CN102593611A - Point focusing flat lens antenna - Google Patents

Abstract

The invention discloses a point focusing flat lens antenna. The point focusing flat lens antenna comprises a shell which has an opening on one side, a feed source and a meta-material flat lens which is used to seal the shell opening. The meta-material flat lens comprises a first flat lens and a second flat lens, wherein the first flat lens is close to the feed source and the second flat lens fits the first flat lens. Through designing refractive index distribution of the first flat lens and the second flat lens, electromagnetic waves emitted by the feed source can be gathered into one point. According to the point focusing flat lens antenna of the invention, a traditional lens part is replaced by the meta-material flat lens; a curved surface with a complex processing shape and high precision requirement does not needed; manufacturing and processing are easy and cost is low.

Description

A kind of point focusing flat-plate lens antenna

Technical field

The present invention relates to the communications field, more particularly, relate to a kind of point focusing flat-plate lens antenna.

Background technology

The point focusing lens antenna is made up of waveguide trumpet antenna and lens usually.Be characterized in that wave beam converges the formation focal spot on the focus of design.Focal length and caliber size can customize by customer requirements.When the focus of two point focusing lens antennas overlapped, the loss between two antennas was minimum.Because near the point that intersects regional less, be to study special material and the microwave of material in the part passes through one of best method of wave property, reflection characteristic.Lens are most important parts in the point focusing lens antenna, but because the lens of traditional point focusing lens antenna need the curved surface of processed complex, and the required precision of curved surface is very high, so difficulty of processing is big, and with high costs.

Summary of the invention

Technical problem to be solved by this invention is to the big defective of its lens difficulty of processing of point focusing lens of the prior art, the simple point focusing flat-plate lens of a kind of processing antenna to be provided.

The technical solution adopted for the present invention to solve the technical problems is: a kind of point focusing flat-plate lens antenna; Said point focusing flat-plate lens antenna comprise a side opening shell, be arranged on the feed of shell opposite side and seal the ultra material flat-plate lens of said shell aperture; Said ultra material flat-plate lens comprises that first flat-plate lens near feed reaches second flat-plate lens of fitting with first flat-plate lens; Said first flat-plate lens comprises first core layer; Said first core layer comprises that a plurality of thickness are identical and refraction index profile is identical the first surpasses sheet of material; The said sheet of material that the first surpasses comprises first base material and is arranged on a plurality of first artificial micro-structural on first base material, and said second flat-plate lens comprises second core layer, and said second core layer comprises that a plurality of thickness are identical and refraction index profile is identical the second surpasses sheet of material; The said sheet of material that the second surpasses comprises second base material and is arranged on a plurality of second artificial micro-structural on second base material, the said refraction index profile n that the first surpasses sheet of material ₁(r) satisfy following formula:

$n_1\left(r\right)=n_{\min }-\frac{\sqrt{{\mathrm{<figure-callout\; id="2"\; label="ss"\; filenames="HDA0000139692310000072.png,HDA0000139692310000102.png"\; state="\{\{state\}\}">ss</figure-callout>}}^2+{r_{\max }}^2}-\sqrt{{\mathrm{<figure-callout\; id="2"\; label="ss"\; filenames="HDA0000139692310000072.png,HDA0000139692310000102.png"\; state="\{\{state\}\}">ss</figure-callout>}}^2+r^2}}{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="HDA0000139692310000071.png,HDA0000139692310000102.png"\; state="\{\{state\}\}">d</figure-callout>}1};$

Wherein, n ₁(r) expression surpasses the first that radius is the refractive index value at r place on the sheet of material, and this radius r is represented any 1 o'clock distance to the axis of first flat-plate lens on first flat-plate lens;

Ss is the distance of feed equivalent point to first flat-plate lens, i.e. the focal length of first flat-plate lens, and said feed equivalent point is on the focus of first flat-plate lens;

D1 is the thickness of first flat-plate lens;

r _MaxExpression the first surpasses the maximum radius of sheet of material;

n _MinExpression the first surpasses the refractive index minimum value of sheet of material;

The said refraction index profile n that the second surpasses sheet of material ₂(r) satisfy following formula:

$n_2\left(r\right)=n_{\max }-\frac{\sqrt{{\mathrm{<figure-callout\; id="0"\; label="d"\; filenames="HDA0000139692310000092.png,HDA0000139692310000102.png"\; state="\{\{state\}\}">d</figure-callout>}0}^2+r^2}-d0}{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HDA0000139692310000072.png,HDA0000139692310000102.png"\; state="\{\{state\}\}">d</figure-callout>}2};$

Wherein, n ₂(r) expression surpasses the second that radius is the refractive index value at r place on the sheet of material, and this radius r is represented any 1 o'clock distance to the axis of second flat-plate lens on second flat-plate lens;

D0 is the focal length of second flat-plate lens;

D2 is the thickness of second flat-plate lens;

n _MaxExpression the second surpasses the refractive index maximum of sheet of material.

Further; Said first base material comprises the substrate and the first right substrate in the first left substrate, first of sheet; The said a plurality of first artificial micro-structural is folded in the first left substrate and first between the substrate and in first between substrate and the first right substrate; Said second base material comprises the substrate and the second right substrate in the second left substrate, second of sheet, and the said a plurality of second artificial micro-structural is folded in the second left substrate and second between the substrate and in second between substrate and the second right substrate.

Further; The said thickness that the first surpasses sheet of material is 0.836mm; Wherein, the thickness of substrate is 0.4mm in first, and the thickness of the first left substrate and the first right substrate is 0.2mm; The thickness that is folded in the thickness of a plurality of first artificial micro-structurals between the substrate in the first left substrate and first and is folded in a plurality of first artificial micro-structurals between the substrate and the first right substrate in first is 0.018mm; The said thickness that the second surpasses sheet of material is 0.836mm, and wherein, the thickness of substrate is 0.4mm in second; The thickness of the second left substrate and the second right substrate is 0.2mm, and the thickness that is folded in the thickness of a plurality of second artificial micro-structurals between the substrate in the second left substrate and second and is folded in a plurality of second artificial micro-structurals between the substrate and the second right substrate in second is 0.018mm.

