FR2704359A1 - Flat antenna. - Google Patents

Abstract

In a planar antenna, equipped with radiating elements, receiving, or emitting each one on two different oscillatory modes of reception signals, or emission signals, independently of each other one obtains, practically without additional expense, by preserving the same opening, the possibility of widening the reception, or widening the emission of electromagnetic waves, by the fact that the radiating elements (21, 22, 23, 24 or 29, 30, 31, 32) are radiating elements multi-band. The radiating elements are preferably installed in a square array and constituting an array of antennas. The radiating elements are then preferably nested one inside the other.

Description

Flat antenna The invention relates to a flat antenna, equipped with elements

  radiating, each receiving or transmitting on two different oscillatory modes of reception signals or emission signals, independently of the

each other.

  A planar antenna of this type is known from DP-A-22 42 316. Square radiating elements are arranged in a plane. A wave type, like a horizontal wave type, is picked up with this antenna on the corresponding parallel sides and is grouped in an output line. On the sides perpendicular to these

  first sides, the wave having been orthogonal polarized-

  relative to the first direction, so the vertically polarized wave is picked up and grouped in a

  separate output line. Due to the transmission if-

  multane of electromagnetic waves with gold polarization

  thogonal it is therefore possible to exploit several times a frequency band (frequency reuse)

  and receive it with a single antenna.

  Feeder systems are also known for which the separation between the different polarized electromagnetic waves is effected by means of polarization switches and / or low noise level converters, for reflector antennas.

or planar antennas.

  Starting from a planar antenna, mentioned at the beginning, the object of the present invention is to perfect it so that the antenna can be used for reception, or for the transmission of a large

  different frequency range, the structure of the an-

should be simple.

  The problem posed is solved, according to the invention, by the fact that, in the planar antenna mentioned at the beginning, the radiating elements are multi-band radiating elements. Thanks to the arrangement according to the invention it is

  possible, with a planar antenna, not only

  receive or emit electromagnetic waves having

  a different polarization, but also a

  something different. An enlargement of the antenna opening is then not necessary and the structure of the antenna is very simple. In addition to what is called the polarization-diversity operating mode, it is also possible to have a superposition of a

  frequency multiplex excitation, so that at ni

  calf of the antenna manufacturing, we obtain a notable economy, of volume, weight and material,

with deep integration.

  It should be noted that, by the planar antenna concept, we mean not only a planar arrangement but also a surface, curved, spherical or cylindrical arrangement, or an antenna arrangement

  made on a spherical, curved or cylindrical surface

  drique. The planar antennas are then normally

  read from directly radiating elements

  plies, or electromagnetically coupled, or electrically

  individual or elementary radiant elements, arranged

surface.

  According to an advantageous embodiment of the invention, the radiating elements are produced in the form of loops. The loops are then in particular nested one inside the other. Each loop of a nested loop arrangement is then resonant for an associated frequency band, or for an associated wave frequency. It is then very advantageous to produce a loop of a nested loop arrangement on one side and another loop on the other side of a support layer intended for the loops. Alternatively, it

  however, it is also possible and advantageous to

  read the nested loops each on a clean support, so as to obtain a multi-layer structure or sandwich structure. This has the advantage that two loops, acting as resonant elements, or as resonators, overlap with respect to their loop surface. This results in greater degrees of freedom in the design of the buckles. Each loop of a radiating element preferably has two connecting lines, so that, in addition to the signals coming from different frequency bands, it is also possible to prepare each time

  in a waveguide two separate signals after polari-

  station. The loops or the radiating elements are of

  annular shape, preferably responding to a symmetrical

  two-dimensional sorting. Therefore, we can receive or transmit two polarization planes simultaneously, this is

  to say two oscillatory modes. It is then

  geux to have a square shape of radiating elements or curls. The coupling of the connection lines can then be carried out on the four sides of the frame, two opposite power supplies exciting modes in the same plane of polarization. If all four lines must not have the function of being supply lines, each time two opposite lines can be used as supply and withdrawal lines, for connection. In this case, only part of the electromagnetic energy is emitted, or sampled, while the rest in the case where the radiating elements are grouped in networks of antennas - is guided towards other radiating elements. There is then a particularly good decoupling of the neighboring supply lines, when the connection lines of the square loops are connected each time with the dimensions which are not parallel, so that a good decoupling results, on the basis of the angle of 90. The radiating elements are preferably connected according to the technique of ribbon waveguides, in the case where they are placed to form a

antenna array.

