CN102136634B

CN102136634B - Ku/Ka frequency band circularly polarization integrated receiving and transmitting feed source antenna

Info

Publication number: CN102136634B
Application number: CN201110004946.1A
Authority: CN
Inventors: 杨仕文; 滕静华; 黄明; 聂在平
Original assignee: University of Electronic Science and Technology of China
Current assignee: University of Electronic Science and Technology of China
Priority date: 2011-01-12
Filing date: 2011-01-12
Publication date: 2014-06-25
Anticipated expiration: 2031-01-12
Also published as: CN102136634A

Abstract

The invention provides a Ku/Ka frequency band circularly polarization integrated receiving and transmitting feed source antenna applied to antenna systems, such as a paraboloid antenna and the like, in satellite communication. The antenna adopts a coaxial nested compact structure, and is applied to Ku frequency band and Ka frequency band at the same time. The basic structure of a feed source comprises a circular waveguide, on which a pointed cone shaped dielectric rod is loaded, a flange, a coaxial waveguide, a symmetrical SMA connector pair, a circular polarizer and an orthogonal mode coupler, wherein the feed source in the Ka frequency band is applied to dual circular polarization, has rotary symmetrical radiation directional diagrams, the circularly polarization axial ratio in Ka double band is smaller than minus 2dB, and the transmitter-receiver isolation is smaller than minus 70dB; and the feed source in the Ku frequency band is applied to dual circular polarization, has rotary symmetrical radiation directional diagrams, a cross polarization level smaller than minus 40dB, and good transmitter-receiver isolation and reflection loss.

Description

The integrated transmitting-receiving feed antenna of a kind of Ku/Ka frequency range line circular polarization

Technical field

The invention belongs to the technical field of Feed Design in radio communication, the Ku/Ka frequency range that it is particularly related to Feed Design in satellite communication system is received and dispatched the technology such as four frequency ranges, line circular polarization are integrated.

Background technology

Along with the development of satellite communication cause, existing C frequency range satellite resource can not meet growing satellite communication demand, and exploitation Ku, Ka wave band is imperative.The flourish of satellite communication cause proposed new requirement to its earth station antenna, for example high-gain, broadband or multiband, low-cross polarization, multi-beam, multipolarization etc.

Feed is the heart of whole antenna system, and high-performance feed is the most important condition of high performance antenna system.How to be operated in broadband or multiband in Ku, the design of Ka frequency range simultaneously, there is the characteristic of low-cross polarization, high-isolation, and can realize the feed of receiving and dispatching dual polarization or multipolarization, better to meet the requirement of other antenna systems such as Luneberg lens antenna, parabolic antenna to feed.

The Ku/Ka corrugation loudspeaker feed source of high-efficiency compact can effectively utilize same radiation actinal surface, makes antenna can be operated in four different frequency ranges simultaneously, makes the utilance of antenna improve three times.In the time of corrugation loudspeaker feed source antenna feed, the signal of four kinds of different frequency ranges, four kinds of different polarization just can transmit simultaneously.Within this four each and every one frequency range, antenna can send two kinds of signals simultaneously, receives two kinds of signals simultaneously, and we can solve the interference producing between signal by transmitting-receiving high-isolation and polarization separation.