Further; Said first flat-plate lens also comprises and is arranged on first impedance matching layer of first core layer near feed one side surface; Said first impedance matching layer comprises the first impedance matching layer lamella that a plurality of thickness are identical; The said first impedance matching layer lamella comprises that first coupling base material of sheet and a plurality of third parties that are arranged on the first coupling base material make micro-structural, and the refraction index profile of the said first impedance matching layer lamella satisfies following formula:

$n_{i1}\left(r\right)={n_{\min }}^{\frac{i1}{\mathrm{<figure-callout\; id="1"\; label="m"\; filenames="HDA0000139692310000071.png,HDA0000139692310000102.png"\; state="\{\{state\}\}">m</figure-callout>}1}}*n_1{\left(r\right)}^{\frac{m1-i1}{\mathrm{<figure-callout\; id="1"\; label="m"\; filenames="HDA0000139692310000071.png,HDA0000139692310000102.png"\; state="\{\{state\}\}">m</figure-callout>}1}};$

Wherein, m1 representes total number of plies of the first impedance matching layer lamella;

I1 representes the numbering of the first impedance matching layer lamella, near the first impedance matching layer lamella of first core layer be numbered 1, near the m1 that is numbered of the first impedance matching layer lamella of feed, numbering increases successively from first core layer to the feed direction.

Further; Said second flat-plate lens also comprises and is arranged on second impedance matching layer of second core layer away from feed one side surface; Said second impedance matching layer comprises the second impedance matching layer lamella that a plurality of thickness are identical; The said second impedance matching layer lamella comprises the second coupling base material of sheet and is arranged on a plurality of four-players of second coupling on the base material makes micro-structural, and the refraction index profile of the said second impedance matching layer lamella satisfies following formula:

$n_{i2}\left(r\right)={n_{\min }}^{\frac{i2}{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="HDA0000139692310000072.png,HDA0000139692310000102.png"\; state="\{\{state\}\}">m</figure-callout>}2}}*n_2{\left(r\right)}^{\frac{m2-i2}{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="HDA0000139692310000072.png,HDA0000139692310000102.png"\; state="\{\{state\}\}">m</figure-callout>}2}};$

Wherein, m2 representes total number of plies of the second impedance matching layer lamella;

I2 representes the numbering of the second impedance matching layer lamella, near the second impedance matching layer lamella of second core layer be numbered 1, near the m2 that is numbered of the second impedance matching layer lamella of air, numbering increases successively from second core layer to direction of air.

Further; Said first the coupling base material comprise sheet first the coupling left substrate, first the coupling in substrate and first the coupling right substrate; Said a plurality of third party make micro-structural be folded in the left substrate of first coupling and first coupling between the substrate and in first coupling substrate and first mate between the right substrate; The said second coupling base material comprises substrate and the right substrate of second coupling in the left substrate of second coupling, second coupling of sheet, said a plurality of four-players make micro-structural be folded in the left substrate of second coupling and second coupling between the substrate and in second coupling substrate and second mate between the right substrate.

Further; The thickness of the said first impedance matching layer lamella is 0.836mm; Wherein, The thickness of substrate is 0.4mm in first coupling; The thickness of first left side coupling substrate and the right substrate of first coupling is 0.2mm, is folded in a plurality of third parties between the substrate in the left substrate of first coupling and first coupling and makes the thickness of micro-structural and be folded in substrate and first in first coupling and mate the thickness that a plurality of third parties between the right substrate make micro-structural and be 0.018mm, and the thickness of the said second impedance matching layer lamella is 0.836mm; Wherein, The thickness of substrate is 0.4mm in second coupling, and the thickness of the second left substrate of coupling and the right substrate of second coupling is 0.2mm, is folded in a plurality of four-players between the substrate in the left substrate of second coupling and second coupling and makes the thickness of micro-structural and be folded in substrate and second in second coupling and mate the thickness that a plurality of four-players between the right substrate make micro-structural and be 0.018mm.

Further, the arbitrary longitudinal section of said ultra material flat-plate lens is of similar shape and area, and the operating frequency of said point focusing flat-plate lens antenna is 8-12GHZ, and centre frequency is 10GHZ, wherein:

The feed equivalent point is 0.23m to first flat-plate lens apart from ss;

The maximum radius r that the first surpasses sheet of material _MaxBe 0.15m, the bore of promptly said point focusing flat-plate lens antenna is 0.3m;

Total number of stories m 1 of the first impedance matching layer lamella is 6;

The total number of plies that the first surpasses sheet of material is 18;

The refractive index minimum value n that the first surpasses sheet of material _MinBe 1.469;

The focal length d0 of second flat-plate lens is 0.6m;

Total number of stories m 2 of the second impedance matching layer lamella is 4;

The total number of plies that the second surpasses sheet of material is 9;

The refractive index maximum n that the second surpasses sheet of material _MaxBe 4.2.

Further, the arbitrary longitudinal section of said ultra material flat-plate lens is of similar shape and area, and the operating frequency of said point focusing flat-plate lens antenna is 8-12GHZ, and centre frequency is 10GHZ, wherein:

The feed equivalent point is 0.23m to first flat-plate lens apart from ss;

The maximum radius r that the first surpasses sheet of material _MaxBe 0.15m, the bore of promptly said point focusing flat-plate lens antenna is 0.3m;

The total number of plies that the first surpasses sheet of material is 21;

The refractive index minimum value n that the first surpasses sheet of material _MinBe 1.469;

The focal length d0 of second flat-plate lens is 0.6m;

The total number of plies that the second surpasses sheet of material is 11;

The refractive index maximum n that the second surpasses sheet of material _MaxBe 4.2.

Further, the longitudinal section of said ultra material flat-plate lens is square, circular or oval.

Further; The said first artificial micro-structural, the second artificial micro-structural, third party make micro-structural and four-player is made all metal micro structures for being made up of copper cash or silver-colored line of micro-structural, said metal micro structure through etching, plating, brill quarter, photoetching, electronics is carved or ion is carved method respectively attached on first base material, second base material, the first coupling base material and the second coupling base material.

Further; Said metal micro structure is the plane flakes; Said metal micro structure has first metal wire and second metal wire of vertically dividing equally each other, and said first metal wire is identical with the length of second metal wire, and the said first metal wire two ends are connected with two first metal branches of equal length; The said first metal wire two ends are connected on the mid point of two first metal branches; The said second metal wire two ends are connected with two second metal branches of equal length, and the said second metal wire two ends are connected on the mid point of two second metal branches, the equal in length of the said first metal branch and the second metal branch.

Further, the inwall of said shell is provided with absorbing material.

