CN1016029B - Plate-type broad-band microwave antenna with reflecting surface - Google Patents

Abstract

The present invention belongs to a flat plate type microwave antenna which comprises a reflector which is composed of a feedback source, a feedback source support rod, an antenna support frame and a plurality of annular rotary paraboloid reflecting surfaces of M<0>, M<1>, M<2> to M<m> which are distributed in a concentric, radial and discrete mode, wherein the outer margins of the reflecting surfaces are all positioned in the same plane; the optical path difference delta p<m> of two adjacent reflecting surfaces is orderly equal to the wavelengths of lambada <max>, lambada-<2>, lambada<3> to lambada<m-1> and lambada<min> in the range of a required working band and follows the logarithm periodic law of delta p<m> = lambada - <max>t + <m-1>. The present invention solves the problems of narrow working band, large volume, complicated manufacture technology, high cost, etc. of the existing flat plate type microwave antenna.

Description

Plate-type broad-band microwave antenna with reflecting surface

The invention belongs to a kind of microwave antenna with reflecting surface, the microwave antenna of being made up of a plurality of different parabolical reflectings surface particularly, it comprises: feed, feed pole, antenna holder and a plurality of with one heart and be the radially ring-type cutting rotation parabolic reflector of discrete distribution.

Antenna in the microwave regime extensive use is the rotation paraboloidal-reflector antenna at present, gain is high though this antenna has, advantages such as main lobe is narrow, secondary lobe is low, bandwidth, but because of its requirement on machining accuracy height, complex manufacturing technology, use the reason of metal material and vpg connection more, make that antenna volume and weight are big, cost is very high, give transportation, install and bring a lot of inconvenience, and often because of alignment error and the stress that deadweight is produced easily make antenna deformation, gain reduces.For this reason, the antenna industry all substitutes it at a kind of tabular antenna of effort research always both at home and abroad, as dielectric lens antenna, Fresnel zone plate antenna, many layered transducer elements formula plate aerial, but all former thereby can not practicality because loss is big, gain is low, frequency band is narrow etc.The microstrip antenna that proposes of someone is also former thereby can not be promoted the use of because main lobe is wide, weight is big, cost is expensive and can only be used for receiving etc. in recent years.

Chinese patent 86 2 11074U disclose the parabolic plate shaped satellite ground station antenna of a kind of many focal lengths, from the specification of this application file and claims, can see, this antenna is to adopt the circular parabolic reflector band of different-diameter radially to arrange in the concentric circles mode, each annulus is in together on the plane, and the difference of its focal length is the integral multiple of operation wavelength.Though this is a new idea to antenna panelization, has certain progressive meaning, but still there are following three substantial drawback: when (one) is the integral multiple of operation wavelength when the focus difference of each ring-type parabolic reflector band, this just determines this antenna setting the effect that has convergence and same-phase stack on the electromagnetic wave operation wavelength, when operation wavelength changes, because of the size of antenna can not change, cause wave path-difference to change and can not realize same-phase stack again, and produce dispersion phenomenon on the contrary, this just determines that this antenna can only be the arrowband, can not satisfy to receive the required bandwidth 500MH of C-band signal _ZRequirement; (2) theoretically, the interior outer rim of opposing band when each ring-type is parabolic on same plane, when the difference of its focal length is the integral multiple of a certain operation wavelength, will leave bigger neutral gear between each zone of reflections everywhere, and antenna gain is significantly reduced.In other words, under the prerequisite that guarantees antenna gain, when outer rim in all zones of reflections is everywhere on same plane, can not make the electromagnetic wave that shines on these zones of reflections all converge on the focus again; (3) its theoretic throat δ=λ, thereby make reflector thickness bigger, antenna volume, weight increase.

The objective of the invention is to overcome above-mentioned the deficiencies in the prior art part and provide that a kind of cost is low, thin thickness, bandwidth, the high tabular microwave antenna of gain.

