Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
  • H01Q9/04—Resonant antennas
  • H01Q9/16—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole
  • H01Q9/28—Conical, cylindrical, cage, strip, gauze, or like elements having an extended radiating surface; Elements comprising two conical surfaces having collinear axes and adjacent apices and fed by two-conductor transmission lines
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q23/00—Antennas with active circuits or circuit elements integrated within them or attached to them
• • 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
  • H01Q3/24—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 orientation by switching energy from one active radiating element to another, e.g. for beam switching
  • H01Q3/247—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 orientation by switching energy from one active radiating element to another, e.g. for beam switching by switching different parts of a primary active element

Definitions

• the field of the invention is that of omnidirectional volume antennas such as biconical or discone antennas, to which the addition of elements in the formation zone of the radiation pattern allows a division of the azimuthal angular space.
• a biconical antenna is obtained by the superposition of two cones facing each other by their pointed end, the supply being effected by the center of the cones.
• the shape of the cones makes it possible to determine a zone of progressive flare where the wave propagates.
• This flaring zone may be of various shapes and may in particular provide an outline such as those used for "Vivaldi" type antennas with quasi-shear profiles; this outline can just as easily be reduced to a simple straight line.
• the discone antenna is made by means of a reflector plane on which a cone is arranged, this association has substantially the same characteristics as the bi-conical antenna in terms of performance.
• the omnidirectional antennas of the known art may have a good directivity in all directions in an azimuth plane but do not allow to benefit from latitude to preferentially influence the directivity in a subset of directions. The transition without contact then makes it easier to integrate the antenna.
• an omnidirectional antenna in which the directivity of the antenna can be modified by varying the electric field at the excitation source thereof, this by means of switching diodes.
• the present invention proposes an antenna integrating a contactless three-dimensional transition between a coaxial excitation line and two conductive elements having a symmetry of revolution, corresponding to the three-dimensional transposition of a micro-ribbon line planar transition. slit line and having elements modifying the radiation of the antenna in at least one flared part of the antenna.
• the invention relates to a wideband omnidirectional antenna comprising at least a first conductive element and a second conductive element having a symmetry of revolution about a common axis of revolution and central openings, said elements being positioned opposite one of the other, at least one of the elements having a progressive flaring zone characterized in that it comprises a central coaxial excitation line and a space between the two conductive elements so as to achieve a contactless transition in three dimensions between the coaxial exciter line and the conductive elements and modifying elements of the radiation pattern in the splay area.
• one of the conductive elements is plane. According to a variant of the invention, at least one of the conductive elements is a cone.
• the smallest diameter of the cone is of greater dimension than the section of the coaxial exciter line.
• At least one of the conductive elements is a half-sphere.
• the modifying elements comprise diodes that can switch from a conductive state to an insulating state or MEMS-type components.
• at least one of the conductive elements comprises radial insulating sectors supporting the modifying elements.
• At least one of the conductive elements comprising insulating sectors is made of plastic and comprises metallized parts.
• the modifying elements are fed by printed tracks directly on the plastic element comprising metallized parts.
• the antenna further comprises metal rods connecting the two conductive elements so as to ensure a continuity of mass.
• the antenna comprises at least one solid insulating part in which is formed a conductive element having a progressive flaring zone.
• FIG. 1 illustrates a first example of an omnidirectional antenna according to the art known
• FIGS. 2a and 2b illustrate two other examples of omnidirectional antenna according to the known art
• FIG. 3 illustrates an antenna structure according to the invention comprising two conical elements and a central coaxial line
• FIGS. a and 4b respectively illustrate a perspective view and a sectional view of an example of an antenna according to the invention and having modifying elements of the radiation pattern;
• FIGS. 5a, 5b and 5c respectively show the radiation patterns of the antenna illustrated in FIGS. 4a and 4b in a three-dimensional view, a view in the azimuth plane and a view in the elevation plane;
• FIG. 6 illustrates the reflection losses of the antenna illustrated in FIGS. 4a and 4b;
• FIG. 7 illustrates a variant in which the cones have an enlargement of the central opening with respect to the dimension of the central exciter line
• FIG. 8 illustrates a variant of the invention in which the conductive elements are made in a solid piece of plastic
• FIGS. 9a and 9b illustrate a variant of the invention in which one of the conductive elements is plane
• FIG. 10 illustrates a variant of the invention in which the conductive elements are half-spheres.
• the antenna according to the invention comprises at least a first element of flared and conductive shape and a second element which is also conductive and which can also be of flared or planar shape.