According to point focusing flat-plate lens antenna of the present invention, the conventional lenses part is replaced by ultra material flat-plate lens, does not need machining shape complicacy, the high curved surface of required precision, makes processing and is more prone to, and cost is cheaper.

Description of drawings

Fig. 1 is the structural representation of the point focusing flat-plate lens antenna of first embodiment of the invention;

Fig. 2 is the perspective diagram that the first surpasses one of them ultra material cell of sheet of material of the present invention;

Fig. 3 is the structural representation that the first surpasses sheet of material of the present invention;

Fig. 4 is the structural representation that the second surpasses sheet of material of the present invention;

Fig. 5 is the structural representation of the first matching layer lamella of the present invention;

Fig. 6 is the structural representation of the second matching layer lamella of the present invention;

Fig. 7 is the structural representation of the point focusing flat-plate lens antenna of second embodiment of the invention;

Fig. 8 is the sketch map of the alabastrine metal micro structure in plane of the present invention;

Fig. 9 is a kind of derived structure of the alabastrine metal micro structure in plane shown in Figure 8;

Figure 10 is a kind of distressed structure of the alabastrine metal micro structure in plane shown in Figure 8.

Figure 11 is phase I of differentiation of the topology of the alabastrine metal micro structure in plane;

Figure 12 is the analogous diagram of the minimum ultra material cell of refractive index;

Figure 13 is the second stage of differentiation of the topology of the alabastrine metal micro structure in plane;

Figure 14 is the analogous diagram of the minimum ultra material cell of refractive index.

Embodiment

Extremely shown in Figure 6 like Fig. 1; Be the point focusing flat-plate lens antenna that first embodiment of the invention provided; Said point focusing flat-plate lens antenna comprise a side opening shell 1, be arranged on the feed 2 of shell 1 opposite side and seal the ultra material flat-plate lens 1000 of said shell aperture K1, feed 2 is preferably horn antenna, like rectangular waveguide horn antenna or circular waveguide horn antenna; The inwall of said shell 1 is provided with absorbing material 3; To absorb the electromagnetic wave of directive shell, feed is disturbed in the reflection of electromagnetic wave of anti-part here, and the performance that influences antenna.Absorbing material of the present invention can be the plate shaped absorbing material of individual layer that directly is attached on the outer casing inner wall; Also can be the absorbing material of bilayer or multi-layer planar shape, like Japanese NEC Corporation ferrite and broken-staple metal fibre are dispersed in the suitable organic polymer resin and process composite material; Also the absorbing material of coating type adds the neoprene rubber coating like lithium Cd ferrite coating, ferrospinel coating or ferrite.Shell is traditional metal shell, and its material is preferably aluminium or aluminium alloy.

In the present embodiment; Said ultra material flat-plate lens 1000 comprises that first flat-plate lens 10 near feed 2 reaches second flat-plate lens 20 of fitting with first flat-plate lens 10; Said first flat-plate lens 10 comprises first core layer 11 and is arranged on first impedance matching layer 12 of first core layer 11 near feed 2 one side surfaces; Said first core layer 11 comprises that a plurality of thickness are identical and refraction index profile is identical the first surpasses sheet of material 110; The said sheet of material 110 that the first surpasses comprises first base material 111 and is arranged on a plurality of first artificial micro-structural 112 on first base material 111; Said second flat-plate lens 20 comprises second core layer 21 and is arranged on second impedance matching layer 22 of second core layer 21 away from feed 2 one side surfaces; Said second core layer 21 comprises that a plurality of thickness are identical and refraction index profile is identical the second surpasses sheet of material 210; The said sheet of material 210 that the second surpasses comprises second base material 211 and is arranged on a plurality of second artificial micro-structural (not indicating among the figure) on second base material 211, the said refraction index profile n that the first surpasses sheet of material 110 ₁(r) satisfy following formula:

$n_1\left(r\right)=n_{\min }-\frac{\sqrt{{\mathrm{<figure-callout\; id="2"\; label="ss"\; filenames="HDA0000139692310000072.png,HDA0000139692310000102.png"\; state="\{\{state\}\}">ss</figure-callout>}}^2+{r_{\max }}^2}-\sqrt{{\mathrm{<figure-callout\; id="2"\; label="ss"\; filenames="HDA0000139692310000072.png,HDA0000139692310000102.png"\; state="\{\{state\}\}">ss</figure-callout>}}^2+r^2}}{d1}---\left(1\right);$

Wherein, n ₁(r) expression surpasses the first that radius is the refractive index value at r place on the sheet of material 110, and this radius r is represented any 1 o'clock distance to the axis Z1 of first flat-plate lens 10 on first flat-plate lens 10;

Ss is a feed equivalent point (the X point among the figure) to the distance of first flat-plate lens 10 (in the present embodiment; Ss is the distance of feed equivalent point X to first impedance matching layer); The i.e. focal length of first flat-plate lens 10, said feed equivalent point X is on the focus of first flat-plate lens 10; The axis Z1 of first flat-plate lens 10 overlaps with the axis Z2 of feed.

D1 is the thickness of first flat-plate lens 10;

r _MaxExpression the first surpasses the maximum radius of sheet of material 110;

n _MinExpression the first surpasses the refractive index minimum value of sheet of material;

The said refraction index profile n that the second surpasses sheet of material 210 ₂(r) satisfy following formula:

$n_2\left(r\right)=n_{\max }-\frac{\sqrt{{\mathrm{<figure-callout\; id="0"\; label="d"\; filenames="HDA0000139692310000092.png,HDA0000139692310000102.png"\; state="\{\{state\}\}">d</figure-callout>}0}^2+r^2}-d0}{d2}---\left(2\right);$

Wherein, n ₂(r) expression surpasses the second that radius is the refractive index value at r place on the sheet of material 210, and this radius r is represented any 1 o'clock distance to the axis of second flat-plate lens 20 on second flat-plate lens 20; The axis of second flat-plate lens 20 overlaps (second flat-plate lens and the coaxial setting of first flat-plate lens) with the axis Z1 of first flat-plate lens 10.

D0 is the focal length of second flat-plate lens 20; Focus is X2.

D2 is the thickness of second flat-plate lens 20;

n _MaxExpression the second surpasses the refractive index maximum of sheet of material 210.

