EP0014650B1 - Adaptives Höchstfrequenz-Raumfilter und dessen Verfahren der Anwendung zur Abschwächung oder Unterdrückung der Nebenzipfel des Strahlungsdiagrammes einer Antenne - Google Patents

Adaptives Höchstfrequenz-Raumfilter und dessen Verfahren der Anwendung zur Abschwächung oder Unterdrückung der Nebenzipfel des Strahlungsdiagrammes einer Antenne Download PDF

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Publication number
EP0014650B1
EP0014650B1 EP80400164A EP80400164A EP0014650B1 EP 0014650 B1 EP0014650 B1 EP 0014650B1 EP 80400164 A EP80400164 A EP 80400164A EP 80400164 A EP80400164 A EP 80400164A EP 0014650 B1 EP0014650 B1 EP 0014650B1
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EP
European Patent Office
Prior art keywords
antenna
wires
diodes
filter
reception
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP80400164A
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English (en)
French (fr)
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EP0014650A1 (de
Inventor
Claude Chekroun
Yves Michel
Henri Sadones
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D'ETUDE DU RADANT Ste
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D'ETUDE DU RADANT Ste
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Application filed by D'ETUDE DU RADANT Ste filed Critical D'ETUDE DU RADANT Ste
Priority to AT80400164T priority Critical patent/ATE3347T1/de
Publication of EP0014650A1 publication Critical patent/EP0014650A1/de
Application granted granted Critical
Publication of EP0014650B1 publication Critical patent/EP0014650B1/de
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q25/00—Antennas or antenna systems providing at least two radiating patterns
    • H01Q25/002—Antennas or antenna systems providing at least two radiating patterns providing at least two patterns of different beamwidth; Variable beamwidth antennas
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
    • H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
    • H01Q3/2605—Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
    • H01Q3/2611—Means for null steering; Adaptive interference nulling
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
    • H01Q3/44—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the electric or magnetic characteristics of reflecting, refracting, or diffracting devices associated with the radiating element
    • H01Q3/46—Active lenses or reflecting arrays

