WO2004105179A1

WO2004105179A1 - An antenna device and a supply device thereto

Info

Publication number: WO2004105179A1
Application number: PCT/SE2003/000839
Authority: WO
Inventors: Carl Gustaf Blom
Original assignee: Perlos Ab
Priority date: 2003-05-23
Filing date: 2003-05-23
Publication date: 2004-12-02
Also published as: AU2003242052A1; CN1813374A; EP1629565A1; CN1813374B

Abstract

A broad band antenna has a radiator, for example a slot (4) in an earth plane (3). A supply device (6) has a first central conductor (9) which, with one end (10), is connected to the circuits in a transeiver which extends along/in association with the radiator (4) and which has one free end (11). The supply device (6) further has a second, helical conductor (13) whose one end (14) is earthed and whose other end (15) terminates freely. The helical conductor (13) surrounds the central conductor (9). In one embodiment, the helical conductor (13) is provided with straight, mutually intersecting conductor sections on opposing sides of a three-layer circuit card. The opposing ends of the conductor sections are electrically connected to one another through the circuit card, and the central conductor (9) is disposed in the central layer of the card.

Description

AN ANTENNA DEVICE AND A SUPPLY DEVICE THERETO. TECHNICAL FIELD

The present invention relates to an antenna device according to the preamble to appended Claim 1.

The present invention also relates to a supply device according to the preamble to appended Claim 14.

BACKGROUND ART

The connection impedance to a transceiver in a radiocommunications apparatus, in daily parlance a so-called cell or mobile telephone, often lies in the range of 50 ohms, and, depending on the design and type of radiator, its impedance may vary greatly, for example in the range of 20-500 ohms. Thus, an adaptation of the impedance is necessary.

In prior art constructions, it is normal to build up an adaptation network of discrete components which are often placed on a circuit card in the mobile telephone. Even if the impedance adaptation in such constructions may be acceptable, the constructions are as a rule rendered more expensive and suffer from high losses. Further, it is not readily possible to include this type of adaptation network in the antenna construction proper, which would be desirable since a simple and compact design and construction would then be attained.

SE-C2-504 342 discloses an adapter network and an antenna where the adapter network operates with low losses. In its simplest form, the network consists of a thin, insulated wire which is wound about an earthed rod of a certain diameter. By a suitable selection of the number of turns, rod diameter and the spacing of the individual turns, it is possible to realise an adapter network which is superior to a simple Pi-network.

While the above-described adapter network and the associated antenna enjoy many advantages, they cannot offer a broad band antenna device which, with a single supply point, caters for the frequency range from approx. 1.7 to 2.6 GHz. To further include the possibility of operation also in the GSM band, i.e. at approx. 900 MHz while retaining a single supply point is impossible.

The use of a single supply point entails a major advantage, since this is a precondition for the application of the filter technology which at present is in the process of developing. Further, it facilitates the use of external antennas.

PROBLEM STRUCTURE

The present invention has for its object to design the antenna device intimated by way of introduction such that it obviates the drawbacks in the prior art technology. In particular, the present invention has for its object to design the antenna device so that this, on the one hand, can operate within a very broad frequency range, from approx. 1.7 GHz to approx. 2.6 GHz and that, on the other hand, it in addition affords the possibility for operation in a lower frequency band, such as the GSM- and GPS-bands, which moreover may be moved without affecting operation within the upper, broad frequency range. The present invention further has for its object to realise an antenna device which may be manufactured economically and rationally and which places very slight demands on available space.

The present invention yet further has for its object to design the supply device intimated by way of introduction so that this obviates the drawbacks in prior art technology, that it functions well on the one hand within a broad, upper frequency range and, on the other hand within a movable lower frequency band together with a plurality of optionally designed radiators regardless of their detailed construction, and finally that it is simple and economical in manufacture.

SOLUTION

The object forming the basis of the present invention will be attained if the antenna device intimated by way of introduction is characterised in that the connection to earth of the first end of the second conductor is disposed via a tuner.

