WO2002054535A1

WO2002054535A1 - Antenna device with switching between internal and external antenna elements

Info

Publication number: WO2002054535A1
Application number: PCT/SE2001/002922
Authority: WO
Inventors: Thomas Bennet; Mats Bruce; Nicklas Carlson; Johan Eidefors; Stellan Fries; Ulf Palin
Original assignee: Amc Centurion Ab
Priority date: 2000-12-29
Filing date: 2001-12-28
Publication date: 2002-07-11
Also published as: SE0102074D0

Abstract

An antenna device (100) for a radio communication device with a feed element (112) is provided. The antenna device comprises a housing (104), an internal antenna element (120) and an axially movable external antenna element (102) having a conductive end portion (106). A separate, axially movable conductive element (110) extends radially outside of the conductive end portion of the external antenna element to perform switching operations. Thereby a sufficient decoupling distance between the feed element and the external antenna element can be maintained while avoiding an end portion with excessive diameter. Also, reflection currents during switching between the external and the internal antenna elements are avoided.

Description

ANTENNA DEVICE WITH SWITCHING BETWEEN INTERNAL AND EXTERNAL ANTENNA ELEMENTS

FIELD OF INVENTION The present invention relates generally to an antenna device and more particularly to a combined antenna device including an internal antenna and an extendable/retractable antenna, wherein extension of the extendible antenna connects that antenna and disconnects the internal an- tenna. The present invention also relates to a portable communication device comprising such an antenna device.

BACKGROUND

It is well known in the portable communication device art, such as with mobile phones, to use a combination of a first internal antenna and a second external extendable/retractable antenna, such as a whip antenna. Because a whip antenna can be cumbersome when extended, it is normally preferred that it be retracted except when the communication device is actively being utilized.

The use of dual antennas poses a special problem regarding the coupling and decoupling of the different antenna devices. Normally, the external antenna should be electrically decoupled from a feeding device when in a retracted position while it should be electrically coupled when in an extended position.

In some cases, to increase antenna performance, there is a requirement that the internal antenna is decoupled from the RF feeding device when the external antenna is in functional mode, i.e., connected to the RF feeding device, and vice versa. This requirement brings a special problem in that a conventional mechanical switch having two positions gives rise to reflection currents that can damage or destroy the RF electronics comprising for example duplexers etc .

Another problem is to achieve sufficient decoupling between the element feeding the antennas and the presently decoupled antenna. A further problem in connection with this is that the conductive stopper provided at the lower end of an extendable/retractable antenna must be of limited diameter in order to occupy as little space as possible in the interior of the radio communication device, in which the antenna is provided. Thus, it is difficult to obtain sufficient decoupling between the extendable/retractable antenna and the mechanical switch in disconnected position due to the limited size of the stopper.

The US patent document US 4,864,182 A discloses an antenna system for a portable radiotelephone with a switch to switch between a transmitting and receiving main antenna element and a call signal-receiving sub antenna element. This is accomplished by a rod-shaped transmitting and receiving main antenna element having a stopper with a cam. The cam acts to displace the sub antenna element from contact with a conductive tube, thereby disconnecting the sub antenna after connecting the main antenna. This avoids the problem of reflection currents and provides decoupling between the antenna elements. However, this introduces the problems caused by the stopper having a large diameter and therefore occupying a large space in the radiotelephone. SUMMARY OF THE INVENTION

An object of the present invention is to provide an antenna device of the kind initially mentioned wherein the above described drawbacks with prior art are avoided.

The invention is based on the realization that a separate axially movable conductive element can be provided for performing the switching operations between an internal and an external antenna element.

According to the present invention there is provided an antenna device as defined in claims 1, 16, and 20.

There is also provided a portable communication device as defined in claim 22.

By means of the antenna device and the portable communication device according to the invention, at least some of the drawbacks associated with prior art are overcome. The antenna device according to the invention minimizes reflection currents while keeping a sufficient decoupling distance between the different antennas .

Preferred embodiments are defined in the dependent claims.

BRIEF DESCRIPTION OF DRAWINGS

The invention is now described, by way of example, with reference to the accompanying drawings, in which:

Fig. 1 is an exploded perspective view of a first embodi- ment of an antenna device according to the invention comprising a whip antenna, Fig. 2 is a detail view of the antenna device shown in fig. 1 with the whip antenna in a retracted position,

Fig. 2a is a sectional view of the antenna device shown in fig. 2,

Fig. 3 is a view similar to that of figure 2 but with the whip antenna in an extended position,

Fig. 3a is a sectional view of the antenna device shown in fig. 3,

Fig. 4 is a perspective view of a second embodiment of an antenna device according to the invention comprising a whip antenna in retracted position,