In the present embodiment; As shown in Figure 3; Said first base material 111 comprises the substrate MB1 and the first right substrate RB1 among the first left substrate LB1, first of sheet, and the said a plurality of first artificial micro-structural (not shown among Fig. 3) is folded in the first left substrate LB1 and first between the substrate MB1 and in first between substrate MB1 and the first right substrate RB1.Preferably; The said thickness that the first surpasses sheet of material is 0.836mm; Wherein, The thickness of substrate is 0.4mm in first, and the thickness of the first left substrate and the first right substrate is 0.2mm, and the thickness that is folded in the thickness of a plurality of first artificial micro-structurals between the substrate in the first left substrate and first and is folded in a plurality of first artificial micro-structurals between the substrate and the first right substrate in first is 0.018mm.

In the present embodiment; As shown in Figure 4; Said second base material 211 comprises the substrate MB2 and the second right substrate RB2 among the second left substrate LB2, second of sheet, and the said a plurality of second artificial micro-structural (not shown) is folded in the second left substrate LB2 and second between the substrate MB2 and in second between substrate MB2 and the second right substrate RB2.Preferably; The said thickness that the second surpasses sheet of material is 0.836mm; Wherein, The thickness of substrate is 0.4mm in second, and the thickness of the second left substrate and the second right substrate is 0.2mm, and the thickness that is folded in the thickness of a plurality of second artificial micro-structurals between the substrate in the second left substrate and second and is folded in a plurality of second artificial micro-structurals between the substrate and the second right substrate in second is 0.018mm.

In the present embodiment; As shown in Figure 5; Said first impedance matching layer 12 comprises the first impedance matching layer lamella 120 that a plurality of thickness are identical; The said first impedance matching layer lamella 120 comprises that first coupling base material 121 of sheet and a plurality of third parties that are arranged on the first coupling base material 121 make the micro-structural (not shown), and the refraction index profile of the said first impedance matching layer lamella 120 satisfies following formula:

$n_{i1}\left(r\right)={n_{\min }}^{\frac{i1}{\mathrm{<figure-callout\; id="1"\; label="m"\; filenames="HDA0000139692310000071.png,HDA0000139692310000102.png"\; state="\{\{state\}\}">m</figure-callout>}1}}*n_1{\left(r\right)}^{\frac{m1-i1}{m1}}---\left(3\right);$

Wherein, m1 representes total number of plies of the first impedance matching layer lamella 120;

I1 representes the numbering of the first impedance matching layer lamella, near the first impedance matching layer lamella of first core layer 100 be numbered 1, near the m1 that is numbered of the first impedance matching layer lamella of feed 2, numbering increases successively from first core layer 100 to feed 2 directions.

In the present embodiment; As shown in Figure 5; The said first coupling base material 121 comprises substrate P M1 and the right substrate P R1 of first coupling among the left substrate P L1 of first coupling, first coupling of sheet, said a plurality of third parties make micro-structural be folded in the left substrate P L1 of first coupling and first coupling between the substrate P M1 and in first coupling substrate P M1 and first mate between the right substrate P R1.Preferably; The thickness of the said first impedance matching layer lamella is 0.836mm; Wherein, The thickness of substrate is 0.4mm in first coupling, and the thickness of first left side coupling substrate and the right substrate of first coupling is 0.2mm, is folded in a plurality of third parties between the substrate in the left substrate of first coupling and first coupling and makes the thickness of micro-structural and be folded in substrate and first in first coupling and mate the thickness that a plurality of third parties between the right substrate make micro-structural and be 0.018mm.

In the present embodiment; As shown in Figure 6; Said second impedance matching layer 22 comprises the second impedance matching layer lamella 220 that a plurality of thickness are identical; The said second impedance matching layer lamella 220 comprises the second coupling base material 221 of sheet and is arranged on a plurality of four-players of second coupling on the base material 221 makes the micro-structural (not shown), and the refraction index profile of the said second impedance matching layer lamella 220 satisfies following formula:

$n_{i2}\left(r\right)={n_{\min }}^{\frac{i2}{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="HDA0000139692310000072.png,HDA0000139692310000102.png"\; state="\{\{state\}\}">m</figure-callout>}2}}*n_2{\left(r\right)}^{\frac{m2-i2}{m2}}---\left(4\right);$

Wherein, m2 representes total number of plies of the second impedance matching layer lamella;

I2 representes the numbering of the second impedance matching layer lamella 220; Be numbered 1 near the second impedance matching layer lamella 220 of second core layer 200; Near the m2 that is numbered of the second impedance matching layer lamella 220 of air, numbering increases successively from second core layer 200 to direction of air.

In the present embodiment; As shown in Figure 6; The said second coupling base material 221 comprises substrate P M2 and the right substrate P R2 of second coupling among the left substrate P L2 of second coupling, second coupling of sheet, said a plurality of four-players make micro-structural 222 be folded in the left substrate P L2 of second coupling and second coupling between the substrate P M2 and in second coupling substrate P M2 and second mate between the right substrate P R2.Preferably; The thickness of the said second impedance matching layer lamella is 0.836mm; Wherein, The thickness of substrate is 0.4mm in second coupling, and the thickness of the second left substrate of coupling and the right substrate of second coupling is 0.2mm, is folded in a plurality of four-players between the substrate in the left substrate of second coupling and second coupling and makes the thickness of micro-structural and be folded in substrate and second in second coupling and mate the thickness that a plurality of four-players between the right substrate make micro-structural and be 0.018mm.

In the present embodiment, the arbitrary longitudinal section of said ultra material flat-plate lens is of similar shape and area, and the longitudinal section here is meant in the ultra material flat-plate lens and the section of axis normal wherein.The longitudinal section of said ultra material flat-plate lens is square, circular or oval, and preferably, the longitudinal section of said ultra material flat-plate lens be a circle, and the ultra material flat-plate lens that obtains like this is a flat cylinder.