The object forming the basis of the present invention will be attained in respect of the supply device if this is characterised in that the end of the first conductor sections or the second conductor sections which are located most proximal the connection end are connected to earth via a tuner.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will now be described in greater detail hereinbelow, with reference to the accompanying Drawings. In the accompanying Drawings:

Fig. 1 shows a circuit card included in a so-called cell or mobile telephone, in which is incorporated the antenna device according to the present invention;

Fig. 2 is a diagram showing the measurement results from measuring a prototype of the device according to the present invention, an operating range being clearly apparent at approximately 900 MHz and a broad band operating range around the central frequency of approximately 2.2 GHz;

Fig. 3 shows a part of a circuit card with a slot antenna designed according to the present invention;

Fig. 4 shows a first embodiment of a tuner according to the present invention;

Fig. 5 shows a variation of the tuner according to Fig. 4;

Fig. 6 shows a second embodiment of the tuner;

Fig. 7 shows a third embodiment of the tuner;

Fig. 8 shows a fourth embodiment of the tuner;

Fig. 9 shows a fifth embodiment of the tuner;

Fig. 10 shows a sixth embodiment of the tuner; Fig. 11 shows a practical embodiment of a supply device which is also shown in Fig.

1; and

Fig. 12 is an exploded view of the supply device according to Fig. 11.

DESCRIPTION OF PREFERRED EMBODIMENT

In Fig. 1, reference numeral 1 relates to a circuit card which, for example, may be disposed in a cell or mobile telephone. The circuit card 1 consists of at least one carrier 2 of dielectric material, as well as at least one metal coating 3, at least on the upper side. The circuit card may, however, consist of a plurality of conductive layers corresponding to the metal coating 3 and a number of interposed layers, sheets or strata of a dielectric material disposed therebetween. On the circuit card 1, there is disposed a radiator which may be of optional type. In the illustrated embodiment, it is shown by way of example as a quarter wave slot radiator. The radiator or the slot 4 is realised in that the metal coating 3 is removed from both sides of the carrier 2 so that the slot will be transparent in respect of radiation. It will be apparent from the Figure that the slot 4 has an aperture 5, which entails that, as was mentioned above, it is tuned for resonance at a quarter wave length. The radiator may also be a half wave radiator which, in the example with a slot radiator, entails that the slot is longer and will lack any counterpart to the aperture 5; hence the slot will be closed as a half wave radiator. Other types of radiators may also come into consideration.

For supplying the radiator, in the above example the quarter wave slot 4, use is made of a supply device 6 which will be described in greater detail below. The supply device 6 may be a separate unit which thus may be mounted a distance from the radiator 4 but which may also be wholly or partly integrated in the circuit card 1. There is no galvanic connection between the supply device 6 and the radiator 4.

If more than one radiator is needed, this is possible according to the present invention, in that more than one radiator is placed in the same earth plane, i.e. in the same metal coating 3. Even if two slots, in the example using slot radiators, are placed physically close to one another, they will not affect one another electrically. Thus, by the employment of more than one slot, it is possible according to the present invention to realise a multi-band antenna where each band has large band width. By the orientation of the slots in different ways, for example by disposing their longitudinal directions at right angles to one another, it is also possible to affect the radiation pattern so that the radiation lobes from the two radiators differ. If, for example, one slot is disposed with its longitudinal direction approximately horizontal, its radiation lobe will be vertically directed, which is a major advantage in a GPS apparatus. Analogously, the radiation lobe will be substantially horizontal with a slot having a vertical longitudinal direction.

The metal coating 3 may also be disposed on a casing for the mobile telephone, both an inner, supporting casing and an outer, decorative shell. In the example above with the slot radiator, it then applies that this is also placed on the casing.

In the example according to Fig. 1, with a quarter wave slot radiator 4, both the radiator and the supply device 6 or exciter each have a longitudinal direction and these longitudinal ^■ directions are mutually parallel. However, for reasons of setting or fme-tuning, it is also possible to cause these longitudinal directions to make an angle with each other. Correspondingly, it is possible to vary the distance between the radiator 4 and the exciter 6 for the same purpose. This applies also if the radiator has a different design than the slot 4 shown above for purposes of exemplification.

Fig. 3 shows, in simplified schematic form, an antenna device according to the present invention. This antenna device is wholly identical in functional respects with that shown in Fig. 1, apart from the orientation.

Thus, Fig. 3 shows an earth plane 3 which may consist of a metal layer, a metal foil or the like on a suitable carrier of insulating, non-magnetic material such as a circuit card or a metallised region of a casing for the mobile telephone. Like the embodiment according to Fig. 1, there is disposed a slot 7 in the earth plane 3 with an open end 8. The slot will therefore be tuned to resonance at a quarter wave length, where the length of the slot determines the relevant wavelength.

