CN102904044A - Feedback radar antenna - Google Patents

Abstract

The invention relates to a feedback radar antenna. The antenna comprises a feed source and a metamaterial panel, wherein the feed source is used for radiating electromagnetic waves; the metamaterial panel is used for converting spherical electromagnetic waves to plane electromagnetic waves and comprises a plurality of core layers with the same refractive index distribution; each core layer of the metamaterial panel comprises a plurality of metamaterial units; each metamaterial unit comprises a unit substrate with one or more holes; the refractive indexes of the core layers of the metamaterial panel are circularly distributed, with own centers as the centers of circles; the refractive index gradually decreases with increase of the radius; and the refractive indexes in positions with the same radius are the same. The feedback radar antenna has the following beneficial effects: by changing the distribution conditions of the refractive indexes inside the metamaterial panel, the far-field power of the antenna is greatly enhanced, and the antenna propagation distance is further promoted; and meanwhile, by arranging a wave-absorbing material layer inside the cavity body of the antenna, the front-to-back ratio of the antenna is increased, and the directivity of the antenna becomes better.

Description

A kind of feedback type radar antenna

Technical field

The present invention relates to the radar antenna field, more particularly, relate to a kind of feedback type radar antenna that uses super material.

Background technology

The rear feed antenna Cassegrain antenna that is otherwise known as is made of parabolic primary reflection surface 2, hyperboloid subreflector 1, Feed Horn 3 and support 4, as shown in Figure 1.Because the real focus of parabolic primary reflection surface 2 overlaps with the virtual focus of hyperboloid subreflector 1, and the phase center of Feed Horn 3 overlaps with the real focus of hyperboloid subreflector 1, penetrate next electromagnetic wave through parabolic primary reflection surface 2 primary events from satellite, again by behind hyperboloid subreflector 1 secondary reflection, be focused in the phase center of Feed Horn 3, with superimposed.Thereby realize radar antenna directional reception or emitting electromagnetic wave.

Usually the method for utilizing die casting and molding or adopting Digit Control Machine Tool to process in order to make parabolic reflector face and hyperboloid subreflector.The technological process of first method comprises: make parabolic mould, casting parabola and carry out the installation of paraboloidal reflector ground.The technique more complicated, cost is high, and paraboloidal shape will relatively accurately could realize the direction propagation of radar 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 the control Digit Control Machine Tool, thus cut out required parabolic shape.This method cutting is very accurate, but makes relatively difficulty of this large-size numerical control machine, and cost compare is high.

Summary of the invention

The object of the invention is to overcome the difficulty of making parabolic reflector face and hyperboloid subreflector in the prior art, a kind of feedback type radar antenna is provided, this antenna no longer sticks to paraboloidal fixed pattern, changes with the super material of flat board, has saved the space; And improve the deviation problem of wide-angle electromagnetic wave incident, improved the efficient of antenna energy radiation.

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

A kind of feedback type radar antenna, described antenna comprises: feed is used for radiated electromagnetic wave; Super material panel, the electromagnetic wave that is used for described feed is given off is converted into plane electromagnetic wave from the sphere electromagnetic wave, described super material panel comprises a plurality of core layers with identical refraction index profile, each core layer of described super material panel comprises a plurality of super material cell, described super material cell comprises the unit base material that one or more aperture is set, the rounded distribution take its center as the center of circle of the refractive index of each core layer of described super material panel, along with the increase refractive index of radius reduces gradually, and the refractive index that radius exists together mutually is identical.

Further, described radar antenna also comprises shell, is used for fixedly feed; And the absorbing material layer of being close to described outer casing inner wall, be used for absorbing the part electromagnetic wave that radiates from feed; Described absorbing material layer and super material panel consist of the cavity of sealing; Described feed is positioned at described cavity.

Further, described super material panel also comprises a plurality of graded beddings that are symmetrically distributed in described core layer both sides, described each graded bedding include sheet substrate layer, sheet packed layer and be arranged on air layer between described substrate layer and the packed layer.

The medium of filling in the described packed layer further, comprise air and with the medium of described substrate layer same material.

Further, be formed with an aperture on described each super material cell, be filled with refractive index in the described aperture less than the medium of unit base material refractive index, and the aperture in all super material cell is all filled the medium of same material, described the arrange rule of aperture in each core layer that is arranged in the super material cell is: the small pore volume that described super material cell forms is take center rounded distribution as the center of circle of each core layer, along with the small pore volume that forms on the super material cell of the increase of radius also increases, and it is identical to have the small pore volume that forms on the super material cell at same radius place.

