CN102480029A - Offset-feed type radar antenna - Google Patents

Abstract

The invention relates to an offset-feed type radar antenna, which comprises a feed source, a metamaterial panel and a reflection plate. The feed source is positioned at the other side of the metamaterial panel and is in a non-aligned area of the metamaterial panel. The metamaterial panel comprises a plurality of core layers with same refractive index distributions. Each core layer comprises a plurality of metamaterial units. Each metamaterial unit comprises a unit substrate and an artificial micro-structure. According to the offset-feed type radar antenna disclosed by the invention, by utilizing the convergence characteristic of the metamaterial on electromagnetic wave, the radar antenna is independent of the shape of electromagnetic convergence equipment; the complex manufacture process for processing the traditional parabolic antenna is saved; simultaneously, the advantage of the traditional parabolic antenna to directionally receive or transmit electromagnetic wave can be realized; furthermore, because the offset-feed type radar antenna is adopted, the feed source cannot block radiation of the electromagnetic wave any longer; and the influence of the radiation electromagnetic wave on the feed source is also avoided.

Description

A kind of offset-feed type radar antenna

Technical field

The present invention relates to the radar antenna field, more particularly, relate to a kind of offset-feed type radar antenna that uses ultra material.

Background technology

Radar antenna becomes plane wave through reflector with the spherical wave of feed radiation, thereby realizes directional reception or launching electromagnetic wave, and the reflector that uses at present is a parabolic shape, and feed is positioned near the focus of reflector.

The operation principle of radar antenna is similar with optical mirror; Existing radar dish is as shown in Figure 1; Comprise burst source 1, paraboloidal reflector 2 and support 3, be placed with emission or receive electromagnetic feed 1, utilize the focus characteristics of paraboloidal reflector 2 in the along of paraboloidal reflector 2; The spherical wave that is sent by feed 1 is transformed into plane wave after paraboloidal reflector 2 reflections, form along the parabolic axially the strongest narrow beam of radiation.

Usually utilize die casting and molding or adopt Digit Control Machine Tool to carry out method for processing in order to make parabolic reflector.The technological process of first method comprises: make parabolic mould, casting parabola and carry out the installation of parabolic reflector.The technology more complicated, cost is high, and paraboloidal shape will the more accurate direction propagation that could realize antenna, so to the requirement of machining accuracy also than higher.Second method adopts large-size numerical control machine to carry out paraboloidal processing, through 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 is than higher.

Ultra material is a kind of artificial composite structure material with the not available extraordinary physical property of natural material.Ultra material is through to the orderly arrangement of micro-structural, can change in the ultra material relative dielectric constant and magnetic permeability at every, thereby the heterogeneity that realizes the refraction index profile of material controlled the propagation path of electromagnetic wave in material.

Summary of the invention

The objective of the invention is to overcome the problem of making the parabolic antenna complex manufacturing in the prior art; A kind of offset-feed type radar antenna is provided; This antenna has proposed a kind of radar antenna with plane reflection plate simple in structure; The antenna of this planar structure has parabolic antenna can directional reception or the advantage of launching electromagnetic wave, the complicated technology when having avoided simultaneously producing parabolic antenna.

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, said antenna comprises: feed is used for radiated electromagnetic wave; Ultra material panel; The electromagnetic wave that is used for said feed is given off is converted into plane electromagnetic wave from the sphere electromagnetic wave; Said antenna also comprises the reflecting plate of being close to said ultra material panel one side, is used for reflection of electromagnetic wave is converged refraction and to the distant place radiation to ultra material panel, and said feed is positioned at the opposite side of said ultra material panel and non-over against the zone at ultra material panel; Said ultra material panel comprises a plurality of a plurality of core layers with refractive index same distribution; Said each core layer comprises a plurality of ultra material cell, and said ultra material cell comprises unit base material and artificial micro-structural, and the refractive index of each core layer of said ultra material panel is the rounded distribution in the center of circle with the orthographic projection of said feed on each core layer; And along with the increase refractive index of radius reduces gradually, and the refractive index that radius exists together mutually is identical.

Further; Said ultra material cell also comprises first packed layer; Said artificial micro-structural between the said unit base material and first packed layer, the material of filling in said first packed layer comprise air, artificial micro-structural and with the medium of said unit base material same material.

