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
  • H01Q9/06—Details
  • H01Q9/14—Length of element or elements adjustable
• • 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
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
  • H01Q5/40—Imbricated or interleaved structures; Combined or electromagnetically coupled arrangements, e.g. comprising two or more non-connected fed radiating elements
  • H01Q5/48—Combinations of two or more dipole type antennas
• • 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
  • H01Q9/18—Vertical disposition of the antenna
• • 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
  • H01Q9/30—Resonant antennas with feed to end of elongated active element, e.g. unipole
• • 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
  • H01Q9/30—Resonant antennas with feed to end of elongated active element, e.g. unipole
  • H01Q9/32—Vertical arrangement of element

Definitions

• the present invention relates to antennas the dimensions of which can be modified in order to modify their radioelectric characteristics with the aim, generally, of making them work, as desired, in one of several frequency bands; these antennas are mainly used at frequencies below 1 GHz.
• Antennas which comprise at least one radiating element of variable electrical length, produced from an alignment of n, with n integer greater than 1, conductive sections separated by switching modules designed to electrically connect all or part of them sections. From that of its two ends where it is supplied, the alignment constitutes a radiating element which is made, as desired, of 1, 2, ... n sections. This is how, in particular, unipolar antennas with variable geometry are produced.
• the switching modules are simply constituted by fixing means, generally a screw and a nut respectively carried by the ends opposite the sections to be electrically connected.
• connection When the connection must be controlled remotely for reasons of ease and / or speed of implementation, it is known to use a switching module of the electrical relay type and connecting means made of two electrical wires to control the relay ; the presence of these wires which are radio-electrically isolated from the conductive sections in a more or less effective manner, limits the performance of the antenna and this limitation is all the greater when the antenna supports high powers or high voltages, such as c 'is the case with antennas operating in HF.
• the present invention aims to avoid the aforementioned drawbacks in antennas whose geometry is adjustable remotely. This is obtained by means of a remote control which implements connection means which do not disturb the radio operation of the antenna, associated with switching means which can be chosen to support high powers or high voltages.
• an antenna with variable geometry comprising at least one alignment of n conductive sections, where n is an integer greater than 1, electrically separated by n-1 intervals, n-1 switching modules respectively assigned to n- 1 intervals with m, where m is a positive integer less than n, of these modules which include a relay with two states and m connecting means respectively associated with the m modules for ensuring their control, with each a first and a second end located at separate locations, the m second ends being connected respectively to the m modules, characterized in that the connection means are made of an electrically insulating material transparent to radio waves, in that at least one of the m switching modules comprises p devices photovoltaic, with p positive integer less than 3, to control its relay and in that the connection means associated with the mod ule with photovoltaic devices are light conductors and have p optical cables which lead respectively to the p devices.
• an antenna with variable geometry comprising at least one alignment of n conductive sections, where n is an integer greater than 1, electrically separated by n-1 intervals, n-1 switching modules respectively assigned to the n -1 intervals with m, where m is a positive integer less than n, of these modules which comprise a relay with two states and m connecting means respectively associated with the m modules for ensuring their control, with each a first and a second end located in separate places, the m second ends being connected respectively to the m modules, characterized in that the connecting means are made of an electrically insulating material transparent to radio waves, in that at least one of the m switching modules has its relay which is a mechanical relay and in that the means of connection associated with the module with mechanical relay comprise an insulating rod, one end of which is connected to the mechanical relay of this module with mechanical relay.
• FIG. 1 a schematic view of an antenna according to the invention
