CN1053767C

CN1053767C - Single parabolic C wave band antenna deflection focusing receiving special-purpose feed

Info

Publication number: CN1053767C
Application number: CN 94106845
Authority: CN
Inventors: 张天林; 张天彬
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-06-24
Filing date: 1994-06-24
Publication date: 2000-06-21
Anticipated expiration: 2014-06-24
Also published as: CN1098562A

Abstract

The present invention relates to a feed source for an antenna system, which is designed for compensating that a gain value of the defocusing position of a single antenna descends more when in multi-satellite reception. The reflecting surface of the feed source of the present invention is a spherical reflecting surface which can focus a part of defocus energy nearby an aperture surface. From a circular waveguide terminal port in a feed source tube to a circular waveguide port is in a horn shape in the vertical height of 4.3cm, the diameter of the circular waveguide terminal end is 6.9cm, and the diameter of the circular waveguide port is 5.8cm. The reflecting surface of the feed source is changed into a structure corresponding to an LNB square waveguide port by circular-square transition. The embodiment feed source receives interval satellite signals of angles of (+/-) 10 DEG in a parabolic antenna of which the phi is three to five m and the F/D is 0.38, and a total gain value can be compensated to more than 1.5dB.

Description

The single parabolic C wave band antenna deflection focusing receiving special-purpose feed

The present invention relates to a kind of antenna element, relate to a kind of single parabolic C wave band antenna deflection focusing receiving special-purpose feed that can receive the multiple satellite tv signal simultaneously or rather.

In recent years, the satellite television application of China had obtained vigorous growth, and applied satellite enabling one by one increased program source, greatly improved diversity, popularization and the coverage of China's various places TV programme.How to receive the TV programme of more a plurality of channels under existing condition, this also is a problem of big audience common concern.At present, the communication satellite capacity that China is using is less, and existing programme channel, communication channel are had to be arranged in respectively several satellites that are in the overhead diverse location in equator and transmitted respectively.The employed satellite earth antenna of ground recruiting unit can only be satellite of one pair of antenna alignment, as receiving the program of other satellites again, has only to increase new antenna again.The C-band frequency that China now uses, its corresponding effective isotropic radiated power EIRPS value is less, so the size of reception antenna is all bigger, bore is generally about 3 meters, thereby taken the major part investment in the satellite television single receiving station equipment, the space that occupies greatly of antenna size is also big in addition, has also brought and has installed and the fixing new problem of aspect, increased installation difficulty, therefore general unit is difficult to realize installing the planning that many antennas receive the multiple satellite tv program.

What satellite earth antenna used is the paraboloid of revolution made from metallic plate or wire netting, and the faint electromagnetic wave that satellite is transmitted focuses on the place, focal position, to improve the electromagnetic intensity of acceptance point, improves gain.For same pair of parabolic antenna, the position of optimum focusing, maximum gain is at the focus place, receiving for C-band is the waveguide mouth place, garden that electromagnetic wave energy is concentrated on φ=6cm, depart from out prime focus, focusing effect variation and gain descend, but if can obtain sufficiently high field intensity, satisfy practical the requirement and also can select for use, so the requirement to satellite earth antenna is so strict not as the imaging of optics concave mirror in the practical application.

Burnt partially technology is the technology of extensive use in the scanning radar, facts have proved, it also is practicable being applied in the satellite television reception.Burnt partially technology in the scanning radar technology is to utilize to move same feed on the focal plane, make and be operated in receipts, under the state of sending out, in fact, receiving, under the state of sending out, what the electromagnetic field distribution neither be symmetrical fully near the feed actinal surface, only be used under single condition of receiving at antenna, its best burnt partially position be used for receiving, situation under the state of sending out is slightly different, the single receipts do not resemble transmitting-receiving yet, the such strictness that requires, as considering sidelobe performance, as long as smooth in the 500MHZ bandwidth, obtain the big gain of trying one's best, the vision signal signal-noise ratio (not weighting) that is received can reach 32-40dB in practicality, can satisfy the reception requirement of different occasions, therefore burnt partially reception technique has wide practical value in satellite television single receiving station.

Adopt the regular parabolic antenna, feed is installed respectively, can receive the signal that several stationary satellites are transmitted simultaneously, realize that the many stars of single antenna receive in its main Jiao, burnt partially position.But because efficient will reduce during burnt partially reception, reduce value and antenna aperture, burnt directly relevant than various factorss such as F/D, satellite angles, with regard to the antenna of F/D ≈ 0.38 commonly used at present, the general antenna that uses the 3M-5M diameter, the inter-satellite angle approaching ± during 10 ° of left and right sides, then yield value descends too much, loses Practical significance thereby many stars are received.