The people such as the Du Biao of No.54 Institute of China Electronics Science & Technology Group disclose a kind of double-slot double-frequeny-range sheared corrugated horn feed in patent CN1438733, and it forms by being harmful to higher mode inhibitor, dual-slot structure wave groove mode converter, the dark ripple struction frequency change of double flute, angle variation changeover portion and the dark ripple struction radiant section of double flute.Be suitable as the feed that the two-bands such as L/C, S/C, S/X and C/Ku share satellite communication and TT&C antenna.In patent CN1317884, poplar can loyal wait people disclose a kind of corrugation loudspeaker feed source that improves offset parabolic antenna cross polarization characteristics, and it is by bimodulus corrugated horn and propagate and end by higher mode the exciter that light wall circular waveguide, coupling cavity, coupling aperture form and form.The satellite communication single-offset parabolic reflector antenna that is particularly suitable for the little F/D focal length/diameter of Ku frequency range does feed source device.The people such as the Wan Xiaomei of No.38 Inst., China Electronic Sci. & Tech. Group Co. are entitled as " double-circle polarization and difference beam broadband corrugation horn feed antenna " and disclose a kind of double-circle polarization and difference beam broadband corrugation horn feed antenna in patent CN101626113, its structure comprises antenna body and coaxial probe, antenna body is cylindric, its top is corrugated portion, and bottom is feed part.Can be used for the wideband dual polarized Monopulse feed of high band, in 60% frequency band range, can realize good Circular polarization ratio.The people such as the Tang Yimin of Electronic Inst No.29, Ministry of Information Industry disclose the orthogonal polarized feed source of a kind of broadband, high-power, high-isolation in patent No. CN1331502.Orthogonal polarized feed source is in meeting broadband, high power capacity, and the isolation of main road, dypass has had the raising of matter, more than reaching 42dB.Domestic disclosed these patents about feed aspect above, their design is all generally two-band, and some meet high-power requirement, and some meet requirement broadband or high-isolation, realize the effective radiation characteristic of antenna system.And feed of the present invention works in Ku, Ka frequency range, can carry out the transmitting-receiving work of line circular polarization simultaneously, in antenna system, do not need multiple feeds just can cover separately four frequency ranges, the problem of wave beam defocusing while solving multiple feeds placement.In the time of Ku frequency range and Ka frequency range transmitting-receiving work, feed has excellent radiation characteristic and high isolation simultaneously.

U.S. specialty inventor Joseph A.Preiss is entitled as " Dual Band Feed with Integrated Mode Transducer " in publication numbers 6005528, and to have set forth a kind of feed structure be that intermediate medium bar loads, periphery is to come nested with the corrugated horn of axial groove, realize the radiation characteristic two frequency ranges, but to the having relatively high expectations of technique, processing cost is larger due to axially grooved.Within 2006, Stephen D.Tafgonski is at IEEE Transactions on Antennas and Propagation, October 2006, Vol.54, p.2862-2868, No.10, delivers " A Multiband Antenna for Satellite Communications on the Move ".Introduced a kind of feed of three frequency ranges, it is operated in 20.2-21.2GHz (K frequency range), 30-31GHz (Ka frequency range), 43.5-45.5GHz (Q frequency range).The advantage of this feed is to be operated in three frequency ranges and multiple polarization simultaneously, and ensures higher aperture efficiency.United States Patent (USP) inventor Robert A.Frosch has introduced a kind of feed that is operated in five frequency ranges in publication numbers 4258366 is entitled as " Multifrequency Broadband Polarized Horn Antenna ", turn all signals of horn mouth radiation by a ripple circular cone, by orthogonal mode structure, signal is coupled out from public transmission waveguide.Because the signal that has multiple frequency ranges transmits jointly, feed needs many band pass filters that each signal is separated at output interface place, increase the isolation between frequency band.It is poor in voltinisms such as the far-field patterns of each frequency range radiation.2009, Bhattacharyya, A. wait at Antennas and Propagation Society International Symposium, on 2009.APSURSI ' 09.IEEE, delivered to be entitled as and in " Multiband Feed using coaxial configuration ", discussed a kind of scheme that adopts coaxial nested structure to realize to be operated in S, Ku, K, Ka frequency range.In the middle of feed, the circular waveguide of flare angle variation is propagated the electromagnetic wave signal of Ku, K, Ka frequency range, and the coaxial waveguide of ladder flare angle variation is propagated the signal of S frequency range.At high band place, the multiple coupling between coaxial waveguide and circular waveguide has impact very significantly to the performance of feed.In article, mention the effective radiation that realizes three frequency ranges with a circular waveguide, but do not mention the isolation between each band signal in feeding network in the back.For we to carry out transmitting-receiving work be ungratified when requiring.

Compare with paper with the patent of invention of mentioning before, the integrated four frequency range feeds of line circular polarization of the coaxial nested structure that the present invention adopts have ensured the isolation between each adjacent band, can make feed in Ku two-band, Ka two-band is carried out transmitting-receiving work simultaneously, separates receiving and transmitting signal and do not need additionally to add filter.The far-field radiation directional diagram of feed is axially symmetrical, and cross polarization is low, good line circular polarization performance and return loss.Traditional dragon uncle lens feed system is by placed side by side to single Ku or Ka feed, its maximum beam position all can produce the skew of certain angle, cannot realize and receive same satellite, this feed has well solved the problem of wave beam defocusing, and it is specially adapted in the feed system of the Large-scale satellite communication antennas such as parabolic antenna.

