CN102480063B - Offset satellite television antenna and satellite television receiving system thereof - Google Patents

Abstract

The invention discloses an offset satellite television antenna, which comprises a metamaterial panel arranged behind a feed source. The metamaterial panel consists of a core layer and a reflector, the core layer comprises at least one core layer slice layer, each core layer slice layer comprises a flaky substrate and a plurality of artificial micro-structures arranged on the substrate, each core layer slice layer can be divided into a plurality of banded areas according to distribution of refractive indexes, a fixed point is used as a circle center, the refractive indexes of positions, with identical radiuses, on the banded areas are identical, the refractive indexes on each banded area are gradually reduced along with increase of the radiuses, and in each two adjacent banded areas, the minimum refractive index of the inner-side banded area is smaller than the maximum refractive index of the outer-side banded area. The flaky metamaterial panel replaces a traditional parabolic antenna, and accordingly the offset satellite television antenna is easy in manufacture and processing and low in cost. In addition, the invention provides a satellite television receiving system comprising the offset satellite television antenna.

Description

A kind of offset-feed type satellite tv antenna and satellite television receiving system thereof

Technical field

The present invention relates to the communications field, more particularly, relate to a kind of offset-feed type satellite tv antenna and satellite television receiving system thereof.

Background technology

The satellite earth receiving station that traditional satellite television receiving system is comprised of parabolic antenna, feed, tuner, satellite receiver.Parabolic antenna is responsible for satellite-signal is reflexed to feed and the tuner that is positioned at the focus place.Feed is loudspeaker that are used for collecting satellite-signal that arrange at the focus place of parabolic antenna, claims again corrugated horn.Its major function has two: the one, the electromagnetic wave signal of antenna reception is collected, and be transformed into signal voltage, the supply high frequency head.The 2nd, the electromagnetic wave that receives is carried out polarization conversion.Tuner LNB (also claiming frequency demultiplier) carries out frequency reducing and signal with the satellite-signal that feed is sent here to amplify and then be sent to satellite receiver.Generally can be divided into C-band frequency LNB (3.7GHz-4.2GHz, 18-21V) and Ku audio range frequency LNB (10.7GHz-12.75GHz, 12-14V).The workflow of LNB is exactly to recycle local oscillation circuit after first the satellite high-frequency signals being amplified to hundreds thousand of times high-frequency signals is converted to intermediate frequency 950MHz-2050MHz, is beneficial to the transmission of coaxial cable and the solution mediation work of satellite receiver.Satellite receiver is that the satellite-signal that tuner transports is carried out demodulation, demodulates satellite television image or digital signal and audio signal.

During receiving satellite signal, parallel electromagnetic wave converges on the feed after reflecting by parabolic antenna.Usually, the feed that parabolic antenna is corresponding is a horn antenna.

But because the Machining of Curved Surface difficulty of the reflecting surface of parabolic antenna is large, required precision is also high, therefore, make trouble, and cost is higher.

Summary of the invention

Technical problem to be solved by this invention is for the defective that existing satellite tv antenna processing is difficult for, cost is high, to provide a kind of offset-feed type satellite tv antenna simple, low cost of manufacture of processing.

The technical solution adopted for the present invention to solve the technical problems is: a kind of offset-feed type satellite tv antenna, described offset-feed type satellite tv antenna comprises the super material panel that is arranged on the feed rear, described super material panel comprises core layer and is arranged on the reflecting plate of core layer one side surface, described core layer comprises at least one core layer lamella, described core layer lamella comprises the base material of sheet and is arranged on a plurality of artificial micro-structural on the base material, described core layer lamella can be divided into a plurality of belt-like zones according to refraction index profile, take a fixed point as the center of circle, the refractive index at same radius place is identical on described a plurality of belt-like zone, and the increase refractive index along with radius on each belt-like zone reduces gradually, adjacent two belt-like zones, be in the minimum value of refractive index of inboard belt-like zone less than the maximum of the refractive index of the belt-like zone that is in the outside, the line of this center of circle and feed is perpendicular to the core layer lamella, and this center of circle not with the center superposition of core layer lamella.

