EP0041077B1 - Antenna-feeding system for a tracking antenna - Google Patents

Antenna-feeding system for a tracking antenna Download PDF

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Publication number
EP0041077B1
EP0041077B1 EP80108118A EP80108118A EP0041077B1 EP 0041077 B1 EP0041077 B1 EP 0041077B1 EP 80108118 A EP80108118 A EP 80108118A EP 80108118 A EP80108118 A EP 80108118A EP 0041077 B1 EP0041077 B1 EP 0041077B1
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EP
European Patent Office
Prior art keywords
coupling
feed system
aerial
exciter
signal
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EP80108118A
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German (de)
French (fr)
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EP0041077A2 (en
EP0041077A3 (en
Inventor
Günter Dr.-Ing. Mörz
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Bosch Telecom GmbH
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ANT Nachrichtentechnik GmbH
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    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/20—Frequency-selective devices, e.g. filters
    • H01P1/213—Frequency-selective devices, e.g. filters combining or separating two or more different frequencies
    • H01P1/2131—Frequency-selective devices, e.g. filters combining or separating two or more different frequencies with combining or separating polarisations

Definitions

  • the invention relates to an antenna feed system for circularly polarized signals with an exciter whose aperture cross section is symmetrical to at least one main axis, and a device for coupling higher wave types as storage signals for tracking the antenna, the excitation of which is proportional to the deviation of the antenna main axes from a received circularly polarized beacon signal .
  • Future communications satellites will be required to illuminate a very specific area of the earth and, as little as possible, shine onto neighboring areas, especially when it comes to supplying neighboring countries with TV programs.
  • the alignment of the transmitting antenna must be stabilized.
  • G. Mörz Analysis and synthesis of electromagnetic wave fields in reflector antennas with the help of multi-type waveguides, Diss. D82, TH- Aachen (1978), p. 46 ff.
  • the transmitting antenna also serves as a receiving antenna for a beacon signal which is emitted by a beacon station arranged in the center of the prescribed illumination area.
  • the invention is based on the object of creating an antenna feed system for circularly polarized signals with an exciter, the aperture cross section of which is symmetrical to at least one main axis, in the manner mentioned at the outset, the two filing signals suitable for antenna tracking and obtained with simple means after the multimode -Monopul principle generated, it has a high polarization purity of the transmitted message signals and affects the required minimum attenuation of the message signals as little as possible.
  • the object is achieved in that a polarization converter, which contains amplitude and phase compensation devices, is arranged between the exciter and the device for coupling higher wave types, that the coupling of the higher wave types in a polarization switch connected to the polarization converter for separating two orthogonally polarized signals happens, which has two message signal inputs and outputs assigned to the two polarization directions for coupling the basic wave types and two outputs for coupling two different fields, which are created by additive and subtractive superimposition of two higher wave types and which contain the storage information of the antenna from the desired direction in Cartesian orientation .
  • the coupling structure for coupling the higher wave types is not arranged in the exciter, but behind it, does not interfere with the excitation of the hybrid modes advantageously used by grooved exciters (see DE-C-26 16 125). They are preferably used because they best meet the high requirements with regard to area efficiency and freedom from cross-polarization, as well as the adjustment of the lobe shapes in the E and H sections of the radiation diagrams.
  • a further advantage of this antenna feed system is the arrangement of the polarization converter between the exciter and the coupling structure. On the one hand, it does not interfere with the excitation of the hybrid modes and, on the other hand, it is possible to provide it with means for the interference effects of the exciter on the two storage signals and compensate for the polarization purity of the transmitted message signals.
  • Figure la shows the field types that are excited in the excitation horn with a rectangular or elliptical cross section and smooth wall.
  • the shaft types H 11 and E 11 there are the two shaft types H 11 and E 11 and with the elliptical cross section, the shaft types H 21 and E 01 (based on the designation of the shaft types in the circular waveguide).
  • the wave types H 11 and E 11 or H 21 and E 01 are superposed in a certain way.
  • the necessary transition from the throat cross section to the cross section of the polarization switch converts the higher wave types containing the storage information into the corresponding wave types of the input waveguide of the polarization switch (e.g. into the H 11 and E 11 waves) .
  • the beacon signal B is deposited Ax
  • the two wave types in the polarization switch are superimposed in phase opposition with mode couplers, resulting in a field in the x direction.
  • the beacon signal is deposited Ay
  • the two wave types are superposed in phase, which, as can be seen from FIG. 1, results in a resulting field in the y direction. Only when the two higher wave types are superposed in the phase direction described above are the coupled signals independent of one another in their storage information.
  • the rectangular exciter horn has a groove structure
  • two wave types are no longer excited, which are superimposed on one another to obtain independent placement signals, but instead the hybrid shaft type HE 21 is obtained with x placement and the HE 12 hybrid shaft type with y placement, each with clear placement information.
  • This case should not be dealt with in any more detail, however, since no major changes need to be made to the feed system.
  • each type of hybrid shaft in turn breaks down into the types of shaft H 11 and E 11 described above.
  • FIG. 2 shows the block diagram of an antenna feed system for circularly polarized signals, the exciter 1 of which is symmetrical only with respect to a main axis of the aperture area, in this embodiment it is rectangular.
  • a polarization converter 2, to which a polarization switch 3 with mode coupling is connected, is arranged behind the exciter with the interposition of a transition to cross-sectional adaptation.
  • the transmission signal S is fed into the input a of the polarization switch 3.
  • the storage signals ⁇ 1 and ⁇ 2 are present at the outputs b and c, which generally contain mixed storage information rather than unambiguous information.
  • the mixing of the storage information is due to different transmission properties of the higher wave types in the waveguides, which has the consequence that the phase-correct superposition of the wave types and thus also the independence of the storage signals is lost. There is an interference that contributes to the coupling of the storage signals. given by the different propagation constants of the excitation horn for the two higher wave types.
  • the different phase rotations of the excitation horn in both its main planes have a disruptive effect on the circularly polarized message signals to be transmitted.
  • the incoming circularly polarized field is elliptically distorted by the different phase rotations.
  • Another interference may result from a different antenna gain in the two main planes of the horn.
  • the circular polarization deteriorates to an elliptical one.
  • Gain and phase differences can also be caused by the reflector material of the antenna.
  • the polarization converter 2 located behind the exciter 1 in which these disturbances occur contains means for compensating for the described amplitude and phase errors.
  • a specific embodiment of such a special polarization converter is described below.
  • This polarization converter and the subsequent polarization switch 3 likewise effect coupling of the storage signals by differently influencing the H 11 and E 11 waves. But irrespective of the individual causes of coupling, the signals ⁇ 1 and ⁇ 2 at the outputs b and c of the polarization switch are decoupled again with a mode coupler by means of a downstream correction coupler 4, for example in the form of a directional coupler normally used. The unmixed storage signals Ax and ⁇ y are then at the outputs of the correction coupler.
  • the correction coupler can be dispensed with if the exciter fulfills certain phase conditions for the higher wave types.
  • the desired superposition of the higher wave types H 21 and E 01 , the then the decoupled storage signals ⁇ x and Ay appear directly at the outputs of the polarization switch 3, are predetermined by the length of the excitation horn. It is therefore possible to generate a field configuration by means of a specific length specification of the excitation horn, which compensates for the interference from the exciter, polarization converter and polarization switch.
  • the length of the horn must be selected so that the individual fields H 21 and E 01 to be overlaid cause a mutual phase angle of 0 ° or a multiple of 180 ° for the corresponding waves at the mode couplings.
  • This phase relationship can also be set by specifying the length of the exciter horn throat, which does not necessarily have to have the same cross-sectional shape as the exciter aperture.
  • the horn throat has a circular cross section (see DE-A-29 39 562.8). The cross section of the horn throat must then be adapted to the cross section of the polarization transducer with a waveguide transition.
  • the received signal E At the output d of the polarization switch 3 is the received signal E, which is broken down in a downstream crossover 5 into the reference signal 1: from the beacon signal and a possibly additionally transmitted message signal N.
  • a control variable for tracking the antenna can be derived from the comparison between the reference signal Z and the storage signals Ax and Ay derived from the beacon signal.
  • an interference signal S 1 appears , which is composed of undesired portions of the transmission signal S reflected in the exciter or on the antenna reflector b.
  • This reflected interference signal S is separated by the crossover 5 from the received signal and received by an absorber 7.
  • FIG. 3a, b show the implementation of a polarization converter with means for polarization conversion for amplitude and phase compensation.
  • FIG. 3a shows the front view
  • FIG. 3b shows the longitudinal section A-A of the polarization converter.
  • the coupling means are adjusted in their combination in the polarization converter that a fed-in, linearly polarized wave at the output of the polarization converter is split into broadband into two orthogonal waves (Ex, Ey) with the same amplitude and 90 ° phase difference (3.01 dB coupling).
  • the means for polarization conversion and amplitude compensation consist of two bevels 8 and 9 with grooves 8 'and 9', which are arranged in two diagonally opposite corners of the square polarization converter, and one which engages in grooves 8 'and 9'.
  • the bevels have an inductive effect and the diagonal dielectric plate has a capacitive character.
  • These two capacitive and inductive coupling means together have an almost frequency-independent coupling behavior. In practice, it can happen that the antenna-related gain difference is frequency-dependent, so that the amplitude compensation must also be made frequency-dependent.
  • the bevels 8, 9 and the plate 10 can be constructed in steps over the length ( ⁇ / 4 transformers).
  • the amplitude compensation is achieved by dimensioning the coupling means described above, which lie in diagonal planes, in such a way that an uneven splitting of a wave fed into the two main planes of the quadratic polarization converter is achieved.
  • the output shaft is not circular, but elliptically polarized, the main axes of the polarization ellipse lying parallel to the central axes of the square output cross section of the polarization converter.
  • the wave components Ex and Ey of the elliptical polarized wave are 90 ° out of phase with each other, but are no longer the same in amount.
  • the amounts of the wave components Ex and Ey can thus be influenced in such a way that a difference in amount between Ex and Ey, caused, for example, by different antenna gains in the x and y planes, can be compensated for; ie the elliptically polarized output wave of the polarization converter in turn generates a circularly polarized field in the radiation field of the exciter in the main beam direction.
  • a phase compensation is provided in the polarization converter, which compensates for phase shifts between Ex and Ey caused by a rectangular or elliptical exciter.
  • the phase compensation is provided by a further dielectric plate 11, which is arranged either horizontally or vertically, in front of the diagonally extending plate 10, depending on whether Ex is to be influenced in relation to Ey or Ey in relation to Ex in phase. Deviating from this, e.g. the phase correction can also be carried out with a rectangular waveguide section placed at the start of the excitation side in front of the square polarization converter, in which a side length is reduced compared to that of the polarization converter (not shown in the drawing). Both means - dielectric plate and rectangular waveguide section - can be used together to compensate for the frequency response of the phase error. Depending on the amount and direction of the frequency response, one or the other compensation means must predominate.
  • This polarization switch with mode coupling begins with a square waveguide 12 in which the two orthogonally polarized waves of the H 10 and H 01 type exist.
  • the polarization converter must be connected to this.
  • two coupling windows 13 and 14 are arranged, which are embedded in the E position transversely to the square waveguide.
  • the width of the coupling window is about half as large as the side length of the square waveguide cross section.
  • the energy of the H 10 shaft that is coupled out at the coupling windows is passed on via a rectangular hollow body 15, 16.
  • Both rectangular waveguides 15 and 16 open into a waveguide branch (double-T branching) which, according to the designation in the block diagram in FIG. 2, forms the input a for the transmission signal S and a waveguide gate b for energy components of the higher wave types H 11 and E 11 .
  • the signal coupled to the waveguide b has been designated 41 in FIG.
  • the coupling window 13 and 14 are each provided with an electrically conductive rod 17 and 18, which is inserted into the side walls of the square waveguide 12. They are a countermeasure to suppress the resonances of higher waveforms that usually occur due to the enlargement of the waveguide space at the level of the coupling window.
  • the signal of the H oj type is passed through a separating structure 19 in the square waveguide 12 to the output d, at which the received signal appears.
  • the door structure 19 consists of a plate arranged between the upper and lower walls of the square waveguide, which, viewed in the direction of expansion, begins near the rear edges of the coupling window. Towards the front, the separating plate 19 is approximately circularly tapered on both sides and extends into a tip 20. This enables the H 10 -type wave arriving from the square waveguide 12 to be deflected into the rectangular waveguides 15 and 16 with low resistance and reflection.
  • the directional damping of the coupling arrangement for the H 11 and E 11 shaft can be influenced over the length of the tip 20. Their length is set to the highest directional damping.
  • the signal coupled here has been designated 42 in FIG. 2, the block diagram of the entire antenna feed system.
  • FIGS. 5a, b and c a possible structural design of the antenna feed system will be described with reference to FIGS. 5a, b and c.
  • the names of the individual elements of the antenna feed system correspond to those of the block diagram in FIG. 2.
  • the polarization converter 2 with amplitude and phase compensation is connected to the exciter 1.
  • the polarization switch 3 with mode coupling with the input a for the transmission signal S, the outputs b and c for the storage signals ⁇ 1 and ⁇ 2, which are generally still coupled and which are broken down into the uncoupled storage signals Ax and Ay with the aid of the correction coupler 4, and the output d for the received signal E.
  • the reference signal ⁇ is split off from the received signal with the crossover 5.
  • the interference signal S 1 and a possibly additional transmitted message signal N which, which is not shown here, would still have to be separated from the interference signal via a further crossover.
  • the interference signal S 1 is finally fed to an absorber not included in the drawing.
  • the correction coupler 4 can only fulfill its function if its coupling damping is adapted to the coupling of the storage signals ⁇ 1 and ⁇ 2 and a defined phase relationship of 90 ° is set at its input. This phase relationship is e.g. by selecting the length of the waveguide leading from the waveguide output b to the correction coupler 4.
  • the components of the antenna feed system can also be formed from a round waveguide.
  • the arrangement of the antenna feed system according to the invention naturally also works with a round exciter as the limit case of the elliptical exciter; in this case there is no need for amplitude and phase compensation in the polarization converter.
  • a receive signal can also be obtained from the transmit input a or a transmit signal can be fed into the output N.