Further, said ultra material panel also comprises a plurality of graded beddings that are distributed in said core layer one side, said each graded bedding include sheet substrate layer, sheet second packed layer and be arranged on the air layer between said substrate layer and the packed layer.

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

Further, the refractive index of each core layer of said ultra material panel is the center of circle with the orthographic projection of said feed on each core layer, along with the Changing Pattern such as the following expression formula of radius r:

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

N in the formula _MaxRepresent the largest refractive index value in said each core layer, d representes the gross thickness of all core layers, ss represent said feed near the distance of the core layer of feed position, the said 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 said ultra material panel is equally distributed, and the Changing Pattern such as the following expression 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 of representing i layer graded bedding, m representes the number of plies of graded bedding, n _MinRepresent the minimum refractive index value in said each core layer, n _MaxRepresent the largest refractive index value in said each core layer, wherein m layer graded bedding and core layer near, along with diminishing gradually away from core layer of m value, the ground floor graded bedding is the outermost layer graded bedding.

Further, said artificial micro-structural is for to form planar structure or the stereochemical structure that electromagnetic field is had response by at least one one metal wire, and said wire is copper wire or filamentary silver.

Further, said wire through etching, plating, brill quarter, photoetching, electronics is carved or ion is carved method attached on the said unit base material.

Further, said artificial micro-structural for derive the shape of deriving of " worker " font, " worker " font, flakes or alabastrine shape any one.

Further, said first substrate layer and second substrate layer make by ceramic material, epoxy resin, polytetrafluoroethylene, FR-4 composite material or F4B composite material.

The present invention is with respect to prior art; Has following beneficial effect: a kind of offset-feed type radar antenna; Flat plane antenna simple in structure through utilizing ultra material to the characteristic that electromagnetic wave converges, makes radar antenna not rely on the shape of electromagnetic wave convergence device; Save the complex fabrication process of processing traditional parabolic antenna, can realize the advantage of traditional parabolic antenna directional reception or launching electromagnetic wave simultaneously again.Also have the present invention to adopt the offset-feed type radar antenna, make feed no longer block, also avoided of the influence of the electromagnetic wave of radiation simultaneously feed to irradiation of electromagnetic waves.

Description of drawings

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

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

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

Fig. 4 is the structural representation of ultra material panel according to the invention;

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

Fig. 6 is the structural representation of core layer according to the invention;

Fig. 7 is the structural representation of ultra material cell according to the invention;

Fig. 8 is a graded bedding structural representation according to the invention;

Fig. 9 is a core layer variations in refractive index sketch map of the present invention;

Figure 10 is a core layer variations in refractive index sketch map of the present invention.

Embodiment

Below in conjunction with embodiment and accompanying drawing, the present invention is done to specify further, but execution mode of the present invention is not limited thereto.

Fig. 2 and Fig. 3 are the structural representations of offset-feed type radar antenna of the present invention; This antenna comprises feed 10, ultra material panel 20 and reflecting plate 30; Said feed 10 and expelling plate 30 lay respectively at the both sides of said ultra material panel 20; Reflecting plate 30 is close to ultra material panel 20 and is linked to each other, and the orthographic projection of feed 10 locas on said ultra material panel 20 is the mid point of ultra material panel 20 bottoms.

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 being that the signal transmission of carrier has significant limitation with the sphere electromagnetic wave at a distance, and decay is fast, the present invention through design one have an electromagnetic wave aggregation feature ultra material panel 20; Should convert most of electromagnetic wave that feed 10 radiates into plane electromagnetic wave from the sphere electromagnetic wave by ultra material panel 20; And after the electromagnetic wave through ultra material panel 20 reflects through reflecting plate 30, converge and radiate through ultra material panel 20 refractions once more, make that the directivity of radar antenna is better, the antenna main lobe energy density is higher; Energy is bigger, and then is that the signal transmission distance of carrier is farther with this plane electromagnetic wave.

