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Title:
HYBRID CLOSED SLOT LTE ANTENNA
Document Type and Number:
WIPO Patent Application WO/2019/086866
Kind Code:
A1
Abstract:
There is disclosed an antenna module for a portable electronic device.The antenna module comprises a substantially planar dielectric substrate having first and second opposed surfaces, and first and second opposed edges. A feed arm comprising a conductive track is disposed on the substrate, the feed arm having a first part extending from the first edge of the substrate towards the second edge of the substrate, and a second part extending substantially laterally from the first part. At least first and second radiating elements are also provided, each radiating element comprising a conductive track disposed on the substrate, each radiating element having a first part extending from the second edge of the substrate towards the first edge, and a second part extending substantially laterally from the first part.Ends of the first parts of the at least first and second radiating elements at the second edge of the substrate are configured for connection to a ground plane.

Inventors:
HU SAMPSON (GB)
LIU QING (GB)
CHEN JIECHEN (GB)
Application Number:
PCT/GB2018/053151
Publication Date:
May 09, 2019
Filing Date:
October 31, 2018
Export Citation:
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Assignee:
SMART ANTENNA TECH LTD (GB)
International Classes:
H01Q1/22; H01Q5/385; H01Q9/42; H01Q13/10
Foreign References:
US20150054693A12015-02-26
US20120081264A12012-04-05
US20120268328A12012-10-25
US20120280890A12012-11-08
CN103779660A2014-05-07
CN103296385A2013-09-11
US20150263430A12015-09-17
US20150036277A12015-02-05
US20170033467A12017-02-02
Attorney, Agent or Firm:
HGF LIMITED (LEEDS) (GB)
Download PDF:
Claims:
CLAIMS:

1. An antenna module for a portable electronic device, the antenna module comprising:

a substantially planar dielectric substrate having first and second opposed surfaces, and first and second opposed edges;

a feed arm comprising a conductive track disposed on the substrate, the feed arm having a first part extending from the first edge of the substrate towards the second edge of the substrate, and a second part extending substantially laterally from the first part; and at least first and second radiating elements, each radiating element comprising a conductive track disposed on the substrate, each radiating element having a first part extending from the second edge of the substrate towards the first edge, and a second part extending substantially laterally from the first part;

wherein ends of the first parts of the at least first and second radiating elements at the second edge of the substrate are configured for connection to a ground plane.

2. An antenna module as claimed in claim 1 , wherein the feed arm is provided with an RF feed. 3. An antenna module as claimed in claim 1 or 2, wherein the feed arm and the first and second radiating elements are disposed on the first surface of the substrate.

4. An antenna module as claimed in claim 1 or 2, wherein at least one of the feed arm and the first and second radiating elements is disposed on the first surface of the substrate and at least one other of the feed arm and the first and second radiating elements is disposed on the second surface of the substrate.

5. An antenna module as claimed in any preceding claim, wherein the feed arm is disposed between the first and second radiating elements.

6. An antenna module as claimed in any preceding claim, wherein the second parts of the radiating elements extend towards each other.

7. An antenna module as claimed in any preceding claim, wherein the first and second radiating elements are configured to couple with the feed arm to provide additional resonances during operation of the antenna module.

8. An antenna module as claimed in any preceding claim, wherein each of the first and second radiating elements is configured to couple with the feed arm to form a coupled grounded-loop antenna arrangement. 9. An antenna module as claimed in any preceding claim, wherein the second parts of the radiating elements couple with the second part of the feed arm during operation of the antenna module.

10. An antenna module as claimed in any one of claims 1 to 8, wherein at least one of the first and second radiating elements comprises at least a third part extending from the second part.

1 1. An antenna module as claimed in claim 10, wherein the third part is substantially parallel to the first part of its respective radiating element.

12. An antenna module as claimed in claim 10, wherein the third part comprises additional meanders.

13. An antenna module as claimed in any one of claims 10 to 12, wherein the third part of the first or second radiating element couples with the first and/or second part of the feed arm during operation of the antenna module.