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  • Variable-Direction Aerials And Aerial Arrays (AREA)
  • Waveguide Aerials (AREA)
  • Aerials With Secondary Devices (AREA)
  • Waveguide Switches, Polarizers, And Phase Shifters (AREA)

Description

Die Erfindung betrifft ein Antennenspeisesystem für zirkular polarisierte Signale mit einem Erreger, dessen Aperturquerschnitt zu wenigstens einer Hauptachse symmetrische ist, und einer Einrichtung zur Ankopplung höherer Wellentypen als Ablagesignale zum Nachführen der Antenne, deren Anregung proportional zur Abweichung der Antennenhauptachsen von einem empfangenen zirkular polarisierten Bakensignal erfolgt.The invention relates to an antenna feed system for circularly polarized signals with an exciter whose aperture cross section is symmetrical to at least one main axis, and a device for coupling higher wave types as storage signals for tracking the antenna, the excitation of which is proportional to the deviation of the antenna main axes from a received circularly polarized beacon signal .

Von künftigen Nachrichtensatelliten wird gefordert, daß sie ein ganz bestimmtes Gebiet auf der Erde ausleuchten und dabei möglichst wenig auf Nachbargebiete überstrahlen, besonders, wenn es etwa um die Versorgung angrenzender Länder mit TV-Programmen geht.Future communications satellites will be required to illuminate a very specific area of the earth and, as little as possible, shine onto neighboring areas, especially when it comes to supplying neighboring countries with TV programs.

