GB2325348A

GB2325348A - Antenna for wireless telephone

Info

Publication number: GB2325348A
Application number: GB9709796A
Authority: GB
Inventors: Ching-Shan Yang; Chad-Cheng Chen; Long-Jyh Pan
Original assignee: Acer Peripherals Inc
Current assignee: BenQ Corp
Priority date: 1997-05-14
Filing date: 1997-05-14
Publication date: 1998-11-18
Also published as: GB9709796D0

Abstract

The antenna comprises an antenna layer 31 attached to the rear inner side of the housing 22, a dielectric layer 32 attached to and completely covering the antenna layer 31, a ground layer 34 attached to and completely covering the dielectric layer 32, an antenna connector 41 for connecting the antenna layer 31 to the antenna terminal (50 Fig. 3 not shown) of the telephone circuit (38), and a ground connector (48) for connecting the ground layer (34) to the ground terminal (52) of the telephone circuit (38).

Description

Antenna for wireless telephone The present invention relates to an antenna of a wireless telephone.

Wireless telephones are widely used for personal communications because of their compact sizes and the progress in communication technologies. Please refer to Fig.l. Fig.l is a perspective view of a prior art wireless telephone 10. The wireless telephone 10 comprises a housing 18, a microphone 16, a speaker 14 and an external antenna 12 which is usually a monopole antenna such as quarter wavelength or flexible monopole antenna. The external antenna 12 can effectively transmit or receive wireless signals but it occupies some external space above the housing 18 which makes it very inconvenient for carrying, especially when placing the telephone 10 in a user's pocket.

Some telephone vendors use contractible antennas to replace the external antenna 12 shown in Fig.l.

Such contractible antennas can be pushed in or pulled out of a wireless telephone by a user for telephone communications. However, such an antenna has the drawbacks that its structure is quite vulnerable and also complex. Frequent push-in and pull-out actions may eventually damage its mechanical structure and also electrical connection.

Please refer to Fig.6. Fig.6 is a diagrammatic view of the electromagnetic field distribution pattern of the antenna 12 shown in Fig.l. The electromagnetic fields of the antenna 12 is radiated toward all directions. If a person holds such a telephone against his face, the electromagnetic fields will directly emit into his head and body. The effect of accumulation of such electromagnetic radiation in the human body is still unknown, especially for those frequent users who have to be exposed to such electromagnetic radiation for a long time everyday. If some protective measures can be taken to restrict such radiation, it may help to protect the user from getting some radiation-related diseases.

With these problems in mind the present invention aims at providing an antenna for wireless telephones which can reduce the size and mechanical complexity of a wireless telephone.

According to an embodiment of the present invention there is provided an antenna, for use in a wireless telephone, for transmitting and/or receiving communication signals from and/or to telephone circuitry within a housing of the telephone, the antenna being retained entirely within the housing during use of the telephone, wherein the antenna is a planar-form antenna which, when in use, is secured to an inner wall of the telephone housing. Such an antenna is mechanically more reliable and more convenient than the previously-proposed antennae described above.

The planar-form antenna is preferably formed on a rear inner wall of the telephone housing such that the radiation emitted therefrom is directed substantially away from a user of the telephone during use thereof.

In particular, the planar-form antenna may comprise a substantially flat metallic layer formed in a predetermined pattern on a rear inner wall of the telephone housing and defining an antenna layer, a dielectric layer formed over the antenna layer, and a further metallic layer formed over the dielectric layer and defining a ground layer.

According to a particular embodiment of the present invention there is provided a hidden antenna installed inside a wireless telephone for transmitting or receiving wireless signals, the telephone comprising a housing having a front side, a rear side and a rear inner side, and a telephone circuit installed inside the housing having an antenna terminal and a ground terminal, the front side of the housing being directed toward a user's face and the rear side of the housing being held by the user's hand during a telephone conversation, characterized in that the antenna comprises: a substantially flat metallic layer in a predetermined pattern attached to the rear inner side of the housing which defines an antenna layer; a dielectric layer attached to the antenna layer; a metallic layer attached to the dielectric layer which defines a ground layer; antenna connecting means for connecting the antenna layer to the antenna terminal of the telephone circuit; and ground connecting means for connecting the ground layer to the ground terminal of the telephone circuit. The hidden antenna installed inside a wireless telephone can reduce the size and mechanical complexity of the wireless telephone.

