GB2314211A

GB2314211A - Antenna for a mobile telephone

Info

Publication number: GB2314211A
Application number: GB9612077A
Authority: GB
Inventors: Paul Anthony Taylor; Gilbert Wunter; David Stokes; David Harvey
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-06-10
Filing date: 1996-06-10
Publication date: 1997-12-17
Also published as: GB9612077D0

Abstract

In an antenna arrangement suitable for mobile telephones, an antenna 3 is positioned away from the user to minimise potential health hazards of RF radiation and to minimise detuning of the antenna. The antenna 3 is positioned away from the user by means of a rigid elongated portion 5 in which is housed a coaxial cable (19, fig. 2) for elecrically connecting the antenna to the mobile telephone. The antenna arrangement may be detachable from the mobile telephone or may be integral with it. The arrangement may feature a "C shaped" bracket 7 for attachment to the mobile telephone.

Description

AN ANTENNA The present invention relates to an antenna which is particularly suitable for use with radio handset, specifically, mobile telephones.

Mobile telephones are now widely being used. Recently, fears have been raised concerning the potential health hazard of RF radiation. In use, the telephones are held against the head of the user with the antenna being at close proximity to the user. This can prove to be particularly hazardous when the phone is in prolonged or frequent use.

Many conventional mobile telephones have an integral antenna positioned at the top of the telephone near the ear piece and its proximity to the head of the user has given rise to concerns of the effect of RF radiation.

Furthermore, such conventional mobile telephone are more easily detuned. The antenna is close to the head of the user. This causes detuning of the antenna leading to intermittent transmission causing annoyance the user, and diminishing battery life of the telephone unit.

The present invention seeks to provide an antenna which overcomes the above problems.

The invention provides an antenna for attachment to a mobile telephone comprising an antenna means, and a substantially rigid elongated portion, one end of the elongated portion being attached to the antenna means and the other end of the elongated portion for attachment to a mobile telephone whereby, in use, the antenna is held clear of the user's head.

In providing means for holding the antenna remote from the telephone, the transmission and reception is carried out away from the head of the user, thus reducing the hazard of RF radiation and improving reception of the antenna.

Preferably, the elongated portion is shielded from electromagnetic radiation to provide the user with additional protection from radiation, the antenna means being electrically connected to the mobile telephone by means of a coaxial cable housed within the shielded elongated portion.

In a preferred embodiment, the antenna is electrically and physically detachable. One way in which this can be achieved is by means of a generally C-shaped bracket, the bracket being attached to the other end of the elongated portion. The bracket slideably fits or clips over the top of the mobile telephone and is provided with a coaxial plug for connecting with a corresponding socket in the mobile telephone which automatically disconnects the existing antenna. Therefore, the antenna of the present invention can be fitted to existing conventional mobile telephone and plugged into an existing socket presently used for connecting a car telephone aerial.

The antenna might be rigidly attached to the bracket in its upright position.

Alternatively, it might be attached at a pivot so that the antenna can be pivoted into a downward position when not in use and pivoted into an upright position when in use.

Alternatively, the antenna may be integral with the mobile telephone. It could be rigidly fixed or pivoted directly to the telephone as mentioned above or alternatively it could be telescopically housed within the body of the telephone and simply pulled out when in use.

Alternatively, the antenna may be fixed directly into the antenna socket of the telephone by means of a corresponding plug socket arrangement.

The present invention also provides a mobile telephone fitted with any one of the features mentioned above.

The present invention will now be described in more detail with reference to the preferred embodiments as shown in the following drawings: Figure 1 shows a front view of an antenna according to an embodiment of the present invention; Figure 2 shows a rear view of the antenna shown in Figure 1; Figure 3 shows the antenna of the present invention when in use; and Figure 4 shows the circuit arrangement of the antenna of the present invention.

The antenna 1 of Figures 1 and 2 comprises an antenna means 3 at one end of a substantially rigid elongated portion 5. The other end of the elongated portion 5 being connected to a bracket 7.

