WO2000069017A1

WO2000069017A1 - A mobile telephone and an antenna for a mobile telephone

Info

Publication number: WO2000069017A1
Application number: PCT/SE2000/000907
Authority: WO
Inventors: Lennart Stjerwall
Original assignee: RICHTNÉR STJERNWALL, Christian; RICHTNÉR STJERNWALL, Caroline
Priority date: 1999-05-06
Filing date: 2000-05-08
Publication date: 2000-11-16
Also published as: AU4793200A; SE9901680L; SE9901680D0

Abstract

A mobile telephone operating with electromagnetic waves has an antenna (6), which has means (7) for restricting the radiation of waves in a first region of the wave radiation area of the antenna so as to reduce the exposing of a user of the mobile telephone to radiation.

Description

A mobile telephone and an antenna for a mobile telephone

FI ELD OF THE INVENTION AND PRIOR ART

The present invention relates to a mobile telephone operating with electromagnetic waves and having an antenna. Furthermore, the invention relates to an antenna for mobile telephones.

The wording "mobile telephone" used herein should be inter- preted in a broad sense. First of all, the wording includes such mobile telephones, which are usable in mobile telephone systems comprising several base stations, each of which has transmitter and receiver. Also the mobile telephones have each such transmitters and receivers. As the mobile telephone and the user thereof move from one cell to another in the mobile telephone system the communication will successively change over from one base station to another so that the mobile telephone constantly may communicate with any base station included in the mobile telephone system, this is in any case what is desired. However, in the concept "mobile telephone" such mobile telephones which are adapted to work with only one single base station are also included. Such a base station has both transmitter and receiver and the mobile telephone itself, which also has a transmitter and a receiver, may be moved away from the base station so as to increase the freedom of movement of a user in an apartment, in a place of work or else in the immediate surrounding. However, since only one base station exists there is a restriction that the mobile telephone may be moved apart only by a largest distance depending on the capacity of the transmitters and receivers.

Today, such mobile telephones are constituted by small units that may be comfortably brought along even if the invention does not exclude larger units as long as they may be rightly described as mobile. The mobile telephones have a speaker to be located at the ear of the user and a microphone intended to be located in a reasonable proximity to the mouth of the user. The antenna of the mobile telephone is generally in such a using position in the immediate vicinity of the head of the user. When a mobile telephone sends signals to a base station this is per- formed by electromagnetic wave movements of significant intensity. These wave movements are radiated in an isotopic way from the antenna of the mobile telephone and accordingly they will expose the user to important doses of electromagnetic radiation. Such radiation has a negative effect on human organ- isms; particularly this is true for such sensitive parts of the body as the brain. Even when a mobile telephone of the type which may co-operate with several base stations is in a state of rest, i.e. when any conversation or other communication initiated by the user does not exist, the mobile telephone is in communica- tion with one or more base stations so that the mobile telephone system on the whole will be able to establish where the mobile telephone is at the time and which base station that suitably will be utilized for this purpose. However, the radiation that arises in this case is normally of less importance since it takes place at lower power and, in addition, when the mobile telephone normally is not in the immediate vicinity of the head of the user. However, also such radiation which arises in the state of rest of the mobile telephone may result in negative effects, especially if the user has high sensitivity to the radiation in question. It would be uncontroversial to state that a great part of humanity has high sensitivity to electromagnetic wave movements of the pre- sent frequencies within the radio wave spectrum, which is usually considered to be within the interval 300GHz-300Hz.

THE OBJECT OF THE INVENTION

The object of the present invention is to describe ways to develop mobile telephone antennas so as to obtain that the users of mobile telephones will be exposed in a reduced degree to the important radiation which the mobile telephones emit when their transmitting units are in function. In that connection it is tried to obtain this result without the need to modify the mobile telephones or their antennas so that the use of them is made more difficult.

SUMMARY OF THE INVENTION

According to the invention the object is primarily obtained by that the antenna of the mobile telephone has means for restricting the radiation of waves in a first region of the wave ra- diation area of the antenna so as to reduce the exposing of a user of the mobile telephone to the radiation. This region of the antenna with restricted radiation of waves is located/may be located for restricting the radiation of waves particularly toward the head of the user when the mobile telephone is in a normal using position, i.e. with the speaker integrated in the mobile telephone located at the ear of the user.

