WO2014127420A1 - Système et procédé d'antenne à large bande - Google Patents
Système et procédé d'antenne à large bande Download PDFInfo
- Publication number
- WO2014127420A1 WO2014127420A1 PCT/AU2014/000154 AU2014000154W WO2014127420A1 WO 2014127420 A1 WO2014127420 A1 WO 2014127420A1 AU 2014000154 W AU2014000154 W AU 2014000154W WO 2014127420 A1 WO2014127420 A1 WO 2014127420A1
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- WO
- WIPO (PCT)
- Prior art keywords
- waveguide
- cavity
- wideband antenna
- coaxial
- wideband
- Prior art date
Links
- 238000000034 method Methods 0.000 title description 16
- 239000000523 sample Substances 0.000 description 25
- 238000013461 design Methods 0.000 description 15
- 230000005540 biological transmission Effects 0.000 description 11
- 239000004020 conductor Substances 0.000 description 7
- 238000013459 approach Methods 0.000 description 4
- 230000007704 transition Effects 0.000 description 4
- 230000008878 coupling Effects 0.000 description 3
- 238000010168 coupling process Methods 0.000 description 3
- 238000005859 coupling reaction Methods 0.000 description 3
- 230000005284 excitation Effects 0.000 description 3
- 230000010287 polarization Effects 0.000 description 3
- 238000001228 spectrum Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 230000010363 phase shift Effects 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 238000005388 cross polarization Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- 210000000554 iris Anatomy 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P1/00—Auxiliary devices
- H01P1/16—Auxiliary devices for mode selection, e.g. mode suppression or mode promotion; for mode conversion
- H01P1/161—Auxiliary devices for mode selection, e.g. mode suppression or mode promotion; for mode conversion sustaining two independent orthogonal modes, e.g. orthomode transducer
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P5/00—Coupling devices of the waveguide type
- H01P5/08—Coupling devices of the waveguide type for linking dissimilar lines or devices
- H01P5/10—Coupling devices of the waveguide type for linking dissimilar lines or devices for coupling balanced lines or devices with unbalanced lines or devices
- H01P5/103—Hollow-waveguide/coaxial-line transitions
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q13/00—Waveguide horns or mouths; Slot antennas; Leaky-waveguide antennas; Equivalent structures causing radiation along the transmission path of a guided wave
- H01Q13/02—Waveguide horns
- H01Q13/0208—Corrugated horns
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q13/00—Waveguide horns or mouths; Slot antennas; Leaky-waveguide antennas; Equivalent structures causing radiation along the transmission path of a guided wave
- H01Q13/02—Waveguide horns
- H01Q13/025—Multimode horn antennas; Horns using higher mode of propagation
- H01Q13/0258—Orthomode horns
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q13/00—Waveguide horns or mouths; Slot antennas; Leaky-waveguide antennas; Equivalent structures causing radiation along the transmission path of a guided wave
- H01Q13/20—Non-resonant leaky-waveguide or transmission-line antennas; Equivalent structures causing radiation along the transmission path of a guided wave
- H01Q13/24—Non-resonant leaky-waveguide or transmission-line antennas; Equivalent structures causing radiation along the transmission path of a guided wave constituted by a dielectric or ferromagnetic rod or pipe
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
- H01Q5/50—Feeding or matching arrangements for broad-band or multi-band operation
- H01Q5/55—Feeding or matching arrangements for broad-band or multi-band operation for horn or waveguide antennas
Definitions
- the present invention relates to the field of antenna devices and, in particular, to an antenna device having a wide frequency range of operation.
- Antenna device of the present invention have a wide range of applications, including, but not limited to Radio Astronomy, Multi-band Satellite Communications (SATCOM) Systems, Signal Surveillance and Intelligence, Spectrum Surveillance, and Electronic Warfare.
- SATCOM Multi-band Satellite Communications
- Antenna devices efficiently couple energy to and from an oscillating electrical signal into a corresponding oscillating electromagnetic field normally initially operational within an associated waveguide. Ideally, the devices are operational over a wide range of frequencies of interest.