Further, described core layer lamella also comprises the packed layer that covers artificial micro-structural.

Further, described core layer comprises a plurality of core layer lamellas that are parallel to each other.

Further, all belt-like zones of the core layer lamella of close reflecting plate have identical variations in refractive index scope in described a plurality of core layer lamellas, and namely the refractive index of each belt-like zone all is by maximum n _MaxBe reduced to continuously minimum value n _Min

Further, the refraction index profile of the core layer lamella of close reflecting plate satisfies following formula in described a plurality of core layer lamella:

$n{\left(r\right)}_m=n_{\max }-\frac{\sqrt{r^2+s^2}-\sqrt{{(M_L+{\mathrm{seg}}_k)}^2+s^2}}{d};$

${\mathrm{seg}}_k=\sqrt{{(v_0+\mathrm{k\λ})}^2-s^2}-\sqrt{{v_0}^2-s^2};$

$k=\mathrm{floor}\left\{\frac{\sqrt{{\left(\right|r-M_L|+\sqrt{{v_o}^2-s^2})}^2+s^2}-v_0}{\mathrm{\λ}}\right\};$

$v_o=\sqrt{{M_L}^2+s^2};$

Wherein, n (r) _mRepresent that radius is the refractive index value at r place on this core layer lamella, m represents the numbering of this core layer lamella and total number of plies of core layer lamella;

S is the vertical range that feed arrives the core layer lamella close with it;

D is the thickness of core layer.

Further, the refraction index profile of other core layer lamella satisfies following formula:

$n{\left(r\right)}_j=n_{\min }+\frac{j}{m}(n{\left(r\right)}_m-n_{\min });$

Wherein, j represents the numbering of core layer lamella, and the core layer of close reflecting plate is numbered m, and to the feed direction, numbering reduces successively by reflecting plate, and the core layer lamella of close feed is numbered 1.

Further, described core layer is comprised of 7 core layer lamellas, i.e. m=7.

Further, the described center of circle is arranged on the lower limb of core layer lamella at a distance of M _LThe position on.

Further, described lower limb is straight line, described M _LThe distance of the expression center of circle and lower limb mid point.

Further, described lower limb is curve, described M _LThe distance on the expression center of circle and lower limb summit.

Further, the a plurality of artificial micro-structural shape of each core layer lamella of described core layer is identical, the a plurality of artificial micro-structural at same radius place has identical physical dimension, and the physical dimension along with the artificial micro-structural of increase of radius on each belt-like zone reduces gradually, adjacent two belt-like zones are in the minimum value of artificial micro-structural physical dimension of inboard belt-like zone less than the maximum of the artificial micro-structural physical dimension of the belt-like zone that is in the outside.

According to offset-feed type satellite tv antenna of the present invention, replaced traditional parabolic antenna by the super material panel of sheet, to make processing and be more prone to, cost is cheaper.

The present invention also provides a kind of satellite television receiving system, comprises feed, tuner and satellite receiver, and described satellite television receiving system also comprises above-mentioned offset-feed type satellite tv antenna, and described offset-feed type satellite tv antenna is arranged on the rear of feed.

Description of drawings

Fig. 1 is the structural representation of offset-feed type satellite tv antenna of the present invention;

Fig. 2 is the perspective diagram of the super material cell of a kind of form of the present invention;

Fig. 3 is the refraction index profile schematic diagram of square core layer lamella of the present invention;

Fig. 4 is the structural representation of the core layer lamella of a kind of form of the present invention;

Fig. 5 is the refraction index profile schematic diagram of semicircular core layer lamella of the present invention;

Fig. 6 is the refraction index profile schematic diagram of the core layer lamella of circle of the present invention.