Definitions

  • the present invention relates to a spatial filter for attenuating or canceling certain secondary lobes of the radiation pattern of microwave antennas, as well as the applications of this filter to eliminating the effects of active or passive interference (jammers, clutter of ground echoes, sea, etc ...) during reception on the antenna, the detection and localization of several jammers likely to blind the antenna on reception, and also the applications of this filter to partial and local attenuation when receiving an antenna.
  • a spatial filter for attenuating or canceling certain secondary lobes of the radiation pattern of microwave antennas, as well as the applications of this filter to eliminating the effects of active or passive interference (jammers, clutter of ground echoes, sea, etc ...) during reception on the antenna, the detection and localization of several jammers likely to blind the antenna on reception, and also the applications of this filter to partial and local attenuation when receiving an antenna.
  • Another method under development is also currently being proposed to reduce the effects of jammers on the antenna, which consists in associating with the main directive antenna a much less directive secondary antenna and subtracting from the signals received by the main antenna those received by the secondary antenna.
  • the gain of the secondary antenna being substantially constant for all directions of the monitored space, the energy received from a possible jammer will be of the same order of magnitude as that coming from the target in the secondary antenna, which n 'is not the case for the main antenna in which the gain in the direction of the jammer is low.
  • This method has many drawbacks: it is not fully adaptive; the signal received from the target is significantly reduced from the first subtraction, this method cannot be used for more than two jammers. It is very expensive because it requires an auxiliary antenna for each external interference and its associated treatment.
  • the method uses for its implementation, as will be seen, an extremely simple technology and employs a very small number of commands, this gives the applications which result therefrom a great interest both in terms of technological simplicity, simplicity of implementation. and order only in terms of cost.
  • this method applies to any antenna, whether mechanical scanning or electronic scanning, which emits a linearly polarized wave. It uses a filter which is constituted by a network of parallel wires, which are placed parallel to the electric field vector of the microwave plane wave, charged by resistors whose values vary continuously as a function of the intensity of the currents. that pass through them that can be modulated at will in each thread. As a function of the law of distribution of the currents in the parallel wires charged with network resistances, there is a spatial modulation of the amplitude of the wave passing through the network. To allow a convenient realization of the filter, the network of parallel wires consists of parallel conducting wires, parallel to the electric field vector of the wave emitted by the antenna, carrying diodes placed in series and distributed at a constant pitch on each of the son.
  • Each diode-carrying wire is supplied with electric current for biasing the diodes in the passing direction, by means of a switch which makes it possible to vary the intensities of this direct current over a wide range of values from the microampere to the tens of milliamps.
  • the invention consists in interposing on the wave path an adaptive spatial filter which, although consisting of a network of conductive wires charged by variable resistors such as diodes having a structure similar to that described in the aforementioned patents FR-A-2 063 967, EP-A-0 000 308 and US-A-3 708 796, is ordered quite differently, as indicated above and as will be explained in more detail below, so that, on emission, the filter is almost transparent, while on reception, one acts on the microwave wave by modifying its amplitude and not its phase, which allows, according to the distribution of the intensities of the retained currents , to attenuate or cancel certain secondary lobes of the antenna diagram on reception.
  • variable resistors such as diodes having a structure similar to that described in the aforementioned patents FR-A-2 063 967, EP-A-0 000 308 and US-A-3 708 796
  • the panel consisting of son-diodes working only in direct-reverse allowed the phase shift without deformation of the beam, for electronic scanning, while according to the invention, the panel still working in direct allows to obtain the deformation of the beam and the attenuation of the desired secondary lobes without phase shift.
  • the intensity modulation is weak for a step of less than one wavelength of the microwave energy in the case of PIN diodes.
  • the filter can at will create in the antenna diagram attenuations or cancellations of secondary lobes in all the determined directions desired other than those of the main lobe.
  • diodes having this property are well known and exist on the market. These are PIN diodes in which it is possible to control the microwave resistance directly via static bias current: this controls the losses by the Joule effect in the diode.
  • Such diodes have been used in particular antennas, such as the TACAN antennas making it possible to obtain rotating radiation, as described in French patent 2,379,177, such an antenna with rotating radiation is obtained by temporal modulation of the currents resulting in the creation of a rotating diagram of the antenna on transmission.
  • the filter adapts to all microwave antennas emitting a linearly polarized wave, being formed by the antenna, the filter placed on the path of the wave makes it possible to attenuate or cancel upon reception the radiation in directions other than that of the main lobe:
  • the modulation of the intensities of the currents in the wires on which the diodes are mounted is a modulation with a spatial period (function of the departments concerned). This modulation of the intensities of current in the wires remaining constant over time, as long as the radiation must be canceled in the directions concerned.
  • the filter adapts to fixed microwave antennas, mechanical scanning antennas, electronic scanning antennas in a plane perpendicular to the electric field vector of the emitted microwave wave.
  • the filter will apply especially well to electronically scanned antennas which have, by construction, higher side lobes than those of conventional antennas.
  • the filter Among the essential applications of the filter is also the location of several jammers, in a time less than the time taken by the echo to reach the antenna.
  • the filter according to the invention is the reduction of the lateral lobes of the reception pattern of an antenna radiating to the transmission in a uniform manner.
  • 31 conductive wires (1) of copper 4/10 mm in diameter are placed parallel to each other.
  • Each of the wires carries PIN diodes (2) (type HP 5082-3080) placed in series, uniformly distributed, the distance (3) between two diodes on the same wire being 21 mm.
  • the wires are spaced from each other by a spacing (4) of 56 mm. All of these wires are placed in the center of a polyethylene strip (5) whose radioelectric constant ⁇ is equal to 2.35 and the loss tangent of 4 - 10- 4 , the thickness (6) of this blade is 36 mm.
  • a battery (8) of 31 switches is connected to the 4 x 31 wires and allows each of the 31 lines to be polarized with currents varying from 200 microamps to 20 milliamps in times less than 20 nanoseconds.
  • FIG. 3 An example of distribution of the current intensities in the diode wires is given in FIG. 3: diagram on which the position of the wires is shown on the abscissa and the current intensity on the ordinates. This distribution is provided for the application described below for the determination of 3 jammers in the case of an antenna of the type below.
  • FIG. 4 shows in dotted lines (9) the diagram of the antenna pointing in a direction (10) in bearing when all the wires are polarized uniformly with currents of 30 milliamps.
  • solid line (11) the modified diagram on which after normalization to the initial diagram we note that three “hollows” (12) (13) (14) were created in three directions (- 37 °, 20 °, 37 °) corresponding with 3 active jammers lighting the antenna in these directions.
  • the diagram (17) corresponds to the diagram when the wires are uniformly polarized.
  • the diagram (15) has a "dip” in the direction (18) of 54 ° and the diagram (16) has a "dip” in the direction (19) of 32 °.
  • the search for one or more active jammers for a given pointing direction will be carried out in less than a microsecond.