- antenna devices (operational in a Multiband frequency domain) include those disclosed in: United States Patent 6,720,932 entitled “Multi -Frequency Antenna Feed”, United States Patent 8.089, 415 entitled “Multiband Radar Feed System and Method”, and United States Patent 6,982,679 entitled: “Coaxial Horn Antenna System”.
- a wideband antenna including: a tapered elongated cavity defined by a first and second wall, a first proximal end of the cavity having a waveguide attached to an electromagnetic emission source; a second distal end of the cavity being electromagnetically transparent; the first wall having a sectional profile being axially tapered to a point; and the second wall being substantially monotonically increasing, to a first order, in radial diameter in section from the proximal to distal ends.
- the cavity can be substantially axially symmetric with the first wall forming a conical shape tapered to a point.
- the point can be spaced apart from the distal end of the cavity.
- the second wall preferably can include a series of slots. The series of slots are preferably substantially axially symmetric.
- a wideband antenna including: an elongated waveguide cavity having: an initial cylindrical waveguide having an initial annulus cross section at a first proximal end, with the thickness of the annulus (to a first order) monotonically expanding along a first axis.
- the diameter of the cross section of the inner surface of the waveguide axially reduces to a point.
- the point can be spaced apart from a distal end of the waveguide.
- Fig. 1 illustrates the wideband coaxial launcher concept of the preferred embodiment
- Fig. 2 illustrates a perspective view of the feed portions of the wideband launcher
- FIG. 3 illustrates a sectional view through the feed portions of the wideband launcher
- Fig. 4 is a graph of the simulated measured frequency response of the wideband launcher
- FIG. 5 illustrates a schematic sectional view of the upper portion of a substantially symmetric 'Bullet' horn arrangement
- Fig. 6 illustrates a schematic sectional view of the Bullet Horn arrangement
- Fig. 7 illustrates a schematic sectional view of a first portion of a corrugated Bullet Horn arrangement
- Fig. 8 illustrates a schematic sectional view of a second operative portion of a corrugated Bullet Horn arrangement
- Fig. 9 illustrates a side perspective sectional view of an antenna design incorporating the principles of the preferred embodiment
- Fig. 10 illustrates a close up view of the feed portion of the antenna of Fig. 9;
- FIG. 11 illustrates a further close up view of the feed portion of the antenna of Fig. 9;
- Fig. 12 illustrates a higher power waveguide feed
- Fig. 13 illustrates further portions of the higher power feed
- Fig. 14 illustrates a shortened high power waveguide feed able to take probe inputs.
- the preferred embodiment provides for an efficient coupling over a wideband balanced excitation of a coaxial waveguide.
- the illustrated designs of the preferred embodiment are for operation in TEn mode and provide for a wideband transition from standard coaxial transmission line primarily to a TEn mode on a coaxial waveguide.
- the waveguide is fed to a coaxial horn antenna, herein after known as a 'Bullet Horn' antenna device.
- the waveguide can then be used to feed various antenna devices, for example, a coaxial horn antenna.
- the mode spectrum of the waveguide in order of increasing cut-off frequency is: TEM, TEn, TE 21 , TE31, TE m i.
- the cut-off frequency of the TE31 mode is three-times the cut-off frequency of the TE n mode. This fixes the practical upper limit for the operating frequency bandwidth of such a feed as 3:1. However, practical considerations mean that the waveguide should be operated somewhat above the TEn cut-off frequency, so a more realistic limit for the frequency bandwidth is probably closer to 2.5:1.
- the spectrum of the coaxial waveguide can be modified by including ridges or c orru g a t ion s into the waveguide, and this approach has the potential to extend this limit.
- a significant practical limit of this type of transition is the need for a balanced feed to the two probes, i.e. they need to be driven with signals of equal amplitude that are 180° out of phase. Generating this equal amplitude split with a 180° phase shift is possible with a component such as a hybrid junction or a Balun, but these components are also frequency- dependent, and their bandwidth limits tend to limit the overall performance of the wideband transition.
- the preferred embodiment takes advantage of the topology of the coaxial waveguide to allow connection via the inner and outer conductors, to allow in-phase excitation of the junction.
- the resulting in-phase power divider can be made to operate over a very wide bandwidth, so that the frequency dependence of the wideband transition is not limited by the performance of the power splitter.
