SE534431C2

SE534431C2 - An antenna device

Info

Publication number: SE534431C2
Application number: SE0951001A
Authority: SE
Inventors: Carl-Gustaf Blom; Thomas Hedlund; Parviz Basirat
Original assignee: Lite On Mobile Oyj
Priority date: 2009-12-21
Filing date: 2009-12-21
Publication date: 2011-08-23
Also published as: WO2011076582A1; SE0951001A1

Abstract

2009-12-21 PRIO223131 UJN/MLR43 ABSTRACT The invention provides an antenna arrangement for a mobile device. Themobile device comprises radio frequency circuits and a ground plane. Theantenna arrangement comprises a conductive element and at least onefeeding element. Said feeding element comprising a conductive pattern isarranged to be connected to the radio frequency circuits wherein theconductive element is a sheet having an outer first surface and an innersecond surface. The conductive element comprises at least two radiatingelements. The radiating elements are arranged to be fed through saidfeeding element. Said radiating elements are physically separated from eachother by isolation means and said feeding element has an extension planewith one side of the feeding element facing the inner second surface of theconductive element with a gap between the conductive element and theconductive pattern of said feeding element. The invention further provides a housing element for the mobile device comprising the antenna arrangement, a corresponding method tomanufacture the housing element and a further antenna arrangement having one radiating element. The invention also provides a mobile device comprising the antenna arrangement. Figure 6 to be used.

Description

2009-12-21 PRIO223131 UJN/MLR An antenna arrangement TECHNICAL FIELD The present invention relates to the field of antenna arrangements andhousing elements for mobile devices, such as mobile phones. The inventionalso covers the field of methods to manufacture a housing element for amobile device as well as mobile devices comprising such an antenna arrangement.

BACKGROUND ART There are today solutions available where antennas are integrated in anexternal cover to a mobile phone. As there is a trend today towards usingmetal as an external surface for external covers there is also a need tointegrate antennas in such an external cover of a mobile phone. One suchsolution is the Nokia patent application WO 2008/122831 A1. This documentdiscloses an antenna arrangement and antenna housing. The antennaarrangement comprises an antenna occupying at least a first plane, aconductive structure that is isolated from the antenna but is arranged to beparasitically fed by the antenna. The conductive structure has a slot andoccupies at least a second plane different but adjacent the first plane.

A drawback with this solution is that there is only one radiating element, inthis case a slot element, limiting the possibilities to achieve multiple band operations with the same antenna arrangement.

There is thus a need for a solution for providing an antenna arrangement withimproved possibilities for achieving multiple band operation where theantenna is integrated in a cover of a mobile phone and where the cover has metal as an external surface.

SUMMARY The object of the invention is to reduce at least some of the mentioneddeficiencies with the prior art solutions and to provide: 0 an antenna arrangement for a mobile device0 a housing element0 a method to manufacture the housing element 0 a mobile device comprising the antenna arrangement to solve the problem to achieve an antenna arrangement with improvedpossibilities for achieving multiple band operation where the antenna isintegrated in a cover for a mobile phone and where the cover has metal as an external surface.

The object is achieved by providing an antenna arrangement for a mobiledevice. The mobile device comprises radio frequency circuits and a groundplane. The antenna arrangement comprises a conductive element and atleast one feeding element, said feeding element comprising a conductivepattern is arranged to be connected to the radio frequency circuits whereinthe conductive element is a sheet having an outer first surface and an innersecond surface. The conductive element comprises at least two radiatingelements. The radiating elements are arranged to be fed through saidfeeding element. Said radiating elements are physically separated from eachother by isolation means and said feeding element has an extension planewith one side of the feeding element facing the inner second surface of theconductive element with a gap between the conductive element and theconductive pattern of said feeding element.

The object is further achieved by providing a housing element for a mobiledevice wherein the housing element comprises the antenna arrangementaccording to any one of claims 1-17 and an internal non-conductive structurewherein the outer first surface of the conductive element is an outer surface of at least a part of an external cover to the mobile device and the innersecond surface of the conductive element is facing one side of said feedingelement. The conductive element and the internal non-conductive structure are integrated into one unit.

The object is further achieved by providing a method to manufacture ahousing element for a mobile device, according to any one of claims 18-21wherein the radiating elements are applied to the internal non-conductivestructure.

The object is still further achieved by providing a mobile device comprising the antenna arrangement according to any one of claims 1-17.

The object is also achieved by providing a further antenna arrangement for amobile device. The mobile device comprises radio frequency circuits and aground plane. The antenna arrangement comprises a conductive elementand at least one feeding element, said feeding element comprising aconductive pattern being arranged to be connected to the radio frequencycircuits wherein the conductive element is a sheet having an outer firstsurface and an inner second surface. The conductive element comprises oneradiating element. The radiating element is arranged to be fed through saidfeeding element and said feeding element having an extension plane withone side of the feeding element facing the inner second surface of theconductive element with a gap between the conductive element and the conductive pattern of said feeding element.

Further advantages are achieved if the invention is also given one or severalcharacteristics according to the dependent claims not mentioned above. This will be further described below.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 schematically illustrates an example of a mobile device.

Figure 2 schematically illustrates one example of the feeding of the antenna arrangement in a side view.

Figure 3a schematically shows one example of a conductive element withlocations of ground connection points at the radiating element and location ofthe feeding element.

Figure 3b schematically illustrates relative positions between different partsof the conductive element and the ground plane.

Figure 3c schematically shows one example of a radiating element with three ground connections.

Figure 4 schematically shows some examples of feeding elements.

Figure 5 is a perspective view from the outside, of an external cover for a mobile device.

Figure 6 is a perspective view seen from the inside of the mobile device showing an example of part of a housing element.

Figure 7 is an exploded perspective view showing an example of aconductive element and an internal non-conductive structure of a mobile device.

Figure 8 is a perspective view of an example of a housing element of themobile device with two feeding elements.

Figure 9 schematically shows an example of an RF matching network.

Figure 10 schematically shows an example of a ground matching network.

Figure 11 is a block diagram of one example of the manufacturing method forthe housing element.

Figure 12 is an exploded perspective view showing an example of an internalnon-conductive structure with radiating elements and a feeding element.

Figure 13 shows a perspective view from the outside of an internal non- conductive structure.

DETAILED DESCRIPTION The invention will now be described with reference to the enclosed drawings.The dimensions in the drawings are not to scale and relations in dimensions between parts in the drawings have been chosen to improve clarity.

A mobile device is defined as a portable communication and/or computerdevice. The mobile device can e.g. be a mobile phone, a handheld computer,a lap top, a Personal Digital Assistant (PDA) or any other type of mobile device.

Figure 1 shows the mobile device 101, exemplified with a mobile phone,comprising a control unit 107 configured to control communication with amobile communication system 103. A keyboard 113, a display 115 and radiofrequency (RF) circuits 109 are connected to the control unit 107 whichtogether with an antenna arrangement 111 are arranged to establish a radio-interface 105 for communication with the mobile communication system 103.The mobile device also comprises at least one ground plane or at least one reference plane providing a ground or reference voltage for AC and DC.Henceforth the expression ground plane or ground is used for a ground orreference plane respective a ground or reference voltage. The antennaarrangement of the mobile device is connected to the RF circuits which inturn are connected to further electronic components. The antennaarrangement is normally also connected to the ground plane of the mobile device.

The invention covers an antenna arrangement for a mobile device. Themobile device comprises RF circuits and a ground plane. The antennaarrangement comprises a conductive element and at least one feedingelement. The feeding element comprising a conductive pattern is arranged tobe connected to the RF circuits.