Um ein Auswandern des von einer Satellitenantenne ausgesandten Strahlungsfeldes auf Nachbargebiete zu verhindern, muß eine Ausrichtstabilisierung der Sendeantenne vorgenommen werden, Beispielsweise ist aus G. Mörz: Analyse und Synthese von elektromagnetischen Wellenfeldern in Reflektorantennen mit Hilfe von Mehrtyp-Wellenleitern, Diss. D82, TH-Aachen (1978), S. 46 ff., eine Sendeantenne bekannt, die als Monopulssensor arbeitet. Und zwar dient hier die Sendeantenne gleichzeitig als Empfangsantenne für ein Bakensignal, das von einer im Zentrum des vorgeschriebenen Ausleuchtgebietes angeordneten Bakenstation ausgesendet wird. In Abhängigkeit von der Hauptachsenabweichung des Erregers der Satelliten-Sendeantenne von dem empfangenen Bakensignal werden höhere Wellentypen angeregt, die über einen direkt hinter dem Erreger befindlichen Modenkoppler angekoppelt und als Ablagesignale verwendet werden. Als Bakensignal wird dabei ein linear polarisiertes Signal benutzt. Im folgenden soll aber ein Antennenspeisesystem mit einer Einrichtung zur Ankopplung höherer Wellentypen als Ablagesignale angegeben werden für zirkular polarisierte Signale, wobei der Erreger auch eine nur zu einer Hauptachse der Aperturfläche symmetrische Form besitzen kann, um etwan ein elliptisches Strahlungsfeld auf der Erde zu erzeugen. Als weitere Bedingung muß bei vorliegendem System berücksichtigt werden, daß die Frequenz des Empfangssignals, das sich aus dem Baken- und einem evtl. zusätzlich übertragenen Nachrichtensignal zusammensetzt, sehr viel größer ist als die des Sendesignals (fg=17,3 ./. 18,1 GHz, fs=1 11,7 ./. 12,5 GHz). Wegen der Bedingung fE»fs ist es nur schwer möglich, die höheren Wellentypen schon im Erreger anzukoppeln, da der Erregerschlund nicht so klein dimensioniert werden kann, daß die höheren Wellentypen zur Totalreflexion gezwungen werden, was Voraussetzung für eine selektive Ankopplung der höheren Wellentypen ist. Andernfalls ist eine sehr aufwendige und platzraubende Koppeleinrichtung nötig. Eine solche Koppeleinrichtung ist z.B. in der DE-B-26 08 092 beschrieben.In order to prevent the radiation field emitted by a satellite antenna from migrating to neighboring areas, the alignment of the transmitting antenna must be stabilized. For example, from G. Mörz: Analysis and synthesis of electromagnetic wave fields in reflector antennas with the help of multi-type waveguides, Diss. D82, TH- Aachen (1978), p. 46 ff., A transmitting antenna known that works as a monopulse sensor. Here, in fact, the transmitting antenna also serves as a receiving antenna for a beacon signal which is emitted by a beacon station arranged in the center of the prescribed illumination area. Depending on the main axis deviation of the exciter of the satellite transmitter antenna from the received beacon signal, higher wave types are excited, which are coupled via a mode coupler located directly behind the exciter and used as storage signals. A linearly polarized signal is used as the beacon signal. In the following, however, an antenna feed system with a device for coupling higher wave types as storage signals for circularly polarized signals is to be specified, whereby the exciter can also have a shape symmetrical only to a main axis of the aperture surface in order to generate an elliptical radiation field on earth. As a further condition, it must be taken into account in the present system that the frequency of the received signal, which is composed of the beacon signal and a possibly additionally transmitted message signal, is very much higher than that of the transmitted signal (fg = 17.3 ./. 18, 1 GHz, f s = 1 11.7. /. 12.5 GHz). Because of the condition fE »f s , it is difficult to couple the higher wave types already in the exciter, since the path of the exciter can not be dimensioned so small that the higher wave types are forced to total reflection, which is a prerequisite for selective coupling of the higher wave types . Otherwise, a very complex and space-consuming coupling device is necessary. Such a coupling device is described for example in DE-B-26 08 092.

Der Erfindung liegt nun die Aufgabe zugrunde, ein Antennenspeisesystem für zirkular polarisierte Signale mit einem Erreger, dessen Aperturquerschnitt zu wenigstens einer Hauptachse symmetrisch ist, nach der eingangs genannten Art zu schaffen, das zwei für die Antennennachführung geeignete und mit einfachen Mitteln gewonnene Ablagesignal nach dem Mehrmoden-Monopulsprinzip erzeugt, wobei es eine hohe Polarisationsreinheit der übertragenen Nachrichtensignale aufweist und die geforderte minimale Dämpfung der Nachrichtensignale möglichst wenig beeinträchtigt.The invention is based on the object of creating an antenna feed system for circularly polarized signals with an exciter, the aperture cross section of which is symmetrical to at least one main axis, in the manner mentioned at the outset, the two filing signals suitable for antenna tracking and obtained with simple means after the multimode -Monopul principle generated, it has a high polarization purity of the transmitted message signals and affects the required minimum attenuation of the message signals as little as possible.

Erfindungsgemäß wird die Aufgabe dadurch gelöst, daß zwischen dem Erreger und der Einrichtung zur Ankopplung höherer Wellentypen ein Polarisationswandler, der Amplituden- und Phasenausgleichsvorrichtungen enthält, angeordnet ist, daß die Ankopplung der höheren Wellentypen in einer an den Polarisationswandler angeschlossenen Polarisationsweiche zum Trennen zweier orthogonal polarisierter Signale geschieht, wobei diese zwei den beiden Polarisationsrichtungen zugeordnete Nachrichtensignaleingänge bzw. -ausgänge zum Ankoppeln der Grundwellentypen und zwei Ausgänge besitzt zum Ankoppeln zweier unterschiedlicher, durch additive und subtraktive Überlagerung zweier höher Wellentypen entstandener Felder, die die Ablageinformationen der Antenne von der Sollrichtung in kartesischer Orientierung enthalten.According to the invention, the object is achieved in that a polarization converter, which contains amplitude and phase compensation devices, is arranged between the exciter and the device for coupling higher wave types, that the coupling of the higher wave types in a polarization switch connected to the polarization converter for separating two orthogonally polarized signals happens, which has two message signal inputs and outputs assigned to the two polarization directions for coupling the basic wave types and two outputs for coupling two different fields, which are created by additive and subtractive superimposition of two higher wave types and which contain the storage information of the antenna from the desired direction in Cartesian orientation .

Zweckmäßige Ausführungsformen der obigen Anordnung sind den Unteransprüchen zu entnehmen.Appropriate embodiments of the above arrangement can be found in the subclaims.

Dadurch, daß erfindungsgemäß die Koppelstruktur für die Ankopplung der höheren Wellentypen nicht im Erreger angeordnet ist, sondern dahinter, wird nicht die Anregung der vorteilhafterweise genutzten Hybridmoden von Rillenerregern (s. DE-C-26 16 125) gestört. Sie finden bevorzugt Anwendung, weil sie am besten die hohen Anforderungen hinsichtlich Flächenwirkungsgrad und Kreuzpolarisationsfreiheit sowie des Angleichs der Keulenformen in den E- und H-Schnitten der Strahlungsdiagramme erfüllen. Einen weiteren Vorteil dieses Antennenspeisesystems stellt die Anordnung des Polarisationswandlers zwischen dem Erreger und der Koppelstruktur dar. Zum einen stört er dort nicht die Anregung der Hybridmoden und zum anderen hat man die Möglichkeit, ihn mit Mitteln zu versehen, die Störeinflüsse des Erregers auf die beiden Ablagesignale und auf die Polarisationsreinheit der übertragenen Nachrichtensignale kompensieren.The fact that, according to the invention, the coupling structure for coupling the higher wave types is not arranged in the exciter, but behind it, does not interfere with the excitation of the hybrid modes advantageously used by grooved exciters (see DE-C-26 16 125). They are preferably used because they best meet the high requirements with regard to area efficiency and freedom from cross-polarization, as well as the adjustment of the lobe shapes in the E and H sections of the radiation diagrams. A further advantage of this antenna feed system is the arrangement of the polarization converter between the exciter and the coupling structure. On the one hand, it does not interfere with the excitation of the hybrid modes and, on the other hand, it is possible to provide it with means for the interference effects of the exciter on the two storage signals and compensate for the polarization purity of the transmitted message signals.