An embodiment of the present invention can also provide the advantage that the hidden antenna can restrict the radiation direction of its electromagnetic waves to prevent it from emitting toward a human body.

Further improvements in this respect are obtained by the features specified in the dependent claims.

The invention is illustrated by way of example with reference to the accompanying drawings, in which Fig.l is a perspective view of a previouslyproposed wireless telephone; Fig.2 is a perspective view of a wireless telephone of the present invention; Fig.3 is a sectional view 3-3 of the wireless telephone shown in Fig.2 which shows the structure of the hidden antenna 30; Fig.4 is a back elevational view of the hidden antenna shown in Fig.3; Fig.5 is a perspective view of the part assemblies of the hidden antenna shown in Fig.3; Fig.6 is a diagrammatic view of the field distribution pattern of the antenna shown in Fig.l; and Fig.7 is a diagrammatic view of the field distribution pattern of the antenna shown in Fig.2.

Please refer to Fig.2. Fig.2 is a perspective view of a wireless telephone 20 according to the present invention. Telephone 20 comprises a plastic housing having a front side 24 and a rear side 22, a speaker 26 installed in the upper part of the front side 24, a microphone 28 installed in the lower part of the front side 24, and a hidden antenna 30 (dotted line) attached to a rear inner side of the housing for transmitting and receiving wireless signals. The front side 24 of the housing will be directed toward a user's face and the lower portion of the rear side 22 is held by a user's hand during a telephone conversation. The upper portion of the rear side 22 is used for wireless signal transmissions and the antenna 30 is attached inside the upper portion of the rear side 22.

Please refer to Figs.3 - 5. Fig.3 is a sectional view 3-3 of the wireless telephone 20 shown in Fig.2 which shows the structure of the hidden antenna 30.

Fig.4 is a back elevational view of the hidden antenna 30 shown in Fig.3. And Fig.5 is a perspective view of the part assemblies of the hidden antenna 30 shown in Fig.3.

The telephone circuit 38 comprises an antenna terminal 50 and a ground terminal 52. The antenna 30 comprises an antenna layer 31 which is a flat metallic layer attached to the rear inner side of the housing, a dielectric layer 32 attached to and completely covering the antenna layer 31 which is used as a medium to transmit wireless signals, a ground layer 34 which is a metallic layer attached to and completely covering the dielectric layer 32, and a connecting mechanism 40 for connecting the antenna 30 to the telephone circuit 38.

The dielectric layer 32 is symmetrically covered above the antenna layer 31, i.e. the dielectric layer 32 is of uniform thickness above the antenna layer 31.

The antenna 30 is a microstrip antenna which is pre-tuned to a predetermined frequency and polarization for transmitting or receiving wireless signals. The antenna layer 31 of the antenna 30 is shaped in a substantially rectangular pattern. Although a microstrip antenna is used as a preferred embodiment in the present invention, other planar-type antennas such as patch antenna can also be used to replace the microstrip antenna 30 disclosed in the present invention.

The connecting mechanism 40 comprises an elongated rectangular post 42 integrally built over the rear inner side of the rear side 22 of the housing, an antenna connecter 41 which is a metallic layer integrally built with the antenna layer 31 and attached over the outer side of the post 42 for connecting the antenna layer 31 to the antenna terminal 50 of the telephone circuit 38, an elongated dielectric tube 44 which is integrally built with the dielectric layer 32 and attached over the outer side of the antenna connector 41, and a ground connecter 48 which is also integrally built with the ground layer 34 and attached over the outer side of the dielectric tube 44 for connecting the ground layer 34 to the ground terminal 52 of the telephone circuit 38.