Even if the physical dimensions will be larger, the present invention also encompasses the possibility of a half wave resonator, in which event in such an embodiment the slot 7 will be longer and closed at both ends. In Fig. 3, the slot 7 is supplied by an exciter or supply device 6 which includes a first or central conductor 9 with a first end 10 and a second end 11. In the practical embodiment, the first conductor 9 may consist of a portion of the central conductor in a coaxial cable 12 whose opposite end (not shown in the Figure) is connected to the circuits in the mobile telephone in which the antenna device is included.

The supply device 6 further includes a second conductor 13 which has a first end 14 and a second end 15. The first end 14 of the second conductor 13 is connected to the screen or earth conductor 16 in the coaxial cable 12 while the second end 15 terminates blind. The second conductor 13 may also be connected to the earth plane 3 and be earthed in it with its first end 14. The first end 14 of the second conductor 13 may also be connected to earth via some other conductor than the screen 16 of the coaxial cable 12.

In the illustrated embodiment, the second conductor 13 is in the physical form of a helix, for which reason it has regions that alternatingly are located on different sides of the first conductor 9 along at least a part of its longitudinal extent. The helix, or the second conductor 13, will therefore three-dimensionally surround, enclose or extend about the first conductor 9. This also applies in the modified embodiments which will be described below. The helix may be shorter than, as long as (Fig. 3), or longer than the second conductor.

The first conductor 9 lies in the longitudinal direction of the slot 7 and in or parallel with the earth plane 3. There is no galvanic contact between the first and the second conductors 9 and 13 respectively, nor between the second conductor 13 and the metal in the earth plane 3 apart from the earthing of the first end 14 of the second conductor. The distance between the first conductor 9 and the earth plane (unless first conductor lies in the earth plane) determines the degree of connection between the first conductor 9 and the slot 7.

The second conductor 13 forms an inductance which is distributed along the longitudinal extent of the first conductor 9. Further, the second conductor 13 forms a capacitance between itself and the first conductor 9, this capacitance also being distributed along the length of the first conductor 9. In addition, there are also capacitances between closely adjacent turns in the second conductor. In the antenna device according to Fig. 3, the length of the slot 7 determines the centre of the resonance range within which the antenna device operates. The length of the central or first conductor 9 is adapted to the length of the slot. However, the length of the first conductor 9 is not particularly critical, but needs only be so large as to provide room for the requisite turns of the second conductor 13.

With the design which is shown in Fig. 3, the antenna device will have a broad band resonance range which is intimated by the arrow A in Fig. 2.

It will be apparent from Fig. 3 that the second ends 11 and 15 of the first and second conductors 9 and 13, respectively, are located approximately the same distance from the coaxial cable 12. In this embodiment, there is no resonance peak B in Fig. 2. If, on the other hand, the second conductor 13 is extended (see Figs. 4-11) so that its second end 15 extends past the second end 11 of the first conductor 9, this "extra length" of the second conductor 13 contributes with a second resonance region of the antenna device, this resonance region being intimated at the arrow B in Fig. 2. With an extended second conductor 13, it is thus possible to realise an antenna device which, on the one hand, has a narrow resonance region at GSM frequency and, on the other hand, a broad resonance region in the area of 1.7 to 2.6 GHz.

Without the influence of the broad band region A (Fig. 2), it is possible to move the low frequency resonance peak B. If the end 14 of the second conductor 13 located most proximal the coaxial cable 12 is connected to earth via a tuner, this implies that the resonance peak B can be moved towards lower frequencies.

In Figs. 4 and 5, which show two variations of one and the same fundamental solution regarding the tuner, as far as this is possible, the same reference numerals have been employed as in Fig. 3. It is thus apparent that the first end 14 of the second conductor 13 is no longer directly connected to earth via the screen 16 of the coaxial cable 12 or any other direct conductor to earth. Instead, the first end of the second conductor 13 is connected to earth 42 via the tuner which, in this embodiment, includes an inductance 43. The inductance 43 can be short-circuited by means of a switch 44 if desired, in which event the embodiment becomes in principle identical to that illustrated in Fig. 3, apart from the extension of the second conductor 13. In the variation according to Fig. 5, the switch 44 and the inductance 43 are to be found, but the end of the inductance facing away from the first end 14 of the second conductor 13 is connected, via a conductor 45, to the screen 16 of the coaxial cable 12 and thereby to earth.