Anhand des in der Zeichnung dargestellten Ausführungsbeispiels wird nun die Erfindung näher erläutert. Es zeigenBased on the embodiment shown in the drawing, the invention will now be explained in more detail. Show it

Figur 1a, b, c die Bildung unabhängiger Ablagesignale bei rechteckiger und elliptischer Erregerapertur,

  • Figur 2 das Blockschaltbild des Antennenspeisesystems,
  • Figur 3a, b den Polarisationswandler,
  • Figur 4 die Polarisationsweiche mit Modenkoppler und
  • Figur 5a, b, c das realisierte Antennenspeisesystem in verschiedenen Ansichten.
Figure 1a, b, c the formation of independent Storage signals for rectangular and elliptical excitation aperture,
  • FIG. 2 shows the block diagram of the antenna feed system,
  • 3a, b the polarization converter,
  • Figure 4 shows the polarization switch with mode coupler and
  • Figure 5a, b, c, the realized antenna feed system in different views.

Zunächst soll die Entstehung der unabhängigen Ablagesignale im Antennenspeisesystem erläutert werden; und zwar für einen Erreger mit rechteckiger und einem mit elliptischer Apertur. Figur la stellt die Feldtypen dar, die im Erregerhorn mit rechteckigem bzw. elliptischem Querschnitt und glatter Wandung angeregt werden. Beim Rechteckquerschnitt sind es die beiden Wellentypen H11 und E11 und beim elliptischen Querschnitt die Wellentypen H21 und E01 (angelehnt an die Bezeichnungsweise der Wellentypen im Rundhohlleiter). Je nach Ablage des zirkular polarisierten Bakensignals B gegenüber den Hauptachsen der Antenne, die durch das Speisesystem ausgeleuchtet wird, werden die Wellentypen H11 und E11 bzw. H21 und E01 in bestimmter Weise superponiert.First, the creation of the independent filing signals in the antenna feed system will be explained; for one exciter with a rectangular and one with an elliptical aperture. Figure la shows the field types that are excited in the excitation horn with a rectangular or elliptical cross section and smooth wall. With the rectangular cross section, there are the two shaft types H 11 and E 11 and with the elliptical cross section, the shaft types H 21 and E 01 (based on the designation of the shaft types in the circular waveguide). Depending on the storage of the circularly polarized beacon signal B with respect to the main axes of the antenna, which is illuminated by the feed system, the wave types H 11 and E 11 or H 21 and E 01 are superposed in a certain way.

Bei nicht rechteckigem Querschnitt (z.B. elliptisch) des Erregerhornschlundes wandelt der notwendige Übergang vom Schlundquerschnitt auf den Querschnitt der Polarisationsweiche die höheren, die Ablageinformation enthaltenden Wellentypen in die entsprechenden Wellentypen des Eingangshohlleiters der Polarisationsweiche um (z.B. in die H11- und E11-Wellen). Im Idealfall werden, wie die Figur 1 b zeigt, bei einer Ablage Ax des Bakensignals B die beiden Wellentypen in der Polarisationsweiche mit Modenkoppler gegenphasig überlagert, woraus ein Feld in x-Richtung resultiert. Bie einer Ablage Ay des Bakensignals werden die beiden Wellentypen gleichphasig superponiert, wodurch sich, wie aus Figur 1 hervorgeht, ein resultierendes Feld in y-Richtung einstellt. Nur dann, wenn als die beiden höheren Wellentypen in oben beschriebener Weise phasenrichtung superponiert werden, sind die angekoppelten Signale in ihrer Ablageinformation voneinander unabhängig.In the case of a non-rectangular cross section (eg elliptical) of the exciter horn throat, the necessary transition from the throat cross section to the cross section of the polarization switch converts the higher wave types containing the storage information into the corresponding wave types of the input waveguide of the polarization switch (e.g. into the H 11 and E 11 waves) . Ideally, as shown in FIG. 1b, when the beacon signal B is deposited Ax, the two wave types in the polarization switch are superimposed in phase opposition with mode couplers, resulting in a field in the x direction. When the beacon signal is deposited Ay, the two wave types are superposed in phase, which, as can be seen from FIG. 1, results in a resulting field in the y direction. Only when the two higher wave types are superposed in the phase direction described above are the coupled signals independent of one another in their storage information.

Besitzt beispielsweise das rechteckige Erregerhorn eine Rillenstruktur, so werden nicht mehr zwei Wellentypen angeregt, die zur Gewinnung unabhängiger Ablagesignale einander überlagert werden, sondern man erhält bei x-Ablage den Hybridwellentyp HE21 und bei y-Ablage den Hybridwellentyp HE12 mit jeweils eindeutigen Ablageinformationen. Auf diesen Fall soll aber nicht näher eingegangen werden, da hierbei an dem Speisesystem keine wesentlichen Änderungen vorzunehmen sind. Beim erforderlichem Übergang von Rillenerreger auf einen Hohlleiter mit glatter Berandung zerfällt nämlich jeder Hybridwellentyp wiederum in die oben beschriebenen Wellentypen H11 und E11.If, for example, the rectangular exciter horn has a groove structure, two wave types are no longer excited, which are superimposed on one another to obtain independent placement signals, but instead the hybrid shaft type HE 21 is obtained with x placement and the HE 12 hybrid shaft type with y placement, each with clear placement information. This case should not be dealt with in any more detail, however, since no major changes need to be made to the feed system. When a transition from a grooved exciter to a waveguide with a smooth edge is required, each type of hybrid shaft in turn breaks down into the types of shaft H 11 and E 11 described above.

Die Figur 2 zeigt das Blockschaltbild eines Antennenspeisesystems für zirkular polarisierte Signale, dessen Erreger 1 nur zu einer Hauptachse der Aperturfläche symmetrisch, in diesem Ausführungsbeispiel rechteckig ist. Hinter dem Erreger ist unter Zwischenschaltung eines Übergangs zur Querschnittsanpassung ein Polarisationswandler 2 angeordnet, an den sich eine Polarisationsweiche 3 mit Modenankopplung anschließt. In den Eingang a der Polarisationsweiche 3 wird das Sendesignal S eingespeist. An den Ausgängen b und c liegen die Ablagesignale Δ1 und Δ2 an, die im allgemeinen nicht eindeutige, sondern vermischte Ablageinformationen enthalten. Die Vermischung der Ablageinformationen kommt durch unterschiedliche Transmissionseigenschaften der höheren Wellentypen in den Hohlleitern zustande, was zur Folge hat, daß die phasenrichtige Superposition der Wellentypen und damit auch die Unabhängigkeit der Ablagesignale verlorengeht. Ein Störeinfluß, der zur Verkopplung der Ablagesignale beiträgt, ist. durch die unterschiedlichen Ausbreitungskonstanten des Erregerhorns für die beiden höheren Wellentypen gegeben.FIG. 2 shows the block diagram of an antenna feed system for circularly polarized signals, the exciter 1 of which is symmetrical only with respect to a main axis of the aperture area, in this embodiment it is rectangular. A polarization converter 2, to which a polarization switch 3 with mode coupling is connected, is arranged behind the exciter with the interposition of a transition to cross-sectional adaptation. The transmission signal S is fed into the input a of the polarization switch 3. The storage signals Δ1 and Δ2 are present at the outputs b and c, which generally contain mixed storage information rather than unambiguous information. The mixing of the storage information is due to different transmission properties of the higher wave types in the waveguides, which has the consequence that the phase-correct superposition of the wave types and thus also the independence of the storage signals is lost. There is an interference that contributes to the coupling of the storage signals. given by the different propagation constants of the excitation horn for the two higher wave types.