Summary of the invention

The transmitting-receiving line circle dual polarization for large-scale antenna systems such as parabolic antennas, the feed of four frequency range high-efficiency compacts in a kind of satellite communication are the object of the present invention is to provide, it works in Ku/Ka wave band, there is rotational symmetric antenna pattern, extremely low cross polarization, the good excellent performance such as return loss and high isolation, and compact conformation, practical.

The line circular polarization four frequency range Ku/Ka feeds of inventing herein adopt coaxial nested version, make the radiation actinal surface of Ku and Ka feed realize isolation spatially.It by ring flange 1, cone-shaped dielectric rod 2, inner circular waveguide 3, Ku feed transmitting sub-miniature A connector to 4, symmetrical short circuit metal post 5, Ku feed receive orthogonal mode to 6, Ka feed receiving port 7, Ka feed emission port 8, coaxial waveguide 9, circular polarizer 10, ladder waveguide 11 form.Wherein, Ku feed transmitting sub-miniature A connector is to 50 ohm of sub-miniature A connectors that often use in 4 employing microwave communications, Ku feed receives orthogonal mode to 6 external national standard rectangular waveguide BJ140, Ka feed receiving port 7 external BJ220, Ka feed emission port 8 external BJ320, symmetrical metallic reflection post 5 is fixed in the middle of coaxial waveguide 9 by welding or punching.

The Ku/Ka feed of inventing herein works in Ku, Ka wave band, Ku feed transmitting sub-miniature A connector to 4 for transmit frequency band f _t(bandwidth 5%), Ku feed receive orthogonal mode to 6 for receiving frequency range f _r(bandwidth 5%). adjust transmitting sub-miniature A connector to 4, receive orthogonal mode to 6, position in coaxial waveguide 9 of symmetrical short circuit metal post 5 and transmitting sub-miniature A connector to 4 be deep into the degree of depth in coaxial waveguide 9, circular waveguide 3 and coaxial waveguide 9 in the relative position of radiation actinal surface and coaxial waveguide 9 ladder waveguide 11 sizes at feed radiation actinal surface, Ku/Ka feed described herein has obtained good return loss and receive-transmit isolation.Wherein, symmetrical short circuit metal post 5 has played the effect that reduces feed length and improve receive-transmit isolation.

Cone-shaped dielectric rod 2 is by the main mould TE propagating in inner circular waveguide 3 ₁₁mould is adjusted into HE ₁₁mould, HE ₁₁mould can obtain rotational symmetric antenna pattern.For ensureing not encouraged except HE ₁₁other patterns beyond mould, the inside radius r of circular waveguide 4 and the relative dielectric constant ε of cone-shaped dielectric rod 1 _rand operation wavelength λ need meet following formula:

2 * r < \frac{1.22}{\sqrt{ϵ_{r} - 1}} λ

In Ka feed, circular polarizer 10 is in circular polarized antenna system, to realize the critical component that polarization changes.Main mould TE in circular waveguide ₁₁mould after circular polarizer, be decomposed into two-way orthogonal, amplitude equates, the main mould signal that phase difference is 90 °, thus formed the signal transmission of circular polarization, the circular waveguide loading through dielectric rod radiate, and has obtained the radiation signal of circular polarization.Orthomode coupler belongs to two-band arrowband orthomode coupler, and it is entered the signal in two frequency ranges in same waveguide and transmitted by orthomode coupler.As shown in Figure 3, transmit via in two-band orthomode coupler feed-in waveguide, then change circularly polarized signal into through two-band circular polarizer, then have double frequency radiation port surface radiation to go out; The circularly polarized signal being received by double frequency radiation actinal surface becomes linear polarization signal through double frequency round polarized device, then is coupled away by standard waveguide mouth by two-band orthomode coupler.The system block diagram of two-band circular polarization Ka feed is as shown below.