Fig. 5 is a view of the antenna device shown in fig. 4 with the whip antenna in an extended position,

Fig. 6 is a perspective view of a third embodiment of an antenna device according to the invention comprising a whip antenna,

Fig. 7 is a view of the antenna device shown in fig. 6 with the whip antenna in an extended position,

Fig. 8 is a perspective view of a fourth embodiment of an antenna device according to the invention comprising a whip antenna in a retracted position,

Fig. 9 is a view of the antenna device shown in fig. 8 but from another direction,

Fig. 10 is a view similar to that of fig. 9 but showing the whip antenna in an extended position, Fig. 11 is a perspective view of a fifth embodiment of an antenna device according to the invention comprising a whip antenna in a retracted position,

Fig. 12 is a view similar to that of figure 11 but with the whip antenna in an extended position,

Figs. 13 and 14 are views showing connection and disconnection, respectively, of an internal antenna used with the antenna device shown in figs. 11 and 12,

Fig 15 is a sectional view of a sixth embodiment of an antenna device according to the invention comprising a whip antenna in a retracted position,

Fig. 15a is a cross-sectional view of the antenna device shown in fig. 15 along line 15a-15a,

Fig. 16 is a view similar to that of fig. 15 but with the whip antenna in an extended position,

Fig. 16a is a cross-sectional view of the antenna device shown in fig. 16 along line 16a-16a,

Fig. 16b is a detail view of a connection portion of the whip antenna shown in fig. 16,

Figs. 17 and 18 are perspective views of a seventh embodiment of an antenna device according to the invention with a whip antenna in extended and retracted position, respectively, and

Figs. 19 and 20 are sectional views of an eighth embodi- ment of an antenna device according to the invention with a whip antenna in retracted and extended position, respectively. DETAILED DESCRIPTION OF THE INVENTION

In the following, a detailed description of a preferred embodiment will be given. Figure 1 shows a first embodiment of an antenna device according to the invention. The antenna device, generally designated 100, comprises an elongated radiating element 102 having the shape of a whip with an insulating non-conductive cover of for example plastics. The radiating element 102 is slidingly mounted in a housing or whip sleeve 104. The whip sleeve is provided with elements or protrusions (not shown) functioning as retaining elements when mounted in the housing of a radio communication device. A conductive metal portion 106, conventionally referred to as stopper, is provided at the lower end of the radiating element 102 as mounted in a radio communication device. The stopper 106 functions as a stop element preventing withdrawal of the radiating element 102 from the whip sleeve 104 and also as a connection portion for connecting the radiating element 102 to feeding electronics (not shown).

A ferrule 108 made of magnetic material is slidingly provided on the whip 102. A conductive metal cam ring 110 is also provided on the whip 102 closer to the top end of the whip. The cam ring 110 has a protruding cam portion 110a with a slanting surface arranged to actuate a resil- ient feed clip 112 connected to RF feed electronics (not shown) . There is provided a slit 104a in the envelope surface of the whip sleeve 104 to accommodate this protruding cam portion 110a. Finally, there is provided a metal washer 114, which is also provided slidingly in relation to the whip 102. In assembled condition, see figs. 2 and 3, the magnet ferrule 108 and the cam ring 110 are provided in the whip sleeve 104 while the metal washer 114 is fixedly attached to the lower end portion of the whip sleeve 104. Thus, the magnet ferrule 108 and the cam ring 110 are limited in their movement by the upper end wall of the whip sleeve and the metal washer 114 provided as a lower end wall of the whip sleeve.

The function of the switch arrangement of the antenna device will now be described in detail with reference to figs. 2, 2a and 3, 3a. In fig. 2, the whip 102 is shown in a retracted position, wherein it is disconnected from the feed clip 112 while the internal antenna element, generally designated 120, is connected to the feed clip. There is also seen how the internal antenna element 120 is provided in a "lower" plane than the whip 102, as shown in the figure. That means that there is a sufficient decoupling distance between the internal antenna element 120 and the whip 102.

In fig. 2 there is shown how the lower end portion of the feed clip 112 presses against an upwardly bent portion 122 of the internal antenna element 120, as viewed in the figure, thereby connecting the internal antenna to feeding electronics (not shown) connected to the feed clip. The feed clip is positioned at a radial distance from the whip 102 that is sufficient to provide a required decoupling therebetween. As an example, a distance between whip and feed clip of about 1 millimeter is considered sufficient in most cases. With the whip 102 in retracted position, the magnet ferrule 108 and the cam ring 110 are held in place by magnetic force provided by the magnet ferrule. More specifically, see fig. 2a, which is a sectional view through the arrangement shown in fig. 2, magnet ferrule 108 is attached by magnetic force to the metal washer 114 acting as bottom end wall of the whip sleeve. The cam ring 110 is also attached to the magnet ferrule 108 by magnetic force. In that way, the combination magnet ferrule — cam ring is prevented from uncontrolled movement in the whip sleeve when the whip is retracted. Thus, in this position there is an axial distance between the cam ring 110 and the feed clip 112. This is important as the cam ring otherwise would contact the feed clip, as will now be explained with reference to figs. 3 and 3a.