Purpose of the present invention can reach by the following technical programs: a kind of plate-type broad-band microwave antenna with reflecting surface comprises feed and pole thereof, antenna holder and with a plurality of with one heart ring-type of discrete distribution cutting rotation parabolic reflector M radially ₀, M ₁, M ₂M _mThe reflector of forming, key of the present invention are that the outer rim of above-mentioned ring-type cutting rotation parabolic reflector is in the same plane, the optical path difference △ ρ of its adjacent two reflectings surface _mEqual antenna successively and require the interior wavelength of working band scope , λ ₂, λ ₃λ _M-1, λ _Min, and follow logarithm period rule △ ρ _m= τ ^M-1

Common rotation parabolic reflector, when electromagnetic wave after feed is assembled, because all electromagnetic optical path differences equal zero all the time, so can make the electromagnetic wave of any frequency all produce the same-phase stack at the feed place.When reflecting surface becomes a plurality of ring-type cutting rotation parabolic reflector M with concentric radially discrete distribution ₀, M ₁, M ₂M _mThe time, will produce an optical path difference △ ρ between each reflecting surface, how can make electromagnetic wave converge to common focus through these reflectings surface, be to continue stack behind the feed, a kind of way is to make the optical path difference of each reflecting surface just in time equal the integral multiple of a certain wavelength, but this electromagnetic wave that can only guarantee this wavelength produces synchronous stack at the feed place, and when electromagnetic wavelength changes, because the size of antenna can not change, thereby the optical path difference of each reflecting surface is also constant, just can not guarantee that so also each road electromagnetic wave all produces the same-phase stack at the feed place, may produce chromatic dispersion on the contrary, so this antenna can only be just useful in a very narrow frequency band range.If we can make each reflecting surface in certain working frequency range scope

～λ _MinIn the electromagnetic wave that reflected converge to feed can basic homophase and average phase-difference very little, the working band width that this had just both guaranteed antenna has guaranteed the gain of antenna again.

Rule according to calculating and logarithm periodic antenna can prove, as the optical path difference △ ρ that gets each reflecting surface _mEqual antenna successively and require the interior wavelength of working band scope

, λ ₂, λ ₃λ _M-1, λ _Min, and meet logarithm period rule △ ρ _m=λ _Moxτ ^M-1The time, then can satisfy above-mentioned requirements.

In order to make antenna panelization, the upper limb of getting each reflecting surface in one plane can obtain tabular antenna reflective face shown in Figure 1 in view of the above.

As shown in Figure 1:

t _m+BC＝△ρ _m＝λ _m

Be t _m+ t _m/ cos θ _m=△ ρ _m

t _m＝△ρ _m/（1+secθ _m）

t ₁＝△ρ ₁/（1+secθ ₁）＝ /（1+secθ ₁）

By following formula as can be known, work as θ ₁→ 0 o'clock, sec θ ₁→ 1, t ₁→

/ 2.t _mMaximum

/ 2 is exactly M ₀Central depths AO, i.e. AO= / 2, the theoretic throat δ of Here it is antenna= / 2.Utilize same process also can prove the theoretic throat δ=λ of CN 86 2 11074 antennas.Obviously

/ 2 is more much smaller than λ, that is to say that antenna ratio CN 86 2 11074 antennas of the present invention are much thin.

If the operating frequency of antenna is f _Min～

, corresponding wavelength is

～λ _Min; The bore of antenna is D; The feed illumination angle theta _MBe α ₁～α ₂,, generally select one near lower limit α for emphasizing antenna gain ₁Numerical value α _b, i.e. θ _M=α _b

Then: antenna thickness δ=AO=λ _Mox/ 2

F ₀-δ＝D/2/tgθ _M

Foveal reflex face focal length F ₀=D/2tg α _b+ λ _Mox/ 2

Adjacent reflecting surface optical path difference △ ρ _m=λ _Moxτ ^M-1

Each reflecting surface focal length of antenna $F_m\mathrm{=F}{}_o+\underset{\mathrm{m=1}}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\Delta \rho }}_m\mathrm{/2}$

