GB2359664A

GB2359664A - Improvements in or relating to antennae

Info

Publication number: GB2359664A
Application number: GB0000400A
Authority: GB
Inventors: Patrick Anthony Gasser
Original assignee: G COM INTERNAT Ltd
Current assignee: G COM INTERNAT Ltd
Priority date: 2000-01-11
Filing date: 2000-01-11
Publication date: 2001-08-29
Also published as: GB0000400D0

Abstract

An antenna 1 in the form of a thin, substantially planar flexible panel allows the antenna 1 to conform to variations in the curvature of a surface on which the antenna 1 is located. The antenna 1 is primarily for use with a mobile phone and can be incorporated in a tax disc holder for securing to a vehicle windscreen or in a housing 12 of vehicle wing mirror 13 to provide a concealed mounting.

Description

2359664 1 IMPROVEMENTS IN OR RELATING TO ANTENNAS This invention concerns

improvements in or relating to antennas for receiving andlor transmitting signals, especially electromagnetic radiation.

The invention has particular, but not exclusive, application to antennas for automotive vehicles and especially concerns antennas for effective operation of a mobile telephone in a vehicle.

Vehicle antennas for in-car radios andlor mobile telephones are commonly externally mounted to avoid shielding by the metal body of the vehicle. Such external mounting renders the antennas susceptible to damage by vandals. Also an externally mounted antenna readily identifies a vehicle, having a radio andlor mobile telephone as a target for a potential thief.

Various proposals to locate antennas in a concealed position within the vehicle have been made but without being entirely successful.

The present invention has been made from a consideration of the problems 20 and disadvantages of existing antennas for automotive vehicles.

It is an object of the present invention to provide an antenna for transmitting andlor receiving a signal which is suitable for mobile telephone systems and can be fitted to an automotive vehicle.

It is another object of the present invention to provide an antenna capable of being fitted in different locations.

2 According to a first aspect of the invention there is provided an antenna for receiving and/or transmitting a signal comprising a thin, substantially planar, flexible panel.

By providing the antenna in the form of a flexible panel, the panel can be adapted for mounting the antenna in a range of locations. For example, the antenna may be mounted on a substantially flat surface such as the inside face of a vehicle window, e.g. the windscreen, with the flexibility of the panel allowing the antenna to conform to variations in the curvature 10 of the window for locating the antenna at any selected position.

Preferably, the panel has a base sheet of non-conducting material such as polyimide and a receiving/transmitting element of conducting material such as copper on one side.

The conducting element provides a large surface area for receiving and transmitting signals and this may be enhanced by the provision of a reflecting element on the opposite side of the base sheet.

Advantageously, the panel is housed in a casing of flexible material transparent to electromagnetic radiation and adapted for mounting on a support surface such as the inner face of a vehicle window. In this way, the antenna is protected and is concealed from view of anyone looking inside the vehicle.

The casing may be adapted to mount a tax disc or other document which has to be carried or displayed for inspection from outside the vehicle. Such alternative use of the casing further contributes to conceal the presence of the antenna.

3 The easing may be substantially flat for mounting on a vehicle window with a pocket in which the tax disc or other document to be displayed can be located.

The casing is preferably opaque so that the contents of the casing cannot be seen and the pocket may be formed by a sheet of clear or transparent plastics attached to one side of the casing, preferably around the marginal edge, with an entry slot for inserting/removing the document to be displayed.

Advantageously, the outer face of the strip is coated with a releasable self-adhesive material for detachably mounting the casing on the vehicle window.

In this way, the casing can be removed when it is desired to replace the document to be displayed and the casing re-mounted on the vehicle window. Also, the casing can be detached and re-fitted to another vehicle.

According to a second aspect of the invention there is provided a casing for housing an antenna and adapted for releasably securing to a vehicle window, the casing and antenna being flexible for conforming to the shape of the surface of the window.

Preferably, the casing has a pocket for locating and displaying a document such as a tax disc when secured to the vehicle window.

According to a third aspect of the invention there is provided a tax disc holder for releasable mounting on an inner face of a vehicle window to display a tax disc for inspection through the window from outside the 4 vehicle, the holder being flexible for conforming to the inner face of the window and having a flexible antenna for receiving andlor transmitting a signal whereby the antenna is concealed when the holder is mounted on the vehicle window.

is The invention will now be described in more detail by way of example only with reference to the accompanying drawings wherein:- Figure 1 shows one side of a flexible panel of an antenna embodying the invention; Figure 2 shows the other side of the flexible panel shown in Figure 1; Figure 3 is a section through the flexible panel shown in Figures 1 and 2; Figure 4 shows one side of a tax disc holder for concealed mounting of the antenna shown in Figures 1 and 2; Figure 5 shows the other side of the tax disc holder shown in Figure 4; Figure 6 shows the antenna of Figures 1 to 3 mounted in the housing for a vehicle wing mirror; Figure 7 shows an alternative holder for the antenna shown in Figures 1 to 3; and Figure 8 shows a modification of the holder shown in Figure 7.

Referring first to Figures 1 to 3 of the drawings, there is depicted an antenna 1 comprising a thin, substantially planar, flexible panel 2.