Störend auf die zu übertragenden zirkular polarisierten Nachrichtensignale wirken sich die unterschiedlichen Phasendrehungen des Erregerhorns in seinen beiden Hauptebenen aus. Das ankommende zirkular polarisierte Feld wird durch die unterschiedlichen Phasendrehungen elliptisch verzerrt. Ein weiterer Störeinfluß ergibt sich möglicherweise durch einen unterschiedlichen Antennengewinn in dan beiden Hauptebenen des Horns. Auch hier wird die zirkulare Polarisation zu einer elliptischen verschlechtert. Gewinn- und Phasenunterschiede können auch durch das Reflektormaterial der Antenne hervorgerufen werden.The different phase rotations of the excitation horn in both its main planes have a disruptive effect on the circularly polarized message signals to be transmitted. The incoming circularly polarized field is elliptically distorted by the different phase rotations. Another interference may result from a different antenna gain in the two main planes of the horn. Here, too, the circular polarization deteriorates to an elliptical one. Gain and phase differences can also be caused by the reflector material of the antenna.

Der hinter dem Erreger 1, in dem diese Störungen auftreten, sich befindende Polarisationswandler 2 enthält Mittel zur Kompensation des geschilderten Amplituden- und Phasenfehlers. Eine konkrete Ausführungsform eines solche speziellen Polarisationswandlers ist weiter unten beschrieben. Dieser Polarisationswandler und die anschließende Polarisationsweiche 3 bewirken ebenso durch unterschiedliche Beeinflussung der H11- und E11-Welle eine Verkopplung der Ablagesignale. Aber unabhängig von den einzelnen Verkopplungsursachen werden die Signale Δ1 und Δ2 an den Ausgängen b und c der Polarisationsweiche mit Modenkoppler mittels eines nachgeschalteten Korrekturkopplers 4, z.B. in Form eines üblicherweise verwendeten Richtkopplers, wieder entkoppelt. An den Ausgängen des Korrekturkopplers liegen dann die unvermischten Ablagesignale Ax und Δy. Auf den Korrekturkoppler kann man verzichten, wenn der Erreger bestimmte Phasenbedingungen für die höheren Wellentypen erfüllt. Zum Beispiel kann beim elliptischen Erreger die gewünschte Überlagerung der höheren Wellentypen H21 und E01, die dann direkt an den Ausgängen der Polarisationsweiche 3 die entkoppelten Ablagesignale Δx und Ay erscheinen läßt, durch die Länge des Erregerhorns vorgegeben werden. Es ist also möglich, durch eine gezielte Längenvorgabe des Erregerhorns eine Feldkonfiguration zu erzeugen, die eine Kompensation der Störeinflüsse von Erreger, Polarisationswandler und Polarisationsweiche bewirkt. Die Länge des Horns muß so gewählt werden, daß die zu überlagernden Einzelfelder H21 und E01 für die entsprechenden Wellen an den Modenankopplungen eine gegenseitige Phasenlage von 0° oder ein Vielfaches von 180° bewirken. Diese Phasenbeziehung läßt sich auch durch Längenvorgabe des Erregerhornschlundes einstellen, der nicht unbedingt die gleiche Querschnittsform wie die Erregerapertur haben muß. So hat vorteilhafterweise bei einem Erreger mit einem Horn elliptischer Apertur der Hornschlund einen kreisrunden Querschnitt (s. dazu DE-A-29 39 562.8). Hierbei muß dann der Querschnitt des Hornschlundes zu dem Querschnitt des Poiarisationswandlers mit einem Hohlleiterübergang adaptiert werden.The polarization converter 2 located behind the exciter 1 in which these disturbances occur contains means for compensating for the described amplitude and phase errors. A specific embodiment of such a special polarization converter is described below. This polarization converter and the subsequent polarization switch 3 likewise effect coupling of the storage signals by differently influencing the H 11 and E 11 waves. But irrespective of the individual causes of coupling, the signals Δ1 and Δ2 at the outputs b and c of the polarization switch are decoupled again with a mode coupler by means of a downstream correction coupler 4, for example in the form of a directional coupler normally used. The unmixed storage signals Ax and Δy are then at the outputs of the correction coupler. The correction coupler can be dispensed with if the exciter fulfills certain phase conditions for the higher wave types. For example, the desired superposition of the higher wave types H 21 and E 01 , the then the decoupled storage signals Δx and Ay appear directly at the outputs of the polarization switch 3, are predetermined by the length of the excitation horn. It is therefore possible to generate a field configuration by means of a specific length specification of the excitation horn, which compensates for the interference from the exciter, polarization converter and polarization switch. The length of the horn must be selected so that the individual fields H 21 and E 01 to be overlaid cause a mutual phase angle of 0 ° or a multiple of 180 ° for the corresponding waves at the mode couplings. This phase relationship can also be set by specifying the length of the exciter horn throat, which does not necessarily have to have the same cross-sectional shape as the exciter aperture. For example, in the case of an exciter with a horn having an elliptical aperture, the horn throat has a circular cross section (see DE-A-29 39 562.8). The cross section of the horn throat must then be adapted to the cross section of the polarization transducer with a waveguide transition.

Am Ausgang d der Polarisationsweiche 3 liegt das Empfangssignal E, das in einer nachgeschalteten Frequenzweiche 5 in das von dem Bakensignal stammende Referenzsignal 1: und ein eventuell noch zusätzlich übertragenes Nachrichtensignal N zerlegt wird. Aus dem Vergleich zwischen Referenzsignal Z und den aus dem Bakensignal abgeleiteten Ablagesignalen Ax und Ay läß sich eine Regelgröße für die Nachführung der Antenne ableiten.At the output d of the polarization switch 3 is the received signal E, which is broken down in a downstream crossover 5 into the reference signal 1: from the beacon signal and a possibly additionally transmitted message signal N. A control variable for tracking the antenna can be derived from the comparison between the reference signal Z and the storage signals Ax and Ay derived from the beacon signal.

Neben dem Referenzsignal 1: und dem Nachrichtensignal N am Tor d der Polarisationsweiche 3 erscheint ein Störsignal S1, das sich aus unerwünschten, im Erreger oder am Antennenreflektor b reflektierten Anteilen des Sendesignals S zusammensetzt. Dieses reflektierte Störsignal S,, das ohne besondere Kompensationsmaßnahmen die Polarisationsreinheit des Strahlungsfeldes verschlechtern würde, wird durch die Frequenzweiche 5 vom Empfangssignal abgetrennt und von einem Absorber 7 aufgenommen.In addition to the reference signal 1: and the message signal N at the gate d of the polarization switch 3, an interference signal S 1 appears , which is composed of undesired portions of the transmission signal S reflected in the exciter or on the antenna reflector b. This reflected interference signal S ,, which would deteriorate the polarization purity of the radiation field without special compensation measures, is separated by the crossover 5 from the received signal and received by an absorber 7.