According to a special preferred embodiment the antenna is adjustable by the user, preferably by that an antenna part, which includes the means for restricting the radiation of the antenna, may be pivoted in relation to the body of the mobile telephone, so that the user may always adjust the antenna part so that the body of the user will be exposed to radiation to the smallest possible extent. When the antenna is located at the head of the user thus the antenna part should be adjusted so that the radiation in the direction towards the head is restricted. If the user has the telephone in a pocket or in any kind of a carrying bag or case, which may be placed on the body, the user may adjust the antenna part so that the radiation restricting means will restrict the radiation in the direction towards the adjacent body part.

To facilitate for the user to perform an adequate adjustment of the antenna part it is preferred that the antenna part has a mark visible from the outside which corresponds to the antenna region with restricted radiation of waves. Even when the antenna is not adjustable in this way but the first region with restricted wave radiation is always so localized that in normal mobile telephone conversations the region restricts the radiation of waves toward the head of the user such a mark leads to that the user may note that the antenna is in the function position desired, i.e. that the antenna has not unintentionally got out of the correct position as a result of any defect or external effect.

Further characteristics and advantages of the invention are discussed in the dependent claims and the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the appended drawings below follows a closer description of embodiments of the invention cited as examples.

In the drawings:

Fig 1 is a perspective view illustrating the main features of a typical mobile telephone,

Fig 2 is a view of the mobile telephone viewed from above, in which it is indicated by means of broken lines outgoing from the antenna how the radiation from the antenna is unrestricted whereas the absence of such radiation indicative lines indicate that in one radiation region the radiation is reduced even if it is not completely eliminated, which in fact would be desired, Figs 3 and 4 are a partly cut perspective view in an assembled state and an exploded view of a conventional antenna, respectively,

Fig 5 is a view of a transmitting member of the antenna in accordance with the invention,

Fig 6 is a view similar to Fig 5 of a modified embodiment ac- cording to the invention,

Fig 7 is a view showing a further variant according to the invention,

Fig 8 is a view showing a further variant of a transmitting member according to the invention,

Fig 9 is a lateral view of the transmitting member according to Fig 8,

Fig 10 is a perspective view of the transmitting member according to Fig 8 applied on a frame,

Fig 1 1 is a cross section view of the frame according to Fig 10,

Figs 12 and 13 are partly cut lateral views illustrating two different embodiments of another type of antenna,

Fig 14 is a perspective detail view of a mobile telephone with an antenna according to the invention in another embodiment,

Fig 15 is an principal view of the antenna according to Fig 14 from above illustrating the radiation of waves of the antenna,

Figs 16 and 17 are cross sections of two different embodiments of antenna envelopes, Fig 18 is a partly cut lateral view of an antenna showing two antenna parts which are pivoted to each other, and

Fig 19 is a perspective exploded view illustrating the antenna according to Fig 18.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The mobile telephone illustrated in Fig 1 has a body generally denoted with 1 , which body has a set of keys 2, a display 3, a speaker 4, a microphone 5 and an antenna 6. As appears from Fig 1 the antenna 6 will be located in the immediate vicinity of the head of the user when the speaker 4 is located in the prox- imity to one of the ears of the user.

According to the invention the antenna 6 has a means 7, indicated by broken lines in Fig 1 , for restricting the radiation of waves in a first region of the wave radiation area of the antenna to reduce exposing of a user of the mobile telephone to the radiation. As is indicated in Fig 1 the means 7 is so localized on the antenna 6 that it will be turned towards the head of a user when the telephone is in the normal conversation position. This causes the consequence which was indicated in Fig 2, namely that the radiation will not be emitted, or in any case be emitted with reduced intensity, in such directions which run towards the head of the user, as indicated by the broken radial lines outgoing from the antenna 6. Even in Fig 2 the restricting means 7 is indicated by a broken line.

As will be more closely described in the following the restricting means 7 comprises a shield, i.e. a member capable of shielding the radiation from the antenna in the first region of the radiation area. It is preferred that the antenna 6 has a mark visible from the outside corresponding to the first region with restricted radiation of waves. For example the mark may consist of a field in a colour differing from the colour of the antenna for the rest. How- ever, any kind of marking technique is sufficient in this respect. Moreover, it is not necessary that the mark has such an extension that it directly corresponds to the extension of the shield itself. Thus, the mark would simply consist of a point or an arrow or the like that demonstrates which part of the antenna that has to be turned towards the head of the user in a normal conversation position.