  The radiating elements are then connected to each other in a parallel connection. It is however particularly advantageous to adopt a serial connection, because the line length is shorter and the possibility of integration is more

simple.

  Preferably, the two different oscillatory modes are orthogonal oscillatory modes,

  although we can also have oscillating modes

non-orthogonal roofs.

  The adjustment of the electrical length of the lines or the adjustment of the excitation phase is also

  advantageously carried out using a phase shifter, in part

  particular dielectric phase shifter. To avoid repetition on this subject, it is particularly referred

  to DE-A-41 20 439 from the same plaintiff.

  According to another advantageous embodiment

  of the invention the directional diagrams of the different

  rents oscillatory modes and / or different oscillatory frequencies are adjustable independently of each other. This can be obtained preferably by the fact that the directional diagrams are adjusted by the wiring route in particular by

  modification of line lengths. The modification

  tion of the line lengths is preferably carried out using switching diodes, or with

  switching of switchable bias voltage.

  It is however also possible to carry out the

  directional diagram adjustment by choice of fac-

  coupling tor. A very advantageous embodiment

  geuse is that in which the planar antenna is integrated on a support with parts of circuit connected. This allows, on the one hand, to minimize the transition losses and, on the other hand, the production, both of circuit parts and also of the network of lines and / or radiating elements can be carried out in a process of unit manufacturing, so that the planar antenna can be manufactured even

more economical.

  The planar antenna is however made of pre-

  ference and alternatively also in the form of a module

  clean antennas. The antenna module is then covered

  pliable on the signal processing circuit, therefore on the active circuit, as is usual for example in the case of coupling with round hollow conductors of the usual converters on the market, in particular what are called "low-noise converters" "(low noise), serving as an interface between primary transmitters and the active part of the transmitter or receiver system, for the transition between hollow conductors

and strip conductors.

  According to a particularly advantageous embodiment of the invention, it is possible to adjust an angle between the normal to the surfaces of the planar antenna and the direction of main radiation, what is called the offset angle, and those of preferably by order of

  the complex excitation of the radiating elements, am-

  fullness and / or in phase. The angular adjustment is then advantageously carried out by the choice of the wiring route between the radiating elements and / or the wiring route.

  connection of the flat antenna. In addition, or going to

  laughing, it is however also possible to carry out the angular adjustment by the choice of the distance between the radiating elements nested one inside the other and / or the radiating elements arranged one with

next to others.

  The orthogonally polar-wave modes

  These are preferably in the form of waveforms.

  linearly spread. You must have or perform

  each time a polarization coupling plane.

  However, it is also possible to use wave modes.

  orthogonally polarized latoirs for reception, or for transmission with two circularly polarized waves. Here too, care must be taken each time

good polarization decoupling.

  The reception, or the emission of waves with four different polarizations, orthogonal and in pairs, as during the reception, or the emission of two waves polarized in a linear or circular way, is possible, simultaneously, with a decoupling, which in the best case is 3 dB and is not suitable for single frequency applications. For operation with different types of polarization, for example linear and / or circular, it is possible to switch strip conductors of different lengths, by

  example with diodes, so that we can compose

  ser a signal with circular polarization, from two orthogonal signals, with linear polarization. This can be done preferably by switching a conductive element on or off and then adding the

  signals, their phase shift being about 90.

  To optimize the illumination of a reflector, it is advantageous to use a screen having a

  frequency selectivity, using which

  wise or differences in amplitude between the incident or emitted waves may be caused by

  through the opening. The illumination of the re-

  flector is then determined in principle from the

  directional characteristic of the antenna module.

  Frequency-selective screens are preferably composed of parasitic elements, which make it possible to obtain an independent diagram synthesis, from the point of view of the phase properties, which can be controlled, of the waves emitted in different frequency ranges. . To avoid repetition on this subject, it is referred to DE-A-4313395, of the same date of request, which, to this extent, is part of

content of these documents.