The antenna arrangement of the invention thus comprises two main parts, aconductive element and at least one feeding element cooperating with theground plane of the mobile device. The two main parts are located adjacentto each other. The feeding element is connected to RF circuits of the mobiledevice through a galvanic or non-galvanic connection and receives RFenergy from the RF circuits in transmit mode (Tx-mode). The non-galvanicconnection can be arranged e.g. via a capacitor. The feeding element isfeeding the radiating elements of the conductive element non-galvanically.This does however not exclude a common ground connection between thefeeding and radiating elements. The feeding element will excite current in theconductive element and the conductive element will radiate RF energy intospace. ln the non-galvanic coupling, electromagnetic energy is thustransferred through a dielectric medium such as air or a dielectric material.Due to the reciprocity principle of antennas the inventive solution isapplicable both for transmission and reception if not otherwise stated.Henceforth in the description the invention will be described for the transmitmode (Tx-mode) if not otherwise stated.

The conductive element is made of a conductive material such as metal andcan e.g. be at least a part of an external cover of a mobile device such as amobile phone. This means that the antenna arrangement can beimplemented e.g. in mobile phones having the external cover, also called theexternal housing, made of metal. This is an important advantage as there is atrend today towards mobile phones having metal covers or covers with anexternal metallization as will be explained. By dividing the conductiveelement in at least two parts, the metal cover or metalized cover of a mobilephone can be used to integrate several antenna functions. Said parts arephysically separated by isolation means. The isolation means can be a slit ora slit filled with a non-conductive material. Said parts are henceforth calledradiating elements.

The invention also provides a housing element comprising the antennaarrangement, a method to manufacture the housing element and a mobiledevice comprising the antenna arrangement according to any one of claims1-17.

Figure 2 schematically shows a side view of one example of the feeding ofthe antenna arrangement comprising a first radiating element 201 and afeeding element 203. Only a part of the first radiating element is shown infigure 2. ln this example the first radiating element 201 is a part of a backcover of a mobile phone. The feeding element 203 is connected to the RF-circuits through at least one first RF-connection 204 and may also beconnected to the ground plane through a first ground connection 205, i.e. atleast one feeding element may be arranged to be connected to the groundplane of the mobile device. There is a gap 207 between the feeding elementand the first radiating element, defining a gap distance. The RF circuits andthe ground plane are located on a Printed Circuit Board (PCB) 202 of themobile phone. The first radiating element is connected to ground via asecond ground connection 206. The first radiating element can have morethan one ground connection, as schematically illustrated with a third ground connection 208. ln certain applications, as will be explained, there is noground connection between the radiating element and the ground. Thefeeding element 203 may have more than one ground connection asschematically illustrated with a fourth ground connection 209. The location ofthe possible ground connection/s of the radiating element and possibleground connection/s of the feeding element will affect the impedancematching of the antenna arrangement to the RF-circuits. Figure 2 also showsa second RF connection 210. A second RF connection can be used e.g. inapplications when the feeding element should cover several frequency bandsand when it is desirable to have a separate RF feed for certain frequencybands. The gap distance does not have to be constant along the feedingelement but can vary due to the shapes and relative positioning of the feeding element and the radiating element.

The feeding element in figure 2 may be manufactured as a stamped metalpart shaped to a desired conductive pattern of the feeding element. Thefeeding element can be applied to the interior of the mobile device byconventional means such as non-conductive spacers. The gap 207 is thedistance between the conductive pattern of the feeding element and the conductive element. ln a further example of the invention it is possible to have more than onefeeding element to each radiating element. This can be an advantageousalternative when a separate feed is desirable for certain frequency bands.

An advantage with the present invention is that there are several possibilitiesfor improved matching, i.e. to adjust the impedance of the antennaarrangement to the impedance of the RF-circuits of the mobile device. Goodmatching means that transmission losses between the RF-circuits and theantenna arrangement are minimized. The invention allows the matching to beperformed by adjusting different parameters as will be described below. Animproved impedance matching will improve both antenna efficiency and bandwidth. The adjustment of the impedance matching, some times referredto as the matching, is also described as tuning of the antenna arrangementor the radiating elements to a certain frequency band or bands.

Figure 3a schematically shows in a perspective view one example of aconductive element 300 with locations of ground connections to the firstradiating element 301 and location of the feeding element 306. Theconductive element 300, having an outer first surface 315 and an innersecond surface 316, is made of a sheet such as a metal sheet or a sheet ofother alternative material and comprises at least two radiating elements, inthis case the first radiating element 301 and a second radiating element 302.The radiating elements thus also have an outer first surface (315) and aninner second surface (316). Examples of metals and other alternativematerial are described in association with figure 5. The radiating elementsare separated by a slit 303 filled with a non-conductive material. A firstground connection point 304 and a second ground connection point 305 atthe first radiating element 301 are also shown as well as the feeding element306 facing the inner second surface of the conductive element. The feedingelement, in this example a double loop antenna, is coupled non-galvanicallyto the first radiating element. ln this case the first radiating element will beinductively loaded through the loops of the feeding element. The radiatingelements comprise in this example a substantially planar part 309 with sideparts 310 extending substantially perpendicular to the planar part at eachside of the planar part except a side towards the slit 303. A coordinatesymbol 307 defines the directions of the x-, y- and z-axis. The y-axis isextending along a length direction of the conductive element and the x-axisextends along a width direction of the conductive element. The z-axis isextending along a height direction of the conductive element coinciding with the extension direction of the side parts.

There is normally one feeding element to each radiating element, i.e. onefeeding element is arranged to feed one radiating element. The feedingelement is facing the inner second surface 316 of the conductive elementand the vertical projection of the feeding element towards the conductiveelement falls within the area of the corresponding radiating element. Theexact location of the feeding element in relation to the radiating element canbe used for fine tuning the matching between the antenna arrangement andthe RF-circuits of the mobile device. lt is also possible to have one feedingelement arranged to feed more than one radiating element, i.e. at least tworadiating elements. This also means that each feeding element will always bearranged to feed at least one radiating element. ln this example of theinvention the vertical projection of the feeding element towards the innersecond surface of the conductive element can fall within the combined areaof the radiating elements being fed by the feeding element. The gap distanceand dielectric material between the feeding element and the radiatingelement affects the matching of the antenna arrangement. Choice ofdielectric material and gap distance can therefore be used for matching theantenna arrangement to the RF-circuits. This is further explained inassociation with figure 6. ln summary the radiating elements are arranged to be fed through a feedingelement. Normally there is one feeding element to each radiating element butone feeding element can also feed two or more radiating elements and therecan be more than one feeding element feeding one radiating element. Theradiating elements are physically separated from each other by isolationmeans and said feeding element has an extension plane. The feedingelement has a first side and a second side with one side facing the innersecond surface of the conductive element with a gap between the conductiveelement and the conductive pattern of said feeding element. The extensionplane can be flat and extend in two dimensions or be curved and extend in three dimensions. 11 The inventive antenna arrangement normally use two or more radiatingelements, each radiating element covering a certain frequency band or bandsor combination of frequency bands used e.g. for GSM (Global System forMobile communication), UMTS (UniversalSystem), Field Communication (NFC)/RFID (Radio FrequencyIdentification), FM-radio, DVB-H (Digital Video Broadcasting-Handheld) usedfor TV, Bluetooth, WLAN (Wireless Local Area Network), HLAN (Hiper LAN),Wimax, UWB (Ultra Wideband), GPS (Global Positioning System) and LTE(Long Term Evolution). The GSM system is divided in GSM-850, GSM-900,GSM-1800 and GSM-1900 working around 850 MHz, 900 MHz, 1800 MHzand 1900 MHz respectively.