Further, be formed with an aperture on described each super material cell, be filled with refractive index in the described aperture greater than the medium of unit base material refractive index, and the aperture in all super material cell is all filled the medium of same material, described the arrange rule of aperture in each core layer that is arranged in the super material cell is: the small pore volume that described super material cell forms is take center rounded distribution as the center of circle of each core layer, along with the small pore volume that forms on the super material cell of the increase of radius reduces gradually, and it is identical to have the small pore volume that forms on the super material cell at same radius place.

Further, be formed with the quantity difference on the described super material cell, the aperture that volume is identical, be filled with refractive index in the described aperture less than the medium of unit base material refractive index, and the aperture in all super material cell is all filled the medium of same material, described the arrange rule of aperture in each core layer that is arranged in the super material cell is: the little hole number that described super material cell forms is take center rounded distribution as the center of circle of each core layer, along with the little hole number that forms on the super material cell of the increase of radius also increases gradually, and it is identical to have the little hole number that forms on the super material cell at same radius place.

Further, be formed with the quantity difference on the described super material cell, the aperture that volume is identical, be filled with refractive index in the described aperture greater than the medium of unit base material refractive index, and the aperture in all super material cell is all filled the medium of same material, described the arrange rule of aperture in each core layer that is arranged in the super material cell is: the little hole number that described super material cell forms is take center rounded distribution as the center of circle of each core layer, along with the little hole number that forms on the super material cell of the increase of radius reduces gradually, and it is identical to have the little hole number that forms on the super material cell at same radius place.

Further, the refractive index of each core layer of described super material panel is take its center as the center of circle, along with Changing Pattern such as the following formula of radius r:

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

N in the formula _MaxRepresent the largest refractive index value in described each core layer, d represents the gross thickness of all core layers, and ss represents described feed to the distance of the core layer of the most close feed position, the described a plurality of core layer inside radius r of n (r) expression place refractive index value.

Further, the refractive index in each graded bedding of described super material panel is equally distributed, and Changing Pattern such as the following formula of refraction index profile between a plurality of graded bedding:

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

N wherein _iThe refractive index value that represents i layer graded bedding, m represents the number of plies of graded bedding, n _MinRepresent the minimum refractive index value in described each core layer, n _MaxRepresent the largest refractive index value in described each core layer, wherein m layer graded bedding and core layer are close, and along with diminishing gradually away from core layer of m value, the ground floor graded bedding is the outermost layer graded bedding.

The present invention is with respect to prior art, have following beneficial effect: a kind of feedback type radar antenna of the present invention is by changing the refraction index profile situation of super material panel inside, so that Antenna Far Field power has strengthened widely, and then promoted the distance that antenna is propagated, simultaneously by one deck absorbing material layer is set in antenna chamber inside, increased the front and back ratio of antenna, so that antenna has more directivity.

Description of drawings

Fig. 1 is rear feed parabolic antenna structural representation in the prior art;

Fig. 2 is the structural representation of a kind of feedback type radar antenna of the present invention;

Fig. 3 is the structural representation of super material panel of the present invention;

Fig. 4 is the structural representation of a plurality of core layers of super material of the present invention;

Fig. 5 is the structural representation of super material cell of the present invention;

Fig. 6 is the structural representation of super material graded bedding of the present invention;

Fig. 7 is core layer variations in refractive index schematic diagram of the present invention;

Fig. 8 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 to this.

Fig. 2 is the structural representation of feedback type radar antenna of the present invention, this antenna comprises feed 10, super material panel 20, shell 30 and absorbing material layer 40, described feed 10 is fixed on the shell 30, absorbing material layer 40 is close to shell 30 inwalls, described absorbing material layer 40 links to each other with super material panel 20, and absorbing material layer 40 and the super material panel 20 common cavitys that form a sealing, described feed 10 is positioned at described cavity.

Usually the electromagnetic wave from feed 10 radiation is the sphere electromagnetic wave, but the electromagnetic far field of sphere directional performance is bad, for remote signal transmission take the sphere electromagnetic wave as carrier significant limitation is arranged, and decay is fast, the present invention is by having the super material panel 20 of electromagnetic wave aggregation feature in feed 10 transmission directions design one, should super material panel 20 most of electromagnetic wave that feed 10 radiates be converted to plane electromagnetic wave from the sphere electromagnetic wave, so that the directivity of radar antenna is better, the antenna main lobe energy density is higher, energy is larger, and then the signal transmission distance take this plane electromagnetic wave as carrier is farther.

