US3864683A - Arrangement for an automatic resetting system for microwave antennas - Google Patents

Arrangement for an automatic resetting system for microwave antennas Download PDF

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Publication number
US3864683A
US3864683A US342427A US34242773A US3864683A US 3864683 A US3864683 A US 3864683A US 342427 A US342427 A US 342427A US 34242773 A US34242773 A US 34242773A US 3864683 A US3864683 A US 3864683A
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section
cross
waveguide
antenna
output
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US342427A
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English (en)
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Gunter Morz
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Licentia Patent Verwaltungs GmbH
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Licentia Patent Verwaltungs GmbH
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S3/00—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received
    • G01S3/02—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received using radio waves
    • G01S3/14—Systems for determining direction or deviation from predetermined direction
    • G01S3/146—Systems for determining direction or deviation from predetermined direction by comparing linear polarisation components
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q25/00—Antennas or antenna systems providing at least two radiating patterns
    • H01Q25/04—Multimode antennas

Definitions

  • ABSTRACT An improved arrangement for an automatic direction finding system for resetting microwave antennas when signals are received from a moving transmitter wherein the higher waveguide wave modes produced in the azimuth plane and in the elevational plane are utilized as deviation information, whereby the advantages of mode couplers for square waveguides may be used with antenna exciter having a circular, octogonal or cross-shaped cross section.
  • the arrangement includes a junction or transition section between an antenna exciter having one of the above mentioned cross section and a waveguide with a square cross section.
  • a mode coupler which is provided with a microwave network, is connected to the waveguide with a square cross section to separate the deviation information of the received signal from the useful signal and the H l-l signal containing the deviation information is fed to a comparator network for further processing to provide resetting signals for the antenna.
  • the present invention relates to an arrangement for an automatic direction finding system for resetting microwave antennas when signals are received from a moving transmitter, in that the higher waveguide wave modes which are produced in the azimuth plane and in the elevational plane upon an angular deflection are utilized as deviation information.
  • the direction finding system is a contributing factor for the quality of a satellite ground station. In such a system, it must be endeavored to beam the antenna as accurately as possible toward the satellite inorder to prevent energy losses.
  • the system must thus be capable of producing resetting signals for angular deviations in the azimuth and elevational planes which signals permit accurate alignment of the antenna with the transmitter via a control loop.
  • mode couplers To decouple the wave modes containing the deviation information, coupling arrangements are used which will be referred to as mode couplers hereinafter.
  • the object of the present invention to utilize the advantages of the H -H mode coupler for square waveguides for other types of exciters, e.g. circular, cross-shaped and octogonal exciters.
  • the arrangement includes a junction or transition section between an antenna exciter having a circular, octogonal or cross-shaped cross section, i.e. a generally doubly polarizable waveguide cross section, and a subsequent waveguide section with a square cross section to which is connected a mode coupler which is provided with a microwave network which separates the deviation information for the antenna of the receiving system from the useful signal.
  • the Hgo-Hoz output signal from the mode coupler containing the deviation information is fed to a comparator network for processing.
  • a wave mode conversion is effected in the junction between exciter cross section and square cross section.
  • the comparator network includes a directional coupler whose inputs are connected via a phase shifting member, with the H and H outputs (P and P of the mode coupler and at whose outputs the setting voltages for the two perpendicular antenna deviations are obtained.
  • the comparator network is provided in the form of a hybrid circuit whose two inputs are connected with the H and H outputs of the mode coupler (P and P and at whose outputs two different types of deviation information can be obtained.
  • the comparator network includes two series-connected hybrid circuits between which a phase member and a damping member are disposed, the first hybrid circuit being connected with the H and H outputs of the mode coupler (P and P Two different types of deviation information are available at the outputs of the second hybrid circuit.
