GB2150355A

GB2150355A - Antenna reflector

Info

Publication number: GB2150355A
Application number: GB08331625A
Authority: GB
Inventors: Kingsley Peter Inmann Fairey
Original assignee: EPIC ENGINEERING GROUP Ltd
Current assignee: EPIC ENGINEERING GROUP Ltd
Priority date: 1983-11-26
Filing date: 1983-11-26
Publication date: 1985-06-26
Also published as: IT8423694A1; GB2150355B; IT8423694A0; DE3441466A1; JPS60134606A; IT1177289B

Abstract

An antenna reflector 1 is assembled from a plurality of rigid panels 4, for example sectors of metal or alloy, releasably secured together. The panels 4 are formed to the required profile with a high degree of accuracy by moulding, casting or pressing techniques, and may be held together by bolts, adhesive or complementary male and female formations. The surface 34 may be machined to any desired profile. Two circumferential rows of panels may be provided, and the assembled shape may be circular or elliptical. <IMAGE>

Description

SPECIFICATION Antenna reflector This invention relates to antenna reflectors such as are used in communication systems.

Heretofore antenna reflectors have had a reflector surface provided by an assembly of stretch formed thin aluminium panels.

The panels are formed by pulling aluminium sheet over profiled formers to just beyond the yield point of the material. When removed from the former however, the panels are unstable and it is necessary to provide the panels with some form of reinforcement to increase their stability.

One method is to rivet and/or bond stiffening ribs to the panels whilst supported on an assembly former.

Another method is to provide a backing panel with honeycomb foil aluminium between the two panels.

Both methods require accurate assembly and checking of the reflector surface profile. Furthermore the panels are still sufficiently unstable as to require assembly on a backing structure after which rechecking of the reflector surface profile is necessary.

This double checking of the finished panels and again after assembly is both expensive and time consuming. Additionally the reflector surface profile has to be re-checked each time the reflector is taken apart either for moving or replacement of a panel.

It is an object of the present invention to provide an antenna reflector which mitigates at least some of the afore-mentioned disadvantages.

According to the present invention an antenna reflector has a reflector surface provided by an assembly of rigid panels each formed by casting, moulding or pressing.

By the present invention the panels are rigid and can be formed to the required profile with a high degree of accuracy so that the reflector can be taken apart and re-assembled as and when required without repeated re-checking of the reflector surface profile.

Preferably adjacent panels are located relative to each other by locating formations formed integrally therewith. As a result accurate assembly of the panels is assured.

The locating formations are conveniently provided by one or more pairs of aligned holes in adjoining sides of adjacent panels through which a bolt or similar releasable fastener may be passed to secure the panels together.

Alternatively the locating formations may be provided by complementary male and female formations, e.g. ribs and grooves, on the adjoining sides of adjacent panels.

In addition to integral locating formations, the panels may have one or more reinforcing formations formed integrally therewith on the rear surface. As a result the assembled panels provided an inherently stable reflector surface profile which is not significantly affected by changes in the gravitational and operational wind forces so that the reflector can be moved through any elevational arc as required.

The reinforcing formations conveniently comprise ribs or like projections on the rear surface of the panels and may be constructed and arranged to provide reinforcement in a selected direction, for example in a dish-shaped reflector reinforcement may be provided in the radial and/or circumferential directions.

Preferably the panels are all similar so as to be interchangeable for ease of assembly and replacement and are formed from aluminium although other lightweight metals or alloys may be used.

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings wherein: Figure 1 is a perspective view of an antenna reflector according to the present invention; Figures 2 and 3 are front and rear perspective views respectively of one of the panels of the reflector shown in Figure 1; Figure 4 is a rear perspective view of two assembled panels; and Figure 5 is a section on the line 5-5 of Figure 4.

Referring to the accompanying drawings, there is shown a dish-shaped antenna reflector 1 such as used in satellite communication systems and comprising a parabolic reflector surface 2 with a central opening 3. The reflector 1 is assembled from a plurality of cast aluminium panels 4 releasably secured together to allow the reflector 1 to be taken apart and re-assembled as required, for example for moving or replacement of a panel.

Each panel 4 is similar for ease of assembly and replacement and has, as viewed in plan, four sides 5, 6,7,8 of which the first and third sides 5 and 7 respectively are opposed and the second and fourth sides 6 and 8 respectively are opposed. The first and third sides 5 and 7 respectively are both curved and in the assembled reflector correspond to the inner and outer peripheral edges 9 and 10 respectively of the reflector surface. The second and fourth sides 6 and 8 respectively are both straight and in the assembled reflector adjoin and are secured to corresponding sides 6 and 8 of adjacent panels 4.

Depending from each side 5, 6,7, 8 of each panel 4 is a flange 11, 12, 13, 14 respectively which together form a continuous skirt, generally indicated at 15, of varying height around the peripheral edge of the panel.

The flange 11 is formed with two steps 16, 17 and, each flange 12, 14 is provided with two raised lugs 18,19. In the assembled reflector the steps 16,17 and lugs 18,19 align with similar formations on adjacent panels 4to assist in the location and mounting of the reflector on a suitable carrier (not shown).