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  • Variable-Direction Aerials And Aerial Arrays (AREA)
  • Noise Elimination (AREA)

Claims (9)

1. Verfahren zur Verminderung oder Beseitigung bestimmter sekundärer Empfangskeulen aus dem Strahlungsdiagramm einer linear polarisierten Hyperfrequenzantenne, gekennzeichnet durch folgende Schritte :
- Man ordnet als Filter vor der Antenne im Sende-Empfangsstrahl ein aus leitenden Drähten (1) bestehendes Gitter an, dessen Drähte parallel zum elektrischen Vektor der hyperfrequenten Wellen verlaufen und die mit diodenartigen Widerständen (2) versehen sind, deren Werte entsprechend der Größe der sie durchfließenden Ströme kontinuierlich variieren ;
- Man läßt während der Sendeperiode der Antenne durch alle Drähte (1) in Durchlaßrichtung der Dioden (2) gleiche Ströme fließen, vorteilhafterweise einige mA ;
- Man läßt während der Empfangsperiode der Antenne durch alle Drähte (1) in Sperrichtung der Dioden (2) ungleiche Ströme fließen, die zwischen einigen µA und einigen mA schwanken, um so eine räumliche Verteilung der Ströme zu erzeugen, die eine Verringerung oder Unterdrückung der gewünschten sekundären Keulen des Diagrammes ergeben.
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß man mit Hilfe eines elektronischen Schalters (8) das Gesetz der räumlichen Verteilung der Ströme in den Drähten sehr schnell ändert, um auf diese Weise nacheinander alle sekundären Keulen des Empfangsdiagrammes der Antenne zu vermindern ;
- Man speichert das oder die verwendeten Verteilungsgesetze, die eine Verminderung oder Unterdrückung der gewünschten Keulen während der verbleibenden Empfangsperiode ergeben.
3. Verfahren nach den Ansprüchen 1 oder 2, dadurch gekennzeichnet, daß man als räumliches Verteilungsgesetz der durch die Drähte fließenden Ströme ein periodisches Verteilungsgesetz verwendet.
4. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß man als räumliches Verteilungsgesetz der durch die Drähte fließenden Ströme ein Gesetz verwendet, das ein räumliches Gleichgewicht der empfangenen Energie ergibt, insbesondere eine Gauß'sche Verteilung.
5. Anwendung des Verfahrens zur Verminderung oder Beseitigung der sekundären Keulen eines Strahlungsdiagrammes einer Hyperfrequenzantenne, die eine linear polarisierte Welle aussendet, nach den Ansprüchen 1 bis 3, zur Lokalisierung von Störsendern, die senkrecht zum elektrischen Feld der von der Antenne abgestrahlten Wellen aufgestellt sind, dadurch gekennzeichnet, daß man das Verteilungsgesetz der durch die Drähte des oder der Gitter fließenden Ströme, die das Filter darstellen, solange variiert, bis ein Minimum der Störung im Empfangsstrahlungsdiagramm der Antenne erreicht ist.
6. Anwendung des Verfahrens zur Verminderung oder Beseitigung der sekundären Keulen eines Strahlungsdiagrammes einer Hyperfrequenzantenne, die eine linear polarisierte Welle aussendet, nach den Ansprüchen 1 bis 3, zur Beseitigung der Einwirkung eines Störsenders, der senkrecht zum elektrischen Feldvektor der von der Antenne abgestrahlten Wellen aufgestellt ist, dadurch gekennzeichnet, daß man die sekundäre Keule des Strahlungsdiagrammes, die sich in Richtung des Störsenders befindet, dadurch beseitigt, daß man das Verteilungsgesetz der Ströme in den das räumliche Filter darstellenden Drähten geeignet wählt.