When the whip 102 is moved from its retracted position shown in figs. 2 and 2a to its extended position shown in figs. 3 and 3a, the lower end portion of the whip 102 comprising the stopper 106 is guided by a plastic straw (not shown) and pulled through the metal washer 114 and further to a position in the whip sleeve 104, see fig. 3a. During the movement thereof, the stopper 106 pushes the magnet ferrule 108 and thereby the cam ring 110 further into the whip sleeve to the positions shown in fig. 3a, where further movement of the cam ring is limited by the inner diameter of the whip sleeve. During the sliding movement of the cam ring, the cam portion 110a thereof engages the feed clip and the slanting cam surface pushes the feed clip in a radial direction from the whip 102.

As soon as the cam portion 110a contacts the feed clip 112, feeding of the external antenna element, i.e., the whip 102, is commenced. More specifically, with the cam portion in contact with the feed clip, the RF electronics can feed the whip via the feed clip 112, the cam ring 110, the magnet ferrule 108, and the stopper 106. This is made possible by the magnet forces keeping together the cam ring, the magnet ferrule and the stopper.

In the position shown in figs. 3 and 3a, the whip is retained in its extended position by frictional forces between the feed clip 112 and the cam ring 110. Alterna- tively or additionally, the magnet ferrule 108 could be kept in place by magnetic forces acting on an internal metal part provided in the whip sleeve 104, for example.

It will be appreciated that the connection between the RF electronics and the whip 102 is established before the internal antenna element 120 is disconnected. In that way, reflection currents are avoided, which is important, as such currents can damage or even destroy sensitive electronic parts of the feeding electronics .

When the whip is moved from extended position to re- tracted position, the above-described procedure is reversed. When the whip 102 is pushed from its position shown in figs. 3 and 3a, the stopper 106, being magnetically attached to the magnet ferrule 108, brings that ferrule and the cam ring attached thereto with it until the magnet ferrule abuts the metal washer 114. As the central opening in the metal washer has a size that allows the stopper 106 to pass therethrough but not the magnetic ferrule 108, the ferrule remains magnetically attached to the washer, see fig. 2a, while the stopper can be further pushed from its extended position. When the cam portion 110a is pulled from its position shown in figs. 3 and 3a, the feed clip, being resilient, resumes its position shown in fig. 2, wherein it contacts the contact portion 122 of the internal antenna element 120. However, during a brief period of time, both the internal antenna element 120 and the whip 102 are connected to the RF electronics, again avoiding reflection currents .

By the device described with reference to fig. 1-3, a simple yet reliable arrangement is provided for efficient selective switching between an internal and an external antenna.

A second embodiment of an antenna device according to the invention will now be described with reference to figs . 4 and 5. An elongated antenna element is the form of a whip 202 is provided slidingly in a cylindrical whip sleeve 204. The whip sleeve 204 is provided with two apertures at the envelope surface thereof, thereby creating a bridge 204a, the function of which will be explained later. The sleeve is also provided with a resilient hook 204b for snap-in mounting in a phone housing.

A snap cylinder 208 is provided slidingly on the whip 202 and partially in the whip sleeve 204. The axial movement of the snap cylinder relatively to the whip sleeve is limited between the positions shown in fig. 4 and fig. 5 by a protrusion 208a on the envelope surface of the snap cylinder 208. In the position shown in fig. 4 the protrusion 208a is in the aperture to the right of the bridge 204a, as viewed in the figure, while in the position shown in fig. 5 the protrusion 208a is in the aperture to the left of the bridge 204a.

A conductive metal whip clip 210 is attached to the bottom end portion of the snap cylinder 208. The whip clip is provided with a portion 210a extending radially outwardly from the whip in the direction of the feed clip 212. The whip clip is also provided with two opposing resilient tongues 210b, the function of which is to grip around a stopper 206, thereby engaging a groove 206a therein (see fig. 5).

The function of this second embodiment will now be described in detail. In the retracted position of the whip 202 shown in fig. 4, an internal antenna element 220 is connected to RF electronics (not shown) through a feed clip 212 pressing against an upwardly bent contact portion 222 of the internal antenna element. In this position of the feed clip, the whip is disconnected. The snap cylinder 208 is kept in place by frictional forces and the protrusion 208a being prevented to move by the bridge 204a. In that way, the radially extending portion 210a of the whip clip is prevented from engaging the feed clip 212. Instead, it is kept on a safe distance therefrom, thereby insuring a required decoupling between the whip arrangement and the feed clip.