14. An antenna module as claimed in any preceding claim, wherein at least one of the feed arm and the radiating arms is provided with matching circuitry to tune resonances of the antenna module.

15. An antenna module as claimed in any preceding claim, wherein at least one of the radiating arms is resonant. 16. An antenna module as claimed in any preceding claim, mounted over a slot in a casing of the portable electronic device, such that the feed arm is drivable by an RF signal supplied to and supported by the slot.

17. An antenna module as claimed in any preceding claim, wherein the first and second parts of each of the feed arm and the radiating elements are respectively arranged in a substantially L-shaped configuration.

18. An antenna module as claimed in any preceding claim, wherein the first and second opposed surfaces of the dielectric substrate are substantially rectangular.

19. An antenna module as claimed in any preceding claim, comprising no more than first and second radiating elements.

20. An antenna module as claimed in any preceding claim, wherein at least one of the feed arm and the first and second radiating elements is formed directly on the substrate. 21. An antenna module as claimed in any preceding claim, wherein at least one of the feed arm and the first and second radiating elements is formed on a flexible printed circuit board which is affixed to the substrate.

22. A portable electronic device comprising a conductive groundplane having a slot formed therein, the slot configured to serve as a slot antenna, and an antenna module as claimed in any preceding claim, the antenna module disposed over the slot such that the feed arm is drivable by the slot antenna.

23. The device of claim 22, wherein the ends of the first parts of the at least first and second radiating elements are connected to the groundplane.

24. The device of claim 22 or 23 depending through claim 8, wherein the slot antenna and the antenna module are operable in a hybrid manner, utilising resonances of both the slot antenna and the coupled grounded-loop antenna arrangement(s).

25. The device of any one of claims 22 to 24, wherein the slot antenna is configured to operate in a 2.3 to 2.69GHz band.

26. The device of claim 25 depending from claim 24, wherein the coupled grounded- loop antenna arrangement(s) is configured to provide a wide response in a 1.88 to

1.92GHz band.

27. An antenna comprising:

a conductive ground plane having an elongate slot formed therein, the elongate slot having first and second opposed longitudinal edges; a feed arm comprising a conductive track extending over the slot, the feed arm having a first part extending from the first edge of the slot towards the second edge of the slot, and a second part extending substantially laterally from the first part; and

at least first and second radiating elements, each radiating element comprising a conductive track extending over the slot, each radiating element having a first part extending from the second edge of the slot towards the first edge, and a second part extending substantially laterally from the first part;

wherein ends of the first parts of the at least first and second radiating elements are connected to the ground plane, and wherein an end of the first part of the feed arm is connected to an RF feed.

Description:
HYBRID CLOSED SLOT LTE ANTENNA

[0001] This invention relates to a hybrid closed slot LTE (Long Term Evolution) antenna. Certain embodiments may provide multi-band coverage by making use of a conventional closed slot resonance and also further resonances through coupled radiating elements, forming a grounded loop with a metal back plate of a device incorporating the antenna.

BACKGROUND

[0002] Firstly, some of the terms used in the main Detailed Description will be explicitly defined so as to ensure that the reader is able fully to understand the concepts described therein.

[0003] In the context of the present application, a "balanced antenna" is an antenna that has a pair of radiating arms extending in different, for example opposed or orthogonal, directions away from a central feed point. Examples of balanced antennas include dipole antennas and loop antennas. In a balanced antenna, the radiating arms are fed against each other, and not against a groundplane. In many balanced antennas, the two radiating arms are substantially symmetrical with respect to each other, although some balanced antennas may have one arm that is longer, wider or otherwise differently configured to the other arm. A balanced antenna is usually fed by way of a balanced feed.