  • the coupling elements of the mode couplers are longitudinal bar couplings.
  • FIGS. la and 1b illustrate the electrical field configurations in a square waveguide.
  • FIGS. 2a and 2b illustrate the electrical field configurations in a cross-shaped waveguide.
  • FIGS. 3a and 3b illustrate the electrical field configurations in a circular waveguide.
  • FIG. 4 is a schematic illustration of mode coupler for a square waveguide used in the resetting system according to the present invention.
  • FIG. 5 is a schematic cross-sectional view showing the coupling elements of a mode coupler of FIG. 4.
  • FIGS. 6a and 6b and FIGS. 7a and 7b show various wave modes in a waveguide with a cross-shaped cross section and their conversion into wave modes of a waveguide with a square cross section.
  • FIGS. and 8b and FIGS. 9a and 9b show various types of wave modes in a waveguide with a circular cross section and their conversion into wave modes of a waveguide with a square cross section.
  • FIG. 10 shows one embodiment of an arrangement according to the invention having a directional coupler in the comparator network.
  • FIG. 11 shows another embodiment of an arrangement according to the invention having a seriesconnected hybrid circuit in the comparator network.
  • FIG. 12 shows a modification of the embodiment of FIG. 11 wherein for a system with a circular antenna exciter the comparator network includes a further hybrid circuit.
  • FIG. 13 shows a physical embodiment of an antennatracking-system consisting of a round Feed-Horn, a junction between the round and the square cross section of the following H -H -mode coupler.
  • FIGS. 1 3 there is shown the electrical field configurations of the higher wave modes in antenna exciters or horns having a square (FIGS. 1a and 1b), a cross-shaped (FIGS. 2a and 2b) and a circular (FIGS. 3a and 3b) cross section for evaluation in monopulse direction finding systems, where thge wave modes are excited when a linearly polarized (E By) wavefront impinges on the antenna from a nonaxial direction.
  • E By linearly polarized
  • the transmitted signal (S) is projected into the aperture plane of the exciter and the deviation from the exciter axis appears as a deviation x(a) or y(b).
  • the H wave and the H wave are suitable for providing the signals for bringing about an automatic resetting of the antenna since they can be decoupled over a wide band by means of a mode coupler such as shown in FIGS. 4 and 5.
  • This mode coupler which is provided with a microwave network is the prerequisite for all the other disclosed embodiments.
  • the mode coupler shown in FIG. 4 comprises a square waveguide section H with a defined opening angle and whose square cross-sectional area decreases along the axis thereof so that the section forms a truncated pyramid.
  • the opening angle is such that the H (and H wave can propagate only in the front portion of the waveguide H so that standing waves result which are coupled out by a total of eight coupling elements (K1 K8) disposed symmetrically in pairs about the periphery of the square waveguide H.
  • Coupling elements KI-K4 are coupled to the H wave and coupling elements K-K8 are coupled to the H wave.
  • the spacing between the coupling elements of each pair e.g.
  • KI and K2 is a/2, where a is the length ofa side of the square cross section, and the coupling elements are disposed in the field intensity maxima of the wave modes to be coupled out.
  • the field amplitude of the H wave is marked A in order to simply explain the functioning of the coupler, without consideration of the characteristic impedance.
  • Each coupling element (Kl-K4) decouples the amplitude A/2 with the coupling elements of each pair decoupling the amplitude A/2 at opposite phases.
  • the coupling element K1 decouples amplitude A/2 while the coupling element K2 decouples amplitude +A/2.
  • the oppositely disposed pairs of coupling elements e.g.
  • KI-K2 and K3-K4 decouple the amplitude with a mirror-image phase (180).
  • Each pair of coupling elements Kl-K2 and K3-K4 feeds a respective 180 hybrid circuit HYl and HY2 which form part of an inner comparator network HYl-HY4.
  • hybrid circuit HYl the opposite phase components from coupling elements K1 and K2 are combined to form the amplitude +A/ 2 at one output 4 thereof and in the hybrid circuit HY2 the opposite phase components from coupling elements K3-K4 are combined to form the amplitude A/ ⁇ /2 at one output 4 thereof.
  • the outputs 4 of the hybrid circuits HY] and HY2 are each connected, via lines of the same length, with the two inputs of 180 hybrid circuit HY5 (outer comparator network) at whose output 4 the full amplitude A of the original H wave appears, i.e. P 'At output 3 of the hybrid circuit'HYS, the decoupled energy component of the HE wave (not a direction finding type) is present which will eventually appear in the square cross section.
  • the amplitude components of coupling element pairs K5 K6 and K7-K8 are combined in respective 180 hybrid circuits HY3 and HY4 whose outputs are combined in a further 180 hybrid circuit HY6 at whose outputs appear the energy portions of the H wave and of the HE wave.