The objective of the invention is to design a kind of C-band single parabolic antenna deflection focusing receiving special-purpose feed, use this feed, the decline of compensating gain value when can be in the satellite drift angle big, receive the subtended angle scope thereby enlarge burnt partially application of parabolic antenna, designed feed also should be able to be suitable for the antenna of all size.

C-band parabolic antenna deflection focusing receiving special-purpose feed of the present invention constitutes by reflecting surface with feed tube, ring flange that reflecting surface is connected as a single entity, it is characterized in that; Described reflecting surface is part can be defocused near the spherical reflector of the concentration of energy bore face; The circular waveguide port is to the short loud-speaker shape that is the bore gradual change between the circular waveguide mouth in the described feed tube; Described circular waveguide port bore φ is 6.9cm, and circular waveguide mouth bore is 5.8cm, and circular waveguide port to the vertical height between the circular waveguide mouth is 4.3cm.

There is 1-2 ladder to cross ripple in the circular waveguide district in the described feed tube.

According to the electromagnetic field principle, circular waveguide bore φ when being used for C-band and receiving is advisable about with 6cm, be used for when partially burnt, the energy at actinal surface place is more diffusing, chooses bigger bore face under possible situation as far as possible, then can collect more energy, the present invention selects the bore face of 6.9cm, short transition time through 4.3cm goes to the circular waveguide that bore is 5.8cm, again through the transition of circle side, becomes the square wave guide structure of corresponding LNB (being commonly called as tuner).

The present invention is by designing the higher feed tube of the burnt partially efficient of bore and choosing the less actinal surface of acutance, to reduce transverse current; And the spiral reflecting surface that routine is used is improved to spherical reflecting surface, at the antenna of different F/D and D value, spherical reflecting surface parameter difference, the concentration of energy that a part is defocused is near the bore face, the decline of the burnt partially gain of compensation is particularly suitable for the bigger antenna of bore.

Further specify technology of the present invention below in conjunction with embodiment and accompanying drawing;

Fig. 1 receives schematic diagram for parabolic antenna

Fig. 2 is the focus characteristics of directional light by spherical reflecting surface

Fig. 3 is the feed perspective view

Fig. 4 is the main sectional structure chart of feed tube among Fig. 3

Fig. 5 is each feed tube top view structure chart among the figure

Fig. 6 is a feed reflecting surface plane graph among Fig. 3

Fig. 7 partly cuts open structure chart for feed reflecting surface among Fig. 3

Fig. 8 is spherical reflecting surface focusing principle figure

Fig. 9 is the half sectional view of feed among Fig. 3.

Figure 10 is installed in structural representation on the parabolic antenna for feed.

Referring to Fig. 1, in the microwave antenna technical research, normal nationality helps the electromagnetic field principle of reciprocity, and analyzing reflection properties and directional diagram wait to determine receiving feature, but only consider that burnt partially reception of receiving feature is difficult to adopt the said method analysis.

Parabolic antenna shown in Fig. 1 receives schematic diagram, when corresponding main Jiao of curve A receives, and the intersection of parabolic antenna and vertical plane; The intersection of parabolic antenna and vertical plane during corresponding Jiao partially of curve B reception, curve A is a standard parabolic upper thread, it can guarantee that parallel beam converges to feed F place, though curve B is a standard parabola, because feed is not in main burnt position, F sees curve B from feed, its parabola that is equivalent to be out of shape then, and it is a point that parallel wave no longer converges through its reflection.

Referring to Fig. 2, directional light is by the focus characteristics of spherical reflecting surface, L is equivalent to the position of focal plane among the figure, and parallel incident ray is focused on two lines of S and T after reflection, ray intersection is on the T line in vertical plane is section RAJE, light in horizontal plane or sagittal plane JAKE then will intersect on the S line, move to minute surface from E if resemble screen, then resemble to become vertical line at the S place, become disk at the L place, become horizontal line at the T place.The position of T and S can be calculated with relevant formula.

Parabolic burnt partially the reception has similar characteristic to spheric reflection, and only paraboloidal burnt partially convergent point is more diffusing, and the calculating of position is more complicated.

For F/D=0.38 parabolic antenna commonly used, when being used in the reception of C-band, reflector precision is required not really high, it is suitable with spherical reflecting surface to think that paraboloidal center accounts for 40% part, and marginal portion and sphere differ gradually big.If inclined to one side Jiao of parabolic antenna is regarded as two parts, promptly a part is the burnt partially reception of sphere, by means of concerning among the figure, determines diapoint; Another part is to be out of shape bigger marginal portion, determines to defocus the position by means of formula and image method, can determine to defocus characteristic.

Above-mentioned branch folding shows, though defocus during burnt partially the reception, but energy distributions is not irregular, but concentrate on relatively near several points, if can try every possible means the diffusing energy from the feed mouth of a part is concentrated on the actinal surface place again, and has identical phase place, the problem of energy decreases in the time of promptly can remedying burnt partially the reception.