  Antenna modules with different directional diagrams, especially for operation

  diversity, are obtained, besides by the structure of the re-

  bucket of feed antennas, also by adj

  tion of other antenna elements, in particular those having resonance at the frequency bands

  higher, these other antenna elements being ground-

  lawful as a provision for canceling what

  this is called the "grading-lobes".

  To promote defocusing / focusing

  desired, there is preferably at least one

  dielectric rod. Advantageously, these lenses pre-

  feel different properties, for different wavelengths. The use of such dielectric lenses certainly undesirably limits the bandwidth. On the other hand, this also results in desired effects during diagram synthesis, in particular when the bands of

  frequencies are located far from each other.

  The invention is explained below using

  of exemplary embodiments, with reference to the figures.

On the drawing:

  Figure 1 is a schematic representation of a re-

  classic antenna bucket with elements

  square radiating elements, FIG. 2 is the schematic representation of an example of embodiment of planar antennas according to the invention; Figures 3a to 3c are schematic embodiments of coupling lines of radiating elements; Figure 4 shows a schematic arrangement of a

  square radiating element aimed at explicitly

  ter and describe oscillatory modes occurring on the radiating element, and Figure 5 is a schematic representation of a parabolic offset reflector, using an embodiment of the antenna

plane according to the invention.

  In FIG. 1, square loops 1, acting as radiating elements, are arranged in an array of antennas, at a distance from each other. In the horizontal direction, the sides respectively opposite to each other of the squares are connected to lines 2, grouped on one side of the network, so that the wave, polarized in the X direction of an incoming electromagnetic radiation

  on the antenna network, goes out on connection 3.

  In the vertical direction, the radiating elements 1 are connected by lines 4, each time at the mutually opposite sides of the square radiating elements and are grouped on one side, so that the wave, polarized in the Y direction, leaves at the outlet. 6. Such an array of antennas, with what is called a

  polarization diversity, is known.

  Figure 2 shows schematically a re-

  antenna bucket according to an embodiment of the invention. As in the antenna network shown

  in FIG. 1, we again have ray-

  nants 21, 22, 23, 24 squares, connected in the way

  known, represented in FIG. 1, by lines ho-

  rizontales 25 and vertical lines 26, so that at the outputs 27, or 28 the polarized wave, in the direction X, or in the direction Y, its frequency fl

  being assigned by dimensions of the radius elements-

nants 21, 22, 23, 24.

  According to the invention, there is then provided inside the radiating elements 21, 22, 23, 24 each time an additional radiating element 29, 30, 31, 32, also square, however having sides of shorter length. These radiant elements

  29, 30, 31, 32 smaller are connected in a cor-

  corresponding to what is the case for large radiating elements 21, 22, 23, 24, in particular by means of horizontal lines 33 and vertical lines 35, each grouped at connections 37, or 38, to which

  outputs the polarized wave in the X direction or the po wave-

  widened in direction Y for these small elements 29, 30, 31, 32. The waves polarized by the small

  radiating elements 29, 30, 31, 32 have a frequency

  quence f2 higher than the resonance frequency fl des

  large radiating elements 21, 22, 23, 24.

  Preferably, lines 25, 26, connecting the

  large radiating elements 21, 22, 23, 24 are produced

  sés on another plane, for example on the other side or on an additional support, that are the lines 33, connecting the small radiating elements 29, 30, 31, 32.

  Using the antenna network according to the

  vention, according to Figure 2, we obtain a planar antenna with a very simple structure, which allows the reception, or the emission of electromagnetic waves, in two frequency bands and, each time, in two polarization planes, without the opening of the antenna must therefore have been greater than for

  the front antenna represents in FIG. 1.

  Different forms of radiating elements and their coupling to the lines or to the distribution networks are shown diagrammatically in FIGS. 3, 3b

and 3c.

  The square radiating element shown in the figure

  gure 3a is a pair, or connected on each side, in particular in the center of the respective side, to a line 39, 40, 41, 42. FIG. 3b represents a nested arrangement of two radiating elements 43, 44, the large radiating element 43 being coupled or connected at angles to

  connecting lines 45, 46. The small radius element-

  nant 44, located internally, is also connected to the corners of the square with lines 47, 48, which extend in another plane than for the large radiating element 43, and their connecting lines 45, 46. The exemplary embodiment shown in Figure 3c differs from that of Figure 3b only by the fact that the connections 45, 46, or 47, 48 of the radiating elements 43, 44 are not coupled to the corners of the square radiating elements 43, 44 but in the middle lengths

sides.