At the antenna known per se which is illustrated in Figs 3 and 4 a first portion 8 is included which portion is intended to be at- tached with the mobile telephone, here by means of a thread joint. A contact member 9 is intended to contact a corresponding contact member in the mobile telephone for establishing of a connection with the transmitting unit of the mobile telephone. This contact member 9 includes a shaft denoted with 10, which penetrates through the member 8. The contact member 10 is in electrically conducting connection with a second conducting member 1 1 , which is penetrated by the shaft 10 and which is electrically insulated from the first mentioned member 8 by means of an insulating sleeve 12, which also has a portion which encloses the shaft 10 and insulates the contact member 9/shaft 10 from the first mentioned member 8.

A frame or sleeve 1 3 is placeable over the second conducting member 1 1 . A transmitting member 14 of the antenna is formed by conducting paths 15 and 16, respectively, arranged on an insulating carrier 19 and intended to be conductingly connected with the transmitting member of the mobile telephone. The carrier 19 is intended to be bent around the sleeve 13 and thus consists of a flexible material, for example a plate, a sheet or a foil of plastic, paper etc. The conducting paths 15 and 16 may for example be achieved by usual plating techniques. In the ex- ample it is illustrated how the carrier 19 has double sets of conducting paths 15, 16, which means that transmitting respective receiving may be performed on two different frequency bands. The conducting paths 15, 16 have connection portions 17, 18, which for example may be located at protruding flaps of the carrier 19. When the carrier 19 is assembled on the sleeve 13 the conducting paths are normally placed outwards whereas the flaps having the connection portions 17, 18 are folded into the sleeve 13 so that when the assembly carrier 1 9/sleeve 13 is pushed over the second member 1 1 the connection portions of the flaps will be in conducting contact with the second member 1 1 but, as a consequence of the insulating sleeve 12, not in conducting contact with the first member 8, which as known is grounded by the connection with the body of the mobile tele- phone. Then an envelope 39 is placed over the carrier 19/sleeve 13 and this envelope is glued or fixed in another way on the first member 8 as indicated in Fig 3.

The carrier 19 is so dimensioned in relation to the sleeve 13 that the conducting paths 15, 16 will enclose the whole circumference of the sleeve 13, i.e. that in the case already known the transmitting member will emit radiation along the whole circumference of the antenna.

A first embodiment of the invention is illustrated in Fig 5. In this case the transmitting member is intended to be of a single band type. The transmitting member 14 comprises as in the previous case a flexible carrier 19 with conducting paths 1 5. The restricting means 7 in the shape of a shield previously discussed is arranged on the carrier 19 itself. The shield 7 consists of a field of electrically conductive material. Preferably this conducting material is arranged on the carrier 19 by plating in the same operation as in the plating of the conducting paths 15. In this embodiment the shield 7 and the conducting paths 15 are intended to be arranged on one and the same side of the carrier. This means that the shield may not overlap the conducting paths 15 since then short-circuiting would take place. However, studying shows that when transmitting by the antenna the radiation decreases successively in the direction up along the antenna. To the right in Fig 5 a small diagram is illustrated. Here the abscissa illustrates the radiation power whereas the ordinate reflects the height of the transmitting member 14. Thus, the radiation intensity from the antenna is high in the lower region of the antenna and decreases successively upwards. Primarily the meander-like windings of the conducting paths 15 in the upper area of the transmitting member 14 will be efficient for receiving purposes. It is then favourable that the shield 7 does not cover these meander-like windings. Nevertheless, by locating the shield 7 as indicated in Fig 5 the main part of the radiation from the antenna will be shielded by means of the shield 7.

Also the shield 7 has a plated contact portion arranged on a flap of the carrier 19. It is preferred that the flap of the contact portion 20 has a plating also on its rear side at the bottom in Fig 5 so that when the transmitting member 14 is folded around a sleeve such as the one shown in Fig 4 denoted 13 the flap 20 will contact the grounded member 8 in Fig 4 with a plated portion on its inside so that thereby also the shield 7 becomes grounded. As previously described with the aid of Fig 4 the flap including the contact portion 17, and belonging to the conduct- ing paths 15, is intended to be folded inwards so as to contact the member 1 1 at the assembling. When the transmitting member 14 is assembled in the antenna the shield 7 will be located so that the shield shields radiation from the antenna in the direction towards the head of the user.

From the description and by the aid of Fig 5 it is understood that it is intended that the plated portions on the carrier 19 will be located outwards.