Embodiment

As shown in Figures 1 to 4, the offset-feed type satellite tv antenna comprises the super material panel 100 that is arranged on feed 1 rear according to the present invention, described super material panel 100 comprises core layer 10 and is arranged on reflecting plate 200 on core layer one side surface, described core layer 10 comprises at least one core layer lamella 11, described core layer lamella comprises the base material 13 of sheet and is arranged on a plurality of artificial micro-structural 12 on the base material 13, described core layer lamella 11 can be divided into a plurality of belt-like zones according to refraction index profile and (use respectively H1 among the figure, H2, H3, H4, H5 represents), take a fixed point as the center of circle, the refractive index at same radius place is identical on described a plurality of belt-like zone, and the increase refractive index along with radius on each belt-like zone reduces gradually, adjacent two belt-like zones, be in the minimum value of refractive index of inboard belt-like zone less than the maximum of the refractive index of the belt-like zone that is in the outside, the line of this center of circle and feed 1 is perpendicular to core layer lamella 11, and this center of circle not with the center superposition of core layer lamella 11, be feed 1 not on the axis of core layer lamella 11, realized the offset-fed of antenna.Feed 1 all has stent support with super material panel 100, and among the figure and not shown support, it is not core of the present invention, adopts traditional supporting way to get final product.Feed is preferably horn antenna in addition.Among the present invention, the described center of circle is arranged on the lower limb of core layer lamella at a distance of M _LThe position on, like this, just avoided the impact of so-called feed shade, at antenna area, machining accuracy, under the identical prerequisite of receive frequency, the gain that can improve antenna.Core layer lamella 11 among Fig. 2 is square, in such cases, and described M _LThe distance of expression center of circle O1 and lower limb B1 mid point B2.Certainly, core layer lamella 11 also can be other shape, for example the described semicircle of Fig. 5.Fig. 2, shape shown in Figure 5 have a common ground, and namely its lower limb B1 is straight line, and the distance of center of circle O1 and lower limb B1 mid point Z1 is M _LCertainly, core layer lamella 11 can also be circle shown in Figure 6; Its lower limb of circle shown in Figure 6 B2 can regard one section circular arc (curve) as, and namely its lower limb B2 is curve, in such cases, and described M _LThe distance of expression center of circle O2 and lower limb B2 summit Z2, namely the distance of center of circle O2 and lower limb B2 mid point Z2 is M _LThe shape of core layer lamella can also have other shape according to different needs, can be the shape of rule, also can be irregular shape.Adopt in the situation of horn antenna M at feed _LValue and the subtended angle of horn antenna, and the angle of inclination is relevant, this can reasonably be adjusted according to different needs, the benefit of design is for so that whole core layer can both play a role certain M like this _LValue can be zero, effect may be weaker, but also can realize the present invention.In addition, among the present invention, reflecting plate is the metallic reflection plate with smooth surface, such as copper coin, aluminium sheet or the iron plate etc. that can be polishing.

As shown in Figures 1 to 4, described core layer 10 comprises a plurality of core layer lamellas 11 that are parallel to each other.A plurality of core layer lamellas 11 fit tightly, each other can be bonding by double faced adhesive tape, perhaps be fixedly connected with by bolt etc.Adjacent core layer lamella 11 also comprises packed layer 15 in addition, and packed layer 15 can air, can be other dielectric-slab also, is preferably the plate-like piece that the material identical with base material 13 made.The base material 13 of each core layer lamella 11 can be divided into a plurality of identical super material cell D, each super material cell D is made of an artificial micro-structural 12, unit base material V and unit packed layer W, and each core layer lamella 11 only has a super material cell D at thickness direction.Each super material cell D can be identical square, it can be cube, also cuboid, the length physical dimension of each super material cell D is not more than 1/5th (are generally incident electromagnetic wave wavelength 1/10th) of incident electromagnetic wave wavelength, so that whole core layer has continuous electric field and/or magnetic responsiveness to electromagnetic wave.Under the preferable case, described super material cell D is that the length of side is the cube of incident electromagnetic wave wavelength 1/10th.Certainly, the thickness of packed layer can be regulated, its minimum value can be down to 0, that is to say does not need packed layer, in such cases, base material and artificial micro-structural form super material cell, namely this moment super material cell D the thickness thickness that equals unit base material V add the thickness of artificial micro-structural, but this moment, the thickness of super material cell D also will satisfy the requirement of 1/10th wavelength, therefore, in fact, thickness at super material cell D is selected in the situation of 1/10th wavelength, and the thickness of unit base material V is larger, and then the thickness of unit packed layer W is less, certainly in the optimum situation, namely be situation as shown in Figure 2, namely the thickness of unit base material V equals the thickness of unit packed layer W, and the material of first unit base material V and packed layer W's is identical.