In order to strengthen the front and back ratio of radar antenna, we normally reduce the electromagnetic wave energy of antenna side lobe and back lobe, adopt among the present invention and be close to one deck absorbing material layer 40 at the inwall of described shell 30, be used for absorbing the electromagnetic wave energy except main lobe direction, described shell 30 is used for fixing described feed 10, generally adopts metal material or ABS material.

Shown in Figure 3, described super material panel 20 comprises a plurality of a plurality of graded beddings 220 that have the core layer 210 of identical refraction index profile and be symmetrically distributed in described core layer both sides, described core layer 210 is the functional layer of super material panel 10 namely, formed by a plurality of super material cell, because super material panel 20 needs electromagnetic wave is produced continuous response, therefore super material cell size should be less than 1/5th of required response electromagnetic wavelength, and present embodiment is preferably 1/10th of electromagnetic wavelength.As shown in Figure 5, described super material cell comprises the unit base material 211 that is provided with one or more apertures 212.Each core layer 210 that is provided with like this aperture 212 is superimposed and just consists of the functional layer of super material panel 20, as shown in Figure 4.

A plurality of core layers 210 of described super material panel 20 namely realize being converted to plane electromagnetic wave from the sphere electromagnetic wave that described feed 10 gives off by changing its inner refraction index profile to realize by the electromagnetic wave equiphase radiation behind the described super material panel 20.The refraction index profile of each super material core layer 210 is all identical among the present invention, only the refraction index profile rule of a super material core layer 210 is described in detail here.By to the design of the density of the medium of the volume of aperture 212, aperture 212 interior fillings and aperture 212 so that the refraction index profile of each super material core layer 210 as shown in Figure 8.Each core layer 210 of super material panel comprises a circular face territory take super material core layer 210 central points as the center of circle, and the circle centre position refractive index in circular face territory is n to the maximum _Max, it is identical to have same radius place refractive index, and radius is larger, and refractive index is less.Provide n among Fig. 8 _Max～n _MinVariations in refractive index figure, but should know that variations in refractive index of the present invention is not as limit.Purpose of design of the present invention is: when making electromagnetic wave through each super material core layer 210, the electromagnetic wave deflection angle is changed and final parallel radiation gradually.By formula S in θ=q Δ n, wherein θ is that the electromagnetic angle of required deviation, Δ n are front and back variations in refractive index differences, and q can determine the desired parameters value and reach purpose of design of the present invention for the thickness of super material function layer and by Computer Simulation.

Fig. 7 is the O-O ' view of super material core layer refractive index profile shown in Figure 8.As common practise we as can be known, electromagnetic refractive index with

Proportional, wherein μ is magnetic permeability, ε is dielectric constant, when a branch of electromagnetic wave propagates into another medium by a kind of medium, electromagnetic wave can reflect, when the refraction index profile of material inside is non-homogeneous, electromagnetic wave will be to the larger position deviation of refractive index ratio, therefore, the refractive index that designs super material panel 20 each points makes it satisfy above-mentioned variations in refractive index rule, need to prove, because in fact super material cell is a cube but not a point, therefore above-mentioned circular face territory is approximate description, and the identical or essentially identical super material cell of actual refractive index distributes at a zigzag circumference.When being similar to computer with the smoothed curve such as the square pixels point-rendering is circular, oval, its specific design carries out the programming mode (for example OpenGL) of described point, curve is shown as smoothly when pixel is very little with respect to curve, and curve shows sawtooth when pixel is larger with respect to curve.

For making functional layer realize the variation of Fig. 7 and refractive index shown in Figure 8, can design the volume of aperture 212, the medium of aperture 212 interior fillings.Below discuss in detail two kinds of preferred embodiments.

As shown in Figure 4, each core layer 210 of super material panel 20 is comprised of a plurality of super material cell, and each super material cell comprises the unit base material 211 that is provided with an aperture 212.Unit base material 211 can be selected high molecular polymer, ceramic material, ferroelectric material, ferrite material etc.The wherein preferred FR-4 of high molecular polymer or F4B material.Corresponding different unit base material 211 can adopt different technique to form aperture 212 at unit base material 211, for example when unit base material 211 is selected high molecular polymer, can form aperture 212 by modes such as drilling machine boring, punch forming or injection mo(u)ldings, when unit base material 211 Ceramics, then can form aperture 212 by modes such as drilling machine boring, punch forming or high temperature sinterings.