Die Figuren 3a, b zeigen die Realisierung eines Polarisationswandlers mit Mitteln zur Polarisationswandlung zum Amplituden- und Phasenausgleich. In Figur 3a ist die Frontansicht und in Figur 3b der Längsschnitt A-A des Polarisationswandlers dargestellt. Im Falle von Erregern mit identischen Ausbreitungs- und Strahlungseigenschaften für die orthogonalen Haupttypen, wie es bei Erregern, die zu zwei Hauptachsen der Aperturfläche symmetrisch sind (z.B. runde oder quadratische Erreger), der Fall ist, werden im Polarisationswandler die Koppelmittel in ihrer Kombination so eingestellt, daß eine eingespeiste, linear polarisierte Welle am Ausgang des Polarisationswandlers in zwei orthogonale Wellen (Ex, Ey) mit gleicher Amplitude und 90° Phasendifferenz breitbandig aufgespalten wird (3,01 dB Kopplung). Diese Wellen bilden dann die Komponenten einer zirkular polarisierten Welle. Erreger mit ungleichen Ausbreitungs- und Strahlungseigenschaften für die orthogonalen Haupttypen, nämlich solche, die nur zu einer Hauptachse der Aperturfläche symmetrisch sind (z.B. rechteckige oder elliptische), haben nur dann identische Ausbreitungs- und Strahlungseigenschaften in den beiden Hauptebenen, wenn das Strahlungsdiagramm des ersten Haupttyps in der E-Ebene identisch mit dem des zweiten Haupttyps in der H-Ebene ist und umgekehrt (E-H-Angleich). In der Praxis ist diese Bedingung meist nicht ausreichend erfüllt, so daß die Gewinnunterscheide insbesondere in Hauptstrahlrichtung zu einem Amplitudenunterschied (Ex≠Ey) führen, was einer Degradation des zirkularen zu einem elliptischen Feld gleichzusetzen ist. Die Mittel für die Polarisationswandlung und den Amplitudenausgleich bestehen beim vorliegenden Ausführungsbeispiel aus zwei Abschrägungen 8 und 9 mit Nuten 8' und 9', die in zwei diagonal gegenüberliegenden Ecken des quadratischen Polarisationswandlers angeordnet sind, und einer in die Nuten 8' und 9' eingreifenden, diagonal verlaufenden, dielektrischen Platte 10. Die Abschrägungen wirken induktiv und die diagonal verlaufende, dielektrische Platte hat kapazitiven Charakter. Diese beiden kapazitiv und induktiv wirkenden Koppelmittel weisen zusammen ein nahezu frequenzunabhängiges Koppelverhalten auf. In der Praxis kann es vorkommen, daß der antennenbedingte Gewinnunterschied frequenzabhängig ist, so daß der Amplitudenausgleich ebenfalls frequenzabhängig gestaltet werden muß. Dies kann bei Zunahme der Kopplung mit der Frequenz mit Hilfe einer überwiegend kapazitiven Kopplung und bei Abnahme mit einer überwiegend induktiven Kopplung geschehen. Für eine geringere induktive Kopplung wird eine dickere oder längere dielektrische Platte in Verbindung mit verkleinerten Abschrägungen in den Ecken verwendet, wogegen für eine verstärkte induktive Kopplung eine kürzere oder dünnere Platte in Verbindung mit vergrößerten Abschrägungen eingesetzt wird. Bei sehr starker Frequenzabhängigkeit kann auch eines der beiden Koppelmittel (Abschrägungen oder dielektrische Platte) fortfallen oder die dielektrische Platte in einer anderen Diagonalen als die Abschrägungen angeordnet werden. Zur Verminderung der Eigenreflexion der induktiven und kapazitiven Koppelmittel können die Abschrägungen 8, 9 und die Platte 10 über die Länge gestuft aufgebaut sein (λ/4-Transformatoren).Figures 3a, b show the implementation of a polarization converter with means for polarization conversion for amplitude and phase compensation. FIG. 3a shows the front view and FIG. 3b shows the longitudinal section A-A of the polarization converter. In the case of pathogens with identical propagation and radiation properties for the main orthogonal types, as is the case with pathogens that are symmetrical to two main axes of the aperture surface (e.g. round or square pathogens), the coupling means are adjusted in their combination in the polarization converter that a fed-in, linearly polarized wave at the output of the polarization converter is split into broadband into two orthogonal waves (Ex, Ey) with the same amplitude and 90 ° phase difference (3.01 dB coupling). These waves then form the components of a circularly polarized wave. Pathogens with unequal propagation and radiation properties for the main orthogonal types, namely those that are only symmetrical to a main axis of the aperture area (e.g. rectangular or elliptical), have identical propagation and radiation properties in the two main planes only if the radiation diagram of the first main type in the E level is identical to that of the second main type in the H level and vice versa (EH adjustment). In practice, this condition is usually not sufficiently fulfilled, so that the profit distinctions lead to an amplitude difference (Ex ≠ Ey), particularly in the main beam direction, which is equivalent to a degradation of the circular to an elliptical field. In the present exemplary embodiment, the means for polarization conversion and amplitude compensation consist of two bevels 8 and 9 with grooves 8 'and 9', which are arranged in two diagonally opposite corners of the square polarization converter, and one which engages in grooves 8 'and 9'. diagonal dielectric plate 10. The bevels have an inductive effect and the diagonal dielectric plate has a capacitive character. These two capacitive and inductive coupling means together have an almost frequency-independent coupling behavior. In practice, it can happen that the antenna-related gain difference is frequency-dependent, so that the amplitude compensation must also be made frequency-dependent. This can take place with an increase in the coupling with the frequency with the aid of a predominantly capacitive coupling and with a decrease with a predominantly inductive coupling. For a lower inductive coupling, a thicker or longer dielectric plate is used in connection with smaller bevels in the corners, whereas for a stronger inductive coupling a shorter or thinner plate is used in connection with enlarged bevels. If the frequency dependence is very strong, one of the two coupling means (bevels or dielectric plate) can also be omitted or the dielectric plate can be arranged on a diagonal other than the bevels. In order to reduce the self-reflection of the inductive and capacitive coupling means, the bevels 8, 9 and the plate 10 can be constructed in steps over the length (λ / 4 transformers).

Der Amplitudenausgleich kommt dadurch zustande, daß die oben beschriebenen, in Diagonalebenen leigenden Koppelmittel so dimensioniert werden, daß eine ungleiche Aufspaltung einer eingespeisten Welle in die beiden Hauptebenen des quadratischen Polarisationswandlers erreicht wird. Dadurch ist die Ausgangswelle nicht zirkular, sondern elliptisch polarisiert, wobei die Hauptachsen der Polarisationsellipse parallel zu den Mittelachsen des quadratischen Ausgangsquerschnitts des Polarisationswandlers liegen. Die Wellenkomponenten Ex und Ey der elliptische polarisierten Welle sind zwar untereinander um 90° phasenverschoben, aber nicht mehr dem Betrag nach gleich. Die Beträge der Wellenkomponenten Ex und Ey können also so beeinflußt werden, daß ein Betragsunterschied zwischen Ex und Ey, z.B. hervorgerufen durch unterschiedliche Antennengewinne in der x-und y-Ebene, wieder ausgeglichen werden kann; d.h. die elliptisch polarisierte Ausgangswelle des Polarisationswandlers erzeugt im Strahlungsfeld des Erregers in Hauptstrahlrichtung wiederum ein zirkular polarisiertes Feld.The amplitude compensation is achieved by dimensioning the coupling means described above, which lie in diagonal planes, in such a way that an uneven splitting of a wave fed into the two main planes of the quadratic polarization converter is achieved. As a result, the output shaft is not circular, but elliptically polarized, the main axes of the polarization ellipse lying parallel to the central axes of the square output cross section of the polarization converter. The wave components Ex and Ey of the elliptical polarized wave are 90 ° out of phase with each other, but are no longer the same in amount. The amounts of the wave components Ex and Ey can thus be influenced in such a way that a difference in amount between Ex and Ey, caused, for example, by different antenna gains in the x and y planes, can be compensated for; ie the elliptically polarized output wave of the polarization converter in turn generates a circularly polarized field in the radiation field of the exciter in the main beam direction.