In the present embodiment, said point focusing flat-plate lens antenna has following parameter particularly:

The operating frequency of said point focusing flat-plate lens antenna is 8-12GHZ, and centre frequency is 10GHZ;

Feed equivalent point X is 0.23m to first flat-plate lens apart from ss, and the promptly X o'clock distance to first impedance matching layer is 0.23m;

The maximum radius r that the first surpasses sheet of material _MaxBe 0.15m, the bore of promptly said point focusing flat-plate lens antenna is 0.3m;

Total number of stories m 1 of the first impedance matching layer lamella is 6, and every layer thickness is 0.836mm;

The total number of plies that the first surpasses sheet of material is 18, and promptly first core layer is made up of 18 layers ultra sheet of material, and every layer thickness is 0.836mm;

The refractive index minimum value n that the first surpasses sheet of material _MinBe 1.469;

The focal length d0 of second flat-plate lens is 0.6m;

Total number of stories m 2 of the second impedance matching layer lamella is 4, and every layer thickness is 0.836mm;

The total number of plies that the second surpasses sheet of material is 9, and promptly second core layer is made up of 9 layers ultra sheet of material, and every layer thickness is 0.836mm;

The refractive index maximum n that the second surpasses sheet of material _MaxBe 4.2.

As shown in Figure 7, be the point focusing flat-plate lens antenna that second embodiment of the invention provided.Different with first embodiment is, in the present embodiment, said first flat-plate lens 10 only comprises first core layer 11, and said second flat-plate lens 20 only comprises second core layer 21.

In the present embodiment, the concrete parameter of said point focusing flat-plate lens antenna is different, as follows:

In the present embodiment, the operating frequency of said point focusing flat-plate lens antenna is 8-12GHZ, and centre frequency is 10GHZ;

Feed equivalent point X is 0.23m to first flat-plate lens apart from ss, and the ss here is the X o'clock distance to first core layer, and is the X o'clock distance to first impedance matching layer among first embodiment;

The maximum radius r that the first surpasses sheet of material _MaxBe 0.15m, the bore of promptly said point focusing flat-plate lens antenna is 0.3m;

The total number of plies that the first surpasses sheet of material is 21, and promptly first core layer is made up of 21 layers ultra sheet of material, every layer thickness 0.836mm;

The refractive index minimum value n that the first surpasses sheet of material _MinBe 1.469;

The focal length d0 of second flat-plate lens is 0.6m;

The total number of plies that the second surpasses sheet of material is 11, and promptly second core layer is made up of 11 layers ultra sheet of material, every layer thickness 0.836mm;

The refractive index maximum n that the second surpasses sheet of material _MaxBe 4.2.

Among the present invention; The said first artificial micro-structural, the second artificial micro-structural, third party make micro-structural and four-player is made all metal micro structures for being made up of copper cash or silver-colored line of micro-structural, said metal micro structure through etching, plating, brill quarter, photoetching, electronics is carved or ion is carved method respectively attached on first base material, second base material, the first coupling base material and the second coupling base material.Preferably, the said first artificial micro-structural, the second artificial micro-structural, third party make micro-structural and four-player and make micro-structural and be the alabastrine metal micro structure in plane shown in Figure 8 develops a plurality of different topology that obtains through topology metal micro structure.

The first surpassing sheet of material can obtain through following method; The i.e. double-sided copper-clad of substrate in first; Obtain a plurality of first metal micro structures (shape of a plurality of first metal micro structures with arrange) through etching method again, at last the first left substrate and the first right substrate are pressed together on both sides respectively, promptly obtain the sheet of material that the first surpasses of the present invention in advance through the Computer Simulation acquisition; The method of pressing can be direct hot pressing; Also can be to utilize PUR to connect, also other mechanical connection certainly, for example bolt connects.

In like manner, the second surpassing sheet of material, the first matching layer lamella and the second matching layer lamella also can utilize identical method to obtain.Then respectively with a plurality ofly the first surpassing sheet of material, the second surpassing sheet of material, the first matching layer lamella and the second matching layer lamella and connect one; Promptly formed first core layer of the present invention, second core layer, first impedance matching layer and second impedance matching layer respectively, first core layer, second core layer, first impedance matching layer and second impedance matching layer have been connected one promptly obtain ultra material flat-plate lens of the present invention.

Among the present invention, said first base material, second base material, the first coupling base material and the second coupling base material are made by ceramic material, macromolecular material, ferroelectric material, ferrite material or ferromagnetic material etc.Macromolecular material is available to have polytetrafluoroethylene, epoxy resin, F4B composite material, FR-4 composite material etc.For example, the electrical insulating property of polytetrafluoroethylene is very good, therefore can not produce electromagnetic electric field and disturb, and have excellent chemical stability, corrosion resistance, long service life.Preferably, among the present invention, the first left substrate LB1 of said first base material and the first right substrate RB1 adopt identical rigid foam plate, said first base material first in substrate MB1 process by the FR-4 composite material; Equally, among the present invention, the second left substrate LB2 of said second base material and the second right substrate RB2 adopt identical rigid foam plate, said second base material second in substrate MB2 process by the FR-4 composite material; Equally, among the present invention, the left substrate P L1 of first coupling of the said first coupling base material adopts identical rigid foam plate with the right substrate P R1 of first coupling, and substrate P M1 is processed by the FR-4 composite material in first coupling of the said first coupling base material; Equally, among the present invention, the left substrate P L2 of second coupling of the said second coupling base material adopts identical rigid foam plate with the right substrate P R2 of second coupling, and substrate P M2 is processed by the FR-4 composite material in second coupling of the said second coupling base material.The dielectric constant of the FR-4 composite material that the present invention adopts is 3.3; Its base material refractive index of processing is higher; Therefore reduce through the rigid foam plate and the first surpass sheet of material, the second surpass the refractive index minimum value of sheet of material, the first matching layer lamella and the second matching layer lamella, to obtain suitable ranges of indices of refraction.

Shown in Figure 8 is the sketch map of the alabastrine metal micro structure in plane; Described alabastrine metal micro structure has the first metal wire J1 and the second metal wire J2 that vertically divides equally each other; The said first metal wire J1 is identical with the length of the second metal wire J2; The said first metal wire J1 two ends are connected with two first F1 of metal branch of equal length; The said first metal wire J1 two ends are connected on the mid point of two first F1 of metal branch; The said second metal wire J2 two ends are connected with two second F2 of metal branch of equal length, and the said second metal wire J2 two ends are connected on the mid point of two second F2 of metal branch, the equal in length of said first F1 of metal branch and second F2 of metal branch.

Fig. 9 is a kind of derived structure of the alabastrine metal micro structure in plane shown in Figure 8.Its two ends at each first F1 of metal branch and each second F2 of metal branch all are connected with identical the 3rd F3 of metal branch, and the mid point of corresponding the 3rd F3 of metal branch links to each other with the end points of first F1 of metal branch and second F2 of metal branch respectively.The rest may be inferred, and the present invention can also derive the metal micro structure of other form.