1, The panel 2 comprises a base sheet 3 made of polyimide or other nonconducting material having a thickness of 50 microns. A receiving/transmitting element 4 is formed on one side face 3.a and a reflector element 5 is formed on the opposite side face 3h of the base sheet 3.

The transmitting element 4 comprises two electrically conducting portions 4a, 4b of identical shape arranged as mirror images about the line A-A. Each element 4a, 4b is also a mirror image about the line B-B.

The reflector element 5 comprises two electrically conducting portions 5. a, 5b of rectangular shape positions at opposite ends of the base sheet 3.

A coaxial cable 6 for connecting the antenna 1 to a receiving unit (not shown) for a mobile phone (not shown) has the central conductor 6a connected to one portion 4a of the element 4 and the sheathing 612 connected to the other portion 4h. The portions 4.a, 4h are thus electrically independent of each other.

The elements 4, 5 are made of copper or other electrically conducting material having a thickness of 35 microns. The elements 4, 5 may be produced by any suitable method, for example by applying a sheet of copper to each side of the base sheet and etching away selected regions of the copper sheets to leave the required shape of the elements 4, 5.

6 As best shown in Figure 3, each element 4, 5 is firmly bonded to the base sheet 3, for example by a layer of acrylic adhesive having a thickness of 25 microns, so that the panel 2 is an integral composite construction.

The antenna 1 could be mounted directly on the inner face of a window (not shown) of a vehicle (not shown). More preferably, however, we prefer to conceal the presence of the antenna 1 by incorporating it into a document holder for mounting on the inner face of the window.

One type of document holder in the form of a tax disc holder 7 is shown in Figures 4 and 5.

The holder 7 is formed by three sheets 7a, 712, 7-e of plastics cut to the shape shown and bonded to each other around the marginal edge, for example by heat welding.

Two adjacent sheets 7a, 712 are made of self-coloured vinyl so as to be opaque. The remaining sheet 7-Q is made of clear vinyl so as to be transparent.

Prior to bonding the sheets 7a, 7b, 7C together, the panel 2 of the antenna 1 is located between the coloured sheets 7g, 7b and an opening 8 for the cable 6 is left at one end when the sheets are bonded together. In this way, the panel 2 is concealed and protected between the sheets 7. a, 7b 25 and cannot be removed without destroying the holder 7 The clear sheet k is formed with a transverse slit 9 between the ends of the holder 7 to allow access to a pocket 10 defined between the sheets 7b, 7c.

7 The outer face of the sheet 7-c is coated with a self-adhesive material for securing the holder 7 to the inner face of the window of a vehicle.

11 A removable face or cover sheet (not shown) is applied to the outer face of the sheet 7-e to protect the adhesive until it is desired to mount the holder 7 on the window. Typically, the face sheet is printed with instructions for assisting the end user to fit the holder 7.

As will now be appreciated, the panel 2 and holder 7 are flexible and can be mounted at any desired position on the vehicle window, usually the bottom left hand corner of the windscreen to display a tax disc 11 mounted in the pocket 10.

By appropriate positioning of the holder 7, the wire 6 can normally be concealed behind the trim of the vehicle so that anyone looking inside the vehicle would not see the panel 2 or the wire 6 and would therefore not suspect the vehicle may contain a mobile phone.

The self-adhesive material applied to the outer face of the sheet 7.C allows the holder 7 to be removed and re-fitted, for example to replace the tax disc 11. Additionally, the holder 7 can be removed and re-fitted in another vehicle. In this way, the owner can transfer the antenna when the vehicle is sold.

Thus, it will be understood that the holder 7 has universal application to all vehicles and the flexibility of the panel 2 and holder 7 allows the holder 7 to conform to different shapes of window from one vehicle to another.

8 It will also be understood that the invention is not limited to the embodiment ab o ve- described. Thus, the size and shape of the panel 2 may be altered from that shown. Also, the size and shape of the elements 4,5 may be varied from that shown. For example, this may enable the antenna to be adapted for different operating frequencies.

The panel 2 may be adapted for mounting directly on a support surface. In this case, it is preferred to apply a protective layer or coating over the elements 4,5 on each side of the base sheet 3 so that the panel 2 is weather-tight.

The flexibility of the panel 2 enables it to conform to the shape of the support surface to which it is fixed. Accordingly, it is envisaged that the panel 2 could be mounted outside the vehicle in a concealed location, for example in the housing for a wing mirror, behind a vehicle bumper or similar location, and the wire 6 routed into the interior of the vehicle for making the appropriate electrical connections.

Figure 6 shows the antenna 1 concealed in a housing 12 for a vehicle wing mirror 13. The housing 12 is made of plastics, typically a plastics moulding, and the mirror 13 is supported by any suitable mechanism (not shown) for adjusting the position of the mirror 13 as will be understood and known to those skilled in the art.

The antenna 1 is mounted behind the mirror 13 on an internal surface 14a of the wall 14 of the housing 12. The wall 14 is aerodynamically shaped to reduce resistance and/or to conform with the style/shape of the vehicle body.