[0004] In contrast, an "unbalanced antenna" is an antenna that is fed against a groundplane, which serves as a counterpoise. An unbalanced antenna may take the form of a monopole antenna fed at one end, or may be configured as a centre fed monopole or otherwise. An unbalanced antenna may be configured as a chassis antenna, in which the antenna generates currents in the chassis of the device to which the antenna is attached, typically a groundplane of the device. The currents generated in the chassis or groundplane give rise to radiation patterns that participate in the transmission/reception of RF signals. An unbalanced antenna is usually fed by way of an unbalanced feed.

[0005] A balun may be used to convert a balanced feed to an unbalanced feed and vice versa.

[0006] A reconfigurable antenna is an antenna capable of modifying dynamically its frequency and radiation properties in a controlled and reversible manner. In order to provide a dynamical response, reconfigurable antennas integrate an inner mechanism (such as RF switches, varactors, mechanical actuators or tuneable materials) that enable the intentional redistribution of the RF currents over the antenna surface and produce reversible modifications over its properties. Reconfigurable antennas differ from smart antennas because the reconfiguration mechanism lies inside the antenna rather than in an external beamforming network. The reconfiguration capability of reconfigurable antennas is used to maximize the antenna performance in a changing scenario or to satisfy changing operating requirements.

[0007] With the current advancement of technology in mobile telecommunications devices such as tablets, laptops and smartphones, the trend is towards supporting more wireless standards while seeking to make the devices thinner and more aesthetically desirable.

[0008] Current wireless services include the use of 4G LTE, a fast cellular data service for networking as WWAN (wireless wide area network). This is similar to WLAN (wireless local area network) operation but utilises fast cellular data protocols such as 4G LTE or even 5G as the data backhaul.

[0009] The desire for thinner devices often requires the use of metal monocoque shells which do not offer good passage of RF signals from an antenna. This is especially a problem for WWAN frequencies. Moreover, this problem is exacerbated when the antenna is located in close proximity to other antennas and/or electronic components on the motherboard. Accordingly, it is a challenge for an antenna design to work over multiple bands.

[0010] It is known to use plastic windows in metal covers or shells, in order that RF signals can pass easily, but this can deter from the aesthetic design of the device and is sometimes associated with the less premium models in a range. Other solutions include creating insulated slots in a rim around the casing to create either dipole or monopole antenna elements, such as on the iPhone4®. However, these are particularly susceptible to user intervention by shorting across the elements with the hand or fingers during use, which results in degradation of the signal.

[0011] Another solution is to use cavity-backed slot antenna arrangements. These types of antenna utilise a slot of free space that is bounded by metal elements, or ground-plane, and have a feed arm in the cavity behind the slot; such an arrangement can be achieved by having a small opening or notch in the metal casing. The shape, size and number of slots, and the size and arrangement of feed arms, typically defines the particular resonances that will occur, and hence the frequencies over which the device will operate.

[0012] This solution is typically less susceptible to outside intervention by fingers or hands blocking the slot or notch and allows more complex designs of resonating structure to be implemented behind the casing, which is not feasible for monopole or dipoles using the casing as radiating elements.

[0013] Papers in the prior art describe the addition of particular metal structures to the slot in order that particular frequency bands can be covered. Tuning circuitry can be added to the feed arm in order to widen the response across active frequency bands. Both of these techniques allow the slot antenna to meet requirements for the challenging operation in the bands used for LTE. However, complicated tuning circuitry can add to the footprint of the antenna and therefore require the bezel, rim or edge of the aesthetic device to be larger than ideally required.

BRIEF SUMMARY OF THE DISCLOSURE

[0014] Certain embodiments of the present disclosure provide a hybrid closed-slot LTE antenna for extremely confined spaces, for example in thin monocoque portable device designs. The antenna may utilise a closed-slot resonance for one LTE band, and may achieve other resonances in other bands through at least two additional grounded resonating elements which couple with a feed arm of the slot and form a double-resonant grounded loop antenna with a metal back plate of a portable device in which the antenna is incorporated.