Neben dem Amplitudenausgleich ist im Polarisationswandler ein Phasenausgleich vorgesehen, der durch etwa einen rechteckigen oder elliptischen Erreger verursachte Phasendrehungen zwischen Ex und Ey kompensiert.In addition to the amplitude compensation, a phase compensation is provided in the polarization converter, which compensates for phase shifts between Ex and Ey caused by a rectangular or elliptical exciter.

Den Phasenausgleich besorgt eine weitere dielektrische Platte 11, die entweder horizontal oder vertikal, je nachdem, ob Ex gegenüber Ey oder Ey gegenüber Ex in der Phase beeinflußt werden soll, vor der diagonal verlaufenden Platte 10 angeordnet ist. Abweichend hiervon kann z.B. die Phasenkorrektur auch mit einem an den erregerseitigen Anfang des vor den quadratischen Polarisationswandler gesetzten rechteckigen Hohlleiterabschnitt vorgenommen werden, bei dem eine Seitenlänge gegenüber der des Polarisationswandlers reduziert ist (nicht zeichnerisch dargestellt). Beide Mittel - dielektrische Platte und rechteckiger Hohlleiterabschnitt - können zusammen zur Kompensation des Frequenzganges des Phasenfehlers eingesetzt werden. Je nach Betrag und Richtung des Frequenzganges muß das eine oder andere Kompensationsmittel überwiegen.The phase compensation is provided by a further dielectric plate 11, which is arranged either horizontally or vertically, in front of the diagonally extending plate 10, depending on whether Ex is to be influenced in relation to Ey or Ey in relation to Ex in phase. Deviating from this, e.g. the phase correction can also be carried out with a rectangular waveguide section placed at the start of the excitation side in front of the square polarization converter, in which a side length is reduced compared to that of the polarization converter (not shown in the drawing). Both means - dielectric plate and rectangular waveguide section - can be used together to compensate for the frequency response of the phase error. Depending on the amount and direction of the frequency response, one or the other compensation means must predominate.

Als Polarisationsweiche mit Modenankopplung wird die für den vorliegenden Anwendungsfall abgeändert, in der DE-A-26 51 935 beschriebene, Weiche eingesetzt.As a polarization switch with mode coupling, the switch described in DE-A-26 51 935 is used for the present application.

Diese aus der Figur 3 hervorgehende Polarisationsweiche mit Modenankopplung beginnt mit einem Quadrathohlleiter 12, in dem die beiden orthogonal polarisierten Wellen vom H10- und H01-Typ existent sind. Hieran ist der Polarisationswandler anzuschließen. In dem Quadrathohlleiter 12 sind zwei Koppelfenster 13 und 14 angeordnet, die in der E-Lage quer zum Quadrathohlleiter eingelassen sind. Die Breite der Koppelfenster ist etwa halb so groß wie die Seitenlänge des Quadrathohlleiterquerschnitts. Die an den Koppelfenstern ausgekoppelte Energie der H10-Welle wird über je einen Rechteckhohlleier 15, 16 weitergeleitet. Beide Rechteckhohlleiter 15 und 16 münden in eine Hohlleiterverzweigung (Doppel-T-Verzweigung), die entsprechend der Bezeichnung im Blockschaltbild der Figur 2 den Eingang a für das Sendesignal S und ein Hohlleitertor b für Energieanteile der höheren Wellentypen H11 und E11 bildet. Das am Hohlleiter b angekoppelte Signal ist in Figur 2 mit 41 bezeichnet worden.This polarization switch with mode coupling, which is shown in FIG. 3, begins with a square waveguide 12 in which the two orthogonally polarized waves of the H 10 and H 01 type exist. The polarization converter must be connected to this. In the square waveguide 12, two coupling windows 13 and 14 are arranged, which are embedded in the E position transversely to the square waveguide. The width of the coupling window is about half as large as the side length of the square waveguide cross section. The energy of the H 10 shaft that is coupled out at the coupling windows is passed on via a rectangular hollow body 15, 16. Both rectangular waveguides 15 and 16 open into a waveguide branch (double-T branching) which, according to the designation in the block diagram in FIG. 2, forms the input a for the transmission signal S and a waveguide gate b for energy components of the higher wave types H 11 and E 11 . The signal coupled to the waveguide b has been designated 41 in FIG.

Die Koppelfenster 13 und 14 sind mit je einem elektrisch leitenden Stab 17 und 18, der in die Seitenwände des Quadrathohlleiters 12 eingefügt ist, versehen. Sie sind eine Gegenmaßnahme, um die durch die Vergrößerung des Hohlleiterraumes in Höhe der Koppelfenster in der Regel entstehenden Resonanzen höherer Schwingungsformen zu unterdrücken.The coupling window 13 and 14 are each provided with an electrically conductive rod 17 and 18, which is inserted into the side walls of the square waveguide 12. They are a countermeasure to suppress the resonances of higher waveforms that usually occur due to the enlargement of the waveguide space at the level of the coupling window.

Das Signal vom Hoj-Typ wird durch eine Trennstruktur 19 im Quadrathohlleiter 12 zum Ausgang d geführt, an dem das Empfangssignal erscheint. Die Trenstruktur 19 besteht aus einem zwischen die oberen und unteren Wände des Quadrathohlleiters angeordneten Blech, das, in Ausbreitunsrichtung gesehen, nahe den hinteren Kanten der Koppelfenster beginnt. Nach vorn ist das Trennblech 19 beidseitig angenähert kreisförmig verjüngt ausgebildet und verläuft in eine Spitze 20. Hierdurch gelingt es, die vom Quadrathohlleiter 12 ankommende Welle vom H10-Typ widerstandsrichtig und reflexionsarm in die Rechteckhohlleiter 15 und 16 umzulenken. Über die Länge der Spitze 20 läßt sich die Richtdämpfung der Koppelanordnung für die H11- und E11-Welle beeinflussen. Ihre Länge wird auf höchste Richtdämpfung eingestellt.The signal of the H oj type is passed through a separating structure 19 in the square waveguide 12 to the output d, at which the received signal appears. The door structure 19 consists of a plate arranged between the upper and lower walls of the square waveguide, which, viewed in the direction of expansion, begins near the rear edges of the coupling window. Towards the front, the separating plate 19 is approximately circularly tapered on both sides and extends into a tip 20. This enables the H 10 -type wave arriving from the square waveguide 12 to be deflected into the rectangular waveguides 15 and 16 with low resistance and reflection. The directional damping of the coupling arrangement for the H 11 and E 11 shaft can be influenced over the length of the tip 20. Their length is set to the highest directional damping.

Am Ende des Trennblechs befindet sich eine weitere Hohlleiterauskopplung c, ebenfalls für Energieanteile der höheren Wellentypen H11 und E11. Das hier angekoppelte Signal ist in Figur 2, dem Blockschaltbild des gesamten Antennenspeisesystems, mit 42 bezeichnet worden. Die Hohlleiterausgänge c und d stellen zusammen mit den durch die Trennstruktur 19 gebildeten Teilhohlleitern eine gefaltete DoppelT-Verzweigung dar.At the end of the separating plate there is a further waveguide coupling c, also for energy components of the higher shaft types H 11 and E 11 . The signal coupled here has been designated 42 in FIG. 2, the block diagram of the entire antenna feed system. The waveguide outputs c and d, together with the partial waveguides formed by the separating structure 19, represent a folded double-T branch.

Zum Schluß soll anhand der Figuren 5a, b und c ein möglicher konstruktiver Aufbau des Antennenspeisesystems beschrieben werden. Die Bezeichnungen der einzelnen Elemente des Antennenspeisesystems stimmen mit denen des Blockschaltbildes der Figur 2 überein.Finally, a possible structural design of the antenna feed system will be described with reference to FIGS. 5a, b and c. The names of the individual elements of the antenna feed system correspond to those of the block diagram in FIG. 2.