Artificial micro-structural 12 of the present invention is preferably metal micro structure, and described metal micro structure is comprised of one or more metal wire.Metal wire itself has certain width and thickness.Metal micro structure of the present invention is preferably the metal micro structure with isotropic electromagnetic parameter, the alabastrine metal micro structure in plane as described in Figure 2.

For the artificial micro-structural with planar structure, isotropism, refer to on this two dimensional surface with arbitrary electromagnetic wave of unspecified angle incident, the electric field response of above-mentioned artificial micro-structural on this plane is all identical with magnetic responsiveness, also is that dielectric constant is identical with magnetic permeability; For the artificial micro-structural with three-dimensional structure, isotropism refers to the electromagnetic wave for incident on three-dimensional either direction, and the electric field response of each above-mentioned artificial micro-structural on three dimensions is all identical with magnetic responsiveness.When artificial micro-structural was 90 degree rotational symmetry structure, artificial micro-structural namely had isotropic feature.

For two-dimension plane structure, 90 degree Rotational Symmetries refer to that it is overlapping with original structure perpendicular to this plane and after crossing any 90-degree rotation of rotating shaft of its symmetrical centre around one on this plane; For three-dimensional structure, if have in twos 3 rotating shafts of vertical and common intersection point (intersection point is pivot), so that this structure all overlaps with original structure behind arbitrary rotating shaft 90-degree rotation or symmetrical with an interface with original structure, then this structure is 90 degree rotational symmetry structures.

The alabastrine metal micro structure in plane shown in Figure 2 is a kind of form of isotropic artificial micro-structural, described alabastrine metal micro structure has the first metal wire 121 and the second metal wire 122 of mutually vertically dividing equally, described the first metal wire 121 two ends are connected with two the first metal branches 1211 of equal length, described the first metal wire 121 two ends are connected on the mid point of two the first metal branches 1211, described the second metal wire 122 two ends are connected with two the second metal branches 1221 of equal length, and described the second metal wire 122 two ends are connected on the mid point of two the second metal branches 1221.

Known refractive index

Wherein μ is relative permeability, and ε is relative dielectric constant, and μ and ε are collectively referred to as electromagnetic parameter.Experiment showed, when electromagnetic wave passes through refractive index dielectric material heterogeneous, can be to the large direction deviation of refractive index (to the large super material cell deviation of refractive index).Therefore, core layer of the present invention has the effect of converging to electromagnetic wave, the electromagnetic wave that satellite sends is at first by converging effect the first time of core layer, through baffle reflection, again by converging effect the second time of core layer, therefore, the refraction index profile of appropriate design core layer, can be so that the electromagnetic wave that satellite sends be successively through converging for the first time, after baffle reflection and second converges, can converging on the feed.In the selected situation of the material of the material of base material and packed layer, the electromagnetic parameter that can obtain super material internal by shape, physical dimension and/or artificial micro-structural the arranging on base material of designing artificial micro-structural distributes, thereby designs the refractive index of each super material cell.At first calculate the electromagnetic parameter spatial distribution (being the electromagnetic parameter of each super material cell) of excess of export material internal from the needed effect of super material, select the shape of the artificial micro-structural on each super material cell according to the spatial distribution of electromagnetic parameter, physical dimension (having deposited in advance multiple artificial micro-structural data in the computer), design to each super material cell can be used the method for exhaustion, for example select first the artificial micro-structural with given shape, calculate electromagnetic parameter, with the result who obtains and the contrast that we want, circulation repeatedly, till the electromagnetic parameter that finds us to want, if found, then finished the design parameter of artificial micro-structural and selected; If do not find, then change a kind of artificial micro-structural of shape, the circulation above repeating is till the electromagnetic parameter that finds us to want.If still do not find, then said process can not stop yet.That is to say the artificial micro-structural of the electromagnetic parameter that has only found our needs, program just can stop.Because this process is all finished by computer, therefore, seem complicated, in fact can finish soon.