[0015] An advantage provided by certain embodiments is effective coverage of multiple LTE bands in a very constrained space. Certain embodiments may make use of an existing slot for other RF emitters and may utilise the metal chassis of the portable device. Isolation may easily be achieved through bridging of the slot.

[0016] The proposed solution also allows a single length of slot, already present in the metal case for other radio frequencies, to be utilised for the LTE(WWAN) antenna due to the compact size.

[0017] The hybrid closed-slot antenna design of certain embodiments can overcome the previously-described problems in that it can be implemented in the most current thin, metal casings in mobile devices, is less susceptible to degradation of the RF signal by user intervention, has a compact design, small footprint, and can operate over a range of LTE frequencies.

[0018] Viewed from a first aspect, there is provided an antenna module for a portable electronic device, the antenna module comprising:

a substantially planar dielectric substrate having first and second opposed surfaces, and first and second opposed edges; a feed arm comprising a conductive track disposed on the substrate, the feed arm having a first part extending from the first edge of the substrate towards the second edge of the substrate, and a second part extending substantially laterally from the first part; and at least first and second radiating elements, each radiating element comprising a conductive track disposed on the substrate, each radiating element having a first part extending from the second edge of the substrate towards the first edge, and a second part extending substantially laterally from the first part;

wherein ends of the first parts of the at least first and second radiating elements at the second edge of the substrate are configured for connection to a ground plane.

[0019] The feed arm may be provided with an RF feed.

[0020] The feed arm and the first and second radiating elements may all be disposed on the first surface of the substrate.

[0021] Alternatively, at least one of the feed arm and the first and second radiating elements is disposed on the first surface of the substrate and at least one other of the feed arm and the first and second radiating elements is disposed on the second surface of the substrate.

[0022] The feed arm may disposed between the first and second radiating elements.

[0023] The second parts of the radiating elements may extend towards each other. Where the feed arm is disposed between the first and second radiating elements, the second parts of the first and second radiating elements may each extend towards the feed arm.

[0024] The first and second radiating elements may be configured to couple with the feed arm to provide resonances additional to those that would be provided by the feed arm itself without the first and second radiating elements being present during operation of the antenna module.

[0025] Advantageously, each of the first and second radiating elements is configured to couple with the feed arm to form a coupled grounded-loop antenna arrangement.

[0026] In some embodiments, the second parts of the radiating elements are configured to couple with the second part of the feed arm during operation of the antenna module.

[0027] The first and second parts of each of the feed arm and the radiating elements may respectively be arranged in a substantially L-shaped configuration. [0028] In some embodiments, at least one of the first and second radiating elements may comprise at least a third part extending from the second part. For example, at least one of the first and second radiating elements may have a Z shape or a Π shape.

[0029] Alternatively or in addition, the feed arm may comprise at least a third part extending from the second part. For example, the feed arm may have a Z shape or a Π shape.

[0030] The third part (of either the feed arm or the first or second radiating element) may be substantially parallel to the first part (of the feed arm or the respective radiating element. The third part may comprise additional meanders. The third part of the first or second radiating element may be configured to couple with the first and/or second part of the feed arm during operation of the antenna module.

[0031] In some embodiments, each of the feed arm and the first and second radiating elements is formed from a plurality of consecutive straight sections of conductive track, the sections being connected to each other substantially at right angles.

[0032] Advantageously, at least one of the feed arm and the radiating arms is provided with matching circuitry to tune resonances of the antenna module.

[0033] In some embodiments, at least one of the radiating arms is resonant.

[0034] The antenna module may be mounted over a slot in a casing of the portable electronic device, such that the feed arm is drivable by an RF signal supplied to and supported by the slot.

[0035] The first and second opposed surfaces of the dielectric substrate may be substantially rectangular.

[0036] In some embodiments, the antenna module comprising no more than first and second radiating elements.