But filled media in the aperture 212, in this preferred embodiments, the medium of aperture 212 interior fillings is air, and the inevitable refractive index less than unit base material 211 of the refractive index of air, when aperture 212 volumes were larger, the refractive index of the super material cell at aperture 212 places was then less.In this preferred embodiments, the arrange rule of aperture 212 in each core layer 210 that is arranged in the super material cell is: aperture 212 volumes that described super material cell forms are take center rounded distribution as the center of circle of each core layer 210, the volume of the aperture 212 that wherein forms on the super material cell of circle centre position is minimum, along with aperture 212 volumes that form on the super material cell of the increase of radius also increase, and it is identical to have aperture 212 volumes that form on the super material cell at same radius place.Can imagine ground, when being filled with refractive index greater than the medium of the same race of unit base material 211 in the aperture 212, then this moment, aperture 212 volumes were larger, the refractive index of the super material cell that aperture 212 is occupied is also larger, therefore be arranged on this moment the interior aperture 212 of super material cell in each core layer 210 arrange rule will with aperture 212 in to be filled to the rule of arranging of air fully opposite.

Another embodiment of the present invention is with the difference of the first preferred embodiments, has the identical aperture of a plurality of volumes 212 in each super material cell, can be reduced at the technology difficulty that aperture 212 is set on the unit base material 211 like this.The place identical with the first preferred embodiments is, in this preferred embodiments in each super material cell all apertures to account for the regularity of distribution of volume of super material cell identical with the first preferred embodiments, namely be divided into two kinds of situations: when the medium refraction index of filling is less than unit base material refractive index in (1) all apertures, each core layer 210 comprise one take its center as the center of circle the circular face territory and the super material cell of center, circular face territory on the minimum number of the aperture 212 that forms, quantity with the aperture 212 that forms on the super material cell of same radius is identical, along with the increase of radius, the quantity of the aperture 212 that forms on the super material cell everywhere of respective radius also increases.This preferred embodiments namely is that this kind situation and all apertures 2 interior filled medias are air; When (2) medium refraction index of all aperture 212 interior fillings is greater than the substrate refractive index, each core layer 210 comprise one take its center as the center of circle the circular face territory and the super material cell of circle centre position on the quantity of the aperture 212 that forms maximum, quantity with the aperture 212 that forms on the super material cell everywhere of same radius is identical, and the quantity of the aperture 212 that forms on the super material cell everywhere along with the increase of radius, respective radius reduces.

In the embodiment of the invention, the refractive index of each core layer 210 of described super material panel 20 is take its center as the center of circle, along with Changing Pattern such as the following formula of radius r:

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

N in the formula _MaxRepresent the largest refractive index value in described each core layer 210, d represents the gross thickness of all core layers, ss represents described feed 10 to the distance of the core layer 210 of the most close feed 10 positions, the described a plurality of core layer inside radius r of n (r) expression place refractive index value.

Usually when electromagnetic wave from a kind of medium transmission to another kind of medium the time, because the problem of impedance mismatch, a part of reflection of electromagnetic wave can appear, affect so electromagnetic transmission performance, among the present invention, when inciding super material panel 20, the electromagnetic wave that radiates from feed 10 can produce reflection equally, in order to reduce reflection to the impact of radar antenna, we pile in core layer 210 both sides of super material panel 20 a plurality of super material graded beddings 220 are set, as shown in Figure 3.

As shown in Figure 6, each super material graded bedding 220 include sheet substrate layer 221, sheet packed layer 223 and be arranged on air layer 222 between described substrate layer 221 and the packed layer 223.Substrate layer 221 can be selected high molecular polymer, ceramic material, ferroelectric material, ferrite material etc.The wherein preferred FR-4 of high molecular polymer or F4B material.Refraction index profile in each graded bedding 220 is uniform, refractive index between a plurality of graded beddings is different, in order to mate the impedance of air and core layer 210, the distance by adjusting described air layer 222 and realize impedance matching by the medium that contains different refractivity in packed layer 223 interior fillings normally, this medium also can be that the material identical with substrate layer 221 also can be air, and wherein the refractive index near the super material graded bedding 220 of air increases gradually near air and towards core layer 210 direction refractive indexes.

Among the present invention among the embodiment, refractive index in each graded bedding 220 of described super material panel 20 is equally distributed, and Changing Pattern such as the following formula of 220 of a plurality of graded beddings (take a plurality of graded beddings 220 of core layer 210 1 sides as example) refraction index profile:

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

N wherein _iThe refractive index value that represents i layer graded bedding, m represents the number of plies of graded bedding, n _MinRepresent the minimum refractive index value in described each core layer, n _MaxRepresent the largest refractive index value in described each core layer, wherein m layer graded bedding and core layer are close, and along with diminishing gradually away from core layer of m value, the ground floor graded bedding is the outermost layer graded bedding.