Among the present invention, the base material of described core layer is made by ceramic material, macromolecular material, ferroelectric material, ferrite material or ferromagnetic material etc.Macromolecular material is available 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 good chemical stability, corrosion resistance, long service life.

Among the present invention, described metal micro structure is the metal wires such as copper cash or silver-colored line.Above-mentioned metal wire can be attached on the base material by etching, plating, brill quarter, photoetching, electronics is carved or ion is carved method.Certainly, also can adopt three-dimensional laser processing technology.

As shown in Figure 1, structural representation for super material panel of the present invention, all belt-like zones of the core layer lamella 117 of close reflecting plate have identical variations in refractive index scope in described a plurality of core layer lamella 11, and namely the refractive index of each belt-like zone all is by maximum n _MaxBe reduced to continuously minimum value n _Min, as an example, n _MaxCan value 6, n _MinValue 1, that is, the refractive index of each belt-like zone all is to be reduced to continuously 1 by 6.The above-mentioned refraction index profile of stating core layer lamella 117 satisfies following formula:

$n{\left(r\right)}_m=n_{\max }-\frac{\sqrt{r^2+s^2}-\sqrt{{(M_L+{\mathrm{seg}}_k)}^2+s^2}}{d}---\left(1\right);$

${\mathrm{seg}}_k=\sqrt{{(v_0+\mathrm{k\λ})}^2-s^2}-\sqrt{{v_0}^2-s^2}---\left(2\right);$

$k=\mathrm{floor}\left\{\frac{\sqrt{{\left(\right|r-M_L|+\sqrt{{v_o}^2-s^2})}^2+s^2}-v_0}{\mathrm{\λ}}\right\}---\left(3\right);$

$v_o=\sqrt{{M_L}^2+s^2}---\left(4\right);$

Wherein, n (r) _mRepresenting that radius is the refractive index value at r place on this core layer lamella, also is that radius is the refractive index of the super material cell D of r on the core layer lamella; Radius refers to the mid point of each unit base material V to the distance of center of circle O1 herein, and the mid point of unit base material V herein refers to the mid point on unit base material V and the conplane surface of center of circle O1.M represents the numbering of this core layer lamella and total number of plies of core layer lamella;

S is that feed 1 is to the vertical range of the core layer lamella 111 close with it;

D is the thickness of core layer;

In the formula, floor represents downward round numbers; K can also be used to represent the numbering of belt-like zone, when k=0, represents first belt-like zone H1; When k=1, represent second the belt-like zone H2 adjacent with first belt-like zone H1; The rest may be inferred.What belt-like zones are the maximum of r determined to have.(normally 1/10th of the incident electromagnetic wave wavelength) that the thickness of each core layer lamella is normally certain, like this, in the selected situation of core layer shape (can be cylinder or square), the size of core layer lamella just can be determined.

By formula (1), formula (2), formula (3) and the determined core layer 10 of formula (4), can guarantee that the electromagnetic wave that satellite sends converges to feed 1 place.This perhaps utilizes optical principle can obtain (namely utilizing equivalent optical path to calculate) by computer simulation emulation.

In the present embodiment, the thickness of core layer lamella 11 is certain, usually below 1/5th of incident electromagnetic wave wavelength X, and preferably 1/10th of the incident electromagnetic wave wavelength X.Like this, if operating frequency selected (being that wavelength is certain), in conjunction with the assembly space requirement of antenna, other variable in the above-mentioned formula of appropriate design just can realize that the electromagnetic wave that satellite sends converges to feed 1 place again.Antenna to optional frequency can so design, and therefore just can design the offset-feed type satellite tv antenna of any frequency that we want.For example, C-band and Ku wave band.The frequency range of C-band is 3400MHz～4200MHz.Frequency 10.7～the 12.75GHz of Ku wave band wherein can be divided into the frequency ranges such as 10.7～11.7GHz, 11.7～12.2GHz, 12.2～12.75GHz.