Figure 10 is a kind of distressed structure of the alabastrine metal micro structure in plane shown in Figure 8; The metal micro structure of this kind structure; The first metal wire J1 and the second metal wire J2 are not straight lines; But folding line, the first metal wire J1 and the second metal wire J2 are provided with two kink WZ, divide equally but the first metal wire J1 remains vertical with the second metal wire J2; Through be provided with kink towards with the relative position of kink on first metal wire and second metal wire, make metal micro structure shown in Figure 10 wind to revolve the figure that turn 90 degrees with the axis of the second metal wire intersection point to any direction all to overlap with former figure perpendicular to first metal wire.In addition, other distortion can also be arranged, for example, the first metal wire J1 and the second metal wire J2 all are provided with a plurality of kink WZ.

Among the present invention; Saidly the first surpass the ultra material cell D a plurality of as shown in Figure 2 that sheet of material 110 is divided into array arrangement; Each ultra material cell D comprises left base board unit U, right base board unit V and middle base board unit Y and is symmetricly set on two first identical artificial micro-structurals 112 of middle base board unit Y two sides; Usually the length and width height of ultra material cell D all is not more than 1/5th wavelength; Be preferably 1/10th wavelength, therefore, can confirm the size of ultra material cell D according to the operating frequency of antenna.Fig. 2 is the technique of painting of perspective; To represent first position of artificial micro-structural in ultra material cell D; As shown in Figure 2; Said first one of the artificial micro-structural is sandwiched between left base board unit U and the middle base board unit Y, and another is sandwiched between right base board unit V and the middle base board unit Y, and surface, two first artificial micro-structural places is represented with SR1 and SR2 respectively.

Known refractive index

wherein μ is a relative permeability; ε is a relative dielectric constant, and μ and ε close and be called electromagnetic parameter.Experiment showed, when electromagnetic wave passes through refractive index dielectric material heterogeneous, can be to the big direction deviation of refractive index.Under the certain situation of relative permeability (usually near 1); Refractive index is only relevant with dielectric constant; Under the situation that first base material is selected; Utilize the arbitrary value (within the specific limits) that only can realize ultra material cell refractive index, under this point focusing lens antenna centre frequency (10GHZ), utilize simulation software the first artificial micro-structural of electric field response; Like CST, MATLAB etc.; The dielectric constant of artificial micro-structural (the alabastrine metal micro structure in plane as shown in Figure 8) that obtains a certain given shape through emulation can be listed data one to one along with the situation that the refractive index variable of topology changes, and the specific refractive index that can design us needs distributes the first surpasses sheet of material 110; In like manner can obtain the second surpassing the refraction index profile of sheet of material, the first matching layer lamella and the second matching layer lamella, thereby obtain the refraction index profile of whole ultra material flat-plate lens 1000.

Among the present invention, the structural design of the first super sheet of material can obtain through Computer Simulation (CST emulation), and is specific as follows:

That (1) confirms first metal micro structure adheres to base material (first base material).During this is bright; The first left substrate LB1 of said first base material adopts identical rigid foam plate with the first right substrate RB1; Described rigid foam plate has a predetermined dielectric constant, said first base material first in substrate MB1 be that 3.3 FR-4 composite material is processed by dielectric constant.

(2) size of definite ultra material cell.The size of the size of ultra material cell is obtained by the centre frequency of antenna, utilizes frequency to obtain its wavelength, gets less than 1/5th a numerical value of wavelength length C D and the width KD as ultra material cell D again.Among the present invention, said ultra material cell D is that long CD and wide KD as shown in Figure 2 is 2.4mm, thickness HD is the square platelet of 0.836mm.

(3) confirm the material and the topological structure of metal micro structure.Among the present invention, the material of metal micro structure is a copper, and the topological structure of metal micro structure is the alabastrine metal micro structure in plane shown in Figure 8, and its live width W is consistent everywhere; The topological structure here is meant the basic configuration that topology develops.

(4) confirm the topology parameter of metal micro structure.As shown in Figure 8, among the present invention, the topology parameter of the alabastrine metal micro structure in plane comprises the live width W of metal micro structure, the length a of the first metal wire J1, the length b of first F1 of metal branch.

(5) confirm the differentiation restrictive condition of the topology of metal micro structure.Among the present invention; The differentiation restrictive condition of the topology of metal micro structure has, the minimum spacing WL between the metal micro structure (promptly as shown in Figure 8, the long limit of metal micro structure and ultra material cell or the distance of broadside are WL/2); The live width W of metal micro structure, the size of ultra material cell; Because the processing technology restriction, WL is more than or equal to 0.1mm, and same, live width W is greater than to equal 0.1mm.Among the present invention, WL gets 0.1mm, and W gets 0.3mm, and ultra material cell is of a size of the long and wide 2.4mm that is, thickness is 0.836mm, and this moment, the topology parameter of metal micro structure had only a and two variablees of b.The passing through like Figure 11 of the topology of metal micro structure corresponding to a certain CF (for example 10GHZ), can obtain a continuous variations in refractive index scope to differentiation mode shown in Figure 14.

Particularly, the differentiation of the topology of said metal micro structure comprises two stages (basic configuration that topology develops is a metal micro structure shown in Figure 8):

Phase I: according to developing restrictive condition, under the situation that the b value remains unchanged, a value is changed to maximum from minimum value, the metal micro structure in this evolution process is " ten " font (except when a gets minimum value).In the present embodiment, the minimum value of a is 0.3mm (live width W), and the maximum of a is (CD-WL), i.e. 2.4-0.1mm, and then the maximum of a is 2.3mm.Therefore; In the phase I, the differentiation of the topology of metal micro structure is shown in figure 11, promptly is the square JX1 of W from the length of side; Develop into maximum " ten " font topology JD1 gradually; In " ten " font topology JD1 of maximum, the first metal wire J1 and the second metal wire J2 length are 2.3mm, and width W is 0.3mm.In the phase I, along with the differentiation of the topology of metal micro structure, the refractive index of the ultra material cell corresponding with it increases (respective antenna one CF) continuously, and is shown in figure 12, when frequency is 10GHZ, and the minimum value n of the refractive index that ultra material cell is corresponding _MinBe 1.469.