The bracket 7 is generally C-shaped and comprises a rear section 9 connecting to two outwardly extending sections 11 and 13. The rear section 9 extends in a direction perpendicular to the longitudinal axis of the elongated portion 5. The bracket 7 slideably fits around the top of a mobile telephone, as shown in Figure 3, so that the rear section 9 is adjacent to the back of the mobile telephone, and the outwardly extending sections 11 and 13 extending partly around each side of the telephone handset leaving the display and keypad areas exposed.

The bracket further comprises a coaxial plug 15 at the inner face of the rear section 9 at the base of the elongated portion 5.

The elongated portion 5 comprises an outer plastic sheath 17 in which is housed a shield coaxial cable 19. One end of the coaxial cable is connected to the bracket 7 at a point 21 on the rear section 9. The connection may be rigid so that the elongated portion 5 is permanently held in its upright position. Alternatively, a pivot may be provided so that the elongated portion 5 can be swivelled between an upright and downward position.

The antenna can then be placed in its downward position when not in use to provide more compact unit.

As shown in Figure 3, the bracket 7 slideably mounts around the top of a mobile telephone 23 near the ear piece 25. The coaxial plug 15 then connects into a corresponding socket at the rear of the telephone at the base of the existing antenna 27 of the mobile telephone 23. This disconnects the existing antenna 27 and connects the antenna 3.

The circuit arrangement of the antenna is shown in Figure 4. A screened coaxial cable 31 extends from the connection with the mobile telephone to the remote antenna coil 33. The coaxial cable is approximately 130mm in length and is screened with silver and housed within a plastic sheath 19. The antenna coil 33 is housed with a plastic sheath 29 forming the antenna means 3. The outer and inner RF transmitters/receiver coils 35, 37 are electrically connected to the outer and inner braids 39, 41 of the coaxial cable 31. The outer coil 35 being formed of 3W turns of 1 mm wire at a height of approximately 8mm. The inner coil 37 comprises 8 turns of 0.7mm wire having approximately lmm spaces between the turns and terminating in a copper disc 43 of approximately 6mm in diameter. The distance between the copper disc and the turns of the inner coil is approximately 4mm and the length of the inner coil is approximately 14mm. This provides the required duplex antenna means suitable for use for standard RF transmission and reception.

The antenna described with reference to the above embodiment may not be detachable.

It may be integral with the telephone unit, either fixed in an upright position, or pivotable between upright and downward positions, or telescopic. Alternatively the antenna may be adapted to plug directly into the socket by removable the existing antenna 27.

The antenna described above therefore provides a means to position the antenna away from the user to minimise the risks of RF radiation and to improve reception of the antenna.

In the light of this disclosure, modifications of the described embodiment as well as other embodiments, all within the scope of the present invention as defined by the appended plans, will now become apparent to the person skilled in the art.

Claims

CLAIMS:

1. An antenna for a mobile telephone comprising an antenna means and a substantially rigid elongated portion, one end of the elongated portion being attached to the antenna means and the other end of the elongated portion for attachment to a mobile telephone whereby, in use, the antenna is held clear of the user's head.

2. An antenna according to claim 1, wherein the elongated portion is shielded from electromagnetic radiation.

3. An antenna according to claim 1 or 2, wherein the antenna further comprises a coaxial cable housed within the elongated means for electrically connecting the antenna means with a mobile telephone.

4. An antenna according to any one of the preceding claims, wherein the antenna is integral with a mobile telephone.

5. An antenna according to any one of claims 1 to 3, wherein the antenna is electrically detachable.

6. An antenna according to any one of claims 1 to 3 and 5, wherein the antenna is physically detachable.

7. An antenna according to claim 6, wherein the antenna further comprises a generally C-shaped bracket, the bracket being attached to said other end of the elongated portion.

8. An antenna according to claim 7, wherein the elongated portion is pivotably attached to the bracket.

9. An antenna according to any one of the preceding claims, wherein the antenna is telescopic.

10. An antenna according to any one of the preceding claims, wherein the antenna includes means for pivotably attaching the other end of the elongated portion to a mobile telephone.

11. A mobile telephone fitted with an antenna according to any one of the preceding claims.

12. An antenna substantially as hereinbefore described with reference to any one of the Figures.

13. A mobile telephone substantially as hereinbefore described with reference to any one of the Figures.