Fig. 4 is the structural representation of ultra material panel 20 shown in Figure 2; Ultra material panel 20 comprises a plurality of core layers 210 and is distributed in a plurality of graded beddings 220 near feed one side; Each core layer 210 is formed by a plurality of ultra material cell; Said ultra material cell comprise first packed layer 213 of unit base material 211, sheet and be arranged on said unit base material 211 and first packed layer 213 between a plurality of artificial micro-structural 212, like Fig. 6 and as shown in Figure 7.The materials of filling in said first packed layer 213 can be air, artificial micro-structural and with the medium of said unit base material same material; Such as; When the equivalent refractive index in the said ultra material cell of needs becomes big, can in first packed layer 213, fill the medium that metal micro structure or filling have big refractive index; When the equivalent refractive index in the said ultra material cell of needs diminishes, can in first packed layer 213, fill air dielectric or not fill any medium.A plurality of ultra material core layers 210 in the ultra material panel 20 are stacked, and equidistantly arrange the ground assembling between each core layer 210, or in twos between the lamella direct forward and backward surface link into an integrated entity bondingly.During practical implementation, the distance between the number of ultra material core layer and each core layer can design according to demand.Each ultra material core layer 210 is formed by a plurality of ultra material cell arrays, and whole ultra material core layer 210 can be regarded as by a plurality of ultra material cell and forms along X, Y, three direction array arrangements of Z, and is as shown in Figure 5.

A plurality of core layers 210 of said ultra material panel 20 promptly realize converting plane electromagnetic wave into from the sphere electromagnetic wave that said feed 10 gives off through the electromagnetic wave equiphase radiation behind the said ultra material panel 20 realizing through changing its inner refraction index profile.The refraction index profile of each ultra material core layer 210 is all identical among the present invention, only the refraction index profile rule of a ultra material core layer 210 is described in detail here.Through to the topological pattern of artificial micro-structural 212, physical dimension with and the design that on the unit base material 211 and first packed layer 213, distributes; The refraction index profile of the core layer 210 in the middle of making satisfies following rule: the refraction index profile of each layer core layer 210 is all identical; Each core layer comprises that one is the semicircle face territory in the center of circle with the orthographic projection of feed 10 on each core layer 210, and the refractive index of circle centre position is maximum n in the said semicircle face territory _MaxAnd along with the increase of radius reduces gradually, the refractive index at same radius place is identical, and is shown in figure 10, provided the variation diagram of refractive index on the r direction, but the variations in refractive index of answering knowledge capital invention is not as limit.Purpose of design of the present invention is: when making electromagnetic wave through each ultra material core layer 210, electromagnetic wave deviation angle is changed and final parallel radiation gradually.Through 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 confirm the desired parameters value and reach purpose of design of the present invention for the thickness of ultra material function layer and through Computer Simulation.

Fig. 9 and shown in Figure 10 for the variation view of ultra material core layer refraction index profile on radius r.We can know as common practise; Electromagnetic refractive index is proportional with

, and wherein μ is a magnetic permeability, and ε is a dielectric constant; When a branch of electromagnetic wave is propagated into other a kind of medium by a kind of medium; Electromagnetic wave can reflect, and when the inner refraction index profile of material was non-homogeneous, electromagnetic wave will be to the bigger position deviation of refractive index ratio; Therefore; The refractive index that designs ultra material panel 20 inner core layer 210 each points makes it satisfy above-mentioned variations in refractive index rule, need to prove, because in fact ultra material cell is a cube but not a point; Therefore above-mentioned semicircle face territory is an approximate description, and the identical or essentially identical ultra material cell of actual refractive index distributes on a zigzag semi-circumference.When being similar to computer with smoothed curves such as square pixels point-rendering semicircle, half elliptics, its concrete design class carries out the programming mode (for example OpenGL) of described point; Curve display is smooth when pixel is very little with respect to curve, and curve display has sawtooth when pixel is big with respect to curve.

For each core layer 210 that makes ultra material panel 20 realizes Fig. 9 and change of refractive shown in Figure 10; Through theoretical and actual proof; Can to the topological structure of said artificial micro-structural 212, physical dimension with and the design that on the unit base material 211 and first packed layer 213, distributes; Unit base material 211 adopts dielectric insulation material to process; Can be ceramic material, macromolecular material, ferroelectric material, ferrite material, ferromagnetic material etc., macromolecular material for example can be, epoxy resin or polytetrafluoroethylene.Artificial micro-structural 212 for certain geometry attached to the metal wire that response can be arranged electromagnetic wave on the unit base material 211, metal wire can be that section is the copper cash of cylindric or flat, silver-colored line etc., generally adopts copper; Because copper wire is relatively cheap; Certainly the section of metal wire also can be other shapes, and attached on the unit base material 211, said first packed layer 213 can be filled the medium of different materials to metal wire through technologies such as etching, plating, brill quarter, photoetching, electronics quarter or ion quarters; Can with unit base material 211 identical materials; Also can be artificial micro-structural, can also be air, and said each core layer 210 is made up of a plurality of ultra material cell; Whenever ultra material cell all has an artificial micro-structural; Each ultra material cell all can produce response to the electromagnetic wave that passes through wherein, thereby influences electromagnetic wave transmission therein, and the size of each ultra material cell depends on the electromagnetic wave of needs response; Be generally required response electromagnetic wavelength 1/10th, can not be regarded as in the space continuously otherwise comprise being arranged in that the ultra material cell of artificial micro-structural 212 forms in the space.