The variant in Fig 6 likewise relates to a transmitting member 14 of the single band type as regards the frequency. This embodi- ment described mainly corresponds to the embodiment described by the aid of Fig 5 with the exception that in this case the conducting paths 16, i.e. conducting paths which are indicated for another frequency band than the ones indicated in Fig 5, and the shield 7 are plated on different sides of the carrier 19. Here it is intended that the conducting paths 16 are to be turned inwards the sleeve 13 according to Fig 4 whereas the shield 7 becomes located outwards. Furthermore, it is clear from Fig 6 that since the conducting paths 16 and the shield 7 are lo- cated on opposite sides of the carrier 19, the shield 7 may overlap with the conducting paths 16 in the extent desired. Thus, it is a matter of doing a suitable compromise between transmitting/receiving inability and radiation protection for the user. Since the conducting paths 16 will be turned inwards any such flap which is illustrated in Fig 5 is not required in this case, but the conduct portion 17 will be constituted by a conducting path portion denoted 17 on the inside of the carrier 19. However, in this case it is indicated how the shield 7 has a contact portion 20 obtained by plating on the side of the carrier 19 which is intended to be placed inwards. This plated contact portion 20 is conductingly connected with the shield layer plated on the other side of the carrier 19 so that when the transmitting member 14 bent around the sleeve 13 is threaded on the member 1 1 according to Fig 4 the contact portion 20 will not contact the member 20 but the grounded member 8.

Also in the embodiment in Fig 7, which relates to a double frequency transmitting member the conducting paths 15 and 16 are plated on one side of the carrier whereas the shield 7 is located on the other side of the carrier and is intended to be placed outwards when the carrier 19 is bent around the sleeve 13 in Fig 4. As to the rest the embodiment according to Fig 7 corresponds to the embodiment described by the aim of Fig 6.

In Figs 8, 9, 10 and 1 1 an alternative embodiment of the invention is illustrated. As previous the transmitting member 14 com- prises a flexible carrier 19 with conducting paths 15, 16. The restricting means 7 in the shape of the shield previously discussed is arranged on the carrier 19 itself. The shield 7 consists of a field of electrically conducting material. Preferably this con- ducting material is arranged on the carrier 19 by plating in the same operation as the plating of the conducting paths 15, 16. In this embodiment the shield 7 and the conducting paths 15, 16 are intended to be arranged on one and the same side of the carrier 19. Both sets of conducting paths 15, 1 6 and the shield 7 have plated connection portions arranged on flaps of the carrier 19.

The transmitting member 14 illustrated in Figs 8 and 9 is produced in the shape of a flexible plate intended to be folded and applied on a frame 13b by means of a suitable adhesive. The frame 13b illustrated in Figs 10 and 1 1 has a special shape for achieving the mutual placing of the conducting paths 15, 16 and the shield 7. In the example of embodiment the frame 13b is designed to achieve that the conducting paths 15, 16 and the shield 7 are placed substantially perpendicularly to each other when the carrier 19 is applied on the frame 13b. For this purpose the frame 1 3b includes a first part 50 intended for the conducting paths 15, 16 and a second part 51 intended for the shield 7, which two parts are located perpendicularly in relation to each other. The carrier 19 is so dimensioned in relation to the frame 13b that the two sets of conducting paths 15, 16 will be located substantially opposite to each other on each side of the first part 50 of the frame 1 3b. Thus, the frame 13b has suitably a cross section in the shape of for example a "T", "H" or "L".

The second part 51 of the frame 13b is intended to be directed so that the shield 7 is turned towards the head of the user when the telephone is in the normal conversation position and thereby is capable to shield the radiation in such directions that run to- ward the head of the user. By the fact that each set of conducting paths 15, 16 is arranged on a respective plane surface 52, 53 of the first part 50 of the frame 13b the antenna 6 will not radiate in a completely isotopic way in so far that the wave radiation will vary in different direc- tions. High radiation of waves will be obtained perpendicularly to the surfaces 52, 53 on which the two sets of conducting paths 15, 16 are arranged and low radiation of waves will be obtained in parallel with these surfaces 52, 53. The differences in radiation due to the fact that the conducting paths 15, 16 are de- signed as thin layers. The surfaces 54, 55 of the conducting paths which are substantially in parallel with the respective surface 52, 53 of the first part 50 have a proportionately large area and contribute with proportionately high radiation perpendicularly to said respective surface 52, 53, whereas the surfaces 56, 57 (corresponding to the thickness of the conducting paths) which are substantially in parallel with the second part 51 and with the shield 7 have a proportionately small area, and contribute with proportionately low radiation in parallel with said respective surface 52, 53.