Second stage: according to developing restrictive condition, when a was increased to maximum, a remained unchanged; At this moment, b is increased continuously maximum from minimum value, the metal micro structure in this evolution process is the plane flakes.In the present embodiment, the minimum value of b is 0.3mm (live width W), and the maximum of b is (CD-WL-2W), i.e. 2.4-0.1-2*0.3mm, and then the maximum of b is 1.7mm.Therefore, in second stage, the differentiation of the topology of metal micro structure is shown in figure 13; Promptly from " ten " font topology JD1 of maximum; Develop into the maximum alabastrine topology JD2 in plane gradually, the alabastrine topology JD2 in the plane of the maximum here is meant that the length b of first J1 of metal branch and second J2 of metal branch can not extend again; Otherwise the first metal branch and the second metal branch will take place to intersect, and the maximum of b is 1.7mm.At this moment, first metal wire and the second metal wire length are 2.3mm, and width is 0.3mm, and the length of the first metal branch and the second metal branch is 1.7mm, and width is 0.3mm.In second stage, along with the differentiation of the topology of metal micro structure, the refractive index of the ultra material cell corresponding with it increases (respective antenna one CF) continuously, and is shown in figure 12, when frequency is 10GHZ, and the maximum n of the refractive index that ultra material cell is corresponding _MaxBe 4.2.

The variations in refractive index scope (1.469-4.2) that obtains ultra material cell through above-mentioned differentiation satisfies design demand.Do not satisfy design demand if above-mentioned differentiation obtains the variations in refractive index scope of ultra material cell, for example maximum is too little, then changes WL and W, and emulation again is up to obtaining the variations in refractive index scope that we need.

According to formula (1); After a series of ultra material cell that emulation is obtained is arranged according to its corresponding refractive index (in fact being exactly a plurality of first artificial micro-structural the arranging on first base material of different topology shape), can obtain the sheet of material that the first surpasses of the present invention.

In like manner, can obtain sheet of material, the first matching layer lamella and the second matching layer lamella of the second surpassing of the present invention.

Combine accompanying drawing that embodiments of the invention are described above; But the present invention is not limited to above-mentioned embodiment, and above-mentioned embodiment only is schematically, rather than restrictive; Those of ordinary skill in the art is under enlightenment of the present invention; Not breaking away under the scope situation that aim of the present invention and claim protect, also can make a lot of forms, these all belong within the protection of the present invention.

Claims (13)

1. point focusing flat-plate lens antenna; It is characterized in that; Said point focusing flat-plate lens antenna comprise a side opening shell, be arranged on the feed of shell opposite side and seal the ultra material flat-plate lens of said shell aperture; Said ultra material flat-plate lens comprises that first flat-plate lens near feed reaches second flat-plate lens of fitting with first flat-plate lens; Said first flat-plate lens comprises first core layer, and said first core layer comprises that a plurality of thickness are identical and refraction index profile is identical the first surpasses sheet of material, and the said sheet of material that the first surpasses comprises first base material and is arranged on a plurality of first artificial micro-structural on first base material; Said second flat-plate lens comprises second core layer; Said second core layer comprises that a plurality of thickness are identical and refraction index profile is identical the second surpasses sheet of material, and the said sheet of material that the second surpasses comprises second base material and is arranged on a plurality of second artificial micro-structural on second base material, the said refraction index profile n that the first surpasses sheet of material ₁(r) satisfy following formula:

$n_1\left(r\right)=n_{\min }-\frac{\sqrt{{\mathrm{ss}}^2+{r_{\max }}^2}-\sqrt{{\mathrm{ss}}^2+r^2}}{d1};$

Wherein, n ₁(r) expression surpasses the first that radius is the refractive index value at r place on the sheet of material, and this radius r is represented any 1 o'clock distance to the axis of first flat-plate lens on first flat-plate lens;

Ss is the distance of feed equivalent point to first flat-plate lens, i.e. the focal length of first flat-plate lens, and said feed equivalent point is on the focus of first flat-plate lens;

D1 is the thickness of first flat-plate lens;

r _MaxExpression the first surpasses the maximum radius of sheet of material;

n _MinExpression the first surpasses the refractive index minimum value of sheet of material;

The said refraction index profile n that the second surpasses sheet of material ₂(r) satisfy following formula:

$n_2\left(r\right)=n_{\max }-\frac{\sqrt{{d0}^2+r^2}-d0}{d2};$

Wherein, n ₂(r) expression surpasses the second that radius is the refractive index value at r place on the sheet of material, and this radius r is represented any 1 o'clock distance to the axis of second flat-plate lens on second flat-plate lens;

D0 is the focal length of second flat-plate lens;

D2 is the thickness of second flat-plate lens;

n _MaxExpression the second surpasses the refractive index maximum of sheet of material.

2. point focusing flat-plate lens antenna as claimed in claim 1; It is characterized in that; Said first base material comprises the substrate and the first right substrate in the first left substrate, first of sheet; The said a plurality of first artificial micro-structural is folded in the first left substrate and first between the substrate and in first between substrate and the first right substrate; Said second base material comprises the substrate and the second right substrate in the second left substrate, second of sheet, and the said a plurality of second artificial micro-structural is folded in the second left substrate and second between the substrate and in second between substrate and the second right substrate.

3. point focusing flat-plate lens antenna as claimed in claim 2; It is characterized in that; The said thickness that the first surpasses sheet of material is 0.836mm; Wherein, the thickness of substrate is 0.4mm in first, and the thickness of the first left substrate and the first right substrate is 0.2mm; The thickness that is folded in the thickness of a plurality of first artificial micro-structurals between the substrate in the first left substrate and first and is folded in a plurality of first artificial micro-structurals between the substrate and the first right substrate in first is 0.018mm; The said thickness that the second surpasses sheet of material is 0.836mm, and wherein, the thickness of substrate is 0.4mm in second; The thickness of the second left substrate and the second right substrate is 0.2mm, and the thickness that is folded in the thickness of a plurality of second artificial micro-structurals between the substrate in the second left substrate and second and is folded in a plurality of second artificial micro-structurals between the substrate and the second right substrate in second is 0.018mm.