- a wideband coaxial launcher concept 1 of the preferred embodiment is illustrated initially in Fig. 1.
- a pair of coaxial concentric waveguides 2, 3 is provided.
- Waveguides 2, 3 extend circumferentially and coaxially about a central axis with waveguide 2 being disposed within waveguide 3, which has a larger radius than waveguide 2.
- the region between waveguides 2, 3 defines an annulus shaped cavity centred about the central axis and extending along the axis.
- the annulus cavity is substantially axially symmetric about the central axis.
- Two probes 5, 6 located within the annulus at substantially diametrically opposed positions are driven from opposite ends with resp ec tive in-phase signals 8 , 9 to generate a balanced excitation. In this way, the need for 180° phase shift circuitry is removed. If the probes 5 , 6 are matched using a system c oax ia l impedance of 100 ⁇ , the two probes can be connected in parallel to a standard 50 ⁇ coaxial line 10 using a tee-junction 11 to generate the in- phase signals. Because the match of the tee-junction depends only on characteristic impedance of the transmission lines, it is inherently frequency-independent, allowing for a wideband driving signal.
- Fig. 1 deals only with a single polarization.
- the orthogonal polarization can be generated using a set of orthogonal probes.
- An advantage over the known circular ridged waveguide wideband orthomode transducer (OMT) is that it is simple to locate the probes for both polarizations in a common plane. This can also apply to a ridged coaxial OMT.
- OMT circular ridged waveguide wideband orthomode transducer
- FIG. 2 One possible implementation of a wideband junction arrangement 20 is shown in Fig. 2.
- the arrangement 20 utilises a symmetrical double-tapered probe structure 21, 22 that can be fed either via a transmission line 23 connected to the inner conductor or a transmission line 24 connected to the outer conductor of the large coaxial waveguide.
- Each probe has a structure that is widest at a point intermediate the inner and outer conductors and which tapers in width towards each conductor, as shown in Fig. 2.
- the probes 21, 22 are connected to equal lengths of 100 ⁇ coaxial transmission line 23, 24, and then via a tee-junction 25 to a 50 ⁇ coaxial line 26 and input connector.
- probe 22 is driven by transmission line 24 from a position external to the outer conductor of the coaxial waveguide and probe 21 is driven by transmission line 23 from a position internal to the inner wall of the coaxial waveguide.
- Impedance matching can be done using three structures: the coaxial cavity 28 behind the probes, the shape of the probes 21, 22 themselves, and a pair of impedance matching stubs 29, 30 placed in front of the probes at a predetermined distance from the respective probes within the annulus. Although a pair of matching stubs 29, 30 is shown in Fig. 2, alternative matching mechanisms can be used, like ridges, irises, steps, etc.
- Fig. 3 illustrates a sectional view through the arrangement 20 of Fig. 2.
- the probes 21, 22 are fed from different ends and are located in a coaxial structure, they are only approximately symmetrical in structure and so the two probes will be slightly different to achieve a balanced feed.
- FIG. 4 An example coaxial feed launcher of the arrangement of Fig. 3 was analysed using the software package CST Microwave Studio. The initial, non optimised results for S- parameters are shown in Fig. 4.
- a first curve 41 shows Sl l at the 50 ⁇ input
- the second curve 42 shows S31 which is the coupling from the 50 ⁇ input to the TE11 mode at the output.
- the target frequency band was 1 to 2 GHz, but a slight overall frequency shift has occurred, giving an operating frequency band of approximately 1.1 to 2.3 GHz.
- the primary function of the wideband coaxial junction is to feed a mated wideband coaxial horn antenna.
- the coaxial horn includes a profiled surface, hereinafter referred to as a "Bullet Horn", which interfaces directly with the wideband coaxial junction.
- a set of parameterized profile curves (like splines for example) can be defined to generate the Bullet Horn shape.
- Two profiles are required, an inner profile and an outer profile.
- An example resultant design of the Bullet Horn structure can be as illustrated in Fig. 5, which illustrates a sectional view through an upper portion of a substantially axially symmetric Bullet Horn 50.