Ku two-band linear polarization feed (as shown in Figure 2) is launched the signal of perpendicular polarization in coaxial waveguide, receives the signal of horizontal polarization.Wherein the emission port of Ku feed adopts the probe of constant amplitude phase-inversion symmetric to encouraging.Suppress in this way the main mould (TEM mould) in coaxial waveguide, and farthest encourage the first higher mode (TE in coaxial waveguide ₁₁mould); The receiving port of Ku feed adopt constant amplitude with symmetrical orthogonal mode to encouraging.Known according to the mode profile in electric field, this mode can be used for suppressing TEM mould in coaxial waveguide equally, has encouraged to greatest extent TE ₁₁mould.

The present invention has following beneficial effect:

(1). compare with three frequency range feeds with conventional two-band feed, structure of the present invention compact efficient more, is integrated in the electromagnetic wave signal of simultaneously receiving and dispatching certain bandwidth, four frequency ranges of four kinds of different polarization in the middle of same feed.

(2). in the Ku receiving and dispatching, Ka frequency range, feed of the present invention has rotational symmetric antenna pattern, good receive-transmit isolation, the good characteristic such as return loss and low-cross polarization.

Brief description of the drawings

Fig. 1 is structural representation of the present invention;

Wherein, the 1st, ring flange, the 2nd, cone-shaped dielectric rod, the 3rd, inner circular waveguide, the 4th, Ku feed transmitting sub-miniature A connector to, the 6th, Ku feed receive orthogonal mode to, the 7th, Ka feed receiving port, the 8th, Ka feed emission port

Fig. 2, Fig. 3 are perspective structure schematic diagrames of the present invention;

Wherein, the 1st, ring flange, the 2nd, cone-shaped dielectric rod, the 3rd, inner circular waveguide, the 4th, Ku feed transmitting sub-miniature A connector to, the 5th, symmetrical short circuit metal post, the 6th, Ku feed receive orthogonal mode to, the 7th, Ka feed receiving port, the 8th, Ka feed emission port, the 9th, coaxial waveguide, the 10th, circular polarizer, the 11st, ladder waveguide

Fig. 4 is return loss and the receive-transmit isolation that Ku feed receives frequency range;

Fig. 5 is return loss and the receive-transmit isolation of Ku feed transmit frequency band;

Fig. 6 is that Ku feed receives frequency range center main pole and the Cross polarization pattern of (12.5GHz) E face, H face frequently;

Fig. 7 is Ku feed transmit frequency band center main pole and the Cross polarization pattern of (14.25GHz) E face, H face frequently;

Fig. 8 is that Ka feed receives frequency range center main pole and the Cross polarization pattern of (20.5GHz) E face, H face frequently;

Fig. 9 is Ka feed transmit frequency band center main pole and the Cross polarization pattern of (30.3GHz) E face, H face frequently;

Figure 10 is the cutaway view of cone-shaped dielectric rod 2, inner circular waveguide 3;

Figure 11 is the system block diagram of two-band circular polarization Ka feed.

Embodiment

With reference to Fig. 1, the line circular polarization four frequency range Ku/Ka feeds of inventing herein by ring flange 1, cone-shaped dielectric rod 2, inner circular waveguide 3, Ku feed transmitting sub-miniature A connector to 4, symmetrical short circuit metal post 5, Ku feed receive orthogonal mode to 6, Ka feed receiving port 7, Ka feed emission port 8, coaxial waveguide 9, circular polarizer 10, ladder waveguide 11 form.Ring flange adopts 180 ° of subtended angle corrugated horn structures; The identical circular cone of cone-shaped dielectric rod two ends Wei Liangge bottom surface radius, the radius of dielectric rod is identical with inner circular waveguide (3), is arranged on ring flange mouth; Ka feed receiving port (7) is positioned on the sidewall of circular waveguide, Ka feed emission port (8) is positioned at circular waveguide end, Ka feed receiving port (7) adopts standard rectangular waveguide BJ220, and Ka feed emission port (8) adopts standard rectangular waveguide BJ320.The each structure of feed connects by following description: inner circular waveguide 3 is nested in coaxial waveguide 9, as the inner wire of coaxial waveguide 9; Ladder waveguide 11 is connected with coaxial waveguide 9; Ring flange 1 is fixed on ladder waveguide 11 ports; Cone-shaped dielectric rod 2 partial insertions are in the inner circular waveguide 3 of ring flange 1 place port; At the end of coaxial waveguide 9, be Ku feed transmitting sub-miniature A connector successively to 4, symmetrical short circuit metal post 5 and Ku feed receive orthogonal mode to 6; Ka feed receiving port 7 in inner circular waveguide 3 away from ring flange 1 side, end place; Ka feed emission port 8 is in inner circular waveguide 3 ends; Circular polarizer 10 is placed in inner circular waveguide 3.Ku feed transmitting sub-miniature A connector, to 50 ohm of sub-miniature A connectors that often use in 4 employing microwave communications, can directly be connected with waveguide coaxial converter, after connect the power splitter of 180 ° of electric bridges; Symmetrical short circuit metal post 5 is fixed in the middle of coaxial waveguide 9 by waveguide part punching outside coaxial; Inner circular waveguide 3 in the middle of feed fixes by the length after prolonging coaxial waveguide 9 short circuit walls.