Under the selected situation of unit base material 211; Shape, size and the spatial distribution on unit base material 211 thereof through adjusting artificial micro-structural 212 and fill the medium of different refractivities at first packed layer 213 can be adjusted everywhere effective dielectric constant and equivalent permeability and then the ultra material of change equivalent refractive index everywhere on the ultra material.When artificial micro-structural 212 adopted identical geometry, the size of the artificial micro-structural in somewhere was big more, and the effective dielectric constant that then should locate is big more, and refractive index is also big more.

The pattern of the artificial micro-structural 212 that present embodiment adopts is the I-shaped pattern of deriving, and can be known by Fig. 5, and the size of the artificial micro-structural 212 of flakes is from being the center of circle with the orthographic projection of feed 10 on each core layer 210; Diminish gradually towards periphery; At circle centre position, the size of alabastrine artificial micro-structural 212 is maximum, and measure-alike in the artificial micro-structural 212 of the flakes at same radius place; Therefore the effective dielectric constant of each core layer 210 by the center of circle to around diminish gradually; The effective dielectric constant in the center of circle is maximum, thus the refractive index of each core layer 210 from the center of circle to around diminish gradually, the refractive index of center of circle part is maximum.

Combine accompanying drawing that embodiments of the invention are described above; But the present invention is not limited to above-mentioned embodiment; The pattern of artificial micro-structural 212 can be two dimension, also can be three-dimensional structure that " worker " font that is not limited to use among this embodiment can be the derived structure of " worker " font; Can be each the orthogonal flakes in bar limit and alabastrine derived structure in three dimensions; Also can be other geometry, wherein different artificial micro-structurals 212 can be that pattern is identical, but its design size is different; Also can be that pattern and design size are all inequality, as long as can parallel ejaculation after the satisfied electromagnetic wave that is sent by antenna element is propagated through ultra material panel 20.

In the embodiment of the invention, the refractive index of each core layer 210 of said ultra material panel 20 to be being the center of circle with the orthographic projection of feed 10 on each core layer 210, along with the Changing Pattern such as the following expression formula of radius r:

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

N in the formula _MaxRepresent the largest refractive index value in said each core layer 210, d representes the gross thickness of all core layers 210, ss represent said feed 10 near the distance of the core layer 210 of feed position, n (r) representes said each core layer 210 inside radius r place refractive index value.

Usually when electromagnetic wave from a kind of medium transmission to another kind of medium the time, owing to the unmatched problem of impedance, a part of reflection of electromagnetic wave can appear; Influence electromagnetic transmission performance like this; Among the present invention,, the electromagnetic wave that radiates from feed 10 can produce reflection equally when inciding ultra material panel 20, in order to reduce the influence of reflection to radar antenna; We are provided with a plurality of ultra material graded beddings 220 in core layer 210 1 sides of ultra material panel 20, and are as shown in Figure 4.

As shown in Figure 8, each ultra material graded bedding 220 include sheet substrate layer 221, sheet second packed layer 223 and be arranged on said substrate layer 221 and second packed layer 223 between air layer 222.Said substrate layer 221 can be selected high molecular polymer, ceramic material, ferroelectric material, ferrite material etc. for use.Wherein preferred FR-4 of high molecular polymer or F4B material.Refractive index between a plurality of ultra material graded beddings 220 is different; In order to mate the impedance of air and core layer 210; The width through adjusting said air layer 222 and realize impedance matching normally through in second packed layer 223, filling the medium that contains different refractivity; This medium also can be and substrate layer 221 identical materials, also can be air, and wherein the refractive index near the ultra material graded bedding 220 of air increases near air and towards core layer 210 direction refractive indexes gradually.