Additionally each flange 12, 14 is locally thickened on the inner side at three spaced apart positions 20, 21,22 where holes 23 are provided which, on assembly of the reflector, align with corresponding holes 23 in the flanges 12, 14 of adjacent panels 4 for the passage of bolts 24 to secure the panels 4 together. The local thickening the panels 4 together.

The local thickening at 22 includes an annular boss 25 in which a threaded bore 26 is provided for receiving threaded bolts (not shown) to secure the assembled reflector to the carrier.

Each panel 4 is reinforced on the rear surface 27 by a plurality of ribs. A centre rib 28 extends between the flanges 11, 13 and proves reinforcement in a radial direction in the assembled reflector. This centre rib also has a raised lug 29 corresponding to the lugs 19 on the flanges 12, 14. Extending between the centre rib 28 and each flange 12, are two spaced apart transverse ribs 30, 31 which provide reinforcement in a circumferential direction in the assembled reflector whilst in each space between the transverse ribs 30,31 on either side of the centre rib there are two diagonal ribs 32,33.

The front surface 34 of each panel 4 forms the reflector surface 2 which may be accurately machined to any required profile by a cutting tool controlled, for example, by a computer.

It will be apparent from the foregoing description that the present invention provides an antenna reflector assembled from similar rigid panels which have an accurate profile and are releasably secured together so that individual panels can be easily replaced and the reflector taken apart and reassembled as required without having to re-check the profile of the reflector surface.

It will be understood that the invention is not limited to the shape and construction of reflector above-described, for example, depending on the application, the reflector may be of any known shape such as circular or elliptical and may be constructed from any number of panels.

The integral formations for locating adjoining sides of adjacent panels may be of any suitable construction, for example each panel may have a male formation on one side and a complementary female formation on the opposed side whereby adjoining sides of adjacent panels are located on assembly by the interengagement of male and female formations.

Instead of each panel having male and female formations on two opposed sides, one panel may have male formations on each of two opposed sides and another panel have female formations on each of two opposed sides whereby panels having male formations are assembled alternately with panels having female formations.

Suitable male and female formations include ribs and grooves, projections and apertures etc.

All constructions and combinations of locating formations on the adjoining sides of adjacent panels are envisaged and are within the scope of the invention.

The integral reinforcing formations may likewise be of any size and shape whilst the panels themselves may be made from any suitable metal or alloy using casting, moulding or pressing techniques.

The skirt around the peripheral edge of each panel may be continuous as described or discontinuous.

The reflector surface.may be machined to a geometrical or non-geometrial profile as desired.

It will be understood that whilst the panels are preferably releasablysecured together they could be non-releasably secured together, for example by welding.

Finally, for each reflector shape there may be a range of different sizes depending on the particular application. For example the diameter of the abovedescribed reflector may be varied by changing the size of the panels or by adding one or more rows of panels extending circumferentially around the outer peripheral edge of the reflector. To facilitate assembly of multi-row reflectors, locating strips may be positioned between adjacent panels in one row and which project between and serve to locate adjacent panels in the next row.

Claims

1. An antenna reflector having a reflector surface provided by an assembly of rigid panels each formed by casting, moulding or pressing.

2. An antenna reflector according to claim 1 wherein adjacent panels are releasably secured along adjoining sides.

3. An antenna reflector according to claim 2 wherein adjoining sides of adjacent panels are located relative to each other by locating formations formed integrally therewith.

4. An antenna reflector according to claim 3 wherein the locating formations comprise at least one pair of aligned holes in the adjoining sides of adjacent panels through which a releasable fastener extends for releasably securing the panels together.

5. An antenna reflector according to claim 3 wherein the locating formations comprise compiementary male and female formations on the adjoining sides of adjacent panels.

6. An antenna reflector according to any one of the preceding claims wherein each panel has a rear surface opposed to the reflector surface on which one or more reinforcing formations are formed integrally.

7. An antenna relector according to claim 6 wherein the reflector surface is dish-shaped and the reinforcing formations are arranged to provide reinforcement in a circumferential and/or radial direction.

8. An antenna reflector according to claim 6 or claim 7 wherein each reinforcing formation comprises an upstanding rib.

9. An antenna reflector according to any one of the preceding claims wherein the reflector surface is machined to a desired profile.

10. An antenna reflector according to any one of the preceding claims wherein the panels are all similar.

11. An antenna reflector according to any one of the preceding claims wherein each panel is formed from a lightweight metal or alloy.

12. An antenna reflector according to any one of the preceding claims wherein the reflector is adapted to be detachably mounted on a carrier.

13. An antenna reflector substantially as hereinbefore described with reference to the accompanying drawings.

14. A method of manufacturing an antenna reflector comprises forming a plurality of rigid panels by casting, moulding or pressing, and assembling the panels to form the reflector by securing adjacent panels along adjoining sides.

15. A method according to claim 14 wherein adjoining sides of adjacent panels are formed with at least one pair of aligned holes for passage of a releasable fastener for releasably securing the panels together.

16. A method of manufacturing an antenna reflector substantially as hereinbefore described with reference to the accompanying drawings.

17. An antenna reflector manufactured by the method according to any one of claims 14 to 16.