The above-described variations illustrate the situation that the inductance 43 or, generally the tuner, can be earthed at any point whatever in that apparatus which the antenna device is intended to serve. However, the earthing point should be selected in such a manner that the earth conductor is as short as possible.

The switch 44 may be produced in accordance with any optional technology, for example so- called MEMS technology.

In the embodiment according to Fig. 6, like the embodiments according to Figs. 4 and 5, the first end 14 of the second conductor 13 is connected to one end of an inductance 43 whose opposite end is connected to earth 42. The inductance has a number of terminals which can be earthed via a switch 47 so that, as a result, a greater or smaller part of the inductance 43 can be connected in between the first end 14 of the second conductor 13 and earth 42.

In the embodiment according to Fig. 7, the inductance 43 is, like that described above, connected between the first end 14 of the second conductor 13 and earth 42. Parallel over the inductance 43, there is connected a variable capacitance 48 which may possibly be designed as a so-called variocap.

In the embodiment according to Fig. 8, the first end 14 of the second conductor 13 is, like that described above, connected to one end qf an inductance 43 whose other end is connected to earth 42. The inductance 43 has a number of terminals 49 which may lie more or less closely together along the inductance 43 and all of which are connected to capacitances 50. The capacitances 50 are connectable earth 42 via a switch 51.

In the position illustrated in Fig. 8 for the switch 51, the first end 14 of the second conductor 13 is earthed via the capacitance 50 illustrated uppermost in the Figure. However, in other positions of the switch 51, a part of the inductance 43 is coupled in between the first end 14, one of the capacitances 50 and earth. In the embodiment according to Fig. 9, the first end 14 of the second conductor 13 is, as described above, connected to the one end of the inductance 43 whose other end is connected to earth. The upper end. of the inductance is connected, via a branch conductor 52, to a number of capacitances 53 which are of different sizes. The opposite ends of the capacitances are connected to a switch 54 by means of which any optional capacitance 53 can be connected to earth.

The embodiment according to Fig. 9 may be described as being a stepwise adjustable variation of the embodiment which is shown in Fig. 7.

Alternatively, the switch 54 may be designed so that it connects in parallel a plurality of the capacitances 53 and connects them to earth.

The embodiment according to Fig. 10 shows an inductance 43 connected between earth 42 and the first end 14 of the second conductor 13. Parallel with the inductance 43, a smaller inductance 55 is disposed with its one end connected to earth and its other end via a switch 5ό connectable to the first end 14 of the second conductor 13.

The above-described embodiments of the tuner may be designed with discrete components and be placed at a suitable site in the apparatus which the antenna is intended to serve. However, they can also be integrated in the exciter ^"or supply device 6 as will be described in greater detail below.

The above-described embodiments of the tuner may also be combined with one another so that additional embodiments are formed. _;

Figs. 11 and 12 show a supply device of the type employed for supplying or exciting the slot 4 in Fig. 1 or a radiator of other design. In this embodiment, the supply device 6 is formed as a separate unit, but may also, as intimated above, be wholly or partly integrated in the circuit card 1 in Fig. 1.

According to the present invention, it is also possible to integrate into a unit, on the one hand, the supply device proper and, on the other hand, the radiator proper which may be of optional type. The supply device according to Figs. 11 and 12 includes a first 25 and a second 24 disk- shaped piece of dielectric material. On the upper side of the second piece 24 of dielectric material, there is a number of conductor sections 26 which are substantially straight, parallel with one another and disposed in slight spaced apart relationship. The conductor sections 26 intersect at an angle a central, longitudinal line through the supply device 6. At opposing ends of these conductor sections 26, there are disposed through-going apertures 27 whose purpose will be described in greater detail below. Further, there is a connection 28 with a through-going aperture 29 and finally the conductor section 26 located most proximal the connection 28 has a connection 40.

