, and the refractive index that radius exists together mutually is identical,

The refractive index of each core layer of described metamaterial panel with the orthographic projection of described feed in each core layer for the center of circle, along with the Changing Pattern of radius r is as following formula:

$n\left(r\right)=n_{\max }-\frac{\sqrt{{\mathrm{ss}}^2+r^2}-\mathrm{ss}}{2d};$

N in formula _maxrepresent the largest refractive index value in each core layer described, d represents the gross thickness of all core layers, and ss represents the distance of described feed to the core layer near feed location, and n (r) represents each core layer inside radius r place refractive index value described.

2. a kind of offset-feed type radar antenna according to claim 1, is characterized in that, described feed point in metamaterial panel orthographic projection in the base mid point of metamaterial panel.

3. a kind of offset-feed type radar antenna according to claim 1, it is characterized in that, described metamaterial panel also comprises the multiple graded beddings being distributed in described core layer side, the air layer that each graded bedding described includes the substrate layer of sheet, the packed layer of sheet and is arranged between described substrate layer and packed layer.

4. a kind of offset-feed type radar antenna according to claim 3, is characterized in that, the medium of filling in described packed layer comprises air and the medium with described substrate layer same material.

5. a kind of offset-feed type radar antenna according to claim 1, it is characterized in that: each metamaterial unit described is formed with an aperture, the medium that refractive index is less than unit base material refractive index is filled with in described aperture, and the aperture in all metamaterial unit all fills the medium of same material, the described arrangement rule of small pore volume in each core layer be arranged in metamaterial unit is: the small pore volume that described metamaterial unit is formed with the orthographic projection of described feed in each core layer for the distribution of center of circle semicircular in shape, along with the small pore volume that the increase metamaterial unit of radius is formed also increases, and it is identical to have the small pore volume that the metamaterial unit at same radius place is formed.

6. a kind of offset-feed type radar antenna according to claim 1, it is characterized in that, each metamaterial unit described is formed with an aperture, the medium that refractive index is greater than unit base material refractive index is filled with in described aperture, and the aperture in all metamaterial unit all fills the medium of same material, the described arrangement rule of small pore volume in each core layer be arranged in metamaterial unit is: the small pore volume that described metamaterial unit is formed with the orthographic projection of described feed in each core layer for the distribution of center of circle semicircular in shape, along with the small pore volume that the increase metamaterial unit of radius is formed reduces gradually, and it is identical to have the small pore volume that the metamaterial unit at same radius place is formed.

7. a kind of offset-feed type radar antenna according to claim 1, it is characterized in that, described metamaterial unit is formed with quantity difference, the aperture that volume is identical, the medium that refractive index is less than unit base material refractive index is filled with in described aperture, and the aperture in all metamaterial unit all fills the medium of same material, the described arrangement rule of little hole number in each core layer be arranged in metamaterial unit is: the little hole number that described metamaterial unit is formed with the orthographic projection of described feed in each core layer for the distribution of center of circle semicircular in shape, along with the little hole number that the increase metamaterial unit of radius is formed also increases gradually, and it is identical to have the little hole number that the metamaterial unit at same radius place is formed.

8. a kind of offset-feed type radar antenna according to claim 1, it is characterized in that, described metamaterial unit is formed with quantity difference, the aperture that volume is identical, the medium that refractive index is greater than unit base material refractive index is filled with in described aperture, and the aperture in all metamaterial unit all fills the medium of same material, the described arrangement rule of little hole number in each core layer be arranged in metamaterial unit is: the little hole number that described metamaterial unit is formed with the orthographic projection of described feed in each core layer for the distribution of center of circle semicircular in shape, along with the little hole number that the increase metamaterial unit of radius is formed reduces gradually, and it is identical to have the little hole number that the metamaterial unit at same radius place is formed.

9. a kind of offset-feed type radar antenna according to claim 3, is characterized in that, the distribution of refractive index homogeneity in each graded bedding of described metamaterial panel, and between multiple graded bedding the Changing Pattern of refraction index profile as following formula:

$n_i={\left(\frac{n_{\max }+n_{\min }}{2}\right)}^{\frac{i}{m}},i=\mathrm{1,2,3},...,m,$

Wherein n _irepresent the refractive index value of i-th layer of graded bedding, m represents the number of plies of graded bedding, n _minrepresent the minimum refractive index value in each core layer described, n _maxrepresent the largest refractive index value in each core layer described, wherein m layer graded bedding and core layer close, diminish gradually away from core layer along with m value, ground floor graded bedding is outermost layer graded bedding.