• the assembly consisting of these two elements is coupled to a coaxial central excitation line.
• This exciting line comprises a metal central rod that provides the antenna power function by bringing a short circuit at the opening between the two conductive elements to allow coupling between the coaxial type of access and the together constituted by the two conductive elements.
• This short circuit is achieved by placing an "open circuit" at a distance of ⁇ / 4 at the end of the metal rod.
• the height above the end of this central rod is also a setting parameter of the adaptation of the antenna.
• FIG. 3 shows an example of an omnidirectional antenna structure, more precisely comprising a first conical element C c i, a second conical element C2 , a central coaxial excitation line L c .
• Each conductive element has a central opening O 1 , O 2 allowing the insertion of the exciter line within said elements and a symmetry of revolution about a central axis A 0 .
• This exciting line comprises a metal central rod Lc-i, the length of penetration of this central rod at the first conductive element is typically of the order of ⁇ / 4 to bring a short circuit at the opening of the biconical antenna.
• the spacing e in the vertical direction Dz between the two conical elements allows the coupling between the coaxial excitatory line mode and the mode of the assembly constituted by the two cones.
• the antenna further comprises modifying elements of the radiation pattern Ri, (guiding elements and reflectors) in the flaring zone of the voluminal antenna as illustrated in FIGS. 4a and 4b.
• These elements are advantageously semiconductor elements that can pass from an insulating state to a conductive state and which fit into the flaring zone of the voluminal antenna. They are fed by printed tracks pi connected to a control circuit and positioned on insulating sectors integrated with one of the conductive elements constituting the voluminal antenna.
• 6a, 6b (4-sector configuration) can be, for example, components such as PIN diodes, varactor diodes or even MEMS-type components which are connected to a control circuit. placed under the structure.
• the conductive element comprising insulating sectors and conducting sectors may advantageously be a plastic part on which metallized sectors S d are made .
• the main piece of plastic can be interconnected to the circuit by means of a mechanical system of clips or pins, it can also be reported for example by welding.
• the continuity of mass between the cones is ensured by means of metal rods Mi connecting the two elements Cc i and C c2 .
• Exemplary embodiment of the omnidirectional antenna illustrated in Figure 4a and 4b comprising four sectors and calibrated to be operational at 5 GHz:
• This antenna comprises a three-dimensional main piece made of "metallized plastic” technology which constitutes the support of the "reference” antenna device and which comprises in a "traditional” configuration two plastic cones positioned head-to-tail, with a hole central to allow the supply of the antenna which can be achieved for example by means of a coaxial cable type access.
• the height of this main room in this example is
• the space between the two cones set at 4mm in this example is an important parameter of optimization, this opening plays a role in the antenna power system which is achieved by a coupling between the mode of the coaxial cable and the mode of the biconical antenna.
• This method The power supply is similar to a coaxial-slot slot-type power supply system that is transposed into a three-dimensional configuration.
• FIGS. 5a, 5b and 5c relating to this type of antenna having 5GHz radiation patterns. These diagrams are shown in Figure 5a (three-dimensional view), 5b (seen in the azimuth plane) and 5c (seen in the elevation plane).
• the directivity is 4.92dB
• the beamwidth at -3dB is 90 ° in elevation and 160 ° in the azimuth plane for a front-to-back ratio of less than -8dB.
• the omnidirectional antenna has an enlargement of the small diameter of the cone x c with respect to the dimensions of the outer cylinder of the coaxial supply cable XL and more precisely with respect to the cylindrical recessed zone. constituting the outer wall of the coaxial cable.
• This variant has the advantage of simpler manufacturing, especially in view of molding constraints when using a plastic part.
• the omnidirectional antenna comprises parts that are no longer hollowed out as in the previously described variants but parts made of "solid" plastic, making it possible to reinforce the mechanical strength of said antenna.
• the figure illustrates this configuration.
• the conductive elements C d and Cc 2 are then formed inside said plastic part P.
• the antenna is a discone antenna having a small footprint due to one of the conductive elements which is plane facing the first conductive element.
• the antenna comprises an upper cone metallized to the interior Bcc, a reflective ground plane Pc 2 with access to the coaxial cable Lc, an opening between the cone and the reflector ground plane.
• the conductive parts comprise a contour of the flaring zone such as those encountered for "Vivaldi” type antennas with quasi-spherical profiles and therefore made up of two Sci half-spheres. and Sc2 coupled to the coaxial excitation line 1c .

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• 2008
  • 2008-06-04 JP JP2010511581A patent/JP5416100B2/ja not_active Expired - Fee Related
  • 2008-06-04 EP EP08760450A patent/EP2156511A1/de not_active Withdrawn
  • 2008-06-04 US US12/452,003 patent/US11271316B2/en active Active
  • 2008-06-04 WO PCT/EP2008/056867 patent/WO2008155219A1/fr active Application Filing
  • 2008-06-04 CN CN200880020242.XA patent/CN101682115B/zh not_active Expired - Fee Related

Non-Patent Citations (1)

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