  • the type of coupling elements Kl-K8 utilized is of high significance since the coupling elements determine the degree of coupling, the band width and the interference in the useful channel.
  • the coupling elements are designed as so-called longitudinal bar couplings which convert a waveguide wave to a coaxial wave. With this type of coupling good coupling values are attained even with relatively low immersion depths.
  • Such a longitudinal bar coupling is described for example in German Pat. No. 1,292,223.
  • FIG. 5 is a schematic longitudinal sectional view of the mode coupler of FIG. 4 at the location of the coupling elements Kl-K8 and showing four of the coupling elements.
  • the bar B (the so-called longitudinal bar) of each of the coupling elements is connected approximately in its center with a respective coaxial conductor L.
  • This coaxial conductor L leads to a laterally attached cavity HO which is coupled in by way of coupling loops S.
  • This cavity H0 is part of one of the hybrid circuits HY1-HY4 shown in FIG. 4. All of the hybrid circuits may if desired be constructed as magic T network.
  • the wave modes occurring in them must be converted to H and H waves of the square cross section. This wave mode conversion is possible only for certain modes. Where possible, according to the invention the mode conversion is effected in a junction between the exciter cross section and the square cross section of the subsequent waveguide. FIG. 6a shows this wave mode conversion.
  • FIG. 6a shows the (H wave in the cross-shaped cross section of an exciter while FIG. 6b shows the converted wave form of the H and H modes in the waveguide with a square cross section.
  • FIG. 7a shows the (H, wave in the cross-shaped cross section of an exciter while FIG. 7b shows the converted wave form of the H and H modes in the waveguide with a square cross section;
  • FIG. 8a shows the (11 wave in the circular cross section of an exciter while FIG.
  • FIG. 8b shows the converted wave form of the H and H modes in the waveguide with a square cross section
  • FIG. 9a shows the H wave in the circular cross section of an exciter
  • FIG. 9b shows the converted wave form of the H and H modes in the waveguide with a square cross section.
  • the H wave ofthe circular waveguide of the exciter will always be converted to H and H waves approximately of the same amplitude in the square waveguide.
  • the wave mode conversion into H and H waves in the square waveguide is effected to a maximum degree only when the lines of symmetry of the fieldconfiguration, as illustrated in FIGS. 6-9 by the dash-dot lines, lie diagonally to the series-connected square waveguide. If these lines of symmetry lie parallel to the edges of the subsequently connected square waveguide, no conversion into H and H waves is possible. Accordingly the square waveguide sections must be'oriented relative to the output waveguide sections of the exciter as shown in FIGS.
  • the wave modes PH20 and Puo2 which are produced as a result of a pure deviation in the X or azimuth direction (FIGS. 2a, 3b) and which are converted to H and H energy components and appear at the outputs of the mode coupler of FIG. 4, are combined in a directional coupler R having the required coupling attenuation to form a single signal V (Ax) at one ofits outputs.
  • a signal V (Ay) will then appear only when a deviation in the y or elevation direction is present.
  • a prerequisite here is that the polarization of the wave has a y component for an x deviation and an x component for a y deviation.
  • the circular or cross-shaped horn is connected to the mode coupler shown in FIG. 4 and the H and H outputs of the outer comparator network HYS, HY6 ofthe mode coupler at which appear the energy components P and PI, are connected to the directional coupler R, which has an adjustable coupling attenuation factor or via a settable phase shifting member PH.
  • the coupling attenuation factor 01 must be set in dependence on the operating frequency of the system since the distribution of the P energies into H and H components is frequency dependent. The necessary condition for the coupling attenuation is given by the relationship (2,; 10 log(P /P The phase between the two signals fed to the directional coupler R is corrected with the settable phase member Ph.
  • FIG. 11 Another possibility for combining the components from a circular or cruciform exciter is shown in FIG. 11.
  • a hybrid circuit HY7 to the outputs of the hybrid circuits HYS and l-IY6 of the mode coupler
  • With circular polarization of the excited wave automatic resetting of the antenna is possible with only the H0 energy component Py With linear polarization however, two wave modes are required.
  • the square mode coupler is here agin adjusted in such a way that the polarization vector lies along the diagonal of the square waveguide as shown in the figure. In this case the H0 energy component P furnishes ameasure for the f deviation; and the H components P furnishes a measure for the r deviation.
  • FIG. 12 shows a modification of the comparator network of FIG. 11 which includes a further hybrid HY8 and a phase shifter PH.