• FIG. 2 a more detailed view of part of the antenna according to FIG. 1,
• FIG. 1 is a schematic sectional view of an antenna according to the invention. It is a unipolar antenna, also called whip antenna.
• This antenna is of variable geometry and comprises a radiating part 1 and a ground plane M.
• the radiating part comprises two conductive sections, aligned, 1 1, 12, separated by an interval with, associated with this interval, a switching module, 2, which will be described in more detail with the aid of FIG. 2; this radiating part is arranged perpendicular to the ground plane M, at the level of a hole T drilled in the ground plane, and is entirely located above the ground plane M.
• the conductive sections 1 1, 12 are cylinders hollow whose opposite ends are respectively electrically connected to two ports of the switching module 2.
• Two optical fibers F1, F2 that is to say electrically insulating light conductors transparent to radio waves, respectively connect two optical connectors C1, C2 located under the ground plane M, at the switching module 2; these fibers pass through the hole T and then inside the section 1 1 taking advantage of the fact that this section is a hollow cylinder open at its two ends.
• a control box, L comprising a laser power source, makes it possible to send, a light pulse, as desired, on the optical connector C1 or on the optical connector C2.
• the transmission-reception access of the antenna is made between the ground plane M and a terminal A located on the conductive section 11 in the immediate vicinity of the ground plane.
• each of the sections 1 1, 12 has been taken substantially equal to 5 meters and, thanks to the switching module 2, the conductive section 12 may or may not be connected to the section 1 1 which gives the antenna a radio height of 10 meters for the low band and 5 meters for the high band.
• FIG. 2 is a schematic view of the switching module 2 of FIG. 1.
• This module includes a relay R and two photovoltaic cells 21, 22.
• Relay R is a bi-stable electromechanical relay whose two stable states are respectively controlled, by current pulses, from two inputs E1, E2.
• the two stable states correspond respectively to the opening and closing of an internal contact in the relay.
• the terminals S1, S2 of this contact constitute the access ports for using the relay; they are respectively connected to sections 1 1 and 12 shown in Figure 1 so as to allow, as indicated above, to ensure or not an electrical connection between these two sections.
• Relay R can be made up of a REED SUPERDIL type relay sold by CELDUC under the reference G31 R3210.
• the optical fibers F1, F2 lead respectively to the light inputs of the photovoltaic cells 21, 22 and the current outputs of these cells are respectively connected to the inputs E1, E2 of the relay R.
• a light pulse originating, as indicated above, from the housing L is routed via the optical connector C1 and the optical fiber F1 to the photovoltaic cell 21; the current pulse which results therefrom at the output of the photovoltaic cell 21 causes the contact of relay R to pass or leave in the closed position, depending on whether this contact was in the open or closed position before the arrival of the pulse.
• the conductive section 11 was hollow in order to pass the optical fibers inside and that, without any noticeable drawback on the plan during operation, the fibers can be placed outside the conductive section and in particular on the conductive section; in the case where the conductive section is full, this way of passing the fibers would also be the only possible.
• FIG. 3 is the simplified diagram of another antenna according to the invention.
• the antenna is here of the horizontal dipole type and each of the two arms of the dipole comprises three aligned conductive sections, separated from each other by switching modules 2a, 3a, 2b, 3b.
• These switching modules represented schematically by a single contact, are, in the antenna which served as an example for the present description, of the same type as the switching module 2 of FIGS. 1 and 2.
• optical fibers not shown, are used to control these modules; they run along the arms of the dipole, coming from the middle of the dipole, to reach the different modules.
• the antenna used as an example for the drawing according to FIG. 3 is an antenna designed for radio links by ionospheric reflection in the band 1.5-12 MHz over a distance of 0 to 500 km.
• the antenna has an electrical span of 15 meters, the sections 1 1 a, 11 b being alone in operation.
• the antenna is then designed to operate between 6 and 12 MHz.
• the electrical span is increased to 30 meters and the antenna is designed to operate between 3 and 6 MHz.
• the electrical span is 60 meters and the antenna is designed to operate between 1, 5 and 3 MHz.