The present invention works in Ku, Ka wave band, transmitting sub-miniature A connector to 4 for transmit frequency band f _t(bandwidth 5%), receive orthogonal mode to 6 for receiving frequency range f _r(bandwidth 5%). adjust transmitting sub-miniature A connector to 4, receive orthogonal mode to 6, position in coaxial waveguide 9 of symmetrical short circuit metal post 5 and transmitting sub-miniature A connector to 4 stretching into the degree of depth in coaxial waveguide 9, receive orthogonal mode to 6 physical dimension and the size of ladder waveguide 11 and the relative position of inner circular waveguide.Line circular polarization four frequency range Ku/Ka feeds described herein have all obtained good return loss and receive-transmit isolation in Ku, Ka transmitting-receiving frequency range.

Cone-shaped dielectric rod 2 is by the main mould TE propagating in inner circular waveguide 3 ₁₁mould is adjusted into HE ₁₁mould, HE ₁₁mould can obtain rotational symmetric antenna pattern.When design, for fear of having encouraged other incentive mode, must suitably select diameter of section make them be operated in cut-off state, generally only need avoid producing asymmetrical wave HE ₁₂and EH ₁₂.The inside radius r of inner circular waveguide 3 and the relative dielectric constant ε of cone-shaped dielectric rod 2 _rand operation wavelength λ need meet following formula:

2 * r < \frac{1.22}{\sqrt{ϵ_{r} - 1}} λ

First select suitable DIELECTRIC CONSTANT ε _rwith the radius r of inner circular waveguide 3, in the inner circular waveguide 3 of feed of the present invention, the material of cone-shaped dielectric rod 2 has been selected conventional polytetrafluoroethylene; Then reasonably select the radius r of inner circular waveguide 3 according to above-mentioned formula; By changing the size (seeing Figure 10) of cone-shaped dielectric rod 2 in inner circular waveguide, can obviously improve the circular polarization characteristics of Ka feed.In the bandwidth of Ka feed transmit frequency band and reception frequency range 5%, be all less than-2dB of its axial Circular polarization ratio.Accept frequency range and transmit frequency band at Ka, the present invention all has rotational symmetric antenna pattern, good circular polarization characteristics.See Fig. 8, Fig. 9.In Ka feed, receiving port and emission port are all made up of orthomode coupler.Size reasonable in design and structure, can reach good return loss and isolation.Wherein, in the transmit frequency band of Ka feed, be less than-18dB of return loss; In the reception frequency range of Ka feed, be less than-20dB of return loss; Be less than-70dB of receive-transmit isolation, has reached excellent performance requirement.