Accordingly, in this connection the restricting means 7 is arranged to shield radiation of waves in said first region including the directions of radiation in which the radiation of waves is low. More precisely, the shield 7 is arranged substantially in parallel with the radiation directions of the antenna in which the radiation of waves is high, which means that the shield 7 of the restricting means is arranged substantially in parallel with the surface normal to the surface of the conducting paths from which most of the wave radiation takes place.

In this way, first better damping in the radiation directions desired, i.e. in directions towards the user, is achieved, second better signal transferring is achieved as a consequence of lesser damping and losses in the other directions of radiation. Some of the radiation which is sent obliquely towards the shield will be reflected and increase the signal strength. To obtain a signal strength as good as possible the extension of the shield 7 and of the conducting paths 15, 16, and the distance between the shield 7 and the conducting paths 15, 16, looked at in the cross section of the frame 13b, may be conventionally adapted to the present wave length of the electromagnetic waves emitted.

In Fig 12 another type of antenna is illustrated, namely an antenna which has a transmitting member formed by a helicoidal coil. Also in this case there is a shield 7 designed according to the invention formed by plating on a flexible carrier 19. The plating on the carrier 19 is located on the side of the carrier, which is turned outwards from the coil 14. For example the carrier 1 9 may be glued to the coil 21 . The carrier 19 comprises also in this case a lower portion 20, which at the bottom has a plated portion turned inwards which is in electrically conducting connection with the plated shield portion 7 on the outside of the carrier 19 so that the shield is conductingly connected with the electrically conducting member 22 which will be connected with the ground of the mobile telephone when the antenna is assembled on the mobile telephone. As previously described the antenna has an envelope 39 which is glued to the member 22.

The variant illustrated in Fig 13 is different from the variant in Fig 8 only by that the shield 7 is intended to be designed or ar- ranged on the inside of the envelope 39. In this case, possibly the shield 7 is plated directly on the inside of the envelope 39 so that the shielding desired is obtained. To the extent there is a risk for unintentional contact between this plated layer and the antenna coil 21 , space members may be placed between the shield and the antenna coil or the shield 7 may be coated with a layer of insulating material. As previously described the electrically conductive material of the shield 7 shall be brought to be conductingly connected with the member 22 for coupling to the ground of the mobile telephone. As previous, in Fig 14, a shield 7 arranged on an antenna 6 is illustrated or alternatively what is denoted 7 in Fig 14 is a mark illustrating the position of the shield. Once again, the extension of the shield 7 on an antenna 6 schematically indicated is illus- trated in Fig 15. The angle extension of the shield which is probably the minimal one desired is illustrated in Fig 15, namely in the order of 90°. This angle extension may be increased for example to 180° if so should be desirable.

In Fig 16 an alternative embodiment, in which only one envelope 39 for an antenna is shown, is illustrated. The idea in this case is that the envelope 39 is produced by two different materials denoted 23 and 24, respectively. These materials are intended to be bound together. For example the envelope 39 may be formed in one and the same operation, for example by compression moulding or injection moulding, in which different materials are injected into the mould so that the configuration illustrated in Fig 16 is achieved. The material denoted 23 may be a material conventionally used for antenna envelopes whereas the material denoted 24 is intended to be a material including one or more constituents resulting in that the material gets the ability to function shielding to radiation. These constituents admixed may be for example metal particles, conducting soot, carbon black, or the like. In the lower region of the envelope 39 the envelope is designed so that the material 24 having the shielding capacity suitably is brought to electrically connect to such an electrically conducting member included in the antenna, which in its turn will be connected to ground when the antenna is placed on the mobile telephone.

Suitably the material 24 is provided with conducting constituents to such an extent that it nearly may be said that the material will form an electrically conductive layer.

The material denoted 23 and the base material in the material denoted 24 are suitably constituted by polymeric materials. The variant in Fig 17 corresponds to the variant in Fig 16 with the only exception of that in this case the material 24 having the shielding capacity and forming the shield 7 is located on the inside of the envelope 39. A further variant is to perform the material injection so that the material forming the shield 7 is placed completely enclosed by electrically conductive material 23, i.e. the shield 7 will be placed inside the material of the envelope 39.