[0037] At least one of the feed arm and the first and second radiating elements may be formed directly on the substrate. This may be achieved by depositing conductive material directly on the substrate, for example by printing, electrodeposition, electro-less deposition or any other suitable process.

[0038] Alternatively or in addition, at least one of the feed arm and the first and second radiating elements may be formed on a flexible printed circuit board (FPCB) which is affixed to the substrate. For example, an FPCB may have formed thereon the feed arm and the first and second radiating elements, together with matching circuitry, and the FPCB can then be wrapped around the substrate and secured in an appropriate manner. [0039] It will be noted that, in certain embodiments, the feed arm and the first and second radiating elements are configured as individual unbalanced or monopole antennas.

[0040] Viewed from a second aspect, there is provided a portable electronic device comprising a conductive groundplane having a slot formed therein, the slot configured to serve as a slot antenna, and an antenna module of the first aspect, the antenna module disposed over the slot such that the feed arm is drivable by the slot antenna.

[0041] The ends of the first parts of the at least first and second radiating elements are preferably connected to the groundplane.

[0042] In some embodiments, the slot antenna and the antenna module are operable in a hybrid manner, utilising resonances of both the slot antenna and the coupled grounded- loop antenna arrangement(s).

[0043] In an exemplary embodiment, the slot antenna is configured to operate in a 2.3 to 2.69GHz band, and/or the coupled grounded-loop antenna arrangement(s) is(are) configured to provide a wide response in a 1.88 to 1.92GHz band.

[0044] Viewed from a third aspect, there is provided an antenna comprising:

a conductive ground plane having an elongate slot formed therein, the elongate slot having first and second opposed longitudinal edges;

a feed arm comprising a conductive track extending over the slot, the feed arm having a first part extending from the first edge of the slot towards the second edge of the slot, and a second part extending substantially laterally from the first part; and

at least first and second radiating elements, each radiating element comprising a conductive track extending over the slot, each radiating element having a first part extending from the second edge of the slot towards the first edge, and a second part extending substantially laterally from the first part;

wherein ends of the first parts of the at least first and second radiating elements are connected to the ground plane, and wherein an end of the first part of the feed arm is connected to an RF feed.

[0045] Embodiments of the third aspect do not require a dielectric substrate for the feed arm and the first and second radiating elements, which may be made of self-supporting metal components, which may be stamped out of metal sheet or the like.

[0046] The feed arm and/or each or both of the first and second radiating elements need not be confined within a footprint of the elongate slot. Indeed, the feed arm, of at least the first part of the feed arm, may extend across the entire width of the elongate slot and over the ground plane beyond the second edge. Likewise, the first part of one or both of the radiating elements may extend across the entire width of the elongate slot and over the ground plane beyond the first edge. The ends of the first parts of the radiating elements may be connected to the ground plane at ground points spaced a distance away from the second edge of the elongate slot so as to increase an area of ground plane available for the generation of surface currents.

[0047] It will be appreciated that various preferred or optional features described in relation to the first and second aspects may also be applied to the third aspect unless clearly incompatible therewith.

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:

Figure 1 shows a metal-cased laptop design with a RF slot;

Figure 2 shows the laptop design of Figure 1 with slot bridging and a reduced slot length;

Figure 3 shows a schematic view of a slot with various antenna modules;

Figure 4 shows a feed arm arrangement;

Figure 5 shows a prior art dual-band solution;

Figure 6 shows a hybrid antenna solution of an embodiment of the present disclosure;

Figure 7 shows an alternative embodiment for a large carrier;

Figure 8 shows an alternative embodiment for a small carrier;

Figure 9 shows an exemplary relative arrangement of a feed arm and first and second radiating elements; and

Figure 10 is an S-parameter plot for an embodiment of the present disclosure.