  Figure 4 shows a radiating element

  square 50 with a conductor connection 51, extending

  in the X direction. The radiating element 50 square

  has the side length L. For the radius element-

  nant 50 supplied from direction X, the following modes are dominant

  ! JJx | - C, .cos (n. .F (X; L)) n = O, 1, 2 ...

  J radiation, is carried out perpendicular-

  ment with respect to the plane of the drawing, the electric field vector Ex then vibrating in the direction X. n is

  then equal to 0, or else is a natural whole number.

  The modes, which can be excited simultaneously according to the principle of superposition and leading to

  the emission of an electric field vector Ey oscil-

lant in the Y direction, are:

  IJ1l - c1, .cos (n. .F (Y; L)) n = O, 1, 2 ...

  Here again we have n = O, or else a number

whole natural.

  The radiating element 50, in the form of a square loop resonator, has, by comparison with the widely used rectangular system, improved bandwidth properties, which can

  be regulated by an appropriate choice of geo-dimensions

  metrics. Compared to the radiating elements an-

  resonant rings, in the case of rectangular or square radiating elements, there is an improvement in the emission of electromagnetic waves at the corners; these

  the latter are therefore to be preferred.

  FIG. 5 schematically represents the use of a planar antenna 52 according to the invention, in connection with a parabolic offset reflector 53. Due to the already explained embodiment of the invention, consisting in providing an offset angle at

  between the normals of the surfaces 54 of the parallel reflector

  bolique 53 and the main radiation direction 55, the offset parabolic reflector 53 of a satellite reception installation can be arranged practically

  vertically, which is desired.

  The invention has been presented above using

  of preferred embodiments. Many va-

  laughing and modifications are however possible for those skilled in the art without thereby leaving the spirit of the invention. The planar antenna according to the invention can be manufactured in a particularly economical manner, in particular because instead of having active components, only passive elements are used, such as PE supports, sheets, bootmakers

  flat, if necessary dielectric lenses etc.

Claims (34)