During movement of the whip 202 to its extended position shown in fig. 5, the tongues 210b of the whip clip 210 engage the groove 206a of the stopper 206. When the whip and the stopper are moved further to the extended position, the extending portion 210a of the whip clip presses against the feed clip, thereby connecting the whip to the RF electronics through the feed clip 212, the whip clip 210 and the stopper 206.

When the whip clip and the snap cylinder 208 to which the whip clip is attached are moved, the protrusion 208a on the snap cylinder is pressed under the bridge 204a and to the other aperture. Thus, the bridge 204a helps keeping the snap cylinder and the whip clip in the extended position shown in fig. 5.

It will be appreciated that the connection between the RF electronics and the whip 202 is established before the internal antenna element 220 is disconnected. In that way, reflection currents are avoided, which is important, as such currents can damage or even destroy sensitive electronic parts of the feeding electronics.

When the whip is moved from its extended position shown in fig. 5 to its retracted position shown in fig. 4, the above-described procedure is reversed. Thus, when pressing down the whip 202, the stopper 206 pulls the protrusion 208a under the bridge 204a to the position shown in fig. 4. This disconnects the extending portion 210a of the whip clip 210 from the feed clip 212 and the resilient feed clip makes contact with the internal antenna element instead. However, during a brief period of time, both the internal antenna element 220 and the whip 202 are connected to the RF electronics, again avoiding reflection currents.

After having become disconnected from the feed clip, the whip clip or more specifically the tongues 210b of the whip clip become disengaged from the circumferential groove 206a in the stopper 206, which is then allowed to be moved to its fully retracted position.

Also with the device described with reference to figs. 4 and 5, a simple yet reliable arrangement is obtained for efficient selective switching between an internal and an external antenna.

A third embodiment of an antenna device according to the invention will now be described with reference to figs. 6 and 7. This embodiment functions in basically the same way as the second embodiment described with reference to figs. 4 and 5. Thus, an elongated antenna element is the form of a whip 302 is provided slidingly in a cylindrical whip sleeve 304. The whip sleeve 304 is provided with two apertures at the envelope surface thereof, thereby creat- ing a bridge 304a, the function of which is the same as that of the bridge 204a of figs. 4 and 5. The sleeve is also provided with a hook (not shown) for snap-in mounting.

A snap cylinder 308 is provided slidingly on the whip 202 and partially in the whip sleeve 204 and functions as snap cylinder 208 of the second embodiment. A conductive metal whip clip 310 is attached to the bottom end portion of the snap cylinder 308 and is provided with a portion 310a extending radially outwardly from the whip in the direction of the feed clip 312. However, there are not tongues provided for gripping around the stopper 306. Instead, the whip clip acts on the stopper through openings (not shown) in the snap cylinder. Indents 310b are provided on the whip clip so as to create corresponding protrusions on the underside thereof, which engage a circumferential groove 306a in the stopper 306 after having entered the snap cylinder.

The function of this third embodiment is identical to that of the second embodiment with the exception that the whip 302 is retained in extended position by forces created by the indents/protrusions on the whip clip.

A fourth embodiment of an antenna device according to the invention will now be described with reference to figs. 8-10. In fig. 8 there is seen how an extend- able/retractable whip antenna arrangement is positioned beside an antenna frame having an internal antenna element 420 provided thereon. The whip antenna arrangement comprises, see also fig. 9, a whip sleeve 404 supporting an elongated radiating element in the form of a whip 402 having a stopper 406 at the lower end thereof. A whip clip 410 is attached to a snap cylinder 408 being slidingly provided partly in the whip sleeve 404. The snap cylinder is provided with a protrusion 408a cooperating with a bridge portion 404a of the whip sleeve. All these parts are functioning as their counterparts in the second and third embodiments described with reference to figs . 4 and 5 and figs. 6 and 7, respectively. However, the whip clip 410 is provided with a radially extending portion 410a having slanting surfaces so as to push a feed clip 412 radially outwardly from the whip 402. By doing this, the feed clip 412 is connected to the whip through the whip clip and the stopper while the internal antenna element 420 is disconnected. Like in the previous embodiments, there is a small overlap between connection and disconnection, thereby avoiding reflection currents. An advantage with having the feed clip displaced radially outwardly instead of axially is that the feed clip does not exert any axial forces on the whip clip which have to the counteracted by frictional forces, for example, in order to keep the whip in its extended position.