• the switching modules can include a relay in a stable state and an unstable state; in this case a single optical fiber and a single photovoltaic cell are sufficient and the control of the unstable state is done by sending a continuous light flux through the optical fiber during the whole time that this unstable state must be maintained; the return to the stable state is done by stopping the sending of the luminous flux.
• This way of proceeding certainly has the advantage of reducing the number of elements to ensure switching but has the disadvantage of requiring, for the maintenance in the unstable state, a continuous luminous flux, that is to say of continuous energy and possibly a more powerful light source than with a relay with two stable states controlled by pulses.
• a third type of switching module can be used; it comprises a relay with two stable states but with a single input, and this relay, of the counter type, changes state with each pulse received on its input.
• this relay of the counter type, changes state with each pulse received on its input.
• this module has the drawback of requiring, for the operator, specific means of signaling the open or closed state of the relay; indeed with the two types of previous modules the remote controls of the open and closed states are distinct and either the last remote control can therefore be easily signaled, or the desired remote control can be carried out for all practical purposes, as a safety measure, in the case of '' a doubt about the state of the relay; it is different with a counter type relay since, in case of doubt about the state of the relay, a safety command cannot be carried out and it is therefore necessary, for example, to know the state of the relay at a given moment, have a modulo 2 counting means for the remote controls carried out from this given moment.
• the relay of a switching module can be of the electronic type.
• the antennas comprising several switching modules
• these modules can be produced some of these modules according to the invention and others according to the known art, for example by connecting certain conductive sections by fixing means of the screw-nut type.
• the photovoltaic cells mentioned above, they can be replaced by batteries of photovoltaic cells, while the optical fibers can be replaced by optical cables comprising several optical fibers in parallel.
• the relays of the modules not ordinary "open-closed" relays but relays which in one of their two states, or even in their two states, switch an impedance, for example: infinite impedance in the open state and impedance Z in the closed state.
• solid tubes for producing the radiating conductive sections, insofar as the optical fibers are routed from outside the antenna.
• FIG. 4 is a schematic sectional view of an antenna which is distinguished from the antenna according to Figure 1 only by the switching module and the control device of this module.
• FIG. 4 shows a unipolar antenna with variable geometry with: - the same radiating part 1 made of two conductive sections, aligned 1 1, 1 2 separated by an interval with, associated with this interval, a switching module, 2 ' , consisting of a two-state relay, open-closed, of the mechanical switch type, - a ground plane M arranged like that of FIG. 1 - and a transmission-reception access between the ground plane and a terminal A located at the bottom of the conductor section 1 1.
• the control of the mechanical switch 2 ′ is ensured by an assembly consisting of a coil with a plunger core, 5, the movable part of which is extended by a rod 6 made of an insulating material, transparent to electromagnetic waves.
• the coil is located under the ground plane M through which the rod 6 passes through a hole Tm.
• the rod is bent at a right angle and comes into contact with the blade of the switch 2 '.
• FIGS 5a, 5b are schematic sectional views which correspond to an alternative embodiment of the antenna according to Figure 4; in this embodiment, always with the same type of antenna, the switching of the conductive section 1 2 is done by means of a switching module constituted by a conductive sleeve 7 which can slide inside the hollow sections 1 1 and 1 2, against the part of these sections situated in the vicinity of the interval which separates them; this sleeve thus acts as a mechanical relay in two states, open-closed, between the hollow sections 1 1 and 12.
• a coil with plunger, 5 is used; it is located under the ground plane M, plumb with the hole T drilled in the ground plane under the radiating part 1.
• the movable part 51 of the coil 5 is extended by a rod 6 '.
• This rod is a straight rod which penetrates, at its upper end, into the sleeve 7 in which it is blocked.
• the movable part 51 is in the retracted or extended position as shown in Figures 5a and 5b respectively.