The antenna reflective face polar equation is:

${\rho }_m\mathrm{=2F}{}_m\mathrm{/(1+cos\theta )=2(F}{}_o+\underset{\mathrm{m=1}}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\Delta \rho }}_m\mathrm{/2)/(1+cos\theta )=(2F}{}_o+\underset{\mathrm{m=1}}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\Delta \rho }}_m\mathrm{)/(1+cos\theta )}$

At each reflecting surface outer rim place, ρ is arranged _m=(F ₀-δ)/cos θ _m

Can get according to the reflecting surface polar equation:

${\rho }_m\mathrm{=(2F}{}_o+\underset{\mathrm{m=1}}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\Delta \rho }}_m\mathrm{)/(1+cos\theta }{}_m)$

Last two formula simultaneous get:

${\theta }_m\mathrm{=sec}{}^{\mathrm{-1}}{\mathrm{［（2F}}_0＋\underset{\mathrm{m=1}}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\Delta \rho }}_m\mathrm{)/(F}{}_0\mathrm{-\delta )-1］}$

As θ=θ _MThe time, have ${\rho }_M\mathrm{=(2F}{}_0+\underset{\mathrm{m=1}}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\Delta \rho }}_m\mathrm{)/(1+cos\theta }{}_M)$

Physical dimension by antenna also can be tried to achieve ρ _M'=(F ₀-δ)/cos θ _M

Obtain the polar equation of antenna reflective face, just must determine △ ρ _m, and calculate △ ρ _m, just must determine N value and τ value.

Because △ ρ _m=λ _Moxτ ^M-1, λ is arranged when m=N _Min=λ _Moxτ ^N-1

Make B=λ _Mox/ λ _Min=λ _Mox/ λ _Moxτ ^N-1=τ ^1-N

lgB＝（N-1）lg（1/τ）

∴N＝1+lgB/lg（1/τ）

Obviously, τ be one less than 1 positive number, when B one regularly, its value is big more, △ ρ _mThe speed of successively decreasing is slow more, and the N value just obtains big more, and promptly the number of rings of antenna increases; The τ value is more little, △ ρ _mThe speed of successively decreasing is accelerated, and the N value just diminishes, and promptly the number of rings of antenna reduces.

In general, set earlier τ, calculate N, and then, calculate N ring and can fill up bore, through accounting repeatedly, till both coincide substantially by the caliber size of antenna by τ and B value.Generally be to calculate relatively ρ _MWith ρ _MThe size of ' value is worked as ρ _M≈ ρ _M' time, just think that selected τ, N value are suitable, with last N and the τ value of determining, calculate △ ρ _m, △ F _m, t _m, θ _mAnd the reflecting surface curvilinear coordinate value of antenna, again in conjunction with the thickness δ of antenna and the focal length F of foveal reflex face ₀, can make the reflecting surface of antenna.

In general, λ _Mox, λ _MinChoosing of value is to determine according to the upper and lower limit of the beamwidth of antenna fully, but sometimes can be according to the experiment test result, and small adjustment is done in the requirement of contrast bandwidth and gain.

These according to the logarithm period rule along concentric ring-types of discrete distribution cutting rotation parabolic reflector radially, when outer rim all is positioned at a plane, though inner edge is not in the plane but its degree of depth t fully _mWith radially increasing and shoal, but all each reflectings surface all are within the parallel-plate, and this dull and stereotyped thickness δ equals foveal reflex face M ₀The degree of depth, δ=λ _Mox/ 2, its value is generally very little.