In this fourth embodiment, see figs. 9 and 10, also a grounding portion of the internal antenna element 420 is disconnected. In figs. 9 and 10 there is shown a ground clip 418 arranged to be connected to an upwardly bent ground connection portion 424 of the internal antenna element. This ground clip 418 is moved to its disconnected position by means of a pin 426 made of plastic or some other non-conductive material and acting between the feed clip 412 and the ground clip 418. Thus, in fig. 9 the internal antenna 420 is shown connected both to the feed clip 412 and the ground clip 418 while in fig. 10 it is shown disconnected from both the feed clip 412 and the ground clip 418.

By disconnecting the ground clip from the internal antenna, an overall increase of the whip antenna performance is sometimes achieved.

A fifth embodiment of an antenna device according to the invention will now be described with reference to figs . 11-14. A whip 502 provided with a conductive stopper 506 is slidingly supported by a whip sleeve 504. There is also a snap cylinder 508 functioning in essentially the same way as the snap cylinder of embodiments two to four.

There is also a whip clip 510 made of a resilient metal strip essentially bent in two. The basic shape of the whip clip appears most clearly in fig. 11, wherein the upper half of the snap cylinder 508 has been removed for the sake of clarity. In that figure there is seen how a wedge-like portion 510a engages an opening in the envelope surface of the snap cylinder 508. However, the wedge 510a is prevented from fully engaging the opening due to the length of the wedge and the whip 502 preventing further penetration of the wedge.

Due to this, the snap cylinder 508 is also prevented from entering the whip sleeve 504 by the whip clip being at a radial distance from the snap cylinder.

When the whip 502 is being moved to its extended position shown in fig. 12, the stopper 506 first enters the snap cylinder 508. The stopper is provided with a circumferential groove 506a creating a waist portion having a dia- meter less than the diameter of the rest of the whip 502. The depth of the groove 506a allows further penetration by the wedge 510a, thereby allowing the snap cylinder to enter the whip sleeve 504, see fig. 11.

When the snap cylinder 508 enters the whip sleeve, the whip clip 510 is brought by its wedge portion 510a in an axial direction with the snap cylinder. This causes a radially outer portion 510b of the whip clip to be deflected by a slide 532 arranged integral with a frame 530 for an internal antenna element 520. The slide is tilted approximately 45 degrees with respect to the axial direction of the whip 502. By means of the deflection, the outer portion 510b of the whip clip is moved further from the whip 502 and contacts a feed clip 512, see fig. 14, being connected to RF electronics (not shown) . This slid- ing movement of the whip clip makes a sufficient decoup- ling distance between the whip 502 and the feed clip 512 feasible.

As in the previous embodiment, an internal antenna element 520 is disconnected when the whip is connected and vice versa.

When moving the whip 502 from extended to retracted positions, the above procedure is reversed. Thus, the snap cylinder 508 moves with the stopper 506 until the wedge portion 510a of the whip clip can disengage the groove 506a in the stopper. This pulls the whip clip to the position shown in fig. 11, effectively decoupling the whip from the feed clip.

With the sliding movement of the whip clip 510 there is possible to have an arrangement like the one in the fourth embodiment disconnecting a ground clip from the internal antenna as well as the feed clip. Thus, see figs. 13 and 14, there is provided a plastic pin 526 between the feed clip 512 and the ground clip 518.

Instead of leaving it without any connection when dis- connecting it from the feed clip, the feed contact portion of the internal antenna element can be connected to a ground device. In that way, when the external antenna element is operating, i.e., in extended position, both the feed portion and the ground portion of the internal antenna element are grounded. In some applications, this is an advantage.

An arrangement for connecting the ground portion of the internal antenna element to ground could work in a simi- lar way to the pin arrangement disconnecting the ground clip used in the fourth and fifth embodiments .

A sixth embodiment of an antenna device according to the invention will now be described with reference to figs . 15, 15a, 16, 16a, and 16b. Fig. 15 is a sectional view of an antenna device 600 comprising a housing 604 made of some non-conductive material, such as injection molded plastic, and having a general shape adapted for mounting in a mobile phone. A whip antenna 602 is slidingly mounted in a through hole 605 in the housing and is movable between a fully retracted position shown in fig. 15 and a fully extended position shown in fig. 16. The whip antenna 602 is provided with a conductive lower end portion or stopper 606 through which the whip antenna is connected to feed electronics (not shown) in the mobile phone. There is also provided a straw 607 guiding the lower portion of the whip antenna when in retracted position.