  • this embodiment makes it possible to compare the H0 and H21 energy components P and P Particularly with circular polarization of the waves, tliis results in the advantage that separate resetting signals are obtained for the x and y deviations.
  • the amplitude of the H wave is approximately equal to the amplitude of the H wave when there is no y deviation.
  • the phase shifter Ph' is used to shift the phase of one of the input signals to hybrid circuit HY8, e.g. the P signal as illustrated, to produce an oppositely phase pair of signals at the input of hybrid HY8.
  • variable damping member D may be additionally employed.
  • FIG. 13 shows a physical embodiment of an antennatracking-system consisting of a round feed-horn, a junction or trasition section between the round and the square cross section of the following l-I -H -mode coupler.
  • the hybrid circuits HYl-HY4 of FIG. 4 are integrated as Magic-T circuits in the body (B) of the coupler.
  • the hybrid circuits HYS and HY6 are connected to the coupler by means of symmetric waveguide components.
  • the two output ports of these hybrids (Pam and F11 must be connected to an additional hybrid (I-IY7 of FIG. 11) which is not shown in FIG. 13. All these hybrids may be magic Ts and the overall electrical lengths between the output ports P -P and the input ports of I-IY7 must be equal.
  • the output ports P P correspond to the ports 4 of the hybrids I-IYl-HY4 in FIG. 4.
  • an automatic direction finding system for resetting microwave antennas when signals are received from a moving transmitter wherein the antenna exciter has a generally doubly polarizable wave-guide cross section and wherein means are provided for detecting and using the higher waveguide modes produced in the azimuth plane and in the elevational plane of the antenna exciter as the deviation information used to reset the antenna; the improvement comprising:
  • a mode coupler means which is provided with a microwave network, connected to said waveguide for separating the deviation information in the received signal from the useful signal and producing an output signal containing same;
  • comparator circuit means connected to the output of said mode coupler and responsive to the output signal therefrom containing the deviation information for processing same to produce the deviation signals necessary to reset the antenna.
  • said comparator circuit means includes a phase shifter connected to one of said two outputs of said mode coupler means, and a directional coupler means, having two outputs and having one of its two inputs connected to the other of said two outputs of said mode coupler means and the other of its two inputs connected to the output of said phase shifter, for combining the two input signals thereto to provide the resetting voltages for the two perpendicular directions of antenna deviation at its respective outputs.
  • said comparator circuit means further includes a phase shifter means having its input connected to one of the outputs of said hybrid circuit for shifting the phase of the input signal thereto so that it is of the opposite phase to the signal at the other output of said hybrid circuit; and a further hybrid circuit having one of its two inputs connected to the output of said phase shifter means and the other of its two inputs and connected to said other output of said hybrid circuit, and at whose two outputs appear respectively the two resetting voltages for the two perpendicular directions of antenna deviation.
  • said comparator circuit means further includes a variable damping means connected between the said other output of said hybrid circuit and the said other of the two inputs of said further hybrid circuit for providing compensation for small level differences in the connections between the hybrid circuits.
  • an automatic direction finding system for resetting microwave antennas when signals are received from a moving transmitter wherein means are provided for detecting and using the higher waveguide modes produced in the azimuth plane and in the elevational plane of the antenna exciter as the deviation information used to resest the antenna; the improvement comprising:
  • transition section with arbitrary cross section for propagating two orthogonally polarized waves with a following waveguide with a square cross section, in which useful modes of the arbitrary cross section for deviation information are converted into H and H -modes;
  • a mode coupler means which is provided with a microwave network, connected to said waveguide for separating the deviation information in the received signal from the useful signal and producing an output signal containing same
  • said mode coupler means includes a plurality of coupling elements with said coupling elements being longitudinal bar couplings, and
  • comparator circuit means connected to the output of said mode coupler and responsive to the output signal therefrom containing the deviation information for processing same to produce the deviation signals necessary to reset the antenna.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Waveguide Aerials (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)
US342427A 1972-03-17 1973-03-19 Arrangement for an automatic resetting system for microwave antennas Expired - Lifetime US3864683A (en)