An den Erreger 1 ist der Polarisationswandler 2 mit Amplituden- und Phasenausgleich angeschlossen. Diesem ist die Polarisationsweiche 3 mit Modenauskopplung nachgeschaltet mit dem Eingang a für das Sendesignal S, den Ausgängen b und c für die im allgemeinen noch verkoppelten Ablagesignale Δ1 und Δ2, welche mit Hilfe des Korrekturkopplers 4 in die unverkoppelten Ablagesignale Ax und Ay zerlegt werden, und dem Ausgang d für das Empfangssignal E. Vom Empfangssignal wird mit der Frequenzweiche 5 das Referenzsignal Σ abgespalten. Am Tor d' der Frequenzweiche 5 liegt das Störsignal S1 und ein evtl. zusätzliche übertragenes Nachrichtensignal N, das, was hier nicht eingezeichnet ist, über eine weitere Frequenzweiche vom Störsignal noch zu trennen wäre. Das Störsignal S1 wird schließlich einem in die Zeichnung nicht mit aufgenommenen Absorber zugeführt.The polarization converter 2 with amplitude and phase compensation is connected to the exciter 1. This is followed by the polarization switch 3 with mode coupling with the input a for the transmission signal S, the outputs b and c for the storage signals Δ1 and Δ2, which are generally still coupled and which are broken down into the uncoupled storage signals Ax and Ay with the aid of the correction coupler 4, and the output d for the received signal E. The reference signal Σ is split off from the received signal with the crossover 5. At the gate d 'of the crossover 5 is the interference signal S 1 and a possibly additional transmitted message signal N, which, which is not shown here, would still have to be separated from the interference signal via a further crossover. The interference signal S 1 is finally fed to an absorber not included in the drawing.

Der Korrekturkoppler 4 kann seine Funktion nur dann erfüllen, wenn seine Koppeldämpfung der Verkopplung der Ablagesignale Δ1 und Δ2 angepaßt ist und eine definierte Phasenbeziehung von 90° an seinem Eingang eingestellt ist. Diese Phasenbeziehung wird z.B. durch Längenwahl-des vom Hohlleiterausgang b zum Korrekturkoppler 4 führenden Hohlleiter eingestellt.The correction coupler 4 can only fulfill its function if its coupling damping is adapted to the coupling of the storage signals Δ1 and Δ2 and a defined phase relationship of 90 ° is set at its input. This phase relationship is e.g. by selecting the length of the waveguide leading from the waveguide output b to the correction coupler 4.

Es sei darauf hingewiesen, daß die Komponenten das Antennenspeisesystem, wie Polarisationswandler, Polarisationsweiche mit Modenankopplungen in ihren zentralen Hohlleiterabschnitt auch aus einem Rundhohlleiter gebildet werden können.It should be noted that the components of the antenna feed system, such as polarization converters, polarization switches with mode couplings in their central waveguide section, can also be formed from a round waveguide.

Die erfindungsgemäße Anordnung des Antennenspeisesystems funktioniert selbstverständlich auch mit einem runden Erreger als Grenzfall des elliptischen Erregers; in diesem Falle erübrigt sich der Amplituden- und Phasenausgleich im Polarisationswandler.The arrangement of the antenna feed system according to the invention naturally also works with a round exciter as the limit case of the elliptical exciter; in this case there is no need for amplitude and phase compensation in the polarization converter.

Weitere Möglichkeiten der Modifikation ergeben sich in der Beschaltung der Ein- und Ausgänge für die Nachrichtensignale. So kann beispielsweise mit Hilfe zusätzlicher Weichenschaltungen auch dem Sendeeingang a ein Empfangssignal entnommen werden oder in den Ausgang N ein Sendesignal eingespeist werden.Further options for modification result from the wiring of the inputs and outputs for the message signals. For example, with the aid of additional switch circuits, a receive signal can also be obtained from the transmit input a or a transmit signal can be fed into the output N.

Claims (8)

1. Aerial feed system for circularly polarised signals with an exciter (1), the aperture cross-section of which is symmetrical to at least one main axis, and an equipment (3) for the coupling of higher wave types as deviation signals for the tracking of the aerial, the excitation of which wave types takes place proportionally to the deviation of the main aerial axes from a received circularly polarised beacon signal, characterised thereby, that a polarisation converter (2), which contains amplitude and phase compensating devices (8, 8', 9, 9', 10, 11), is arranged between the exciter (1) and the equipment (3) for the coupling of higher wave types and that the coupling-in of the higher wave types occurs in an in itself known polarisation filter (3), which is connected to the polarisation converter (2) and for the separation of two orthogonally polarised signals, wherein this filter (3) possesses two communication signal inputs or outputs (a, d) for the coupling of the fundamental wave types and two outputs for the coupling of two different fields which have arisen through additive and subtractive superimposition of two higher wave types and contain the deviation data of the aerial from the target direction in Cartesian orientation.
2. Aerial feed system according to claim 1, characterised thereby, that the polarisation converter (2) consists of a square wave guide, that it possesses a coupling attenuation differing from 3.01 dB for the amplitude compensation, wherein bevels (8, 9) in two diagonally opposite edges of the wave guide and a dielectric plate (10), engaging in grooves (8', 9') and being between two diagonally opposite corners, are arranged as coupling means and that a further dielectric plate (11) is arranged in the wave guide horizontally or vertically between the wave guide walls for the phase compensation.
3. Aerial feed system according to claim 1 or 2, characterised thereby, that a portion of rectangular cross-section is provided at the end at the exciter side in the polarisation converter (2) of otherwise square cross-section for the phase compensation.
4. Aerial feed system according to claim 1 or 2, characterised thereby, that the coupling means in the polarisation converter (2) are so dimensioned that they counteract the frequency dependence, caused by the exciter, of the gain difference and of the phase difference of the waves in both the main planes.
5. Aerial feed system according to claim 1, characterised thereby, that a frequency filter (5), which separates the reference signal (Σ) originating from the received beacon, an additional communications signal (N) and an interference signal (S), which comes into being through reflection of transmitted signal components at the aerial, one from the other is connected to the output (d) of the polarisation filter (3) and that the output of the frequency filter, at which the interference signal (S1) appears, is terminated by an absorber (7).
6. Aerial feed system according to claim 1, characterised thereby, that a correction network for the coupling-out of the deviation signals is connected to the outputs (b, c) for the deviation signals (Δ 1, A2) of the polarisation filter (3).
7. Aerial feed system according to claim 6, characterised thereby, that a directional coupler is used as correction network.
8. Aerial feed system according to claim 1, characterised thereby, that the length of the exciter horn throat is so dimensioned that the wave guide wave types employed for obtaining the deviation data are so set in their phase position one relative to the other that the mutually independent deviation signals are present directly, without use of a correction network, at the outputs (b, c) of the polarisation filter (3).
EP80108118A 1980-05-30 1980-12-22 Antenna-feeding system for a tracking antenna Expired EP0041077B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19803020514 DE3020514A1 (en) 1980-05-30 1980-05-30 AERIAL FEEDING SYSTEM FOR A TRACKABLE AERIAL
DE3020514 1980-05-30

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EP0041077A2 EP0041077A2 (en) 1981-12-09
EP0041077A3 EP0041077A3 (en) 1981-12-16
EP0041077B1 true EP0041077B1 (en) 1985-02-20

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EP80108118A Expired EP0041077B1 (en) 1980-05-30 1980-12-22 Antenna-feeding system for a tracking antenna

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US (1) US4365253A (en)
EP (1) EP0041077B1 (en)
JP (1) JPS5724105A (en)
CA (1) CA1164088A (en)
DE (2) DE3020514A1 (en)

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Also Published As

Publication number Publication date
JPS5724105A (en) 1982-02-08
US4365253A (en) 1982-12-21
DE3070235D1 (en) 1985-03-28
EP0041077A2 (en) 1981-12-09
JPH0369201B2 (en) 1991-10-31
DE3020514A1 (en) 1981-12-10
EP0041077A3 (en) 1981-12-16
CA1164088A (en) 1984-03-20

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