To feed the stopper, a feed clip 612 connected to the feed electronics is provided in the housing 604. The feed clip is also arranged to act on a plastic pin 626. Shown in fig. 15 is also a ground clip 618 for an internal antenna element 620 provided on the housing 604. There is also a feed contact portion (not shown) provided on the internal antenna element and arranged to contact the feed clip 612. This arrangement of connecting and disconnecting the internal and external antennas functions in the same way as in the fourth and fifth embodiments described with reference to figs. 8-14 and will not be described further. When the whip antenna 602 is in the retracted position, the main longitudinal axis thereof is essentially parallel to the main longitudinal axis of the hole 605. In the vicinity of the feed clip 612, the whip antenna runs in a groove in a protrusion 608, see fig. 16. This groove has a width that is larger than the diameter of the whip but is smaller than the diameter of the stopper 606. In that way, there is a sufficient isolation distance between the retracted whip antenna 602 and the feed clip 612 connec- ted to the internal antenna element 620.

When the whip antenna 602 is in the extended position shown in fig. 16, the axial direction thereof is tilted by an angle α, see fig. 16b, showing a detail view of the area around the feed clip 612. This tilting is due to the protrusion 608 in the wall of the opening 605 forcing the stopper 606 of the whip antenna towards the feed clip 612 and thereby connecting it to the stopper and subsequently disconnecting it from the internal antenna element 620. Also, when the stopper acts on the feed clip, the pin 626 is actuated and disconnects the ground of the internal antenna as in the above-described fourth and fifth embodiments .

The whip antenna 602 is maintained in the extended position by means of a waist portion 606a of the stopper engaging the protrusion 608, see fig. 16b. In that way, no separate retaining element is needed for the whip antenna. The upper portion of the opening 605 is preferably made narrower than the stopper so as to prevent further upward movement from the position shown in fig. 16. When the whip antenna 602 is moved from the extended to the retracted position by means of manual force exerted on the whip, the stopper 606 is guided by the shape of the opening 605 to the retracted position.

With the antenna device shown in figs. 15 and 16, sufficient isolation of the antenna elements is attained while the design is kept simple and without additional parts for connecting the stopper of the external antenna to the feed clip.

Although in this embodiment the whip antenna is tilted relatively to the support structure, it will be realized that it is the radial movement of the stopper that is important, not the tilting per se. Thus, it would also be possible to displace the entire whip antenna radially.

In figs. 17 and 18 there is shown a seventh embodiment of an antenna device according to the invention. Like in the previous embodiments, the antenna device, generally designated 700, comprises an internal antenna element 720 and an extendible/retractable whip antenna 702 comprising a stopper 706. The whip antenna 702 is supported by a housing (not shown). The internal antenna and the whip are fed through a resilient feed clip 712 connected to a feeding arrangement (not shown) provided on a printed circuit board 730. The internal antenna element 720 is provided with a ground clip 718 for the grounding of the internal antenna element and a contact portion 722 for contacting the feeding clip 712.

The stopper 706 is divided into two separate portions, a first outer portion 706a and a second inner portion 706b with a diameter slightly less than the diameter of the outer portion 706a. The outer portion 706a is provided with an insulating cover made of plastics for example while the inner portion 706b is a metal ferrule providing galvanic contact to the whip 702. This provides for a switching operation that will be described in detail in the following.

In fig. 17, the whip is shown in its extended position, wherein it is connected to the feed clip 712 via its conductive stopper portion 706b. In this position the feed clip has been moved to the position indicated in the figure by means of a tongue 712a integral with the feed clip 712 and the outer stopper portion 706a having a larger diameter than portion 706b.

In fig. 18 there is shown how the whip 702 has been moved to its retracted position. When the stopper 706 disengages the feed clip 712, the resilient feed clip moves in the direction indicated by the dashed arrow to a more "upright" position, wherein its contacts the contact portion 722 of the internal antenna element 720. In a transitional period during movement from the position shown in fig. 17 to the position shown in fig. 18, the feed clip contacts both the inner stopper portion 706b and the contact portion 722, thereby avoiding reflection currents during switching.

The reverse operation, i.e., when the whip 702 is moved from its retracted position shown in fig. 18 to its extended position shown in fig. 17, functions in a corresponding way. The inner conductive stopper portion 706b first contacts the feed clip 712, thereby establishing contact between the feeding arrangement and the whip 702 while still maintaining feeding of the internal antenna element 720. The stopper 706 then pushes the feed clip from contact with the internal antenna element with the conductive stopper portion 706b in galvanic contact with the feed clip, effectively disconnecting the internal antenna while feeding the whip.

The solution described above with reference to figs. 17 and 18 provides an inexpensive and robust antenna device wherein switching between an internal antenna and a whip antenna is effected in an efficient way.

In figs. 19 and 20 there is shown an eighth embodiment of an antenna device according to the invention. Like in the previous embodiments, the antenna device, generally designated 800, comprises an internal antenna element (not shown) and an extendible/retractable whip antenna 802 comprising a conductive stopper 806 through which the whip antenna is fed. The whip antenna 802 is supported by a housing in the form of an elongated sleeve or cylinder 804, which is movable between a retracted position shown in fig. 19 and an extended position shown in fig. 20. The internal antenna and the whip are fed through a resilient feed clip 812 connected to a feeding arrangement (not shown) provided on a printed circuit board, for example.