  1. Flat antenna, fitted with radius elements   nants, each receiving or transmitting on two different oscillatory modes of reception signals or emission signals, independently of each other, characterized in that the radiating elements (21, 22, 23, 24; 29, 30, 31, 32; 43, 44) are elements radiant multi-bands.   2. planar antenna according to claim 1,   characterized in that the radiating elements (21, 22, 23, 24; 29, 30, 31, 32; 43, 44) are produced under form of curls.   3. Flat antenna, according to any one of   claims 1 and 2, characterized in that the elements   radiant elements (21, 22, 23, 24; 29, 30, 31, 32, 43, 44) are nested.   4. Flat antenna, according to any one of   previous claims, characterized in that   each radiating element (21, 22, 23, 24; 29, 30, 31,   32; 43, 44) of an arrangement of radiating elements   bricks is resonant for an associated frequency band. 5. Flat antenna, according to any one of   previous claims, characterized in that a   radiating element of an arrangement of nested radiating elements is produced on one side and another radiating element is produced on the other face of a support layer intended for the radiating elements (21, 22, 23, 24; 29, 30, 31, 32; 43, 44; 50).   6. Flat antenna, according to any one of   previous claims, characterized in that the   nested radiating elements (21, 22, 23, 24; 29, 30, 31, 32; 43, 44) are each produced on a clean support.   7. Flat antenna according to any one of the re-   previous sales, characterized in that the nested radiating elements (21, 22, 23, 24; 29, 30, 31, 32; 43, 44) are each produced on a single support.   8. Flat antenna according to any one of the re-   previous sales, characterized in that each   radiating element has two connecting lines.   9. Flat antenna, according to one of the claims   previous actions, characterized that the elements radiant are annular in shape.   10. Flat antenna according to any one of   previous claims, characterized in that the   radiating elements (21, 22, 23, 24; 29, 30, 31, 32;   43, 44) respond to two-dimensional symmetry.   11. Planar antenna according to any one of   previous claims, characterized in that the   radiating elements (21, 22, 23, 24; 29, 30, 31, 32;   43, 44) are produced in the form of a square frame.   12. Planar antenna according to any one of   previous claims, characterized in that in   in the case of a radiating element (21, 22, 23, 24; 29, 30, 31, 32; 43, 44) square, the connecting lines (25, 26; 34, 35; 45, 46; 47, 48 ) are connected to the non-parallel sides of the radiating elements (21, 22, 23, 24 29, 30, 31, 32; 43, 44).   13. Flat antenna according to any one of   previous claims, characterized in that the   radiating elements (21, 22, 23, 24; 29, 30, 31, 32;   43, 44; 50) are arranged in an array of antennas.   14. Flat antenna according to any one of   previous claims, characterized in that the   radiating elements (21, 22, 23, 24; 29, 30, 31, 32;   43, 44; 50) are connected using the conduction technique gang tutors.   15. Planar antenna according to any one of   previous claims, characterized in that the   radiating elements (21, 22, 23, 24; 29, 30, 31, 32; 43, 44; 50) are connected together according to a connection in parallel.   16. Flat antenna according to any one of   previous claims, characterized in that the   radiating elements (21, 22, 23, 24; 29, 30, 31, 32; 43, 44; 50) are connected together according to a connection serial.   17. Flat antenna according to any one of   previous claims, characterized in that the   two different oscillatory modes are modes orthogonal oscillatory.   18. Planar antenna according to any one of   previous claims, characterized in that the   directional diagrams of the different modes oscillated   roofs and / or frequency ranges are adjustable   independently of one another.   19. Flat antenna according to any one of   previous claims, characterized in that the   the directional diagrams are adjusted conductor route.   20. Flat antenna according to any one of   previous claims, characterized in that the   the directional diagrams are adjusted by means of   specification of the lengths of the lines.   21. planar antenna according to claim 20, characterized in that the modification of the lengths   lines are made using switching diodes   tion. 22. planar antenna according to claim 20, characterized in that the modification of the lengths   lines is made by the choice of the factor of   beach. 23. Flat antenna according to any one of   previous claims, characterized in that the   the electrical length of the lines is adjusted with phase shifters.   24. Flat antenna according to claim 23, characterized in that the phase shifter is a dielectric phase shifter. 25. Flat antenna according to any one of   previous claims, characterized in that   the planar antenna is integrated on a support using circuit parts connected.   26. Planar antenna according to any one of   previous claims, characterized in that   the planar antenna is produced in the form of a module clean antennas.   27. Flat antenna according to any one of   previous claims, characterized in that the   antenna module can be coupled to the circuits of   signal processing by means of a conduction transition hollow conductor.   28. Flat antenna according to any one of   previous claims, characterized in that a   angle () can be adjusted between the normal of the sur-   faces (54) of the planar antenna and its main direction of radiation (55) by amplitude and / or phase control of the complex excitation of the radiating elements (21, 22, 23, 24; 29, 30, 31, 32; 43, 44;). 29. Flat antenna according to any one of   previous claims, characterized in that the   angular adjustment is made by choosing the wiring route between the radiating elements (21, 22, 23, 24; 29, 30, 31, 32; 43, 44; 50) and / or the wiring route connection of the flat antenna.   30. Planar antenna according to any one of   previous claims, characterized in that the   angular adjustment is carried out by the choice of the   tance (a) between the radiating elements (21, 22, 23, 24; 29, 30, 31, 32; 43, 44; 50) nested one inside the other and / or the radiating elements (21, 22, 23, 24; 29, 30, 31, 32; 43, 44; 50) arranged one at a time next to others.   31. Flat antenna according to any one of   previous claims, characterized in that the   orthogonally polarized wave modes   present as linearly polarized waves.   32. Flat antenna according to any one of   previous claims, in that the modes undulate-   orthogonally polarized roofs are sent or received   in the form of two circularly polarized waves.   33. Flat antenna according to any one of   previous claims, characterized in that at least   a selective frequency isolation screen is provided.   34. Flat antenna according to any one of   previous claims, characterized in that at   the less a dielectric lens is provided.