- the Bullet Horn arrangement includes two profiled surfaces 51, 52 defined by a number of spline-nodes e.g. 53 that are used as parameters to define the surface geometry.
- spline nodes are the parameters that can be utilized to optimize the overall performance of the combined wideband coaxial junction and Bullet Horn.
- Fig. 6 illustrates a sectional profile view of one form of Horn geometry, illustrating its substantially symmetric nature.
- the optimization process can take into account a set of user defined performance requirements such as the overall input return loss, gain, cross-polarization maximum and sidelobe levels.
- An optimization procedure adjusts the inner and outer profiles and "shapes" the Bullet Horn profile to meet or come as close as possible to a desired performance targets.
- the Bullet Horn geometry can be, at present, either smooth-walled or corrugated. Whilst Fig. 5 and Fig. 6 illustrate a smooth walled design, Fig. 7 and Fig. 8 illustrate a corrugated wall design.
- Fig. 7 illustrates a first sectional view 70 of the top portion of an axially symmetric Bullet Horn design. The top portion initially includes tapered spline profiled surfaces 72, 73, which then feed out to a corrugated horn profile end. The corrugations provide for low cross polarisation of the antenna system.
- Fig. 8 illustrates the overall geometry of the corrugated horn arrangement.
- FIG. 9 to Fig. 11 illustrate sectional views through one investigated design.
- a corrugated horn arrangement 90 is illustrated having a front end 91 with a corrugated and radially expanding outer profiled surface and a back end 92 having a radially tapered inner profiled surface 93.
- the coaxial feed in is provided in back section 94.
- the front end 91 and back end 92 are connected at a point where the inner surface 93, which is conical in shape, tapers to a point.
- front end 91 includes a series of corrugated slots along the outer profiled surface.
- Fig. 10 illustrates an enlarged view of the back portion of the Bullet Horn antenna, showing the stepwise profiled surfaces 92, 93.
- the surfaces 92, 93 are stepwise tapered so as to include a series of distinct but interconnected taper levels.
- surfaces 72, 73 of Fig. 7 can include stepwise profiled sections.
- the profiles surfaces can include various degrees of smoothing, which define the size of each taper level.
- the outer profiled surface increases substantially monotonically in radial diameter from a proximal end adjacent the back end 92 to a distal end adjacent front end 91. At the distal end, the cavity is electromagnetically transparent.
- the coaxial feed in is provided by means of coaxial cable 98 which is split into two cables 96, 97 which deliver signals to the probes phased appropriately to excite the TE n mode.
- the tapering of inner profiled surface 93 corresponds to a tapering of the inner surface of the annulus between conductors. Therefore, an inner core of the annulus tapers down to a point beyond which the region within waveguide 3 is circular in radial cross section.
- Fig. 11 illustrates the feed in portion 94 of Fig. 10 in more detail.
- the coaxial cable 98 is split with two equal lengths 96, 97 being fed to corresponding probes 101, 102.
- the coaxial cable 97 passes through a core cavity 106 and attaches to the probe 102.
- Cavity tuning is provided by tuning stubs 103, 104.
- a preferred approach is to utilise a wideband waveguide structure, such as a ridged rectangular waveguide. This second approach would be facilitated by the replacement of the probe feeds by coupling slots.
- Fig. 12 illustrates one form of Electromagnetic (EM) model of a coaxial OMT 120 with double ridged waveguide ports including ports 121 tol24.
- the double ridged waveguide ports can be fed with a double ridged waveguide network containing wideband E-plane Tee junctions.
- Such an arrangement 130 is illustrated in Fig. 13, wherein the coaxial OMT 120 is fed by double ridged waveguide ports 121 to 124 which are in turn coupled to E-plane Tee junctions 131, 132.
- Tee junctions 131, 132 can be respectively configured to deliver input electromagnetic signals in orthogonal polarisations.
- Tee junctions 131, 132 split the power from each of the orthogonal polarised signals to deliver a first polarisation along waveguide ports 121 and 122, and a second polarisation along waveguide ports 123 and 124.
- ports 121 and 122 are diametrically opposed to each other.