On the first piece 25 of dielectric material, there is disposed, on that side which is turned to face towards the second piece 24 of dielectric material, a first or central conductor 30 which corresponds to the first conductor 9 in Fig. 3 and which, in its one or first end 10, has a connection 31 corresponding to the connection 28 on the second piece of dielectric material, as well as a through-going aperture 36. On the opposing side, in Fig. 12, the lower side of the first piece of dielectric material 25, there is a number of conductor sections 33 which, in their opposing ends, have through-going apertures 34. The conductor sections 33 make an angle of 180-α with a central, longitudinal line through the supply device 6. Hereby, the conductor sections 33 will intersect or cross the conductor sections 26. Finally, the conductor section 33 located most distal from the connection displays a connection 41. On the unification of the two pieces 24 and 25, and on soldering or plating through the apertures 27, 34, 29 and 36, a supply device will be obtained with a central or first conductor 30 which is surrounded by or enclosed in a "flattened helix" consisting of the conductor sections 26 and 33 as well as the through platings through the above-mentioned apertures. In practice, the first conductor 30 should be as tightly surrounded or enclosed in this "flattened helix" as possible, for which reason the length of the conductor sections 26 and 33 is less than that shown in the Figures.

The supply device according to Fig. 11 may, as an alternative to the described embodiment, be composed of three different pieces of dielectric material, where each piece has an electrically conductive layer from which the conductor sections 26, 30 and 33 are produced.

In recent times, techniques have evolved that make it possible to realise, interiorly in one single continuous piece of dielectric material, a three-dimensional conductor pattern. Such a technique may be employed for producing a supply device according to Fig. 11. A supply device is possible applying such a technique which, in terms of construction, more closely approximates the embodiment according to Figs. 3 to 10, where, hence, the counterpart to the conductor 30 (the conductor 9 in Fig. -3) may have a more circular than flat cross section and where the helix may be cylindrical, conical or "round".

In Fig. 11, which shows the complete supply device 6, the reference numerals from Fig. 3 have been inserted whereby the analogy between the two constructions is clearly apparent.

In Fig. 1, there is a number of connection points for connection of the supply device 6 to the circuit card 1. In particular, there is a connection 37 for connecting to the first end 10 of the first conductor 9 (reference numerals 28 and 31 in Fig. 12), in addition there is a connection 38 for connection to the first end 14 of the second conductor 13 (the connection 40 in Fig. 12) and a connection 39 for connection to the second end 15 of the second conductor 13 (the connection 41 in Fig. 12).

In the embodiments described in the foregoing, the earth plane 3 and the supply device 6 were placed substantially in a common plane. Possibly, certain conductor sections, for example the conductor sections 26, 30 and 33 in Fig. 12, in the supply device 6 may be disposed in the circuit card 1. Alternatively, if the circuit card has several layers, the whole supply device 6 may be integrated in the circuit card, while the radiator is disposed as a metallised pattern on the casing of the mobile telephone.

In the alternative with the metal layer 3 in the form of a metallisation and in the alternative with the radiator in the form of a metallic pattern, it is advantageous for reasons of production engineering if the metallisation is not blanket covering but is in the form of a lattice, grid or net where the "mesh size" is slight in relation to the pertinent wavelength.

In the foregoing embodiments, the first conductor 9 has been shown as a straight conductor. However, this configuration is not necessary, but the first conductor can just as well be a meandering conductor, a zigzag conductor, an undulating conductor, or a conductor of other configuration as long as it has portions of the second conductor which alternatingly are located on different sides of, or surround the first conductor.

Claims

WHAT IS CLAIMED IS:

1.. An antenna device with large band width, comprising a radiator (4, 7) and a supply device (ό) connected to circuits in a radiocommunications apparatus, the supply device (6) including, on the one hand, a first conductor (9) with a first (10) and a second (11) end, said first conductor (9, 30)

a) being connected with its first end (10) to the circuits in the radiocommunications apparatus, which b) extends along/in connection with the radiator (4, 7) and which c) is non galvanically connected thereto

and, on the other hand, a second conductor (13; 26, 33) with a first (14) and a second (15) end, said second conductor with its first end (14) being connected to earth and alternatingly being located on different sides of the first conductor (9) or surrounding it along at least a part of the longitudinal extent thereof, characterised in that the connection to earth of the first end (14) of the second conductor (13) is provided via a tuner.

2. The antenna device as claimed in Claim 1, characterised in that the tuner includes at least one inductance.

3. The antenna device as claimed in Claim 1 or 2, characterised in that the second end (15) of the second conductor (13; 26, 33) terminates blind.

4. The antenna device as claimed in any of Claims 1 to 3, characterised in that the radiator (4, 7) is a slot in an electrically conductive, in configuration substantially planar earth plane (3); that the first conductor (9, 30) has a substantially straight portion which is located in the slot and which is substantially parallel with or lies in the earth plane (3).

