Satellite antennas for receiving and focusing microwave energy are often referred to as satellite dishes, however, they need not necessarily have a circular profile they may for example be square or elliptic in shape.

The recent growth in satellite technology ^' and the associated growth in satellite T.V. has lead to an increase in the number of satellite dishes which are mounted on sides or roofs of houses. Some people view these satellite dishes as an eyesore. Where the building is of a traditional nature or has a particularly aesthetic character, the opinion that the satellite dishes are grotesque may have good reason.

According to a first aspect of the present invention there is provided a satellite antenna which is at least partially transparent or translucent to visible light.

In one embodiment the dish has a wire gauze, supported on or between layers of transparent or

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translucent material, which may be a plastics material such as Perspex or acrylic or PVC. By laminating the gauze between layers of material like this the invention also overcomes another problem which is exhibited by meshed antennas, namely that water droplets have condensed onto the meshing of meshed antennas, the condensed moisture droplets acting as miniature reflectors thereby dissipating the received signal and lowering the efficiency of the mesh antenna. By mounting the gauze within a laminate "sandwich" this problem has been removed.

Furthermore, the associated problem of snow and ice, in colder climates is not present when using the invention as the smooth dish surface permits snow and ice to be wiped off its surface relatively easily.

The gauze may be a fine wire gauze, which would, without the transparent plastics support, deform or break. The fact that at least one laminate supports the gauze enables a very fine gauge of gauze to be used, typically gauze having a gauge of the order of 0.0254 centimetres in diameter, with a packing of between 50 to

2 100 squares per 6.45 centimetres

The appearance of such a gauze at close range resembles a cob-web, at further distances the gauze appears transparent. Some gauzes, may be so fine that

they would almost be invisible. Such gauzes may be microscopic.

Printing such a fine mesh of conductors would also be possible as would sputtering. If these sputtering techniques were used the conductive layer would be invisible. If thick sputtering were used, subsequent etching may be required.

Although reference has been made to a gauze, it would be possible to use a very thin sheet of metal or other frequency resistive substance or a dispersion of a substance, in such a way that the metal or resistive substance will reflect microwaves incident on the dish.

The terms transparent or translucent used to describe the antenna are intended to encompass an antenna, a substantial portion of which permits light to pass through it. To this end the antenna may support a fine mesh of gauze: it may comprise a conductive layer through which a plurality of holes have been drilled; it may comprise a helical coil of one or more wires supported on a transparent or translucent substrate; or it may comprise a transparent or translucent member which supports only a portion of the conductive wire or gauze, whilst another portion is exposed outside the support.

Although the conductive material itself may not be transparent, if supported in a sufficiently fine or thin mesh, gauze or film it may be difficult to detect at ranges greater than a few metres. The transparent support may appear to be frosted or tinted at close range, if the reflective layer comprises a gauze or mesh having a small characteristic dimension (e.g. a small diameter wire. Similarly, if reflective portions are used, in which a plurality of holes have been drilled or punched, the dish would appear sieve-like at close range. What is important is, that from a distance the antenna takes on a transparent or translucent appearance, thus making it less conspicous when mounted on a building.

In short what is meant by transparent or translucent is that in the case of an antenna comprising transparent portions and portions which are not transparent positions, is that the total area of transparent portions greatly exceeds the total area of non-transparent portions and that because the non transparent portions are dispersed throughout the antenna, the antenna appears from a reasonable distance transparent or translucent.

The term dish is intended to encompass the general shape of the reflecting surface of the antenna. Clearly

a complete circular dish shaped antenna does not have to be used. A sliver of a larger dish may be used. For example this may be an elliptic or a rectangular portion. Also whatever the shape is, it is important that this is capable of reflecting a preferred band of radiation to one or more focal point or points.

Preferably an antenna comprises a support structure and microwave reflecting material, the microwave reflecting material being supported by the support structure so as to adopt a predetermined configuration characterised in that the support structure and the reflecting material are transparent or translucent.

Advantageously the support structure comprises a continuous dish on or within which a discontinuous conductive material is disposed.

In an alternative embodiment a satellite dish may have a metallised or other conductive deposition laid or printed on a transparent surface. Such an arrangement will permit the dish to act in the same way as a clear material to light, yet still reflect and focus microwaves because the vapourised metal adheres to its surface in a very thin film. The microwave reflective substance may be stuck onto the surface or printed onto the surface in very closely spaced lines or very small dots spaced closed together. Printing may be effected on

a flat portion of material which may then be formed into a dome; or printing may be effected on the dish after it has been formed. Of course, printing may be performed on only one surface, in which case thus the dish could be manufactured more cheaply than by using two sheets of laminate.

All the above embodiments would permit a satellite dish to be mounted on a roof or on the side of a house or building without it substantially impairing any view of the house or building.

Although reference has been made to the satellite dish being made from a plastics material it may be formed wholly or partially from glass. The dish may comprise laminated layers of glass, or it may have a laminated glass layer which is electrically conductive sandwiched in sheets of conventional glass. Glass such as Cadmium Mercury Telluride (CMT) or Indium Tin Oxide (ITO) may be used. The conductive layer may be laminated between layers of glass and/or layers of plastics materials, as described below.

Of course satellite antennas often require supporting and stabilising.

According to a second aspect of the present invention there is provided a mounting bracket for an

antenna which bracket is at least partially transparent or translucent to light.