Referring to Fig. 3, Fig. 9, many stars receive the efficient burnt partially feed of single parabolic antenna by reflecting surface 1, and feed tube 2 and ring flange 3 combination of entities constitute, and ring flange 3 is one-body molded with feed tube 2, and reflecting surface 1 is fixed with feed tube 2 coaxial inside and outside suits.

Shape and portion size referring to the embodiment of feed tube shown in Fig. 4, Fig. 5, the figure.

Among Fig. 4,2 is the feed tube, and 21 is garden waveguide port (garden waveguide mouth), and 22 is pairing bore face, and 23 is the ladder transition.

According to the electromagnetic field principle, the circular waveguide bore when C-band receives should be chosen about φ=6.0cm and be advisable, and the energy that is used for actinal surface place when partially burnt is more diffusing, then can collect more energy if choose bigger bore face under possible condition as far as possible.

The present invention is through a large amount of experiments, choose the bore face of φ=6.9cm, the port wall thickness is less than 1mm, and port surface is sharp-pointed, go to the circular waveguide of φ=5.8cm from the tubaeform transition of about 4.3cm of a weak point of port surface arrangement, become the square wave guide mouth structure of corresponding LNB again through the transition of circle side.Feed tube circular waveguide has ladder in the district, is generally 1-2, is two ladders shown in the figure, can be clear that this circle side transition structure from the top plan view of Fig. 5.

Referring to Fig. 6 to Fig. 8, in the time of can thinking burnt partially the reception according to aforementioned principles, focus no longer is one, but each is a series of in front and back, the centre is the optimum position, and the concentration of energy of supposing to defocus is respectively prefocusing center and back focusing center at T shown in Figure 8, S 2 points, now design a curved surface, it should be able to satisfy following 3 conditions;

1. the T point as point in kind, make it after spheric reflection, can be imaged on waveguide actinal surface edge, the diapoint that is about to T point position is regarded the fusiformis object point as, makes it present the real image that dwindles after reflection in the actinal surface place;

2. from object point through spheric reflection to picture point, the distance of process should be the integral multiple of wavelength;

3. the S point should be regarded a virtual object point as, and it again through spheric reflection, can concentrate its energy through feed tube external cylindrical surface reflection (being equivalent to the face reflection) to the actinal surface place as far as possible.

Shape and each several part size from the spherical reflecting surface shown in Fig. 6, Fig. 7 it should be noted, for the different antennas different with bore D of F/D, the shape and the position of spherical reflecting surface are slightly different, need to set respectively by above-mentioned three conditions.

When using small aperture antenna, because the main lobe width broad, when burnt partially, the gain drop-out value is less, so the effect that small aperture antenna uses burnt partially special-purpose feed reflecting surface is obvious not as big antenna, when on the antenna of φ=3.2 meter, using, the big 0.4-0.5dB of comparable general ripple reflecting surface yield value.

Referring to Figure 10, Figure 10 illustrates the parabolic antenna structure that main feed and offset-fed are installed, and 91 is parabolic antenna among the figure, and 92 is the main feed feed, and 93 is the offset-fed feed.

All introduce the relation curve of the multiple that burnt partially gain drop-out value and main lobe angle are arranged in the theory textbook of general microwave antenna, and burnt footpath is faster than little decline, by these curve calculatings, parabolic antenna for F/D=0.38, φ=3.2 meter, receive ± 10 ° satellite-signal, yield value about 4.7dB that descends for the antenna of φ=4.5 meter about 9.6dB that then descends, we can say and not have Practical significance.The antenna-feedback system that uses feed source device of the present invention to constitute can reach following index but under these conditions.

Satellite position	F/D 0.38
	F/D 0.38		3.2 rice	4.5 rice
	± 10 ° of burnt partially drop-out values	-3dB	3.2 rice	4.5 rice	-4.5dB

The embodiment feed is at φ=3.0-5, and 0 meter, in the parabolic antenna of F/D=0.38, when receiving the satellite-signal of ± 10 ° of angular spacings, to compare with general feed, the overall gain value can compensate more than the 1.5dB.

Claims

1, a kind of C-band single parabolic antenna deflection focusing receiving special-purpose feed is made of the reflecting surface that is connected as a single entity, feed tube, ring flange, it is characterized in that; Described reflecting surface is part can be defocused near the spherical reflector of the concentration of energy bore face; The circular waveguide port is tubaeform to the weak point that is the bore gradual change between the circular waveguide mouth in the described feed tube; Described circular waveguide port bore φ is 6.9cm, and the port wall thickness is less than 1mm, and circular waveguide mouth bore is 5.8cm, and circular waveguide port to the vertical height between the circular waveguide mouth is 4.3cm.

2, C-band single parabolic antenna deflection focusing receiving special-purpose feed according to claim 1 is characterized in that: in the circular waveguide district 1-2 ladder transition arranged in the described feed tube.