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DE2212996A DE2212996C3 (de) 1972-03-17 1972-03-17 Einem beweglichen Sender nachfuhrbare Horn antenne

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US (1) US3864683A (enrdf_load_stackoverflow)
JP (1) JPS5617623B2 (enrdf_load_stackoverflow)
CA (1) CA990833A (enrdf_load_stackoverflow)
DE (1) DE2212996C3 (enrdf_load_stackoverflow)
FR (1) FR2176840B1 (enrdf_load_stackoverflow)
GB (1) GB1412352A (enrdf_load_stackoverflow)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4043654A (en) * 1971-02-12 1977-08-23 Xerox Corporation Display system
US4210915A (en) * 1977-10-05 1980-07-01 Endress U. Hauser Gmbh U. Co. Microwave antenna with exponentially expanding horn structure
US4343005A (en) * 1980-12-29 1982-08-03 Ford Aerospace & Communications Corporation Microwave antenna system having enhanced band width and reduced cross-polarization
US4578679A (en) * 1982-05-05 1986-03-25 Ant Nachrichtentechnik Gmbh Method and apparatus for obtaining antenna tracking signals
US4630059A (en) * 1983-06-18 1986-12-16 Ant Nachrichtentechnik Gmbh Four-port network coupling arrangement for microwave antennas employing monopulse tracking
US5216433A (en) * 1991-11-15 1993-06-01 Hughes Aircraft Company Polarimetric antenna
RU2276334C1 (ru) * 2005-02-09 2006-05-10 Общество с ограниченной ответственностью Производственное предприятие "Парус" Радиоволновый измеритель уровня
US20150340752A1 (en) * 2014-05-26 2015-11-26 The Board Of Trustees Of The Leland Stanford Junior University RF Waveguide Phase-Directed Power Combiners

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT974574B (it) * 1972-09-15 1974-07-10 Finike Italiana Marposs Micrometro comparatore con disposi tivo rapido ed automatico di azzera mento
JPS5635763Y2 (enrdf_load_stackoverflow) * 1976-04-30 1981-08-24
DE3020514A1 (de) * 1980-05-30 1981-12-10 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt Antennenspeisesystem fuer eine nachfuehrbare antenne

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2931033A (en) * 1955-07-19 1960-03-29 Bell Telephone Labor Inc Multi-mode automatic tracking antenna system

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2931033A (en) * 1955-07-19 1960-03-29 Bell Telephone Labor Inc Multi-mode automatic tracking antenna system

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4043654A (en) * 1971-02-12 1977-08-23 Xerox Corporation Display system
US4210915A (en) * 1977-10-05 1980-07-01 Endress U. Hauser Gmbh U. Co. Microwave antenna with exponentially expanding horn structure
US4343005A (en) * 1980-12-29 1982-08-03 Ford Aerospace & Communications Corporation Microwave antenna system having enhanced band width and reduced cross-polarization
US4578679A (en) * 1982-05-05 1986-03-25 Ant Nachrichtentechnik Gmbh Method and apparatus for obtaining antenna tracking signals
US4630059A (en) * 1983-06-18 1986-12-16 Ant Nachrichtentechnik Gmbh Four-port network coupling arrangement for microwave antennas employing monopulse tracking
US5216433A (en) * 1991-11-15 1993-06-01 Hughes Aircraft Company Polarimetric antenna
RU2276334C1 (ru) * 2005-02-09 2006-05-10 Общество с ограниченной ответственностью Производственное предприятие "Парус" Радиоволновый измеритель уровня
US20150340752A1 (en) * 2014-05-26 2015-11-26 The Board Of Trustees Of The Leland Stanford Junior University RF Waveguide Phase-Directed Power Combiners
US9640851B2 (en) * 2014-05-26 2017-05-02 The Board Of Trustees Of The Leland Stanford Junior University RF waveguide phase-directed power combiners

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Publication number Publication date
JPS496861A (enrdf_load_stackoverflow) 1974-01-22
FR2176840B1 (enrdf_load_stackoverflow) 1980-04-30
FR2176840A1 (enrdf_load_stackoverflow) 1973-11-02
GB1412352A (en) 1975-11-05
CA990833A (en) 1976-06-08
DE2212996C3 (de) 1980-09-25
DE2212996B2 (de) 1980-01-31
JPS5617623B2 (enrdf_load_stackoverflow) 1981-04-23
DE2212996A1 (de) 1973-09-27

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