In retracted position, see fig. 19, the stopper 806 of the whip antenna is disconnected from the feed clip 812, which instead is connected to the internal antenna element. When the whip antenna 802 is moved to its extended position shown in fig. 20, the stopper thereof enters the sleeve 804 and stops when it abuts the upper inner wall of the sleeve, as is indicated in fig. 20. When the whip antenna is extended further, the sleeve is moved with the whip from the sleeve position shown in fig. 19 to the sleeve position shown in fig. 20.

The sleeve 804 is provided with a protruding portion 804a, which protrudes in the direction of the feed clip 812. The sleeve 804 is also provided with an electrically conductive element or coating interconnecting the upper portion of the inner surface and the outer surface of the protruding portion 804a. Approximately halfway between its retracted and extended end positions of the sleeve, the protruding portion 804a thereof begins to engage the feed clip 812. This results in that the whip antenna 802 is fed through the feed clip 812, the conductive element or coating of the sleeve 804 and the conductive stopper 806 being in electrical contact with the inner surface of the sleeve. Because the protruding portion 804a is provided with a slanting surface or slope, there is a slight overlap between the connection of the whip antenna and the disconnection of the internal antenna, eliminating any reflection currents due to the switching of antennas.

When the whip is move further to the fully extended position, the internal antenna is disconnected while the whip antenna is continuously fed due to the contact between the sleeve 804 and the feed clip 812.

The reverse operation, i.e., when the whip 802 is moved from its extended position shown in fig. 20 to its retracted position shown in fig. 19, functions in a corresponding way. The sleeve 804 is moved downwardly with the whip until the protruding portion 804a disengages from the feed clip 812, effectively disconnecting the whip antenna while feeding the internal antenna.

The solution described above with reference to figs. 19 and 20 provides an antenna device wherein switching be- tween an internal antenna and a whip antenna is effected in an efficient way. With the telescopic arrangement the position of the switch can be high up in the phone, giving extra length to the whip external of the phone housing. The increased length of the whip helps increas- ing talk position performance.

It is realized that the antenna device according to the invention can be varied within the scope defined by the appended claims. Thus, in the first embodiment described with reference to figs. 1-3, the magnet 108 and the cam ring 110 are provided as two separate parts. It will be appreciated that these two parts also can be made as a unitary magnetic part.

Whenever a plastic material is mentioned as a suitable material, it is to be understood that other non-conduc- tive materials could be used as well.

In the embodiment described with reference to figs. 15 and 16, a waist portion of the stopper cooperates with a protrusion so as to maintain the whip antenna in extended position. It will be realized that any suitable configu- ration of stopper and protrusion is possible as long as the retaining function is achieved.

Claims

1. An antenna device for a radio communication device, said radio communication device having RF electronics provided with a feed element (112; 212; 312; 412; 512; 812), said antenna device comprising:

- a housing (104; 204; 304; 404; 504; 804),

an internal antenna element (120; 220; 320; 340; 520; 820) connectable to said feed element,

- an external antenna element (102; 202; 302; 402; 502; 802) supported by said housing and being axially movable between an extended end position and a retracted end position, said external antenna element being pro- vided with a conductive end portion (106; 206; 306; 406; 506; 806),

characterized by

an axially movable conductive element (110; 210; 310; 410; 510; 804) extending radially outside of said con- ductive end portion of said external antenna element, said conductive element being arranged,

- when said external antenna element is in said extended end position,

to connect to said feed element and to said conductive end portion, and

to disconnect said feed element from said internal antenna element, and - when said external radiating element is in said retracted end position,

to disconnect from said conductive end portion, and

- to allow said feed element to connect to said internal antenna element.

2. The antenna device according to claim 1, wherein said conductive element (110) comprises a magnetic portion (108) arranged to contact said conductive end por- tion (106) in said extended end position for said external antenna element (102) by means of magnetic force.

3. The antenna device according to claim 2, wherein said magnetic portion (108) is arranged to contact a metallic portion (114) of said housing (104) in said retracted end position for said external antenna element (102) by means of magnetic force such as to keep said conductive element (110) in a fixed position.

4. The antenna device according to claim 2 or 3 , wherein said magnetic portion (108) is arranged to con- tact a metallic portion of said housing (104) in said extended end position for said external antenna element (102) by means of magnetic force such as to keep said conductive element (110) in a fixed position, in which said conductive element is in contact with said feed element (112).