The antenna connecter 41 is used for electrically connecting the antenna layer 31 and the antenna terminal 50 of the telephone circuit 38. Since the frequencies of the wireless signals transmitted or received by the telephone circuit 38 are usually in microwave range, mechanical discontinuity between the antenna terminal 50 and the antenna connecter 41 may greatly affect the quality of the transmitted or received signals. A flexible high frequency conductive gasket 36 is installed between the antenna connecter 41 and the antenna terminal 50 to solve the mechanical discontinuity problem. The dielectric tube 44 comprises an opening 46, and the conductive gasket 36 is mounted in the center of the opening 46 which connects the antenna terminal 50 and the antenna connecter 41 together.

Please refer to Fig.4. It shows that the antenna layer 31 (area circled by dotted line) is in a substantially rectangular shape. The antenna layer 31 is completely covered by the dielectric layer 32. And the ground layer 34 completely covers both the dielectric layer 32 and the rear inner side of the housing. The ground layer 34 is used as a shielding layer which can block EMI (electromagnetic interference) generated by the telephone circuit 38 and also confines the radiation direction of the electromagnetic waves generated from the antenna layer 31 to prevent it from emitting toward a human body.

Please refer to Fig.5. The antenna layer 31 and the antenna connecter 41 are formed by sputtering a layer of highly conductive metal such as copper over a rectangular region on the rear inner side of the housing and also on the surface of the post 42. The dielectric layer 32 and the dielectric tube 44 which are made by plastics are then attached above the antenna layer 31 to completely cover it. And the ground layer 34 is then created by sputtering a layer of highly conductive metal above the dielectric layer 32 and also the rear inner side of the housing.

Finally, the conductive gasket 36 is connected to the antenna connector 41 through the opening 46. Such a method of making the antenna 30 over the rear inner side of the housing is quite easy and also costs less when compared with previously-proposed external antennae.

Please refer to Fig.7. Fig.7 is a diagrammatic view of the field distribution pattern of the antenna 30 shown in Fig.2. It clearly shows that the radiation field of the antenna 30 installed on the rear inner side of the telephone 20 is confined toward outward directions and very little microwave radiation will be emitted toward a human body. Besides, the antenna 30 occupies no external space which makes it very portable. A user can easily put the telephone 20 inside his pocket. Comparing with those contractible antennae, the hidden antenna 30 comprises no movable part and it is not exposed outside the telephone.

Reliability of such an antenna is much higher than those contractible antenna. In fact, no damage can be made to the antenna 30 unless the housing of the telephone 20 is broken.

Claims

1. A hidden antenna installed inside a wireless telephone for transmitting or receiving wireless s s, the telephone comprising a housing having a fi side, a rear side and a rear inner side, and a telephone circuit installed inside the housing having an antenna terminal and a ground terminal, the front side of the housing being directed toward a user's face and the rear side of the housing being held by the user's hand during a telephone conversation, characterized in that: the antenna comprises: (1) a substantially flat metallic layer in a predetermined pattern attached to the rear inner side of the housing which defines an antenna layer; (2) a dielectric layer attached to the antenna layer; (3) a metallic layer attached to the dielectric layer which defines a ground layer; (4) antenna connecting means for connecting the antenna layer to the antenna terminal of the telephone circuit; and (5) ground connecting means for connecting the ground layer to the ground terminal of the telephone circuit.

2. The hidden antenna of claim 1 wherein the dielectric layer is symmetrically covered above the antenna layer.

3. The hidden antenna of claim 1 wherein the ground layer of the hidden antenna is also covered in the rear inner side of the housing.

4. The hidden antenna of claim 1 wherein a high frequency co;-riecting device is installed between the antenr connecting means and the antenna terminal of the toe phone circuit for passing high frequency wireless signals therebetween.

5. The hidden antenna of claim 1 wherein the hidden antenna is a microstrip antenna.

6. The hidden antenna of claim 1 wherein the predetermined pattern of the antenna layer is in a substantially rectangular pattern.

7 The hidden antenna of claim 1 wherein the rear side of the housing comprises a lower portion which is held by the user's hand during a telephone conversation and an upper portion for wireless signal transmissions, and wherein the antenna layer is attached inside the upper portion of the housing.

8. The hidden antenna of claim 1 wherein the antenna layer is completely covered by the dielectric layer.

9. The hidden antenna of claim 1 wherein the dielectric layer is completely covered by the ground layer.