On all each reflectings surface tabular base material that to place a thickness be δ, make the fluctuating on its surface identical with reflecting surface, between face and the face transition face of reflection electromagnetic wave not, the tabular antenna reflector that then can to obtain a theoretic throat be δ.Inside as the tabular base material that each reflecting surface is placed a thickness fully is δ; then can obtain a complete parallel tabular antenna reflector; so not only transportation, folding convenient, but also can protect reflecting surface not to be out of shape, to go bad, to wear out by erosions such as wind, rain and dust.The following lower floor's base material of reflecting surface and transition face can be by light weight, deformation is little, inexpensive, and the material that intensity is bigger is made, form as compactings such as plastics, timber, hard foams, the above base material of reflecting surface and transition face can by transparent to electromagnetic wave, be refractive index level off to 1 and the material of lighter weight make, as polyurethane hard foam, fiberglass etc.Also can protect as glass fibre reinforced plastics casing there not being the reflecting surface of upper strata base material to reinstate one to the transparent hard material of electromagnetic wave together with lower floor's base material one.

Reflector can be by making thin metal layer, the substrate surface that is attached to press forming as aluminium foil, also can be by making at substrate surface spray applying metal thin layer.

This tabular antenna can be made two, and three or several piece connect with hinge or other mechanism therebetween, be beneficial to folding and transportation, the support of antenna can be with common fixed support, and also available common band is adjusted the support of A﹠E azimuth and elevation, the also available antenna holder that can fold.

Accompanying drawing drawing of the present invention is described as follows:

Fig. 1 is a reflecting surface principle schematic of the present invention;

Fig. 2 is a C-band satellite earth antenna outside drawing that adopts the present invention to make;

Fig. 3 is the structure chart of this C-band satellite earth antenna reflector.

As shown in Figure 1, this invention has m the ring-type cutting rotation parabolic reflector 1 with concentric radially discrete distribution, and the centre of reflecting surface is the rotation parabolic reflector 2 that a degree of depth is δ, and this reflecting surface 2 is foveal reflex face M ₀, its focal length is F ₀, between the reflecting surface transition face 3 of not reflection electromagnetic wave, the optical path difference △ ρ between adjacent two reflectings surface _m=λ _Moxτ ^M-1

Fig. 2, Fig. 3 adopt the present invention and a C-band satellite antenna making.The operating frequency f of antenna is 3.7～4.2GH _Z, corresponding wavelength λ is 8.108～7.143cm, λ _Mox=8.108cm, λ _Min=7.143cm; The bore D=3 rice of antenna; The feed illumination angle theta _MBe 50～60 °,, get a lower limit θ for emphasizing the gain of antenna _M=52.3 °.Adopt above data, can calculate according to the present invention:

Antenna thickness δ=

/ 2=8.108/2 ≈ 4.1cm

Foveal reflex face focal length F ₀=D/2/tg θ _M+ δ=150/tg52.3 °+4.1

≈120cm

Bandwidth B=1.135

Through adjusting repeatedly and can getting: during as τ=0.9843, n=9,9 cyclic groups originally fill up 3 meters bores.3 meters of actual specific are more bigger, and at this moment two kinds of processing methods are arranged, and a kind of is to satisfy the bore requirement, and the 9th reflecting surface deducted redundance; Another kind is that antenna aperture D is slightly enlarged a bit, does by the actual size of the 9th reflecting surface.

Optical path difference △ ρ ₁～△ ρ ₉Be respectively: 8.108cm, 7.981cm, 7.855cm, 7.732cm, 7.611cm, 7.491cm, 7.374cm, 7.258cm, 7.144cm.

Focus difference △ F ₁～△ F ₉Be respectively: 4.054cm, 3.990cm, 3.928cm, 3.866cm, 3.805cm, 3.746cm, 3.687cm, 3.629cm, 3.572cm.

θ ₁～θ ₉Be respectively: 28.759 °, 34.234 °, 38.476 °, 41.925 °, 44.817 °, 47.292 °, 49.443 °, 51.335 °, 53.016 °.

t ₁～t ₉Respectively: 3.788cm, 3.612cm, 3.449cm, 3.299cm, 3.159cm, 3.028cm, 2.906cm, 2.791cm, 2.683cm.

The coordinate figure of the reflecting surface of asking according to the above rectangular equation of asking data, reflecting surface polar equation or being converted into can be made the reflecting surface of this C-band antenna.