9 In this embodiment, the internal surface 14a is concave and the flexible panel 2 of the antenna 1 can bend to conform to the shape of the internal surface 14a for mounting the antenna 1 on the wall 14 by any suitable means.

The panel 2 is preferably made weathertight by the application of a protective coating before or after attaching to the inner surface 14a and the flexible cable 6 is routed into the interior of the vehicle through the mounting (not shown) for the housing 12.

The housing 12 provides a concealed mounting for the panel 2 outside the vehicle so as to reduce any adverse affect on performance of the antenna 1 from shielding by the metal body of the vehicle. It will be understood the same advantages may be obtained when mounting the panel 2 behind the 15 bumper or other external trim panel made of plastics.

External mounting of the panel 2 may be preferred by vehicle manufacturers where the antenna 1 is provided as original equipment but such arrangements may not allow the antenna 1 to be easily transferred to 20 another vehicle.

For this reason, the incorporation of the antenna 1 in an accessory such as the tax disc holder 7 abovedescribed which the user can transfer to another vehicle is especially suitable for retro-fitting a mobile phone system in a vehicle.

It will be appreciated that the holder 7 is not limited to use as a tax disc holder and could be used to display any document, for example, a parking permit, membership of a club or a breakdown/recovery service, an insurance certificate or any other type of document which the owner of the vehicle may wish or be required by law to display.

The shape and configuration of holder 7 may be altered to suit the intended application. Thus, Figures 6 and 7 show a generally rectangular holder 7 for the panel 2 with an opening 8 for the cable 6 in the corner (Figure 6) or centrally on one side (Figure 7). The construction of the holder 7 may be similar to that described above.

Other modifications are possible as will be apparent to those skilled in the art. Thus, the holder 7 may display more than one document at a time. The holder 7 may be provided with a pocket on the side remote from the surface to which the holder 7 is attached. Such pocket may be provided for the user to store documents, information which the user may need to refer to or use, for example, a driving licence, MOT certificate, map, etc. Such pocket may be provided in addition to or in place of the pocket on the side attached to the support surface, for example if the holder 7 is not intended to display a document or other information for inspection from outside the vehicle. In this case, the self-adhesive material would be provided on the surface of the casing containing the antenna.

Although the invention has been described with particular reference to mobile phones, the antenna 1 may be used for other purposes in addition to or in place of its use for receiving/transmitting signals for a mobile phone. Thus, the antenna 1 could be used as a car radio receiver or as a GPS receiver. Where more than one application of the antenna 1 is employed, the signals may be routed through a splitter box or other device for directing the signal to/from the appropriate system in the vehicle.

11

Claims

1. An antenna for receiving andlor transmitting a signal comprising a thin, substantially planar, flexible panel.

2. An antenna according to claim 1 wherein, the panel has a base sheet of non-conducting material and a receiving/transmitting element of conducting material on one side.

- 3. An antenna according to claim 2 wherein, the non-conducting material is polyimide and the conducting material is copper.

4. An antenna according to claim 2 or claim 3 wherein, the receiving/transmitting element provides a large surface area for receiving and transmitting signals.

5. An antenna according to any one of claims 2 to 5 wherein, a reflecting element is provided on the opposite side of the base sheet.

6. An antenna according to any one of the preceding claims wherein, the panel is housed in a casing of flexible material transparent to electromagnetic radiation and adapted for mounting on a support surface.

7. An antenna according to claim 6 wherein, the casing is adapted to mount a vehicle tax disc or other document for display and inspection from outside a vehicle.

8. An antenna according to claim 7 wherein, the casing is substantially flat for mounting on a vehicle window with a pocket in which the tax disc or other document to be displayed can be located.

12 9. An antenna according to claim 8 wherein, the casing is opaque so that the contents of the casing cannot be seen and the pocket may be formed by a sheet of clear or transparent plastics attached to one side of the casing with an entry slot for inserting/removing the document to be displayed.

10. An antenna according to claim 9 wherein, the outer face of the pocket is coated with a releasable self-adhesive material for detachably mounting the casing on the vehicle window.

11. An antenna according to any one of the preceding claims in combination with a tax disc holder for releasable mounting on an inner face of"a vehicle window to display a tax disc for inspection through the window from outside the vehicle 12. The combination of claim 11 wherein, the holder is flexible for conforming to the inner face of the window and the antenna is concealed when the holder is mounted on the vehicle window.

13. An antenna according to any one of claims 1 to 5 in combination with a vehicle wing mirror.

14. An antenna for receiving and/or transmitting a signal substantially as hereinbefore described with reference to Figures 1 to 3 of the accompanying drawings.

15. An antenna for receiving and/or transmitting a signal in combination with a tax disc holder substantially as hereinbefore described with reference to Figures 1 to 5 of the accompanying drawings.

13 16. An antenna for receiving andlor transmitting a signal in combination with a vehicle wing mirror substantially as hereinbefore described with reference to Figures 1 to 3 and Figure 6 of the 5 accompanying drawings.

17. An antenna for receiving and/or transmitting a signal substantially as hereinbefore described with reference to Figures 7 and 8 of the accompanying drawings