According to a further variant which is described with the aid of Figs 16 and 17 it may be established that it would also be possible to create the shield 7 by placing a metal foil forming the shield in a mould for production of the envelope 39, which foil will be attached to the polymeric envelope material for the rest by melting when being shaped.

It has already been mentioned that a shield material located on the inside of the envelope 39 would be applied by plating or other layer forming technique. Certainly, the shield would also be created by putting a layer forming the shield 7 on the outside of a prefabricated envelope 39 afterwards by plating , gluing or other layer applying technique.

A modified embodiment of an antenna 6 is illustrated in Figs 18 and 19, which antenna has an antenna part 25 which may be pivoted in relation to the body of the mobile telephone, which part comprises the shield previously described for restricting the radiation of the antenna, whereby the localizing of this shield (not shown in Figs 18 and 19) may be varied by pivoting the antenna part 25. In addition to the first mentioned antenna part 25, which may be pivoted, the antenna 6 has a second antenna part 26, which is connectable with the mobile telephone by interconnecting members 27. The first and the second antenna parts 25, 26 are pivotally connected to each other. The second antenna part 26 comprises a first element 28, which may be fixed to the mobile telephone, and a second element 29, which may be fixed to the first element 28 by means of for example a thread joint. These two elements 28, 29 are arranged to jointly hold a third element 30, which may be pivoted in relation to the first and second elements 28, 29 and included in the first antenna part 25, the envelope 31 of the antenna being rigidly connected to said third element with respect to pivoting for example by a glue joint. The three elements 28, 29 and 30 are of electrically conductive material. As in the embodiment according to Figs 3 and 4 it is here indicated how there is a sleeve 32 corresponding to the sleeve 13 inside the envelope 31 . Around this sleeve 32 for example a transmitting member according to any of the Figures 5-7 may be placed. A contact member 33 to contact a corresponding contact member of the mobile telephone has a shank 34 protruding through the ring-shaped elements 28, 29 and 30. Around the shank 34, which like the contact member 23 consists of an electrically conductive material, a sleeve 35 of an insulating material extends. A fourth electrically conductive element 36 is in conductingly contact with the shank 34 which element is electrically insulated in relation to the second and the third elements 29 and 30, respectively, by means of a radially protruding flange of the sleeve 35. The conducting paths of the transmitting member of the antenna are brought in conductingly contact with the fourth conducting element 36 when the assembling is performed whereas the shield suitably placed on the transmitting member, or if any other type of shield would be chosen, is brought into conductingly contact with the third element 30 in the way previously described.

As already mentioned the third conducting element 30 may be pivoted in relation to the first and the second elements 28, 29, to enable the second antenna part 25 to be varied in respect of the pivoting position . For achieving a suitably balanced inertia regarding such pivoting there is a friction ring 37 of a suitable material achieving the friction. This friction ring 37 acts friction promoting either between the third element 30 and the first element 28 or between the third element 30 and the second element 29, or as in the example, the inertia-ring 37 is in friction contact with all three elements 28, 29 and 30. As a consequence of the thread engagement of the second element 29 with the first element 28 the second element 29 may be tightened to a balanced extent so that the friction ring 37 may be squeezed to the extent desired.

When the envelope 31 is placed on the antenna and gluing of the envelope to the third element 30 simultaneously a gluing joint is established which interlocks the envelope 31 with the fourth conducting element 36 and with the interior sleeve 32 so that when a user effects the envelope 31 with respect to pivoting the components 30, 31 , 32 and 36 together with the present transmitting member for example according to Figs 5-7 will follow in the pivoting so that the user may adjust the protection shield in the pivoting position which results in maximal protec- tion against radiation with retained relation between the protection shield and the transmitting member. The friction ring 37 ensures that the resistance against such pivoting becomes so large that unintentional pivoting does not take place during normal managing of the mobile telephone.

When the envelope 31 being pivoted in the way described also the sleeve 35 and/or the shank 34/contact member 33 may possibly follow depending on the friction conditions, which in practice does not have any significance for the function. Further- more, from Fig 18 it appears that the lowest portion 47 of the sleeve 35 will function insulating between the shank 34/contact member 33 and the first element 28.