Referring to Fig. 2 as can be known, this antenna is made up of support 4, reflector 5, feed 6 and feed pole 7, reflector 5 constitutes by three, two reflectors of outside link to each other with the reflector of centre by hinge, can fold in case of necessity, and middle reflector is installed on the support 4, support 4 can fold, and can rotate by a rotating mechanism 13 of bottom, feed 6 is over against the reflector center and be in the reflector focus, is fixed on the reflector by a feed pole 7 of inserting the reflector center.

Referring to Fig. 3, the reflector of this antenna has lower floor's base material 8 that a polyurethane hard foam compacting forms, and posts a center rotation parabolic reflector M who makes with aluminium foil on the surface of lower floor's base material 8 ₀With 9 ring-type cutting rotation parabolic reflectors 9; between adjacent two reflections is the transition face 10 of not reflection electromagnetic wave; on reflecting surface 9 and transition face 10, be coated with the upper strata base material made from the polyurethane hard foam 11; the outside at upper and lower layer base material is surrounded by a containment vessel 12 made from fiberglass, has so just constituted a complete parallel tabular antenna reflector.Because fiberglass and hard foam all are transparent materials to electromagnetic wave, loss is very little, so do not influence metal aluminum foil to electromagnetic converging action.The effect of upper strata base material and fiberglass is to protect reflecting surface not by extraneous weathering, erosion, can not be out of shape and help folding and transportation.

In conjunction with above embodiment as can be seen, the present invention has following advantage compared to existing technology:

1, makes the optical path difference △ ρ of each reflecting surface _mChange with the logarithm period rule, the gain that not only can guarantee antenna is about single port and directly rotates 75～85% of paraboloidal-reflector antenna, but also can guarantee the working band width of antenna.

2, make the upper limb of each reflecting surface be in same plane, can make the theoretic throat δ of this antenna only be λ _Mox/ 2, therefore have higher (gain/thickness) ratio, littler volume, lighter weight.Help folding, transport and install, debug.

3, because this antenna volume, weight are very little, and manufacture craft is fairly simple, and can adopt cheap nonmetallic materials, thereby cost is greatly lowered, only be to rotate 1/3～1/5 of parabolic reflector with bore.

4, adopt the antenna of made of the present invention, not only can be used as collection of letters antenna, also can be used as transmission antenna and radar, communication, radio astronomy antenna simultaneously.Provide possibility for making high radar, the communication equipment of mobility.

Claims (4)

1, a kind of plate-type broad-band microwave antenna with reflecting surface comprises feed, feed pole, antenna holder and with a plurality of ring-type of discrete distribution cutting rotation parabolic reflector M radially with one heart ₀, M ₁, M ₂M _mThe reflector of forming, the outer rim of described ring-type cutting rotation parabolic reflector is all in the same plane, it is characterized in that: the optical path difference △ ρ of adjacent two reflectings surface _mEqual antenna successively and require the interior wavelength X of working band scope _{M σ x}, λ ₂, λ ₃... λ _M-1, λ _Min, and follow logarithm period rule △ ρ _m=λ _Maxτ ^M-1

2, plate-type broad-band microwave antenna with reflecting surface according to claim 1 is characterized in that: the optical path difference △ ρ of described adjacent two reflectings surface _mEqual the C-band antenna successively and require working band scope interior wavelength 8.108cm, λ ₂, λ ₃λ _M-1, 7.143cm.And follow logarithm period rule △ ρ _m=8.108 τ ^M-1

3, plate-type broad-band microwave antenna with reflecting surface according to claim 1 and 2 is characterized in that: described reflector is a complete parallel tabular reflector that comprises upper strata base material, lower floor's base material and base material outside containment vessel.

4, plate-type broad-band microwave antenna with reflecting surface according to claim 3 is characterized in that: described upper strata base material is to be made by the polyurethane hard foam, and described containment vessel is to be made by fiberglass.

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