Mobile Telecommunications Near ln one example of the invention, adapted for operation at the frequencybands GSM-900, GSM-1800 and GSM-1900, the conductive element, groundconnection points and feeding element can be configured as follows. Thesize of the planar area is approximately 100 mm in length and 50 mm inwidth. The side parts extend approximately 6 mm in z-direction. Thecoordinates mentioned below are calculated with the origin of the x/y/zcoordinate system located at point 308. The first ground connection point 304will then be located approximately at x/y/z coordinate 45/98/0 mm and thesecond ground connection point approximately at x/y/z coordinate 10/95/0mm. An RF connection pad 311 and a ground connection pad 312 of thefeeding element 306 are located in the area with x-coordinates approximately20-30 and y-coordinates approximately 70-80 mm. The RF connection padand the ground connection pad are normally positioned close to each other,in this example within a few millimetres. The location of these pads relativeeach other has influence on the matching of the feeding loops which is a wellknown fact to the skilled person. The feeding element can have the extensionplane in the x/y plane at a Z-coordinate for the conductive pattern of thefeeding element of 0,5-2 mm, i.e. there is a gap of 0,5-2 mm between theconductive pattern of the feeding element and the radiating element. Othergap distances are also possible, as will be explained. The gap can be filled 12 with a non-conductive material, as an internal non-conductive structure, aswill be described in association with figure 7 or the feeding element can beextended from the radiating element with other conventional means such asspacers and the gap will then comprise of air or a combination of air and non-conductive material. The feeding element can be a double loop antenna withan outer 313 and an inner 314 loop both having an approximately quadraticshape with dimensions 12x12 mm for the outer loop and 8x8 mm for theinner loop. A separation between the two loops can be about 1,5-2 mm andcan vary along the extension of the loops as will be shown in the example offigure 4. This separation distance between the loops can vary considerablyand the only requirement is that the inner loop runs inside the outer loop. ln this example the distance between the first and the second groundconnection points is about 35 mm. Moving them closer will shift resonancefrequency towards lower frequencies. lncreasing the distance between theground connection points, the antenna will become electrically shorter andthe resonance frequency will move to higher frequencies and low bandmatching, e.g. at GSM-900, will get worse.

Figure 3b schematically illustrates relative locations between different partsof the conductive element 300, with the planar part 309 and the side parts310, and the ground plane 317 located at a PCB. There is a first distance 318between the ground plane and an edge of the side part most distal from theplanar part and a second distance 319 between the extension plane of theplanar area and the extension plane of the ground plane. The first distance inthe example of figure 3a is about 0,5-2 mm and the second distance about 8mm. These distances can however vary depending on the application, buttypically the first distance is within 0,1 - 10 mm and the second distance within 1 - 20 mm.

Figures 3a and 3b show the conductive element made in a metal sheet or theother alternative material and formed as a rectangular box with a planar part 13 309 and planar side parts 310 being approximately perpendicular to theplanar part. The conductive element can however be designed to the desiredshape of at least a part of an external cover of a mobile device. This meanse.g. that the planar parts can be curved in a third dimension and therectangular shape can e.g. be more oval. ln the general case the metal sheetor the other alternative material of the conductive element can have a freeform surface. The surface form is then described using e.g. Non UniformRational B-spline (NURBS).

There can also be more than two ground connection points, as areschematically illustrated in figure 3c showing a perspective view of a radiatingelement 320 with a first 321, a second 322 and a third 323 ground connectionto the ground plane of a Printed Circuit Board (PCB) 324. Each groundconnection is galvanically connected to a corresponding ground connectionpoint at the inner second surface of the conductive element, in this case thepart of the inner second surface belonging to the first radiating element. Theground connection to the radiating elements can also be made non-galvanically through e.g. a ground matching network as explained inassociation with figure 10. A galvanic RF connection 326 is arrangedbetween the RF circuits of the PCB and the feeding element 325. Byintroducing the third ground connection it will be possible e.g. to create awider band width including e.g. also UMTS frequencies around 2,2 GHz inaddition to the coverage of GSM- 900, GSM-1800 and GSM-1900 as shownin the example of figure 3a. ln figure 3c the side parts of the radiatingelement have been left out for clarity reasons. By introducing one or severalground connections to the feeding element it is also possible to affect the impedance matching of the antenna arrangement to the RF-circuits.

The ground connections to the radiating and feeding elements and the RFconnections to the feeding elements can also be connected throughswitching means preferably located at the PCB, 324. The operation of the radiating element can be configured to cover different frequency bands by 14 selecting certain ground connections to be connected or disconnected to theground plane through said switching means. The switching means can comprise e.g. switches realized with Microelectromechanical(MEMS) or Field Effect Transistors (FET) or PIN (P-type lntrinsic and N-type of semiconductor) diodes. systems The connection of the radiating element to the ground plane can also berealized via a ground matching network as will be explained in association with figure 10.

The feeding element with the first side and the second side as shown infigure 3, and also in figure 2, may be manufactured as a stamped metal partshaped to a desired conductive pattern of the feeding element. The feedingelement can be applied to the interior of the mobile device by conventionalmeans such as non-conductive spacers. Other examples of feeding elementswill be described in association with figure 4.

The feeding element can preferably be an H-field antenna such as a helixconnected to ground or a single or multiple loop antenna. Other types offeeding elements are however possible within the scope of the invention aslong as electromagnetic energy is transferred between the feeding elementand the conductive element. Some examples of feeding elements are shownin figure 4. An H-field antenna is defined as an antenna with anelectromagnetic field having a dominating H-field. A typical example of an H-field antenna is a loop antenna. Normally at least one of the feeding elementsis an H-field antenna. Typically at least one of the feeding elements is asingle loop or a double loop antenna.

Figures 4a to 4e schematically show some examples of differentconfigurations of conductive patterns for loop antennas, the loop antennasbeing used as feeding elements. Figure 4f shows a helix antenna with aground connection and figure 4g a capacatively loaded radiating element using a patch antenna as feeding element. All feeding elements describedbelow have a conductive pattern manufactured of a conductive material suchas copper or other metal or metal alloy or other suitable conductive material.The conductive pattern can be shaped as rectangular, circular or triangularloops or as helixes or patches as will be described below. The loops can beof single-, double- or triple-type as will be illustrated. The conductive patternsare applied to a non-conductive substrate such as a rigid or flexible PCB. Thenon-conductive substrate is not shown in figures 4a-4f for clarity reasons. Aflexible PCB is also called a flexfilm. All illustrated examples of loop antennashave an RF pad 402 for connection to the RF circuits and a ground pad 403for connection to the ground plane of the mobile device. The conductivepattern can thus be applied to a first surface of the non-conductive substrate,the second surface of which can be applied to the conductive element forfeeding at least one radiating element from each feeding element. Thefeeding element in the examples in figures 4a - 4f below thus comprises thenon-conductive substrate (although not shown in the figures 4a-4f) with theconductive pattern. The second surface of the non-conductive substrate canalso be applied to an internal non-conductive structure. Alternatively theconductive pattern of the feeding element is applied directly to the internalnon-conductive structure, the internal non-conductive structure in this casefunctioning also as a non-conductive substrate for the feeding element. ln theexamples above, one side of the feeding element, which can be the first orthe second side of the feeding element, thus comprises the first surface ofthe non-conductive substrate with the conductive pattern. The opposite sideof the feeding element comprises the second surface of the non-conductivesubstrate. Choice of type of non-conductive substrate will affect the matchingof the antenna arrangement. The internal non-conductive structure is described in association with figure 7.

Figure 4a shows an example of a single loop antenna 401 with the RF pad402 and the ground pad 403. The location of the RF and ground connectionto the feeding element does not necessarily have to be as shown in the 16 examples in figures 4a to 4g. For matching purposes it can be suitable tomake these connections at other points at the feeding element. RF matchingnetworks and/or ground matching networks, as described in association withfigures 9 and 10, can also be used between the RF pad and the RF circuits and between the ground pad and the ground plane.

Fig 4b shows an example of a double loop antenna 404 with a first loop 405and a second loop 406. The distance d between the loops can vary along the loop as illustrated.

Figure 4c shows an example of a triple loop antenna 407 with a first loop408, a second loop 409 and a third loop 410.