• the conductive sleeve 7 makes contact only with the section 11, so that the antenna is designed to operate with only this section as a radiating element.
• the conductive sleeve 7 makes contact with the two sections 1 1 and 1 2 and, this time, the antenna is designed to operate with the two sections 1 1 and 1 2 as radiating elements.
• FIGS 6a, 6b are schematic sectional views which correspond to an alternative embodiment of the antenna according to the invention.
• a switching module 7 ′ is used which, instead of ensuring a connection by conductive element between two radiating sections, ensures a connection by capacitive coupling.
• this antenna is distinguished from the antenna according to FIGS. 5a, 5b only by the switching module 7 '; therefore it was considered preferable, to bring out the difference, to show, in Figures 6a, 6b that the part of the antenna located in the vicinity of the switching module.
• the switching module 7 ′ has two sleeves: an inner sleeve 70 an outer sleeve 71.
• the inner sleeve is a conductive sleeve; an insulating rod, 6 ′, identical to the rod 6 ′ according to FIGS. 5a, 5b penetrates into the sleeve 70, at its upper end and is locked inside the sleeve.
• the sleeve outer of small thickness, is a dielectric sleeve, blocked, at its lower part, inside a conductive section, hollow 1 1 and, at its upper part, inside a hollow conductive section 12 .
• the inner sleeve 70 slides in the outer section 71.
• the rod 6 ' is shown in the lower position, with the entire sleeve 70 contained in the section 11; in this position, the module 7 'does not provide an electrical connection between the sections 11 and 12.
• FIG. 6b the rod 6' is shown in the high position, with the sleeve 70, the bottom part of which is contained in the section 11 and the upper part in the section 12.
• the facing portions of the section 11 and the sleeve 70 on the one hand and of the section 12 and the sleeve 70 on the other hand constitute the plates of two capacitors respectively.
• the sections 1 1 and 12 are thus connected by these two capacitors arranged in series.
• the dielectric sleeve 71 makes it possible to greatly reduce the wear due to sliding since it eliminates the metal-to-metal friction of the embodiment according to FIGS. 5a, 5b.
• the section 12 of FIGS. 6a, 6b has a length greater than that of the section 12 of the antenna according to FIGS. 5a, 5b; this is due to the capacity supplied by the switching module, capacity which results in a decrease in the electrical length of the antenna.
• the invention is not limited to the examples described, thus it can be applied in the case of more than two aligned radiating sections; the insulating rods for controlling the switching modules can then be placed next to each other or made concentrically.
• the conductive sleeves of the modules must be pierced with eccentric holes to allow the passage of the insulating rods for controlling the modules placed at the above them.
• the insulating rods will be curved so that they can be controlled in translation independently of each other, so as to pass the lower modules by the eccentric holes and so as to be centered when they penetrate into their respective modules.
• rods In the case where the rods are concentric, they must, at least all except one, include an off-center part, at their lower end, to allow them to be controlled in translation independently of one another.
• the translational commands of the insulating rods can be carried out in various ways and, in particular, manually.
• the conductive sections can be full when the insulating rods are external as in the case of FIG. 4.
• the switching modules can be made up of sleeves which, instead of penetrating into the conductive sections, surround these conductive sections; but here again the switching module is arranged at the interval between the two sections which it switches and the switching is ensured by sliding the conductive sleeve along the sections.

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• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Variable-Direction Aerials And Aerial Arrays (AREA)

Applications Claiming Priority (5)

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• 1998
  • 1998-01-13 FR FR9800245A patent/FR2759498B1/fr not_active Expired - Fee Related
  • 1998-02-06 US US09/355,918 patent/US6195065B1/en not_active Expired - Lifetime
  • 1998-02-06 DE DE69809392T patent/DE69809392T2/de not_active Expired - Lifetime
  • 1998-02-06 EP EP98910784A patent/EP0958635B1/de not_active Expired - Lifetime
  • 1998-02-06 AU AU65038/98A patent/AU6503898A/en not_active Abandoned
  • 1998-02-06 CA CA002279987A patent/CA2279987A1/en not_active Abandoned
  • 1998-02-06 WO PCT/FR1998/000232 patent/WO1998035402A1/fr active IP Right Grant

Non-Patent Citations (1)

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