7. Räumliches Filter zur Durchführung des Verfahrens nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß dieses, wie an sich bekannt, ein Gitter aus leitenden Drähten (1) enthält, die parallel zum elektrischen Feldvektor der hyperfrequenten Welle verlaufen und die mit Widerständen, insbesondere mit Dioden (2) bestückt sind, deren Widerstandswerte entsprechend der Größe der sie durchfließenden Ströme variieren, daß ein Schalter (8) vorgesehen ist, der eine Änderung der durch die genannten Drähte fließenden Ströme in dem Sinne erlaubt, daß während der Sendeperiode der Antenne gleiche Ströme von mindestens einigen mA in Durchlaßrichtung der Dioden und während der Empfangsperiode der Antenne ungleiche Ströme in Sperrichtung der Dioden nach einem vorbestimmten Verteilungsgesetz fließen, das eine Verminderung der sekundären Keulen des Empfangsdiagrammes der Antenne ergibt.
8. Filter nach Anspruch 7, dadurch gekennzeichnet, daß die genannten Widerstände Dioden sind und daß mehrere Dioden auf jedem Draht, wie an sich bekannt, in Reihe geschaltet sind.
9. Filter nach Anspruch 8, dadurch gekennzeichnet, daß wie an sich bekannt, die auf den Drähten des Gitters in Reihe geschalteten Dioden auf jedem Draht im gleichen Abstand (3) angeordnet sind.
EP80400164A 1979-02-05 1980-02-04 Adaptives Höchstfrequenz-Raumfilter und dessen Verfahren der Anwendung zur Abschwächung oder Unterdrückung der Nebenzipfel des Strahlungsdiagrammes einer Antenne Expired EP0014650B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT80400164T ATE3347T1 (de) 1979-02-05 1980-02-04 Adaptives hoechstfrequenz-raumfilter und dessen verfahren der anwendung zur abschwaechung oder unterdrueckung der nebenzipfel des strahlungsdiagrammes einer antenne.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR7902918A FR2448231A1 (fr) 1979-02-05 1979-02-05 Filtre spatial adaptatif hyperfrequence
FR7902918 1979-02-05

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EP0014650A1 EP0014650A1 (de) 1980-08-20
EP0014650B1 true EP0014650B1 (de) 1983-05-11

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US (1) US4344077A (de)
EP (1) EP0014650B1 (de)
AT (1) ATE3347T1 (de)
DE (1) DE3063006D1 (de)
FR (1) FR2448231A1 (de)

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Publication number Priority date Publication date Assignee Title
DE3441269A1 (de) * 1984-01-23 1989-12-28 Cmh Sarl Verfahren zur modulation der amplitude der sekundaerkeulen der strahlungscharakteristik einer uhf-antenne, anwendung des verfahrens und filter zur durchfuehrung des verfahrens
DE3441269C2 (de) * 1984-01-23 1999-06-10 Cmh Sarl Verfahren zur Lokalisierung von Störern durch Veränderung der Sekundärkeulen des Strahlungsdiagrammes

Also Published As

Publication number Publication date
FR2448231B1 (de) 1983-06-24
FR2448231A1 (fr) 1980-08-29
DE3063006D1 (en) 1983-06-16
ATE3347T1 (de) 1983-05-15
US4344077A (en) 1982-08-10
EP0014650A1 (de) 1980-08-20

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