The loop examples shown in figures 4a-4c have a mainly rectangular orquadratic shape. A loop can also have any other shape as exemplified infigure 4d with a triangular loop 411 and in figure 4e with a circular loop 412.Different parts of the loop or loops can have different widths. An example ofthis is shown in figure 4d where the different sides in the triangle havedifferent widths. This is an advantage because different widths can createmore resonances which is a way to increase the band width or create amultiple band antenna. The widest part of the loop can e.g. be responsiblefor a first resonance, the widest and second widest in series for a secondresonance and all widths in series for a third frequency. The first resonancecan e.g. be a ß-wave resonance for a high GSM frequency and the secondand third resonance frequency can e.g. be 1A-wave resonances for lower frequencies.

The conductive pattern of the feeding element can also be a helix 413 wherea short 414 is connected to the ground pad 403. The short can be connectedto the helix at a location along the helix giving a good matching between theRF-circuits and the feeding element according to principles well known to theskilled person. The helix can e.g. be realized as a flat helix on two layers of a 17 non-conductive substrate such as a PCB. The conductive pattern of the helixpattern starts at a first layer of the PCB, runs through a first plated hole to asecond layer, continuous on the second layer, runs through a second platedhole to the first layer, continuous on the first layer, runs through a third platedhole to the second layer, continuous on the second layer, .....and so on. Thefeeding element in this case comprises the PCB with the conductive helixpattern. ln this particular case the gap distance is the distance from theradiating element to the conductive pattern in the layer being closest to the radiating element.

Figure 4g shows a further example of a feeding element with a conductivepattern shaped as a patch 415 connected to the RF circuits via the RFconnection 416. The radiating element 417 is connected via a groundconnection 418 to the ground plane of the mobile device. The ground plane islocated at a PCB 419, holding also the RF circuits. With this feedingarrangement RF energy is transferred between the feeding element and theconductive element through a capacitive coupling via a gap 420 between theconductive pattern and the radiating element. Gap distances are discussed inassociation with figure 6. ln this example the feeding element is ungrounded.Other ungrounded feeding elements such as helixes or monopoles are alsopossible within the scope of the invention. ln this example the feedingelement with its two sides is a patch-shaped metal sheet. The conductive pattern is thus patch shaped. ln order to broaden the bandwidth of the antenna arrangement the feeding element can also comprise a parasitic element.

Figure 5 is a perspective view of one example of the invention showing aconductive element 500 from the outside of a mobile device. The conductiveelement is in this example an external cover of a mobile phone divided inthree radiating elements, a first radiating element 501, a second radiatingelement 502 and a third radiating element 503. The three radiating elements 18 are physically separated from each other by isolation means, in this examplecomprising a first slit 504 and a second slit 505. The conductive element, andthus also the radiating elements, are manufactured of a well conductive metalsuch as aluminium, copper, silver, titan, gold or suitable metal alloys (likestainless steel) or other alternative material like plastics plated with a wellconductive metal surface using e.g. Vacuum Metallization (VM) or PhysicalVapour Deposition (PVD). A further alternative material for manufacturing theconductive element can be metals like iron, zinc and magnesium beingplated with a well conductive metal as aluminium, copper, silver, titan, gold orsuitable metal alloys using VM or PVD. The isolation means in this exampletwo slits are filled with a non-conductive material such as e.g. plastics of typeABS (Acrylonitrile Butadiene Styrene), PC (Polycarbonate) or PA(Polyamide) or plastic compounds or glass fibre reinforced plastics. This non-conductive material can be the same material as used for the internal non-conductive structure as will be discussed in association with figure 7. ln theexample of figure 5 the external cover also includes an opening 506 to beused for a camera lens and in this case the number of slits is one less thanthe number of radiating elements. The plastic materials mentioned above andother non-conductive materials are also dielectric materials, as is well knownto the skilled person. The internal non-conductive structure and the non-conductive substrate, manufactured of non-conductive materials, can thusalso be said to be manufactured of dielectric materials. The dielectric materialchosen for the internal non-conductive structure and the non-conductivesubstrate shall have good, low loss, RF-properties, as is well known to the skilled person.

The non-conductive substrate is typically a non-conductive material as knownin the art, used for manufacturing of Printed Circuit Boards and flexfilms orany suitable non-conductive material, e.g. plastics mentioned above for useas slit filling. 19 ln one example of the invention the conductive element of the housingelement comprises three radiating elements. The first radiating element 501is in this example dedicated to the frequencies of GSM bands GSM-850,GSM-900, GSM-1800 and GSM-1900 (operating from about 850 to 1900MHz) as well as the UMTS band (1920 - 2170 MHz). The second radiatingelement 502 is dedicated for FM-radio frequencies (operating at 30-300MHz). The third radiating element 503 is dedicated to WLAN frequencies(e.g. 2,4 or 5 GHz band). The second radiating element is located between the first and the third radiating elements.

Figure 6 shows a part of a housing element 600 with the part of theconductive element shown in figure 5 comprising the first radiating element601. The first radiating element has a outer first surface 602 and a innersecond surface 603. The outer first surface of the conductive element in thisexample is an outer surface of a part of an external cover to the mobiledevice. The inner second surface is facing one side of the feeding elementand is an interior surface of a part of the external cover. A feeding element604, in this case a double loop antenna, is applied to the inner secondsurface 603 of the mobile device. The conductive pattern of the feedingelement comprises a double loop with a first loop 606 and a second loop 607.The conductive pattern of the loops are of conductive material, such ascopper, and can e.g. be printed or plated to a first surface of a flexible or rigidnon-conductive substrate 605 such as a flexfilm or PCB. A second surface ofthe non-conductive substrate is then applied to the first radiating element byany conventional means such as gluing. The feeding element thus comprisesthe conductive pattern and the non-conductive substrate. The gap betweenthe conductive pattern of the feeding element and the radiating element is inthis example equal to the thickness of the non-conductive substrate. The first radiating element has an opening 610 for e.g. a camera lens. ln the example of figure 6 the feeding between the feeding element and theradiating element is arranged with a non-galvanic coupling. This means that the RF energy fed to the feeding element from the RF circuits iselectromagnetically coupled to the radiating element. This is accomplished bylocating the feeding element in the vicinity of the radiating element. The gapdistance between the conductive pattern of the feeding element and theradiating element is normally within 0,1-7 mm, preferably within 0,1-5 mm butmost preferably within 0,1-3 mm. The gap distance can be used as aparameter for matching of the radiating element to a certain frequency band.

The feeding between the RF-circuits of the mobile device and the feedingelement is preferably arranged with a galvanic coupling. This can bearranged by any conventional means such as a spring contact or pogo pinplaced on the PCB of the mobile device and contacting RF pad 608 andground pad 609 on the loop antenna. The feeding between the RF-circuits ofthe mobile device and the feeding element can also be arranged with a non-galvanic coupling, e.g. through a capacitance arranged between the RF-circuits and the feeding element. The feeding between the RF-circuits of themobile device and said feeding element/s can thus be arranged with at leastone galvanic and/or at least one non-galvanic coupling. There is at least oneRF connection to each feeding element.

The feeding between the RF-circuits and the feeding element can also bearranged via an RF matching network to further improve the number ofmatching possibilities. An example of such a matching possibility is shown infigure 9. ln the example of figure 6 the loop antenna is conveniently arranged aroundthe opening 610. This is not a necessary requirement but the feedingelement just has to be in the vicinity of the radiating element as described above.

The radiating element is normally arranged to be connected, galvanically ornon-galvanically, to the ground plane of the mobile device at, at least, one 21 point. This is schematically illustrated with the ground connection point 611.ln certain realizations of the invention the radiating element can beunconnected to the ground plane. This can be advantageous, but notnecessary, for radiating elements operating at higher frequencies such as e.g. WLAN frequencies.