The antenna according to Figs 18 and 19 is assembled in the following way. The second element 29 is threaded through the central opening in the third element 30 and then through the friction ring 37. Thereafter the second element 29 is screwed into the first element 28 so that a suitable pressing of the friction ring 37 is achieved. By a collar on the element 29 it will hold the third element 30 between itself and the first element 28. To facilitate tightening of the second element 29 it may have a suitable grip for a key etc in its upper end. Then the sleeve 35 is pushed into the right position through the elements 28, 29 and 30 and the contact member 33 is applied with its shank 34 protruding through the sleeve 35. Then the fourth element 36 is ap- plied on the end of the shank 34, whereupon the sleeve 32, the transmitting member not illustrated and the envelope 31 are applied in a way previous described. It is by this ensured that a mark arranged on the outside of the envelope 31 becomes located just in front of the shield of the antenna. When applying the outer envelope 31 being applied the glue applying required is performed. Finally, the antenna is screwed in the present mobile telephone, and then the user may adjust the position of the shield by pivoting the antenna part 25 in relation to the antenna part 26 according to what is desired.

It is obvious that the invention is not restricted to the embodiments described above given as examples. Many detail modifications will be apparent for a man skilled in the art when the idea of the invention has been disclosed. For example it should be pointed out that although it has been described above that the shield 7 is suitably connected with the ground of the mobile telephone, this is not a necessity. Also an ungrounded shield will effectively reduce radiation even if grounding is intended in the preferred case. Furthermore, it is pointed out that for the sake of simplicity the expression "transmitting member" has been used above for the antenna part, which actually emits the electromagnetical wave motion from the antenna. This expression has been chosen because it is just at the moment of transmitting from the mobile telephone that the most serious cases of radiation arise. The fact that the transmitting member actually also has a receiving function is obvious in the light of the de- scription above even if it would be technically possible to separate the transmitting function from the receiving function in such a way that different components were provided for these functions.

Claims

1 . A mobile telephone operating with electromagnetic waves and having an antenna, characterized in that the antenna (6) of the mobile telephone has means (7) for restricting the radiation of waves in a first region of the wave radiation area of the antenna so as to reduce the exposing of a user of the mobile telephone to the radiation.

2. A mobile telephone according to claim 1 , characterized in that the restricting means (7) comprises at least one shield arranged for shielding the radiation in the first region of the radiation area.

3. A mobile telephone according to claim 1 or 2, characterized in that it has a speaker (4) integrated in the mobile telephone and intended to be placed at the ear of the user and that the first region (7) of the antenna, with restricted radiation of waves, is located/may be located for restricting the radiation of waves toward the head of the user.

4. A mobile telephone according to any preceding claim , characterized in that its antenna (6) on its outside has a visible marking (7) corresponding to the first region of the antenna with restricted radiation of waves.

5. A mobile telephone according to any preceding claim , characterized in that its antenna (6) has an antenna part (25) which may be pivoted in relation to the body of the mobile telephone, which antenna part includes the means (7) for restricting the radiation of the antenna, so that the location of the restricting means may be varied by pivoting the antenna part.

6. A mobile telephone according to claim 5, characterized in that the antenna (6), in addition to said antenna part (25) which may be pivoted, has a second antenna part (26) which is connectable with the mobile telephone by interconnecting members (27) and in that the first and second antenna parts are pivotally connected with each other.

A mobile telephone according to any preceding claim, characterized in that the restricting means (7) is arranged to shield radiation of waves in said first region including the directions of radiation in which the radiation of waves is low.

8. A mobile telephone according to claim 2, characterized in that the shield (7) is arranged substantially in parallel with the directions of radiation of the antenna in which the radiation of waves is high.

9. A mobile telephone according to claim 2 or 8, characterized in that transmitting members (14) of the antenna are formed by conducting paths (15, 16) intended to be conductingly connected with the transmitting unit of the mobile telephone and that the shield (7) of the restricting means is arranged substantially in parallel with the surface normal to the surface of the conducting paths (15, 16) from which most of the radiation of waves takes place.

10. A mobile telephone according to claim 2, 8 or 9, characterized in that transmitting members (14) of the antenna are formed by conducting paths (15, 16) arranged on an insulating carrier (19) and intended to be conductingly connected with the transmitting unit of the mobile telephone and in that the shield (7) of the restricting means is arranged on the carrier.

1 1 . A mobile telephone according to claim 10, characterized in that the conducting paths (15, 16) and the shield (7) are ar- ranged in overlapping relation and divided by the carrier (19) itself or an insulating layer arranged between the conducting paths and the shield.

