FR2597663A1 - Parabolic antenna and method for its production - Google Patents

Abstract

The antenna is characterised in that the reflecting surface consists of a weft of conductive material embedded in synthetic resin. The weft employed is preferably a mat of carbon fibres.

Description

 The present invention relates to a parabolic antenna intended to receive or emit high and hyper frequency microwave radiation.

 The demand for direct reception of satellite television broadcasts is growing. The first condition for receiving sufficient power is to concentrate the radiation arriving on the reception area using a parabolic antenna. The main quality demanded of such an antenna is to have a correct performance.

The latter is expressed by the ratio of the energy captured to the energy received. The reflectors currently available are made up of a frame, either metallic or synthetic resin, on which an aluminum or zinc powder is applied embedded in a layer of polyurethane. The efficiency of such an antenna is between 0.35 and 0.45.

 The object of the invention is to increase the yield significantly.

 To this end, according to the invention, the parabolic antenna intended to pick up or emit high and hyper frequency radio radiation, comprising a synthetic resin support and a reflecting surface, is characterized in that said reflecting surface is produced by a weft of conductive material incorporated in a jug of synthetic resin. According to an essential characteristic of the invention, said frame will consist of a mat of carbon fibers.

 The invention also relates to the method of manufacturing antennas of the type described above and which will now be described, in relation to the attached figure which is a partial section of an antenna according to the invention.

 To make a satellite dish, we first make a convex mold in the shape of a paraboloid of revolution sectioned along a plane perpendicular to its axis. For large diameter antennas, the antenna can be subdivided, and consequently the mold into n portions of. parabolotde equal between them by cutting this one by radial planes so as to obtain kinds of petals.

 On the mold or molds thus produced, and previously covered with a non-stick substance, a first thin layer based on polyurethane will be sprayed which will be left to dry completely. Then, a second layer of resin, also thin and based on polyester, will then be sprayed, and, before the drying thereof, the weft of conductive material will be very carefully spread with the roller so as to eliminate any air bubbles. . This operation should be done at a controlled temperature, preferably between 20 and 250C. We will then spray a third layer of resin also based on polyester on the weft and we will pass a roller to eliminate the slightest air bubble. Finally we will perform on the whole a stratification based on glass fibers and polyester resin so as to solidify the assembly, and we can then produce a structure, for example honeycomb to obtain a mechanically rigid assembly.

 In the figure, there is shown in 1 an element of the convex mold, # the thin layer of polyurethane, in 3 the weft of carbon fiber between its two layers 4 and 5 of polyester resin, finally in 6 the stratification based on glass and polyester fibers gave b its strength after demolding.

 Very good results have been obtained with carbon fiber mats whose weight per square meter is between 20 and 50 grams. The yield obtained with such a device is of the order of 0.60 and can reach 0.75, which constitutes a great advantage compared to the technique used up to now. In addition, with respect to this technique.

we have a significant weight gain and mechanical strength beyond traditional composites.

Claims (3)

R E V E N D I C A T I O N S 1. Parabolic antenna intended to collect or emit radiation  high and hyper frequency microwave, including a resin support  synthetic and reflective surface, characterized in that  said reflecting surface is produced by a weft of material  conductive incorporated in the plastic support.  the frame is constituted by a mat of carbon zabre.  2. Satellite dish according to Claim 1, characterized in that 3. Method for manufacturing a corresponding satellite dish  to any one of claims 1 or 2, characterized in that  that we take a convex mold in the shape of a paraboloid of revolution,  in that we spray on the mold previously coated with a  uses a first thin layer (2) based on non-stick  polyurethane, which is left to dry, which is then sprayed  second thin layer (4) based on polyester resin, knowing the  drying of which one carefully spreads or rolls the weft of  conductive material so as to eliminate any air bubbles, in  preferably operating between 20 and 250C, then spraying  a third thin layer (5) of polyester resin on the trome,  pass a roller over this layer to remove any  air bubble, and finally that we have on the whole a stratification  based on glass fibers and polyester resin to give  all the desired stiffness before demolding.