Figure 7 is an exploded perspective view of one example of how to assemblethe conductive element comprising the first 701, the second 702 and the third703 radiating element. The three radiating elements are applied to theinternal non-conductive structure 704. This can be accomplished by adhesivemoulding or insert moulding as will be further explained in association withfigure 11, describing one example of a manufacturing method of the housingelement. The non-conductive material used in the moulding process will thenfill up the slits between the radiating elements such that the filling will becomeflush with the outer first surface of the conductive element. Figure 7 alsoshows an internal slit 705 which can be used in any of the radiating elementsto facilitate the possibility to cover two or more frequency bands or forbroadening the bandwidth of a certain frequency band. For tuning purposesthe edges of the internal slit can be straight, curved or even meandered. Thewidth of the internal slit can also vary along the slit. The internal slit is not an isolation means.

Figure 8 shows an example of an assembled housing element comprising thefirst, second and third radiating elements, 801-803, with a first and second slit804-805. The housing element in this example also comprises the internalnon-conductive structure and the feeding element/s. The internal non-conductive structure 806 is moulded to the radiating elements. The materialof the internal non-conductive structure fills the slits and the filled slitfunctions as the isolation means between the radiating elements. Thenumber of slits is one less than the number of radiating elements in theexamples of the invention when the slit is physically separating one radiating 22 element from another. This is not valid in the case a slit is also made internally within a radiating element as shown in figure 7.

The housing element 800 of figure 8 for a mobile device comprises anantenna arrangement according to any one of claims 1-17 and the internalnon-conductive structure 704, 806 wherein the outer first surface of theconductive element is an outer surface of at least a part of an external coverto the mobile device and the inner second surface of the conductive elementis facing one side of the feeding element/s. The internal non-conductivestructure is in this example located between the conductive element and thefeeding element/s. The conductive element and the internal non-conductivestructure are integrated into one unit. ln this example the feeding element/sis/are also attached to the internal non-conductive structure. This is howevernot necessary as will be explained. Figure 8 also shows a first feedingelement 807 comprising a double loop antenna as described in associationwith figure 6. This double loop antenna is used to excite the first radiating element 801 through a non-galvanic coupling.

A second feeding element 808 realized as a single loop antenna is feedingthe third radiating element 803 non-galvanically. The feeding elementsrealized as e.g. a conductive pattern on a non-conductive substrate or aconductive pattern of stamped metal can be applied to the internal non-conductive structure through any conventional means such as gluing or theycan be applied during a moulding process. The feeding element/s is/are thusintegrated with the internal non-conductive structure and the internal non-conductive structure is attached to the conductive element thus forming aone-piece housing element. Each radiating element normally has at least oneground connection arranging contact between the ground plane of the mobiledevice and the radiating element (not shown in figure 8). ln certainapplications, as described in association with figure 6, the ground connectionfor the radiating element is not necessary. The first radiating element can bematched for use in the GSM frequency bands and the third radiating element 23 can be matched for use in WLAN applications or as a GPS antenna. Thesecond radiating element can e.g. be used for FM (Frequency Modulation)radio. A feeding element for FM radio is not shown in figure 8. A suitablefeeding element for a radiating element covering FM frequencies can be aloop antenna with an RF and/or a ground matching network. An extensioncoil can be used in series with the loop, between the RF pad of the loop andthe RF circuits, to decrease the dimensions of the loop. By a combination ofthe sizes for the loop antenna and the radiating element, the configuration ofthe matching network and choice of extension coil a resonance frequency inthe FM band can be achieved.

The conductive element of the housing element can be at least a part of an external cover to a mobile device, e.g. the back cover of a mobile phone.

Figure 9 schematically shows an example of the RF matching networkmentioned above. The feeding element 901, is illustrated with a loop antennawith the ground pad 914 and the RF pad 915, connected from the groundpad 914 to the ground plane 902 of the mobile device. The RF pad 915 ofthe loop antenna is connected to a first terminal 910 of an RF generator 907through a first connection point 903, a first capacitor 904, a secondconnection point 905 and a first inductor 906. The second terminal 911 of theRF generator is connected to ground 902 through a third connection point908 and a fourth connection point 909. A second capacitor 912 is connectedbetween the second and third connection points and a second inductor 913 isconnected between the first and fourth connection points. The matchingnetwork in this example comprises the first and second capacitor and the firstand second inductor. The matching components can be located at a PCB ofthe mobile device holding also the RF circuits. Alternatively the matchingcomponents can be located at the non-conductive substrate, such as aflexfilm, holding the feeding element. The RF generator is part of the RFcircuits of the mobile device. The matching between the RF circuits and the antenna arrangement can now be tuned by varying the component values of 24 the matching components. Typical values in the frequency bands GSM-900and GSM-1800/1900 for the first and second capacitor can be around 1-100pF and for the first and second inductor around 1-100 nH, but also valuesbelow 1 pF and 1 nH are possible. This is just one example of a configurationfor a ground matching network. The matching network can comprise more orless components than shown in this example. ln its simplest form it can e.g.comprise just one capacitor or one inductor. ln more complicatedconfiguration active components like switching means can also be used. Theconfiguration and dimensioning principles of the matching components toachieve matching at different frequencies are well known to the skilled person and therefore not further discussed here.

Figure 10 schematically shows an example of a ground matching networkwhere the feeding element 1001 or the radiating element (not shown in figure10) is connected to the ground plane 1002 of the mobile device via twoparallel connection paths. The feeding element 1001 is illustrated with a loopantenna with the ground pad 1010 and the RF pad 1011. The two parallelconnection paths start at the ground pad 1010 and ends at the ground plane1002. The RF pad is connected to the RF circuits. The first connection pathcomprises a third capacitor 1003 and the second connection path comprisesa third 1004 and fourth 1005 inductor in series. This ground matchingnetwork adds a further possibility to match the antenna arrangement to thedesired frequency band or bands. Typical values in the frequency bandsGSM-900 and GSM-1800/1900 for the third capacitor can be around 1-100pF and for the third and fourth inductor around 1-100 nH, but also valuesbelow 1 pF and 1 nH are possible. This is just one example of a configurationfor a ground matching network. The matching network can comprise more orless components than shown in this example. ln its simplest form it can e.g.comprise just one capacitor or one inductor. ln more complicatedconfiguration active components like switching means can also be used. Theconfiguration and dimensioning principles of the matching components to achieve matching at different frequencies are well known to the skilledperson and therefore not further discussed here.

The matching or tuning of the radiating elements of the antenna arrangementto a certain frequency band can be made by adjusting one or several of following parameters: 0 size of radiating element 0 size and type of feeding element 0 positioning of the feeding element in relation to the radiating element 0 location and number of ground connection points at the radiatingelement 0 location of RF pad and ground pad of the feeding element 0 location and number of RF-connections to the feeding element 0 width and shape of the slits between radiating elements 0 the gap distance between the feeding element and the radiatingelement 0 dimensioning of the RF matching network 0 dimensioning of the ground matching network 0 choice of dielectric material or dielectric medium in the gaps and slits(also internal ones) and choice of dielectric material for the internal non-conductive structure and the non-conductive substrate.

These tuning parameters are examples of tuning parameters that can beused to create e.g. 1A-wave, %-wave or full wave resonances. Other types ofresonances, well known to the skilled person, are also possible within thescope of the invention. The term resonance frequency for an antenna is alsowell known to the skilled person and therefore not further discussed here. A1A -wave resonance is preferably used at low frequencies as GSM-850 andGSM-900 as this will require a radiating element with smaller dimensions than when using e.g. ß-wave or full wave resonances. The dimensions of the 26 radiating elements are roughly proportional to the wavelength at theresonating frequency divided by 4, 2 or 1 for 1A-wave, ß-wave and full waveresonances respectively. However it is the combination of tuning parametersmentioned above and in the description that decides the resonancefrequency/ies of the antenna arrangement. This means that the radiatingelement itself does not necessarily have to have a dimension of 1A-wave, a%-wave or a full wave of the resonance frequency/ies.