According to a third aspect of the present invention there is provided a mounting bracket for an antenna dish having a ball-in-socket joint between the dish and a mounting structure, said pivot incorporating a limiting arrangement adapted to permit only limited angular movement about the joint.

The ball-in-socket joint can be used to enable the antenna to be pointed at the correct angle of azimuth to the horizon so that the antenna is pointing at a satellite transmitting the desired signal. The said limiting arrangement may be provided to prevent the satellite dish from tipping from the intended angle, once this has been set. Such an arrangement may prevent the antenna from being knocked or blown from the position at which they are set.

It is also desirable when installing satellite antennas that they are not in any way damaged as a dented antenna could result in an impared signal and hence lower the efficiency of the antenna as the microwave reflector. The limiting arrangement may therefore act to prevent the antenna from swinging during installation so as to prevent the antenna from banging against a house, roof or wall.

With regard to the first aspect of the invention, the mounting bracket may be formed from polycarbonate or other clear plastics or other material .

Where the second aspect is combined with the third aspect the ball-in-socket joint, which may comprise a spherical ball or an egg-shaped ball, may incorporate a transparent or translucent ball . Other structural components, preferably all or most other structural components, including for example the mounting structure which may be a mounting plate, are preferably also formed from transparent or translucent materials. Even coaxial leads, connectors etc. may be transparent or translucent.

Preferably the arrangement of the joint and the mounting structure may be such that the dish can only drop slightly below the required minimum angle in relation to the country for which the dish is designed to be used. For example, in the UK, a minimum elevation of 20 degrees from horizontal walls or flat roofs would be appropriate, rising to a maximum elevation of 30 degrees plus 5 degrees tolerance.

A further embodiment may embrace all three of the aforementioned aspects such that a transparent antenna is provided with a transparent support and stabilising

means .

Most preferably, the dish has a central feed tube communicating with an aperture in the dish and having a reflector at its outer end whereby radiation picked up by the dish is reflected on to the reflector so as to be directed from there down the tube through the aperture in the dish on to detector equipment behind the dish. All or substantially all of these parts are preferably transparent or translucent.

With regard to the materials used to make the transparent/translucent parts, whether the transparent dish according to the first aspect of the invention, or the dish or the mounting parts of the later aspects of the invention, this may consist of a plastics material and/or a glass material and/or any other suitable material. Requisite reflective properties may be derived from the inherent properties of the material e.g. by using conductive material, or material rendered conductive by incorporation of conductive trace materials or the like, or by surface attachment or incorporation within the body of the material of an appropriate substance or structure such as a metallic film, wires or the like.

In an alternative preferred embodiment the material is a glass or plastics material such as

polycarbonate, with a surface metallic film deposited by a vaporisation technique or otherwise so that the film is essentially invisible at least from one side. However other similar plastics such as PVC or Acrylic may be used.

The invention will now be described by way of examples only and with reference to the figures wherein:-

Figure 1 illustrates diagramatically a transparent satellite dish mounted on the side of a house, the satellite dish being of the half-silvered mirror type;

Figure 2 illustrates in detail a satellite dish having a laminated gauze;

Figure 3 is a diagrammatic sectional view of one form of a mounted antenna according to the invention;

Figures 4-9 and 10-15 are respectively diagrammatic sectional views and plan views of different dish configurations.

Referring to Figure 1 a transparent dish 1 is mounted on the side of a house 2 by way of three support struts 3. The dish 1 has a microwave convertor 4 mounted at its focus . The convertor 4 converts microwaves to a frequency of lower signal and passes this signal along a

coaxial cable either to conventional video viewing apparatus or, in the case of data signal to telecommunications and/or data processing equipment.

The dish 1 itself is formed from a mould or a cast. The reflective surface is formed by depositing a fine metal layer 52 on a surface of the moulded or casted dish 1.

Referring to Figure 2, which illustrates an alternative embodiment of the invention, a satellite dish la has two skins 50 and 51 between which is sandwiched a gauze 6. The microwave converter 5 is shown mounted on a single support strut 7 which is connected to the base region 10 of the dish. The support struts 3 are shown connected to the same base region 10 of the dish.

As shown in Figure 3 a transparent dish 20 is mounted by way of a support 100. The support 100 comprises a ball-in-socket joint 21 and a wall plate 22 for fixing to an upright wall 23 surface.

The dish has a central aperture 24 with an axially disposed tube 25. At the outer end of the tube 25 there is a curved reflector 26 mounted on the tube 25 by spacing struts (not shown). Behind the aperture 24 in the dish 20 there is a detector device 27 connected by

cables (not shown) to receiving equipment 28.

The tube 25 is formed from transparent glass or plastics material which is metallised on its inner surface. The reflector 26 is similarly formed from metallised transparent material.

The components behind the dish including the detector device 26, the ball-in-socket joint 21 and the wall plate 22 are all formed from transparent or translucent materials.

As shown, the ball 21a of the joint 21 is clamped adjustably within a housing 29 and an adjustable telescopic link 30 is provided between the mounting plate 22 and the joint 21. In this way the angular position of the dish 20 can be fixed and it can be ensured that the dish 20 cannot move too far from the desired setting, nor can it strike the wall 23 if the dish 20 slips or is moved away from its setting.

Figure 4- 15 show alternative configurations for the dish 20.

Although reference has been made throughout to a satellite receiving dish 20, the antenna may of course be used as a transmitter.

It is of course to be understood that the invention is not intended to be restricted to the details of the above embodiments which are described by way of example only.