Among the embodiment, 220 refractive index is equally distributed in each graded bedding of said ultra material panel 20, and the Changing Pattern of 220 refraction index profile of a plurality of graded bedding such as following expression formula among the present invention:

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

N wherein _iThe refractive index value of representing i layer graded bedding 220, m representes the number of plies of graded bedding 220, n _MinRepresent the minimum refractive index value in said each core layer 210, n _MaxRepresent the largest refractive index value in said each core layer 210, wherein m layer graded bedding 220 and core layer 210 near, along with diminishing of m value is the outermost layer graded bedding away from 210, the 1 layers of graded bedding of core layer gradually.

In sum; A kind of offset-feed type radar antenna of the present invention makes antenna far field power strengthen widely through changing the refraction index profile situation of ultra material panel 20 inside, and then has promoted the distance that antenna is propagated; Increase the front and back ratio of antenna simultaneously, made antenna have more directivity; Also have the present invention to adopt the offset-feed type radar antenna, make feed no longer block, also avoided of the influence of the electromagnetic wave of radiation simultaneously feed to irradiation of electromagnetic waves.

The foregoing description is a preferred implementation of the present invention; But execution mode of the present invention is not restricted to the described embodiments; Other any do not run counter to change, the modification done under spirit 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. offset-feed type radar antenna, said antenna comprises: feed is used for radiated electromagnetic wave; Ultra material panel; The electromagnetic wave that is used for said feed is given off is converted into plane electromagnetic wave from the sphere electromagnetic wave; It is characterized in that; Said antenna also comprises the reflecting plate of being close to said ultra material panel one side, is used for reflection of electromagnetic wave is converged refraction and to the distant place radiation to ultra material panel, and said feed is positioned at the opposite side of said ultra material panel and non-over against the zone at ultra material panel; Said ultra material panel comprises a plurality of a plurality of core layers with refractive index same distribution; Said each core layer comprises a plurality of ultra material cell, and said ultra material cell comprises unit base material and artificial micro-structural, and the refractive index of each core layer of said ultra material panel is the rounded distribution in the center of circle with the orthographic projection of said feed on each core layer; And 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 offset-feed type radar antenna according to claim 1; It is characterized in that; Said ultra material cell also comprises first packed layer; Said artificial micro-structural between the said unit base material and first packed layer, the material of filling in said first packed layer comprise air, artificial micro-structural and with the medium of said unit base material same material.

3. a kind of offset-feed type radar antenna according to claim 1; It is characterized in that; Said ultra material panel also comprises a plurality of graded beddings that are distributed in said core layer one side, said each graded bedding include sheet substrate layer, sheet second packed layer and be arranged on the air layer between said substrate layer and the packed layer.

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

5. a kind of offset-feed type radar antenna according to claim 1 is characterized in that the refractive index of each core layer of said ultra material panel is the center of circle with the orthographic projection of said feed on each core layer, along with the Changing Pattern such as the following expression formula of radius r:

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

N in the formula _MaxRepresent the largest refractive index value in said each core layer, d representes the gross thickness of all core layers, ss represent said feed near the distance of the core layer of feed position, the said a plurality of core layer inside radius r of n (r) expression place refractive index value.

6. a kind of offset-feed type radar antenna according to claim 1 is characterized in that, the refractive index in each graded bedding of said ultra material panel is equally distributed, and the Changing Pattern such as the following expression 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 of representing i layer graded bedding, m representes the number of plies of graded bedding, n _MinRepresent the minimum refractive index value in said each core layer, n _MaxRepresent the largest refractive index value in said each core layer, wherein m layer graded bedding and core layer near, along with diminishing gradually away from core layer of m value, the ground floor graded bedding is the outermost layer graded bedding.

7. a kind of offset-feed type radar antenna according to claim 1 is characterized in that, said artificial micro-structural is for to form planar structure or the stereochemical structure that electromagnetic field is had response by at least one one metal wire, and said wire is copper wire or filamentary silver.

8. a kind of offset-feed type radar antenna according to claim 7 is characterized in that, said wire through etching, plating, brill quarter, photoetching, electronics is carved or ion is carved method attached on the said unit base material.

9. a kind of offset-feed type radar antenna according to claim 7 is characterized in that, said artificial micro-structural for derive the shape of deriving of " worker " font, " worker " font, flakes or alabastrine shape any one.

10. a kind of offset-feed type radar antenna according to claim 3 is characterized in that said first substrate layer and second substrate layer make by ceramic material, epoxy resin, polytetrafluoroethylene, FR-4 composite material or F4B composite material.

Images