Figure 11 is a block diagram showing one example of a manufacturingmethod of the housing element. ln a forming step 1101 the conductingelement is formed in a deep drawn sheet metal process. Also other processcan be used such as stamping or hydro forming of sheet metal. When theconductive element is manufactured using other alternative material with ametal plating realized with VM or PVD, the forming of the conductive elementcan be made in a conventional moulding process. The conductive element isat least a part of an external cover of the mobile device. The conductiveelement is henceforth exemplified with a back cover to a mobile phone. ln theforming step, the metal back cover will obtain its free form outer surfaceaccording to the chosen industrial design. The conductive element is thus afree form sheet of metal or the other type of the alternative material as mentioned above. ln a cutting step 1102 the back cover is cut into 2 or more radiating elementsby one or more slits physically separating the back cover into the radiatingelements. Holding means are attached to the radiating elements to hold theback cover together in one unit during moulding. The holding means can bepoint welded metal strips across the slits at each side of each slit, holding theradiating parts together in one piece. The holding means extend outside theouter outline of the back cover in order not to disturb the subsequentmoulding step. As variations in the slit width can cause variations in tuning,the holding means are preferred in order to keep the variations in slit width low during the manufacturing process. The cutting step also includes cutting 27 of e.g. holes for cameras and/or speaker openings. The cutting step can alsoinclude cutting of internal slits. The cutting can be performed with water jetcutting or alternative methods as laser cutting or stamping and bending.Variations in the width and shape of the slit will affect the tuning of theradiating elements. The width can e.g. vary along the slit; the edges of the slitcan be straight, curved or even meandered. This tuning feature canpreferably be used during development and early test run phases for final matching of the antenna arrangement. ln a moulding step 1103 the internal non-conductive structure is formed andthe radiating elements of the conductive element are applied to the internalnon-conductive structure. This can be accomplished with adhesion mouldingor insert moulding which are well known moulding processes to the skilledperson. ln the moulding process the slits are filled with the resin used in themoulding process. The resin forms the internal non-conductive structure andfills the slits such that the slit filling becomes flush with the outer first surfaceof the conductive element. Typical resins are non-conductive materials suchas plastics like e.g. ABS, PC, PA and other polymers used for handhelddevices and compounds of different polymers and also glass fiber reinforcedpolymers (well known to the skilled person). The slit filling can also beapplied in a separate step using any type of suitable non-conductive materialor the slit can be left open, i.e. without any filling in the slit but with theinternal non-conductive structure under the slit sealing the interior of themobile device from the outside of the mobile device. This separate filling stepcan e.g. be used when there is a desire to use the slit for decorativepurposes. For decorative or other purposes the slit filling can also extendoutside the outer first surface of the conductive element, i.e. the slit fillingdoes not necessarily have to be flush with the outer first surface of theconductive element. Internal slits can be with or without filling in the sameway as described for slits above. 28 The internal non-conductive structure is preferably also arranged to includeholding features like screw towers, battery holding features, bumpers andribs for improving the rigidity of the housing element. The feeding elementcan also be applied to the internal non-conductive structure in the insertmoulding process. lf adhesive moulding or insert moulding is used thefeeding element can be applied during moulding process, which is also aprocess well known to the skilled person. The feeding element can also beapplied as a separate production step later in the manufacturing process,using any conventional means, such as gluing or Pressure SensitiveAdhesive Process (PSA).

The internal non-conductive structure can also be manufactured as aseparate component using a conventional plastic tool. ln a separate step theradiating elements are then assembled to the internal non-conductivestructure by conventional means such as glue, adhesive or ultrasonicwelding. An example of an internal non-conductive structure is shown infigure 7. ln this example the internal non-conductive structure is covering amain part of the inner second surface of the conductive element except forholes for e.g. camera lenses or minor holes e.g. for allowing contact betweenground connection points at the inner second surface of the conductiveelement and the ground plane of the mobile device. ln other examples theinternal non-conductive structure can have more holes and cover a smallerpart of the inner second surface of the conductive element. ln one examplethe internal non-conductive structure can comprise a plastic frame along theside parts of the conductive element and a structure to fit into the slitsbetween the radiating elements. The radiating elements are applied to theplastic frame type of internal non-conductive structure. When the internalnon-conductive structure is of plastic frame type a large part of the innersecond surface of the conductive element will not be covered by the internalnon-conductive structure. The conductive pattern of the feeding element canthen e.g. be applied to the first surface of the non-conductive substrate suchas a flexfilm, the second surface of which is applied by an adhesive to the 29 inner second surface of the conductive element, in this case a part of theback cover of a mobile phone. The gap between the conductive pattern of thefeeding element and the conductive element is in this example equal to thethickness of the flexfilm. When the internal non-conductive structure is of theplastic frame type the feeding element can be applied to the inner secondsurface of the conductive element via the non-conductive substrate or someother non-conductive element. An example of this frame-type of internal non-conductive structure is described in association with figures 12 and 13. ln a removal step 1104 the holding means are removed to disconnect any galvanic contact between the radiating elements.

Holes in the internal non-conductive structure have been arranged during themoulding process in order to be able to contact suitable ground connectionpoints at the radiating elements intended for connection to the ground planeof the mobile device, in the examples of the invention when the radiatingelement is connected to ground. ln these examples at least one groundconnection point at the inner second surface of at least one of the radiatingelements is/are arranged to be connected in a contacting step 1105 to theground plane of the mobile device. The area around these groundconnection points at the inner second surface of the conductive element, inthis case the back cover, can, in a separate process, be plated with e.g. goldin order to improve contacting to the ground plane. ln the contacting step1105 contact springs are laser or point welded to the ground connectionpoints. Holes in the internal non-conductive structure can also be arrangedfor other purposes such as for attaching metal snaps to the inside of the back COVGI”.

Paint, such as clear lacquer or coloured clear lacquer is applied to the outerfirst surface 315 of the back cover in a surface treatment step 1106. ln a marking process, using e.g. printing or laser marking, a logotype, name, camera type/size can be applied to the outer first surface of the back cover.This surface treatment step can also be used to concea| the slits. ln a final testing step 1107 the antenna arrangement, now integrated in thehousing element, is tested to check that the performance of the antenna overthe bandwidth is according to specification. The testing is performed byintroducing the housing element into a test arrangement. An advantage withthis procedure is that the antenna performance is checked when the antennais integrated in the housing element, thus avoiding mismatches caused by anantenna cover being assembled to an antenna arrangement after testing of the antenna.

The above described manufacturing process is just one example of apossible manufacturing process for a housing element and the productionsteps do not necessarily have to be performed in the order described above. ln an alternative realization of the invention, the feeding element is notintegrated to the housing element but is located separated from the housingelement e.g. on a PCB of the mobile device. The gap between the conductivepattern of the feeding element and the conductive element will then typicallybe filled with air or a combination of air and a non-conductive material suchas the internal non-conductive structure. ln the manufacturing process described above all radiating elements areapplied to the internal non-conductive structure in the moulding step 1103. lnan alternative process, one or several of the radiating elements are applied tothe internal non-conductive structure in a separate process. ln this processthe radiating elements can be applied permanently by conventional meanssuch as gluing or the radiating elements are applied by conventionalarrangements such as snapping means to allow the radiating elements to beremoved by the user. This can be advantageous if one of the radiating elements e.g. is used also as a battery hatch. 31 Figure 12 is an exploded perspective view of one example of a housingelement 1200 with the frame type of internal non-conductive structure 1204and the first 1201, second 1202 and third 1203 radiating elements. The firstradiating element has a first hole 1207 which can be used as an opening fora camera lens. The feeding element with its first and second sides comprisesin this example a flexfilm 1206 having a first surface and a second surfaceand the conductive pattern 1205 plated to the first surface of the flexfilm1206. ln this example the non-conductive substrate thus is a flexfilm. Theconductive pattern is in this example a double loop. The feeding element islocated in a first recess 1210 at a surface of the frame type of internal non-conductive structure 1204 facing the interior of the mobile device, this surfacebeing defined as the interior frame side. The second surface of the ﬂexfilm isin the example of figure 12 applied at the interior frame side around a secondhole 1208 in the frame type of internal non-conductive structure. The ﬂexfilmhas a third hole 1215. The second and third holes have substantially thesame size and shape as the first hole. The double loop is thus locatedaround the second hole 1208 and the third hole 1215 in the same mannerillustrated in figure 6. When the first radiating element and the feedingelement is assembled to the frame type of internal non-conductive structurethe first hole 1207, the second hole 1208 and the third hole 1215 are aligned.The feeding element can either be applied to the frame type of the internalnon-conductive structure in a separate process or during the moulding step1103. ln an alternative realization of the invention (not shown in figure 12) thefirst surface of the flexfilm with the conductive pattern can be applied to thefirst recess 1210.