- Ports 123 and 124 are similarly diametrically opposed to each other. All four ports are arranged around the circumference of a cylindrical waveguide. The cylindrical waveguide is able to be interconnected with the feed portion of the Bullet Horn antenna described above.
- the double ridged waveguide output ports are transformed into standard coaxial ports 141-144.
- the coaxial ports are on opposing sides which results in each pair of ports being in anti-phase if fed by the same simple coaxial splitter as proposed for the wideband coaxial launcher.
- the wideband coaxial junction and Bullet Horn design can be used together to achieve user defined wideband performance in terms of return loss, radiation pattern and gain.
- any one of the terms comprising, comprised of or which comprises is an open term that means including at least the elements/features that follow, but not excluding others.
- the term comprising, when used in the claims should not be interpreted as being limitative to the means or elements or steps listed thereafter.
- the scope of the expression a device comprising A and B should not be limited to devices consisting only of elements A and B.
- Any one of the terms including or which includes or that includes as used herein is also an open term that also means including at least the elements/features that follow the term, but not excluding others. Thus, including is synonymous with and means comprising.
- exemplary is used in the sense of providing examples, as opposed to indicating quality. That is, an "exemplary embodiment” is an embodiment provided as an example, as opposed to necessarily being an embodiment of exemplary quality.
- some of the embodiments are described herein as a method or combination of elements of a method that can be implemented by a processor of a computer system or by other means of carrying out the function.
- a processor with the necessary instructions for carrying out such a method or element of a method forms a means for carrying out the method or element of a method.
- an element described herein of an apparatus embodiment is an example of a means for carrying out the function performed by the element for the purpose of carrying out the invention.
- Coupled may mean that two or more elements are either in direct physical or electrical contact, or that two or more elements are not in direct contact with each other but yet still co-operate or interact with each other.
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Abstract
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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AU2014218514A AU2014218514B2 (en) | 2013-02-21 | 2014-02-20 | Wideband antenna system and method |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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AU2013900586 | 2013-02-21 | ||
AU2013900586A AU2013900586A0 (en) | 2013-02-21 | Wideband antenna system and method |
Publications (1)
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WO2014127420A1 true WO2014127420A1 (fr) | 2014-08-28 |
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PCT/AU2014/000154 WO2014127420A1 (fr) | 2013-02-21 | 2014-02-20 | Système et procédé d'antenne à large bande |
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WO (1) | WO2014127420A1 (fr) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR3071672A1 (fr) * | 2017-09-28 | 2019-03-29 | Thales | Repartiteur de puissance pour antenne comportant quatre transducteurs orthomodes identiques |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1037305A2 (fr) * | 1999-03-16 | 2000-09-20 | TRW Inc. | Antenne cornet pour deux fréquences avec une structure piège à deux profondeurs pour égalisation de diagrammes de rayonnement dans les plans E et H |
US20050151695A1 (en) * | 2004-01-14 | 2005-07-14 | Ming Chen | Waveguide apparatus and method |
-
2014
- 2014-02-20 AU AU2014218514A patent/AU2014218514B2/en not_active Ceased
- 2014-02-20 WO PCT/AU2014/000154 patent/WO2014127420A1/fr active Application Filing
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1037305A2 (fr) * | 1999-03-16 | 2000-09-20 | TRW Inc. | Antenne cornet pour deux fréquences avec une structure piège à deux profondeurs pour égalisation de diagrammes de rayonnement dans les plans E et H |
US20050151695A1 (en) * | 2004-01-14 | 2005-07-14 | Ming Chen | Waveguide apparatus and method |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR3071672A1 (fr) * | 2017-09-28 | 2019-03-29 | Thales | Repartiteur de puissance pour antenne comportant quatre transducteurs orthomodes identiques |
EP3462532A1 (fr) * | 2017-09-28 | 2019-04-03 | Thales | Répartiteur de puissance pour antenne comportant quatre transducteurs orthomodes identiques |
US10673118B2 (en) | 2017-09-28 | 2020-06-02 | Thales | Power divider for an antenna comprising four identical orthomode transducers |
Also Published As
Publication number | Publication date |
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AU2014218514B2 (en) | 2018-02-08 |
AU2014218514A1 (en) | 2015-09-10 |
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