In sum, a kind of feedback type radar antenna of the present invention is by changing the refraction index profile situation of super material panel 20 inside, so that Antenna Far Field power has strengthened widely, and then promoted the distance that antenna is propagated, simultaneously by one deck absorbing material layer 40 is set in antenna chamber inside, increased the front and back ratio of antenna, so that antenna has more directivity.

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

Claims (10)

1. feedback type radar antenna, described antenna comprises: feed is used for radiated electromagnetic wave; Super material panel, the electromagnetic wave that is used for described feed is given off is converted into plane electromagnetic wave from the sphere electromagnetic wave, it is characterized in that, described super material panel comprises a plurality of core layers with identical refraction index profile, each core layer of described super material panel comprises a plurality of super material cell, described super material cell comprises the unit base material that is provided with one or more aperture, the rounded distribution take its center as the center of circle of the refractive index of each core layer of described super material panel, along with the increase refractive index of radius reduces gradually, and the refractive index that radius exists together mutually is identical.

2. a kind of feedback type radar antenna according to claim 1 is characterized in that described radar antenna also comprises shell, is used for fixing described feed; And the absorbing material layer of being close to described outer casing inner wall, be used for absorbing the part electromagnetic wave that radiates from feed; Described absorbing material layer and described super material panel consist of the cavity of sealing; Described feed is positioned at described cavity.

3. a kind of feedback type radar antenna according to claim 1, it is characterized in that, described super material panel also comprises a plurality of graded beddings that are symmetrically distributed in described core layer both sides, described each graded bedding include sheet substrate layer, sheet packed layer and be arranged on air layer between described substrate layer and the packed layer.

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

5. a kind of feedback type radar antenna according to claim 1, it is characterized in that: be formed with an aperture on described each super material cell, be filled with refractive index in the described aperture less than the medium of unit base material refractive index, and the aperture in all super material cell is all filled the medium of same material, described the arrange rule of small pore volume in each core layer that is arranged in the super material cell is: the small pore volume that described super material cell forms is take center rounded distribution as the center of circle of each core layer, along with the small pore volume that forms on the super material cell of the increase of radius also increases, and it is identical to have the small pore volume that forms on the super material cell at same radius place.

6. a kind of feedback type radar antenna according to claim 1, it is characterized in that, be formed with an aperture on described each super material cell, be filled with refractive index in the described aperture greater than the medium of unit base material refractive index, and the aperture in all super material cell is all filled the medium of same material, described the arrange rule of small pore volume in each core layer that is arranged in the super material cell is: the small pore volume that described super material cell forms is take center rounded distribution as the center of circle of each core layer, along with the small pore volume that forms on the super material cell of the increase of radius reduces gradually, and it is identical to have the small pore volume that forms on the super material cell at same radius place.

7. a kind of feedback type radar antenna according to claim 1, it is characterized in that, be formed with the quantity difference on the described super material cell, the aperture that volume is identical, be filled with refractive index in the described aperture less than the medium of unit base material refractive index, and the aperture in all super material cell is all filled the medium of same material, described the arrange rule of little hole number in each core layer that is arranged in the super material cell is: the little hole number that described super material cell forms is take center rounded distribution as the center of circle of each core layer, along with the little hole number that forms on the super material cell of the increase of radius also increases gradually, and it is identical to have the little hole number that forms on the super material cell at same radius place.

8. a kind of feedback type radar antenna according to claim 1, it is characterized in that, be formed with the quantity difference on the described super material cell, the aperture that volume is identical, be filled with refractive index in the described aperture greater than the medium of unit base material refractive index, and the aperture in all super material cell is all filled the medium of same material, described the arrange rule of little hole number in each core layer that is arranged in the super material cell is: the little hole number that described super material cell forms is take center rounded distribution as the center of circle of each core layer, along with the little hole number that forms on the super material cell of the increase of radius reduces gradually, and it is identical to have the little hole number that forms on the super material cell at same radius place.

9. the described a kind of feedback type radar antenna of any one is characterized in that according to claim 1～8, and the refractive index of each core layer of described super material panel is take its center as the center of circle, along with Changing Pattern such as the following formula of radius r:

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

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

10. a kind of feedback type radar antenna according to claim 1 is characterized in that, the refractive index in each graded bedding of described super material panel is equally distributed, and Changing Pattern such as the following formula of refraction index profile between a plurality of graded bedding:

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

N wherein _iThe refractive index value that represents i layer graded bedding, m represents the number of plies of graded bedding, n _MinRepresent the minimum refractive index value in described each core layer, n _MaxRepresent the largest refractive index value in described each core layer, wherein m layer graded bedding and core layer are close, and along with diminishing gradually away from core layer of m value, the ground floor graded bedding is the outermost layer graded bedding.

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