Alternatively the second surface of the flexfilm can be applied via anadhesive layer or glue directly to the inner second surface of the firstradiating element 1201 around the first hole 1207. 32 The frame type of internal non-conductive structure 1204 has a large thirdhole 1209. The second radiating element 1202 is applied to the surface of theframe type of internal non-conductive structure facing the exterior of themobile device, this surface being defined as the exterior frame side, and iscovering the third hole 1209. This solution can be advantageous when thesecond radiating element is used as a detachable hatch covering e.g. abattery. The second radiating element is attached to the frame type ofinternal non-conductive structure in a separate process by e.g. snappingmeans. The feeding element for the second radiator can in this example beapplied directly to the radiating element as described in association withfigure 6.

The third radiating element 1203 can be applied to the frame type of internalnon-conductive structure in the moulding step 1103 as described earlier. Asecond recess 1211 at the interior frame side is intended for location of afeeding element for the third radiating element. The second recess 1211 canbe replaced with a hole with the same or larger dimensions as the recess andthe feeding element can then be applied directly at the inner second surfaceof the third radiating element as described in association with figure 6.

Figure 12 also shows a first rib 1212 and a second rib 1213 making the frametype of internal non-conductive structure more rigid. Screw towers 1214 arealso integrated into the frame type of internal non-conductive structure. Thescrew towers can be used to fasten e.g. a PCB.

Figure 13 shows a frame type of internal non-conductive structure 1300 withthe second 1208 and the third 1209 holes as seen from the exterior of themobile device. First 1301 and second 1302 slit ribs are integrated into theexterior frame side. The first slit rib is filling the slit between the first andsecond radiating element and the second slit rib is filling the slit between thesecond and third radiating element when the radiating elements are appliedto the frame type of internal non-conductive structure. ln the example of 33 figure 13 the isolation means thus comprises the slit filled with the slit rib.Small holes 1303-1305 in the frame type of the internal non-conductivestructure can be used to allow ground connections between the ground planeand the ground connection points at the radiating elements.

As mentioned above the manufacturing method described is just oneexample of how the housing element can be accomplished. A commonfeature for manufacturing of the housing element for the mobile deviceaccording to any one of the claims 18-21 of the invention is that the radiatingelements are applied 1103 to the internal non-conductive structure. ln one example of the method at least one ground connection point at theinner second surface of at least one of the radiating elements is/are arrangedto be connected in a contacting step 1105 to the ground plane of the mobile device. ln one example of the method the internal non-conductive structure is fillingthe gaps between the radiating elements. ln one example of the method said feeding element is applied to the internalnon-conductive structure for feeding at least one radiating element from eachfeeding element. ln one example of the method said feeding element is applied to a firstsurface of a non-conductive substrate, the second surface of which is appliedto the conductive element for feeding at least one radiating element fromeach feeding element. ln one example of the method the outer first surface of the conductiveelement is an outer surface of at least a part of an external cover to themobile device and the inner second surface is facing one side of said feeding 34 element, the conductive element, the internal non-conductive structure and said feeding element being integrated into one unit. ln one example of the method said radiating elements are applied to the internal non-conductive structure in a moulding process. ln one example of the method said radiating elements are attached to eachother during the moulding step 1103 by holding means located across theslits at each side of each slit, holding the radiating elements together in a onepiece conductive element. ln one example of the method the holding means are removed in a removalstep 1104 to disconnect any galvanic contact between the radiating elements. ln one example of the method the internal non-conductive structure ismanufactured as a separate component and said radiating elements areassembled to the internal non-conductive structure. ln a further embodiment of the antenna arrangement for the mobile device itis possible that the conductive element comprises just one radiating element.ln this case there is no need for an isolation means. An internal slit in theradiating element as described in association with figure 7 is howeverpossible. This also means that the manufacturing method as described infigure 11 can be simplified. The cutting step 1102 does not have to includeholding means and cutting of slits and the removal step 1104 can be deleted.ln this embodiment the mobile device comprises radio frequency circuits anda ground plane. The antenna arrangement comprises a conductive elementand at least one feeding element, said feeding element comprise aconductive pattern being arranged to be connected to the radio frequencycircuits wherein the conductive element is a sheet having an outer first surface and an inner second surface. The conductive element comprises one radiating element. The radiating element is arranged to be fed through saidfeeding element and said feeding element having an extension plane withone side of said feeding element facing the inner second surface of theconductive element with a gap between the conductive element and the conductive pattern of said feeding element.

The invention is not limited solely to the examples described above, but insteadmany variations are possible within the scope of the inventive concept definedby the appended claims. Within the scope of the inventive concept theattributes of different examples and applications can be used in conjunctionwith or replace the attributes of another example or application.

Claims

1. An antenna arrangement for a mobile device (101), said mobile devicecomprising radio frequency circuits (109) and a ground plane (317), theantenna arrangement (111) comprising a conductive element (300, 500) andat least one feeding element (203, 306, 325, 401, 404, 407, 415, 604, 807,808), said feeding element comprising a conductive pattern being arrangedto be connected to the radio frequency circuits, c h a r a c t e r i z e d in thatthe conductive element (300, 500) is a sheet having an outer first surface(315) and an inner second surface (316), the conductive element comprisingat least two radiating elements (201, 301, 302, 320, 417, 501-503, 601, 701-703, 801-803, 1201-1203), the radiating elements being arranged to be fedthrough said feeding element, said radiating elements being physicallyseparated from each other by isolation means (303, 504, 505, 804, 805) andsaid feeding element having an extension plane with one side of said feedingelement facing the inner second surface (316) of the conductive element witha gap (207, 420) between the conductive element and the conductive pattern of said feeding element.

2. An antenna arrangement according to claim 1, c h a r a c t e r i z e d in that the conductive element (300, 500) is a free form surface.

3. An antenna arrangement according to claim 1 or 2, c h a r a c t e r i z e din that the conductive element (300, 500) is made of a well conductive metal.

4. An antenna arrangement according to claim 3, c h a r a c t e r i z e d in thatthe metal is aluminium, copper, silver, titan, gold or suitable metal alloys.

5. An antenna arrangement according to claim 1 or 2, c h a r a c t e r i z e din that the conductive element (300, 500) comprises plastics plated with awell conductive metal surface using Vacuum Metallization, VM, or PhysicalVapour Deposition, PVD, or the conductive element comprises iron, zinc and 37 magnesium being plated with a well conductive metal as aluminium, copper, silver, titan, gold or suitable metal alloys using VM or PVD.

6. An antenna arrangement according to any one of the preceding claims,c h a r a c t e r i z e d in that the conductive element (300, 500) being at leasta part of an external cover of the mobile device (101), the outer first surface(315) of the conductive element being an outer surface of said external COVGI”.

7. An antenna arrangement according to any one of the preceding claims,c h a r a cte r i z e d in that the gap (207, 420) is filled with air or a non- conductive material.

8. An antenna arrangement according to any one of the preceding claims,c h a r a cte r i z e d in that each radiating element is arranged to begalvanically or non-galvanically connected to the ground plane of the mobile device at, at least, one point.