As shown in Figure 1, in the present embodiment, the refraction index profile of other core layer lamella satisfies following formula:

$n{\left(r\right)}_j=n_{\min }+\frac{j}{m}(n{\left(r\right)}_m-n_{\min })---\left(5\right);$

Wherein, j represents the numbering of core layer lamella, and the core layer of close reflecting plate is numbered m, and to the feed direction, numbering reduces successively by reflecting plate, and the core layer lamella of close feed is numbered 1.

In the present embodiment, as shown in Figure 1, described core layer is comprised of 7 core layer lamellas, i.e. m=7.Namely by reflecting plate to the feed direction, the refraction index profile of each core layer lamella is followed successively by:

The 7th core layer lamella: $n{\left(r\right)}_7=n_{\max }-\frac{\sqrt{r^2+s^2}-\sqrt{{(M_L+{\mathrm{seg}}_k)}^2+s^2}}{d};$

The 6th core layer lamella: $n{\left(r\right)}_6=n_{\min }+\frac{6}{7}(n{\left(r\right)}_7-n_{\min });$

The 5th core layer lamella: $n{\left(r\right)}_5=n_{\min }+\frac{5}{7}(n{\left(r\right)}_7-n_{\min });$

The 4th core layer lamella: $n{\left(r\right)}_4=n_{\min }+\frac{4}{7}(n{\left(r\right)}_7-n_{\min });$

The 3rd core layer lamella: $n{\left(r\right)}_3=n_{\min }+\frac{3}{7}(n{\left(r\right)}_7-n_{\min });$

The 2nd core layer lamella: $n{\left(r\right)}_2=n_{\min }+\frac{2}{7}(n{\left(r\right)}_7-n_{\min });$

The 1st core layer lamella: $n{\left(r\right)}_1=n_{\min }+\frac{1}{7}(n{\left(r\right)}_7-n_{\min });$

Fig. 4 is a kind of core layer lamella 11 of form, a plurality of artificial micro-structural 12 shapes of each core layer lamella 11 of described core layer are identical, be the alabastrine metal micro structure in plane, and the central point of metal micro structure overlaps with the mid point of unit base material V, the a plurality of artificial micro-structural at same radius place has identical physical dimension, and the physical dimension along with the artificial micro-structural 12 of the increase of radius on each belt-like zone reduces gradually, adjacent two belt-like zones are in the minimum value of artificial micro-structural 12 physical dimensions of inboard belt-like zone less than the maximum of artificial micro-structural 12 physical dimensions of the belt-like zone that is in the outside.Because the refractive index of each super material cell is to reduce gradually along with the size reduction of metal micro structure, therefore artificial micro-structural physical dimension is larger, then its corresponding refractive index is larger, therefore, can realize the by formula distribution of (1) of refraction index profile of core layer lamella by this mode.

According to different needs (different electromagnetic waves), and different designs needs, core layer 10 can comprise the core layer lamella 11 as shown in Figure 4 of the different numbers of plies.

In addition, the present invention also provides the present invention that a kind of satellite television receiving system also is provided, comprise feed, tuner and satellite receiver, described satellite television receiving system also comprises above-mentioned offset-feed type satellite tv antenna, and described offset-feed type satellite tv antenna is arranged on the rear of feed.

Feed, tuner and satellite receiver are existing technology, no longer state herein.

The above is described embodiments of the invention by reference to the accompanying drawings; but the present invention is not limited to above-mentioned embodiment; above-mentioned embodiment only is schematic; rather than restrictive; those of ordinary skill in the art is under enlightenment of the present invention; not breaking away from 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 (11)

1. offset-feed type satellite tv antenna, it is characterized in that, described offset-feed type satellite tv antenna comprises the super material panel that is arranged on the feed rear, described super material panel comprises core layer and is arranged on the reflecting plate of core layer one side surface, described core layer comprises at least one core layer lamella, described core layer lamella comprises the base material of sheet and is arranged on a plurality of artificial micro-structural on the base material, described core layer lamella can be divided into a plurality of belt-like zones according to refraction index profile, take a fixed point as the center of circle, the refractive index at same radius place is identical on described a plurality of belt-like zone, and the increase refractive index along with radius on each belt-like zone reduces gradually, adjacent two belt-like zones, be in the minimum value of refractive index of inboard belt-like zone less than the maximum of the refractive index of the belt-like zone that is in the outside, the line of this center of circle and feed is perpendicular to the core layer lamella, and this center of circle not with the center superposition of core layer lamella.