5. The antenna device according to claim 1, wherein said conductive element (210; 310;410,-510) comprises a retaining portion (210b;310b;410b;510a) arranged to keep said conductive element and said conductive end portion (206;306;406;506) interconnected by means of frictional force.

6. The antenna device according to claim 5, wherein said retaining portion comprise resilient tongues (210b) arranged to cooperate with a groove (206a) in said conductive end portion (206).

7. The antenna device according to claim 5, wherein said retaining portion comprise a protrusion (310b; 410b) arranged to cooperate with a groove (306a; 406a) in said conductive end portion (306; 406).

8. The antenna device according to claim 5 , wherein said conductive element (210; 310; 410 ) is attached to a non-conductive cylinder (208 ; 308; 408) arranged on said external antenna element (202;302;402).

9. The antenna device according to claim 8, wherein said non-conductive cylinder (208; 308; 408 ) is provided with a protrusion (208a; 308a; 408a) on the envelope surface thereof, said protrusion being arranged to cooperate with a bridge portion (204a;304a;404a) on said housing (204; 304; 404) such as to keep said non-conductive cylinder in fixed positions.

10. The antenna device according to claim 5, wherein said conductive element (510) is arranged to be moved radially outward from said external antenna element (502) by a guide element (532) fixedly attached to a support frame (530) .

11. The antenna device according to claim 1, comprising a grounding element arranged to connect a feed portion of said internal antenna element to a ground de- vice in said extended end position for said external antenna element.

12. The antenna device according to claim 1, comprising a ground element (418; 518) connectable to said internal antenna element (420; 520) and a disconnecting element (426; 526) arranged to disconnect said ground element in said extended end position for said external antenna element (402; 502).

13. The antenna device according to claim 12, wherein said disconnecting element (426; 526) is a non- conductive element, preferably a plastic pin, arranged between said feed element (412; 512) and said ground element (418; 518).

14. The antenna device according to any of the preceding claims, wherein said external antenna element (102; 202; 302; 402; 502) and said feed element (112; 212; 312; 412; 512) are separated by a distance of at least one millimeter in said retracted end position for said external antenna element.

15. The antenna device according to claim 1, wherein said housing (804) functions as said conductive element and is axially movable between an extended end position and a retracted end position, and wherein said housing (804) comprises a protrusion (804a) arranged to contact said feed element (812).

16. An antenna device for a radio communication device, said radio communication device having RF electronics provided with a feed element (612), said antenna device comprising: a housing (604) ,

an internal antenna element (620) connectable to said feed element,

an external antenna element (602) supported by said housing and being movable between an extended end position and a retracted end position, said external antenna element being connectable to said feed element at a conductive end portion (606) of said external antenna element,

- wherein said feed element is arranged to connect to said conductive end portion and thereafter disconnect from said internal antenna element with an isolation distance from said internal antenna element when said external antenna element is moved to said extended end position, and said feed element is arranged to connect to said internal antenna element and thereafter disconnect from said conductive end portion with an isolation distance from said external antenna element when said external antenna element is moved from said ex- tended end position,

characterized by

- a displacement element (608) arranged in said housing (604) for displacing said conductive end portion (606) radially towards said feed element (612) when said ex- ternal antenna element is in said extended position, such as to connect said conductive end portion to said feed element and thereafter disconnect said feed element from said internal antenna element.

17. The antenna device according to claim 16, wherein said displacement element (608) is provided as a protrusion in said opening (605).

18. The antenna device according to claim 17, wherein said protrusion is provided with a groove having a width larger than the diameter of said external antenna element (602) but smaller than the diameter of said conductive end portion (606).

19. The antenna device according to claim 17 or 18, wherein said protrusion (608) is arranged to maintain said external antenna element (602) in extended position by engaging a waist portion (606a) of said conductive end portion (606) .

20. An antenna device for a radio communication device, said radio communication device having RF electronics provided with a feed element (712), said antenna device comprising:

an internal antenna element (720) connectable to said feed element,

- an external antenna element (702) being axially movable between an extended end position and a retracted end position, said external antenna element being provided with an end portion (706a, 706b),

characterized in that

- said end portion comprises an insulating end portion (706a) and a conductive end portion (706b) and has a diameter exceeding the diameter of said external antenna element (702) so as to disconnect said feed element (712) from said internal antenna element (720) when said external antenna element is moved from its retracted end position to its extended end position, and wherein said insulating end portion (706a) contacts said feed element (712) when said external antenna element (702) is in its extended end position.

21. The antenna device according to claim 20, wherein said insulating end portion (706a) has a diameter exceeding the diameter of the conductive end portion (706b).

22. A portable radio communication device, comprising a device housing and RF circuitry,

characterized by

an antenna device according to any of claims 1-21 mounted in said device housing and connected to said RF circuitry.