EP0290969A2 - Unfoldable antenna with two reflecting surfaces - Google Patents

Abstract

Antenna consisting of a main reflecting surface (1), a sub reflector (2) and an unfolding device of the secondary surface, made up of the following primary parts: a motor (3); a supporting structure (4) for the sub-reflector and a telescopic positioning rod (5).

The antenna, so configured, minimizes space occupancy problems during the launch phase of satellites for space applications and during transportation, for ground applications, yet assuring that correct positioning of the reflecting surfaces takes place during operation.

Description

• This invention regards an antenna with two generic reflecting surfaces, of which one is unfoldable.
• The purpose of this invention is to provide a system which, with regard to antennae for on board satellites applications, reduces the space occupied during launch phase and which, during transportation, with regard to ground antennae, when fitted to self propelled or trailed vehicles, also requires minimum accomodation space.
• Reduced dimensions, achieved by folding, imply consequent weight reduction, and therefore also less stress on the supporting structure and on the folding surface either for on board or ground based applications.
• Positioning of the operating configuration may be activated by remote control, for on board systems, or manually for groundbased systems.
• The invention presented here belongs to the telecommunications field, more precisely to that of remote sensing as it may be utilized both as on board equipment and as transportable ground station equipment.
• At the present state of groundbased application techniques for transportable antennae, dismantling of the assembly on the field by experienced personnel equipped with suitable tools for realignment is also made possible.
• The present invention solves the problem concerning experienced personnel and suitable and expensive equipments to verify the alignment of the parts.
• As far as on board satellite applications are concerned, to the authors' notice there is no solution known may be checked during launch and may be made operative once in orbit by means of remote controls.
• The invention will now be described with reference to one of its presently preferred forms of implementation, and is reported as an illustration without being limited to it and with reference to the tables of drawings enclosed.
• Figure 1 shows the schematic configuration of the antenna:
  a) side view
  b) cutaway view
  c) top view
  The following parts are visible:
  1) reflector
  2) sub-reflector
  3) hinge actuator motor
  4) unfolding structure
  5) telescopic rod
  6) hinges
  7) supporting structure
  8) interface structure
  9) settable end of run
  10) fixing area of the foldable structure.
• Figure 2 shows the schematic configuration of the antenna in the minimum dimensions situation.
• Figure 3 shows the schematic configuration of a symmetrical two reflector antenna.
• Figure 4 shows the schematic configuration of the antenna fitted to a self propelled vehicle.
• Once again, with reference to the tables of drawings enclosed, operation of the antenna presented herein will be described.
• Figure 1 shows that the antenna consists of a reflector 1 fixed to a bearing structure which in turn is connected to an interface structure 8. Connection of elements 7 and 8 varies according to the type of system to be implemented.
• Structure 7 carries hinge 6 and motor 3 interfaces, set to unfold and to lock the system in minimum dimensions situation 10. When the locking mechanism 10 is unlocked, motor 3 moves the unfolding structure 4 to which the sub reflector is connected.
• Movement of structure 4 around hinges 3, through hinges 6, shortens telescopic rod 5 which carries a settable end race 9 which determines the system operating position together with the motors which remain powered.
• To minimize impact of the end race, the unfolding speed reduction depends on the type of system application; for on board equipment, motor 3 is connected to a break (such as eddy current, spring type, etc); on the contrary for self propelled ground equipment, opening speed reduction may be achieved by means of lamination of fluids within the telescopic rod 5 itself or by means of a suitable device connected to motors 3; furthermore, for self propelled ground systems, the motor applied may reverse direction of progress so as to restore the minimum dimension configuration of the antenna.
• For on board systems which must be opened once only, the motor may be of the spring type.

Claims (4)

1. Antenna consisting of two reflecting surfaces, one main (1) and one secondary, a sub-reflector (2), characterized by being provided with an unfolding system of the secondary surface, where its main parts are a motor (3), a bearing structure (4), a positioning telescopic rod (5).

2. Two-reflector antenna, as per claim 1, which is characterized by the fact that it may be configured for minimum space occupancy by virtue of sub reflector 2 which may be folded onto reflector 1.

3. Two reflector antenna, as per claims 1 and 2, which consists of hinges 6, motorized hinges 3, lattice structure 4 and telescopic rod 5.

4. Two-reflector antenna, as per claims above, where the unfolding angle of the sub reflector, and therefore the pointing (alignment), may be set by means of the end race 9 on telescopic rod 5.

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