Receive orthogonal mode pair by symmetrical short circuit metal post 5 and Ku feed are set in coaxial waveguide, thereby realized Ku feed high receive-transmit isolation in working band.Ku feed receive-transmit isolation as shown in Figure 4, Figure 5.From simulation result, at the receive-transmit isolation of Ku feed two-band all more than 50dB.Ku feed from transmitting sub-miniature A connector to 4 or receive orthogonal mode to the electromagnetic wave signal of 6 feed-ins coaxial waveguide, if directly to free space radiation, can produce very large reflection loss.In design, we add step conversion waveguide 11 in the outer waveguide of coaxial waveguide, to reduce the reflection loss of coaxial waveguide to radiation actinal surface, are beneficial to Ku feed and in operating frequency range, regulate coupling.By rational optimized dimensions, Ku feed is at the be all less than-10dB of return loss of transmit frequency band and reception frequency range.See Fig. 4, Fig. 5.Meanwhile, Ku feed is at transmit frequency band and receive frequency range and have rotational symmetric far-field radiation directional diagram, lower than excellent performances such as the cross polarizations of-40dB.See Fig. 6, Fig. 7.

Therefore the compact four frequency range feed performances of line circular polarization integrated high-efficiency that, this patent provides fully meet the performance requirement of the antenna system such as Luneberg lens antenna, parabolic antenna to feed.

Above, to those skilled in the art description of the invention is provided so that their easy to understand with use the present invention.For those skilled in the art, be apparent to the various changes of these embodiment, and without performing creative labour.Therefore, the present invention is not only limited to scheme described here, but the scope consistent with described claim.

Claims

For the integrated transmitting-receiving feed antenna of Ku/Ka frequency range line circular polarization of satellite communication based on a coaxial waveguide nested structure, comprise that ring flange (1), cone-shaped dielectric rod (2), inner circular waveguide (3), Ku feed transmitting sub-miniature A connector receive orthogonal mode to (6), Ka feed receiving port (7), Ka feed emission port (8), coaxial waveguide (9), circular polarizer (10), ladder waveguide (11) to (4), symmetrical short circuit metal post (5), Ku feed.The each structure of feed connects by following description: inner circular waveguide (3) is nested in coaxial waveguide (9), as the inner wire of coaxial waveguide (9); Ladder waveguide (11) is connected with coaxial waveguide (9); Ring flange (1) is fixed on ladder waveguide (11) port; Cone-shaped dielectric rod (2) partial insertion is in the inner circular waveguide (3) of ring flange (1) place port; At the end of coaxial waveguide (9), be that Ku feed transmitting sub-miniature A connector receives orthogonal mode to (6) to (4), symmetrical short circuit metal post (5) and Ku feed successively; Ka feed receiving port (7) in inner circular waveguide (3) away from side, ring flange (1) end place; Ka feed emission port (8) is in inner circular waveguide (3) end; Circular polarizer (10) is placed in inner circular waveguide (3); Wherein, Ku feed transmitting sub-miniature A connector adopts 50 ohm of sub-miniature A connectors that often use in microwave communication to (4), Ku feed receives orthogonal mode to (6) external national standard rectangular waveguide BJ140, the external BJ220 of Ka feed receiving port (7), the external BJ320 of Ka feed receiving port (8), symmetrical metallic reflection post (5) is fixed in the middle of coaxial waveguide (9) by welding or punching.
2. the integrated transmitting-receiving feed antenna of a kind of Ku/Ka frequency range line circular polarization of stating according to claim 1, is characterized in that described Ku feed transmitting sub-miniature A connector receives orthogonal mode to (4) and Ku feed and (6) are realized in coaxial waveguide receives and dispatches two-wire and polarize.
3. the integrated transmitting-receiving feed antenna of a kind of Ku/Ka frequency range line circular polarization of stating according to claim 1, is characterized in that described symmetrical short circuit metal post (5) and Ku feed receive orthogonal mode (6) have been realized to the high-isolation of feed in Ku frequency range transmitting-receiving work.
4. the integrated transmitting-receiving feed antenna of a kind of Ku/Ka frequency range line circular polarization of stating according to claim 1, has introduced ladder waveguide (11) between it is characterized in that in described ring flange (1) and coaxial waveguide (9).
5. the integrated transmitting-receiving feed antenna of a kind of Ku/Ka frequency range line circular polarization of stating according to claim 1, it is characterized in that the selection of described cone-shaped dielectric rod (2) position, the identical circular cone of cone-shaped dielectric rod two ends Wei Liangge bottom surface radius, the radius of dielectric rod is identical with inner circular waveguide (3), is arranged on ring flange mouth.