9. An antenna arrangement according to any one of the preceding claims,c h a r a c t e r i z e d in that one feeding element (203, 306, 325, 401, 404,407, 415, 604, 807, 808) is arranged to feed one radiating element (201, 301,302, 320, 417, 501-503, 601, 701-703, 801-803, 1201-1203).

10. An antenna arrangement according to any one of claims 1-8,c h a r a c t e r i z e d in that one feeding element (203, 306, 325, 401, 404,407, 415, 604, 807, 808) is arranged to feed at least two radiating element(201, 301, 302, 320, 417, 501-503, 601, 701-703, 801-803, 1201-1203).

11. An antenna arrangement according to any one of the preceding claims,c h a r a cte r i z e d in that the isolation means (303, 504, 505, 804, 805)comprises a slit or a slit filled with a non-conductive material. 38

12. An antenna arrangement according to claim 11, c h a r a c t e r i z e d inthat the non-conductive material is piastics as ABS, PC, PA or piastic compounds or glass fibre reinforced piastics.

13. An antenna arrangement according to any one of the preceding claims,c h a r a c t e r i z e d in that at least one of the feeding elements (203, 306,325, 401, 404, 407, 415, 604, 807, 808) is an H-field antenna (401, 404,407).

14. An antenna arrangement according to claim 13, c h a r a c t e r i z e d inthat at least one of the feeding elements (203, 306, 325, 401, 404, 407, 415,604, 807, 808) is a single loop (401) or a double loop (404) antenna.

15. An antenna arrangement according to any one of the preceding claims,c h a r a c t e r i z e d in that at least one of the feeding elements (203, 306,325, 401, 404, 407, 415, 604, 807, 808) is/are arranged to be connected tothe ground plane (317) of the mobile device (101 ).

16. An antenna arrangement according to any one of the preceding claims,c h a r a cte r i z e d in that the feeding between said feeding element/s(203, 306, 325, 401, 404, 407, 415, 604, 807, 808) and said radiatingelement/s (201, 301, 302, 320, 417, 501-503, 601, 701-703, 801-803, 1201- 1203) is arranged with a non-galvanic coupling.

17. An antenna arrangement according to any one of the preceding claims,c h a r a c t e r i z e d in that the feeding between the RF-circuits (109) of themobile device (101) and said feeding element/s (203, 306, 325, 401, 404,407, 415, 604, 807, 808) is arranged with at least one galvanic and/or at leastone non-galvanic coupling and in that there is at least one RF connection(204, 326, 416) to each feeding element. 39

18. A housing element (600, 800) for a mobile device, c h a r a c t e r i z e dby comprising the antenna arrangement (111) according to any one of claims1-17 and an internal non-conductive structure (704, 806, 1204, 1300)wherein the outer first surface (315) of the conductive element (300, 500) isan outer surface of at least a part of an external cover to the mobile device(101) and the inner second surface (316) of the conductive element is facingone side of said feeding element (203, 306, 325, 401, 404, 407, 415, 604,807, 808), the conductive element and the internal non-conductive structure being integrated into one unit.

19. A housing element according to claim 18, c h a ra cte r i z e d in thatsaid feeding element/s (203, 306, 325, 401, 404, 407, 415, 604, 807, 808)is/are integrated with the internal non-conductive structure (704, 806, 1204,1300), the internal non-conductive structure being attached to the conductive element thus forming a one-piece housing element (600, 800).

20. A housing element according to claim 18 or 19, c h a r a c t e r i z e d inthat the conductive element (300, 500) is a back cover of a mobile phone.

21. A housing element according to any one of the preceding claims 18-20,c h a r a c t e r i z e d in that the conductive element (300, 500) comprisesthree radiating elements (201, 301, 302, 320, 417, 501-503, 601, 701-703,801-803, 1201-1203), a first radiating element (501, 701, 801, 1201) beingdedicated to GSM and UMTS frequencies, a second radiating element (502,702, 802, 1202) being dedicated for FM-radio frequencies and a thirdradiating element (503, 703, 803, 1203) being dedicated to WLANfrequencies, the second radiating element being located between the firstand the third radiating elements.

22. A method to manufacture a housing element for a mobile device (101),according to any one of claims 18-21 wherein the radiating elements areapplied (1103) to the internal non-conductive structure.

23. A method according to claim 22, c h a r a c t e r i z e d in that at least oneground connection point at the inner second surface of at least one of theradiating elements is/are arranged to be connected in a contacting step (1105) to the ground plane of the mobile device.

24. A method according to claim 22 or 23, c h a r a c t e r i z e d in that theinternal non-conductive structure is filling the gaps between the radiating elements.

25. A method according to any one of claims 22 - 24, c h a r a c t e r i z e d inthat said feeding element (203, 306, 325, 401, 404, 407, 415, 604, 807, 808)is applied to the internal non-conductive structure (704, 806, 1204, 1300) forfeeding at least one radiating element (201, 301, 302, 320, 417, 501-503,601, 701-703, 801-803, 1201-1203) from each feeding element.

26. A method according to any one of claims 22 - 24, c h a r a c t e r i z e din that said feeding element (203, 306, 325, 401, 404, 407, 415, 604, 807,808) is applied to a first surface of a non-conductive substrate, the secondsurface of which is applied to the conductive element (300, 500) for feedingat least one radiating element(201, 301, 302, 320, 417, 501-503, 601, 701-703, 801-803, 1201-1203) from each feeding element.

27. A method according to any one of claims 22-26, c h a r a c t e r i z e d inthat the outer first surface (315) of the conductive element (300, 500) is anouter surface of at least a part of an external cover to the mobile device (101)and the inner second surface (316) is facing one side of said feeding element(203, 306, 325, 401, 404, 407, 415, 604, 807, 808), the conductive element,the internal non-conductive structure and said feeding element being integrated into one unit. 41

28. A method according to any one of claims 22-27, c h a r a c t e r i z e d inthat said radiating elements (201, 301, 302, 320, 417, 501-503, 601, 701-703, 801-803, 1201-1203) are applied to the internal non-conductivestructure (704, 806, 1204, 1300) in a moulding process.

29. A method according to claim 28, c h a r a c t e r i z e d in that saidradiating elements (201, 301, 302, 320, 417, 501-503, 601, 701-703, 801-803, 1201-1203) are attached to each other during the moulding step (1103)by holding means located across the slits at each side of each slit, holdingthe radiating elements together in a one piece conductive element.

30. A method according to claim 29, c h a r a c t e r i z e d in that the holdingmeans are removed in a removal step (1104) to disconnect any galvaniccontact between the radiating elements (201, 301, 302, 320, 417, 501-503,601, 701-703, 801-803, 1201-1203).

31. A method according to any one of claims 22-27, c h a r a c t e r i z e d inthat the internal non-conductive structure (704, 806, 1204, 1300) ismanufactured as a separate component and said radiating elements areassembled to the internal non-conductive structure.

32. A mobile device (101) comprising the antenna arrangement (111)according to any one of claims 1-17.

33. An antenna arrangement for a mobile device (101), said mobile devicecomprising radio frequency circuits (109) and a ground plane (317), theantenna arrangement (111) comprising a conductive element (300, 500) andat least one feeding element (203, 306, 325, 401, 404, 407, 415, 604, 807,808), said feeding element comprising a conductive pattern being arrangedto be connected to the radio frequency circuits, c h a r a c t e r i z e d in thatthe conductive element (300, 500) is a sheet having an outer first surface(315) and an inner second surface (316), the conductive element comprising 42 one radiating element (201, 301, 302, 320, 417, 501-503, 601, 701-703, 801-803, 1201-1203), the radiating element being arranged to be fed through saidfeeding element and said feeding element having an extension plane withone side of the feeding element facing the inner second surface (316) of theconductive element with a gap (207, 420) between the conductive elementand the conductive pattern of said feeding element.