12. A mobile telephone according to claim 10 or 1 1 , character- ized in that the carrier (19) is plate- or sheet-like and flexible.

13. A mobile telephone according to any of the claims 10-12, characterized in that the carrier (19) is arranged on a frame (13, 13b) having a special shape for achieving the mutual placing of the conducting paths (15, 16) and the shield.

14. A mobile telephone according to claim 13, characterized in that the frame (13b) is designed to achieve that the conducting paths (15, 16) and the shield (7) are placed substantially perpendicularly to each other when the carrier (19) is applied on the frame.

15. A mobile telephone according to claim 14, characterized in that the frame (13b) has a first part and a second part ar- ranged substantially perpendicularly to each other.

16. A mobile telephone according to claim 2, characterized in that transmitting members (14, 21 ) of the antenna are arranged inside an envelope (31 , 39) and that the shield (7) is arranged between the transmitting member and the envelope.

17. A mobile telephone according to claim 2, characterized in that transmitting members (14, 21 ) of the antenna are arranged inside an envelope (31 , 39) and the shield (7) is de- signed in the envelope or arranged thereon.

18. A mobile telephone according to claim 17, characterized in that the shield (7) is constituted by a conducting coating on the inside or outside of the envelope.

19. A mobile telephone according to claim 17, characterized in that the envelope (39) is made of two different materials (23, 24) bound together, and that one of these materials is electrically conductive and forms the shield (7).

20. A mobile telephone according to claim 19, characterized in that the two materials (23, 24) are bound together by melting of at least one of the materials.

21 . A mobile telephone according to any preceding claim, characterized in that the restricting means (7) is connected to the ground of the mobile telephone.

22. A mobile telephone according to claim 6, characterized in that the second antenna part (26) comprises a first element

(28) which may be fixed to the mobile telephone, a second element (29) which may be fixed to the first element and that these two elements are arranged to jointly hold a third element (30), which may be pivoted in relation to the first and the second elements and included in the first antenna part

(25), the envelope (31 ) of the antenna being rigidly connected to said third element with respect to pivoting.

23. A mobile telephone according to claim 22, characterized in that the three elements (28, 29, 30) are of electrically conductive material and that the shield (7) is conductingly connected with at least one (30) of them.

24. A mobile telephone antenna, characterized in that it has means (7) for restricting the radiation of waves in a first region of the radiation area of the antenna so as to reduce the exposing of a user of the mobile telephone to the radiation.

25. A mobile telephone antenna according to claim 24, charac- terized in that the restricting means (7) comprises at least one shield arranged to shield the radiation in the first region of the radiation area.

26. A mobile telephone antenna according to claim 24 or 25, characterized in that the restricting means (7) is arranged to shield radiation of waves in said first region including the radiation directions in which the radiation of waves is low.

27. A mobile telephone antenna according to claim 25, charac- terized in that the shield (7) is arranged substantially in parallel with the radiation directions of the antenna in which the radiation of waves is high.

28. A mobile telephone antenna according to claim 25 or 27, characterized in that transmitting members (14) of the antenna are formed by conducting paths (15, 16) intended to be conductingly connected with the transmitting unit of the mobile telephone and that the shield (7) of the restricting means is arranged substantially in parallel with the surface normal of the surface of the conducting paths (15, 16) from which most of the radiation of waves takes place.

29. A mobile telephone antenna according to claim 25, 27 or 28, characterized in that transmitting members (14) of the an- tenna are formed by conducting paths (15, 16) arranged on an insulating carrier (19) and intended to be conductingly connected with the transmitting unit of the mobile telephone and that the shield (7) of the restricting means is arranged on the carrier.

30. A mobile telephone antenna according to claim 29, characterized in that the carrier (19) is plate- or sheet-like and flexible.

31 . A mobile telephone antenna according to claim 29 or 30, characterized in that the carrier (19) is arranged on a frame (13, 13b) having a special shape for achieving the mutual placing of the conducting paths (15, 16) and the shield (7).

32. An antenna of a mobile telephone according to claim 31 , characterized in that the frame (13b) is designed to achieve that the conducting paths (15, 16) and the shield (17) are placed substantially perpendicularly to each other when the carrier (19) is applied on the frame.

33. A mobile telephone antenna according to claim 32, characterized in that the frame (13b) has a first part and a second part arranged substantially perpendicularly to each other.