5. The antenna device as claimed in any of Claims 1 to 4, characterised in that the radiator (4, 7) is a slot in an electrically conductive earth plane (3), the slot having a centre line with a longitudinal direction; and that the first conductor (9, 30) is located outside the slot a distance from and substantially parallel with the centre line along the longitudinal direction.

6. The antenna device as claimed in any of Claims 1 to 3, characterised in that the radiator is a metallised pattern disposed on a casing for the radiocommunications apparatus.

7. The antenna device as claimed in Claim 6, characterised in that the supply device (6) has a first longitudinal direction; and that the radiator has a second longitudinal direction; and that the first and the second longitudinal directions make an angle with one another.

8. The antenna device as claimed in any of Claims 1 to 3, characterised in that the radiator (4, 7) is a slot in an electrically conductive metallisation on a casing for the radiocommunications apparatus.

9. The antenna device as claimed in Claim 8 characterised in that the supply device (6) has a first longitudinal direction; that the slot (4, 7) has a second longitudinal direction; and that the first longitudinal direction and the second longitudinal direction make an angle with one another.

10. The antenna device as claimed in any of Claims 4, 5, 6 or 8, characterised in that the earth plane, the metallised pattern and the metallisation are formed non-blanket covering, with a grid or net structure.

11. The antenna device as claimed in any of Claims 1 to 10, characterised in that the second end (11) of the first conductor (9, 30) extends out beyond the second end (15) of the second conductor (13).

12. The antenna device as claimed in any of Claims 1 to 10, characterised in that the second end (11) of the first conductor (9, 30) is located in the region of the second end (15) of the second conductor (13).

13. The antenna device as claimed in any of Claims 1 to 10, characterised in that the second end (15) of the second conductor (13; 26, 33) extends out beyond the second end (11) of the first conductor (9).

14. A supply device comprising a carrier of electrically insulating and non-magnetic material and a number of conductive layers, the carrier having a longitudinal direction, a first side of the carrier having a number of first conductor sections (33) which make and angle 180-α with the longitudinal direction and which bisect it, and a second side of the carrier has a number of second conductor sections (26) which make an angle α with the longitudinal direction, opposing ends of the first conductor sections (33) being located in register with opposing ends of the second conductor sections (26) and mutually registering ends of the first and the second conductor sections being galvanically connected to one another and a third, elongate conductor section (30) extending along the longitudinal direction, and being galvanically discrete from the first and second conductor sections (33, 36, respectively) and being located therebetween and having a connection end, characterised in that the end of the first conductor sections (33) or the second conductor sections (26) which are located most proximal the connection end are connected to earth via a tuner.

15. The supply device as claimed in Claim 14, characterised in that the carrier includes a first (25) and a second (24) piece of electrically insulating and non-magnetic material; that the first conductor sections (33) are disposed on a first side of the first piece (25); that the third conductor section (30) is disposed on a second side of the first piece (25) turned to face towards the second piece (24); and that the second conductor sections (26) are disposed on a second side of the second piece (24) turned to face away from the first piece (25).

16. The supply device as claimed in Claim 15, characterised in that it is designed as a unit which is provided with connections (28, 31, 40, 41) and designed for surface mounting where a first (40) of said connections is intended for connection to earth or the tuner, while a second (28, 31) of them is the connection end of the third conductor section (30).

17. The supply device as claimed in Claim 16, characterised in that the unit includes the tuner.

disposed on a circuit card (1), and provided with a slot (4, 7), characterised in that a supply device (6) as claimed in any of Claims 14 to 17 is disposed in or covering the slot.

19. An antenna device for a radiocommunications apparatus which has an earth plane (3), in which are disposed two slots (4, 7) which have longitudinal directions which are substantially at right angles to one another and which are of different lengths, characterised in that a supply device (6) as claimed in any of Claims 14 to 17 is allocated to each slot, as well as tuned to an operating frequency for each respective slot.

20. An antenna device for a radiocommunications apparatus, characterised in that a supply device as claimed in any of Claims 14 to 17 together with a radiator is disposed as a separate unit.

21. An antenna device for a radiocommunications apparatus, characterised in that a supply device as claimed in any of Claims 14 to 17 is allocated to a radiator provided as a metallisation on a casing for the radiocommunications apparatus.