2. offset-feed type satellite tv antenna according to claim 1 is characterized in that, described core layer lamella also comprises the packed layer that covers artificial micro-structural.

3. offset-feed type satellite tv antenna according to claim 2 is characterized in that, described core layer comprises a plurality of core layer lamellas that are parallel to each other.

4. offset-feed type satellite tv antenna according to claim 3, it is characterized in that, all belt-like zones of the core layer lamella of close reflecting plate have identical variations in refractive index scope in described a plurality of core layer lamella, and namely the refractive index of each belt-like zone all is by maximum n _MaxBe reduced to continuously minimum value n _Min

5. offset-feed type satellite tv antenna according to claim 4 is characterized in that, the refraction index profile of the core layer lamella of close reflecting plate satisfies following formula in described a plurality of core layer lamellas:

$n{\left(r\right)}_m=n_{\max }-\frac{\sqrt{r^2+s^2}-\sqrt{{(M_L+{\mathrm{seg}}_k)}^2+s^2}}{d};$

${\mathrm{seg}}_k=\sqrt{{(v_0+\mathrm{k\λ})}^2-s^2}-\sqrt{{v_0}^2-s^2};$

$k=\mathrm{floor}\left\{\frac{\sqrt{{\left(\right|r-M_L|+\sqrt{{v_o}^2-s^2})}^2+s^2}-v_0}{\mathrm{\λ}}\right\};$

$v_o=\sqrt{{M_L}^2+s^2};$

Wherein, n (r) m represents that radius is the refractive index value at r place on this core layer lamella, and m represents the numbering of this core layer lamella and total number of plies of core layer lamella;

S is the vertical range that feed arrives the core layer lamella close with it;

D is the thickness of core layer;

λ is the incident electromagnetic wave wavelength;

Floor represents downward round numbers;

The described center of circle is arranged on the lower limb of core layer lamella at a distance of M _LThe position on.

6. offset-feed type satellite tv antenna according to claim 5 is characterized in that, the refraction index profile of other core layer lamella satisfies following formula:

$n{\left(r\right)}_j=n_{\min }+\frac{j}{m}(n{\left(r\right)}_m-n_{\min });$

Wherein, j represents the numbering of core layer lamella, and the core layer of close reflecting plate is numbered m, and to the feed direction, numbering reduces successively by reflecting plate, and the core layer lamella of close feed is numbered 1.

7. offset-feed type satellite tv antenna according to claim 6 is characterized in that, described core layer is comprised of 7 core layer lamellas, i.e. m=7.

8. offset-feed type satellite tv antenna according to claim 6 is characterized in that, described lower limb is straight line, described M _LThe distance of the expression center of circle and lower limb mid point.

9. offset-feed type satellite tv antenna according to claim 6 is characterized in that, described lower limb is curve, described M _LThe distance on the expression center of circle and lower limb summit.

10. according to claim 2 to the described offset-feed type satellite tv antenna of 9 any one, it is characterized in that, the a plurality of artificial micro-structural shape of each core layer lamella of described core layer is identical, the a plurality of artificial micro-structural at same radius place has identical physical dimension, and the physical dimension along with the artificial micro-structural of increase of radius on each belt-like zone reduces gradually, adjacent two belt-like zones are in the minimum value of artificial micro-structural physical dimension of inboard belt-like zone less than the maximum of the artificial micro-structural physical dimension of the belt-like zone that is in the outside.

11. satellite television receiving system, comprise feed, tuner and satellite receiver, it is characterized in that described satellite television receiving system comprises that also described offset-feed type satellite tv antenna is arranged on the rear of feed such as the described offset-feed type satellite tv antenna of claim 1 to 10 any one.

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