4. point focusing flat-plate lens antenna as claimed in claim 3; It is characterized in that; Said first flat-plate lens also comprises and is arranged on first impedance matching layer of first core layer near feed one side surface; Said first impedance matching layer comprises the first impedance matching layer lamella that a plurality of thickness are identical; The said first impedance matching layer lamella comprises that first coupling base material of sheet and a plurality of third parties that are arranged on the first coupling base material make micro-structural, and the refraction index profile of the said first impedance matching layer lamella satisfies following formula:

$n_{i1}\left(r\right)={n_{\min }}^{\frac{i1}{m1}}*n_1{\left(r\right)}^{\frac{m1-i1}{m1}};$

Wherein, m1 representes total number of plies of the first impedance matching layer lamella;

I1 representes the numbering of the first impedance matching layer lamella, near the first impedance matching layer lamella of first core layer be numbered 1, near the m1 that is numbered of the first impedance matching layer lamella of feed, numbering increases successively from first core layer to the feed direction.

5. point focusing flat-plate lens antenna as claimed in claim 4; It is characterized in that; Said second flat-plate lens also comprises and is arranged on second impedance matching layer of second core layer away from feed one side surface; Said second impedance matching layer comprises the second impedance matching layer lamella that a plurality of thickness are identical; The said second impedance matching layer lamella comprises the second coupling base material of sheet and is arranged on a plurality of four-players of second coupling on the base material makes micro-structural, and the refraction index profile of the said second impedance matching layer lamella satisfies following formula:

$n_{i2}\left(r\right)={n_{\min }}^{\frac{i2}{m2}}*n_2{\left(r\right)}^{\frac{m2-i2}{m2}};$

Wherein, m2 representes total number of plies of the second impedance matching layer lamella;

I2 representes the numbering of the second impedance matching layer lamella, near the second impedance matching layer lamella of second core layer be numbered 1, near the m2 that is numbered of the second impedance matching layer lamella of air, numbering increases successively from second core layer to direction of air.

6. point focusing flat-plate lens antenna as claimed in claim 5; It is characterized in that; Said first the coupling base material comprise sheet first the coupling left substrate, first the coupling in substrate and first the coupling right substrate; Said a plurality of third party make micro-structural be folded in the left substrate of first coupling and first coupling between the substrate and in first coupling substrate and first mate between the right substrate; The said second coupling base material comprises substrate and the right substrate of second coupling in the left substrate of second coupling, second coupling of sheet, said a plurality of four-players make micro-structural be folded in the left substrate of second coupling and second coupling between the substrate and in second coupling substrate and second mate between the right substrate.

7. point focusing flat-plate lens antenna as claimed in claim 6; It is characterized in that; The thickness of the said first impedance matching layer lamella is 0.836mm; Wherein, the thickness of substrate is 0.4mm in first coupling, and the thickness of first left side coupling substrate and the right substrate of first coupling is 0.2mm; Being folded in a plurality of third parties between the substrate in the left substrate of first coupling and first coupling makes the thickness of micro-structural and is folded in substrate and first in first coupling and mate the thickness that a plurality of third parties between the right substrate make micro-structural and be 0.018mm; The thickness of the said second impedance matching layer lamella is 0.836mm, and wherein, the thickness of substrate is 0.4mm in second coupling; The thickness of the second left substrate of coupling and the right substrate of second coupling is 0.2mm, is folded in a plurality of four-players between the substrate in the left substrate of second coupling and second coupling and makes the thickness of micro-structural and be folded in substrate and second in second coupling and mate the thickness that a plurality of four-players between the right substrate make micro-structural and be 0.018mm.

8. point focusing flat-plate lens antenna as claimed in claim 7; It is characterized in that the arbitrary longitudinal section of said ultra material flat-plate lens is of similar shape and area, the operating frequency of said point focusing flat-plate lens antenna is 8-12GHZ; Centre frequency is 10GHZ, wherein:

The feed equivalent point is 0.23m to first flat-plate lens apart from ss;

The maximum radius r that the first surpasses sheet of material _MaxBe 0.15m, the bore of promptly said point focusing flat-plate lens antenna is 0.3m;

Total number of stories m 1 of the first impedance matching layer lamella is 6;

The total number of plies that the first surpasses sheet of material is 18;

The refractive index minimum value n that the first surpasses sheet of material _MinBe 1.469;

The focal length d0 of second flat-plate lens is 0.6m;

Total number of stories m 2 of the second impedance matching layer lamella is 4;

The total number of plies that the second surpasses sheet of material is 9;

The refractive index maximum n that the second surpasses sheet of material _MaxBe 4.2.

9. point focusing flat-plate lens antenna as claimed in claim 3; It is characterized in that the arbitrary longitudinal section of said ultra material flat-plate lens is of similar shape and area, the operating frequency of said point focusing flat-plate lens antenna is 8-12GHZ; Centre frequency is 10GHZ, wherein:

The feed equivalent point is 0.23m to first flat-plate lens apart from ss;

The maximum radius r that the first surpasses sheet of material _MaxBe 0.15m, the bore of promptly said point focusing flat-plate lens antenna is 0.3m;

The total number of plies that the first surpasses sheet of material is 21;

The refractive index minimum value n that the first surpasses sheet of material _MinBe 1.469;

The focal length d0 of second flat-plate lens is 0.6m;

The total number of plies that the second surpasses sheet of material is 11;

The refractive index maximum n that the second surpasses sheet of material _MaxBe 4.2.

10. like claim 8 or 9 described point focusing flat-plate lens antennas, it is characterized in that the longitudinal section of said ultra material flat-plate lens is square, circular or oval.

11. point focusing flat-plate lens antenna as claimed in claim 7; It is characterized in that; The said first artificial micro-structural, the second artificial micro-structural, third party make micro-structural and four-player is made all metal micro structures for being made up of copper cash or silver-colored line of micro-structural, said metal micro structure through etching, plating, brill quarter, photoetching, electronics is carved or ion is carved method respectively attached on first base material, second base material, the first coupling base material and the second coupling base material.

12. point focusing flat-plate lens antenna as claimed in claim 11; It is characterized in that; Said metal micro structure is the plane flakes; Said metal micro structure has first metal wire and second metal wire of vertically dividing equally each other, and said first metal wire is identical with the length of second metal wire, and the said first metal wire two ends are connected with two first metal branches of equal length; The said first metal wire two ends are connected on the mid point of two first metal branches; The said second metal wire two ends are connected with two second metal branches of equal length, and the said second metal wire two ends are connected on the mid point of two second metal branches, the equal in length of the said first metal branch and the second metal branch.

13. point focusing flat-plate lens antenna as claimed in claim 1 is characterized in that the inwall of said shell is provided with absorbing material.

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