DETAILED DESCRIPTION

[0049] A fully metal case for a laptop computer has a single slot running horizontally, in the upper (screen) part of the case to allow RF communication for the various antenna elements to be included in the design. Figure 1 illustrates the arrangement according to a first embodiment, comprising a laptop 1 of metal casing design, with upper and lower casing sections 2, 3 relating to the screen and keyboard areas. In the upper screen section 2, there is a horizontal slot 4 in the casing prepared for use with various radio antenna elements. The metal casing in the upper screen section 2 constitutes a ground plane 15.

[0050] A typical slot 4 used in such designs has dimensions of around 2.5mm width by 200mm length, although this can be any reasonable dimensions allowed by the laptop 1 and casing design. Such metal covers on portable devices also act as large ground-planes with respect to the RF properties of the device. Similarly, if the slot 4 is bridged by any further device or circuit board, this will act to change the length of the available slot 4. For example, in the top part of screen section 2, there is normally a camera module 5, as shown in Figure 2. Such bridging of the slot 4 reduces the length of the slot 4 available for a slot antenna module and provides isolation between adjacent slot antennas.

[0051] In Figure 2, it can be seen that the camera module 5, and any other module or element 6 bridging the slot 4, effectively reduces the length and effectively sections the slot 4 into portions. In this case, with the camera 5 and the other module 6, there are now three effective slot lengths: A, B and C. However, in many implementations there will be more effective slot lengths. Typically, a slot 4 will have a ground or bridge connection between successive slot antenna elements. Such a configuration, illustrating typical radio elements of LTE 7, 8, Wi-Fi 9, 10 and a camera module 5, is shown in Figure 3.

[0052] It is also typical from the arrangements such as that shown in Figure 3 that the size of each antenna module 7, 8, 9, 10 is very constrained, especially in order to fulfil depth requirements of the thin metal casings, and also in order to fit in the specific sectioned part of the slot 4. It is further a requirement that the LTE antenna 7, 8 can operate in the correct frequency bands. Typically, LTE standards require the compact antenna arrangement to operate over more than one distinct frequency band. For example, in China, the TDD bands utilise 1.88-1.92 GHz, and another band at 2.3-2.69 GHz. This kind of operation in a simple, passive and compact antenna arrangement is technically demanding, especially if it is required for the radiating elements to be resonant in the lower frequency bands in a confined space, since there will be restrictions on the lengths of the radiating elements. Accordingly, the present Applicant proposes the use of a hybrid arrangement.

[0053] The proposed solution uses a dielectric carrier 1 1 , designed to the exacting requirements of the space both along the length of slot 4, and the thickness of the casing to support the antenna elements. Typical carrier dimension requirements are in the range: height 8 to 12mm, width 30 to 60mm, and depth 2 to 5mm. It will be appreciated that these are merely given as specific examples, and other dimensions may find utility. A first element disposed on the carrier 11 is a feed arm 12, which excites the slot 4, and behaves as a closed slot antenna tuned to operate in the higher band (e.g. 2.3-2.69 GHz). This solution is illustrated in Figure 4, situated on the carrier 11 in the laptop device 1.

[0054] In order to fulfil the second band requirement (e.g. 1.88-1.92 GHz) it is proposed that an additional radiating element 13 is added to the carrier 1 1 , the element 13 configured to be resonant and to couple with the feed arm 12 to generate the required frequency response. The additional radiating element 13 is grounded to the ground plane 15.

[0055] A conventional approach to this problem is illustrated in Figure 5. Such a solution, however, has been experimentally shown to be too narrow band to fully cover the lower band.

[0056] The present Applicant has surprisingly found that the addition of another radiating element 14, coupled with the feed-arm 12, and also grounded to the ground plane 15 constituted by the back-plate of the screen section 2, creates a coupled loop antenna arrangement as shown in Figure 6. This provides a wider-band response in the lower band and adequately covers the 1.88-1.92 GHz as required. It should be noted that the radiating elements 13, 14 can both be tuned to the same frequency response in order to increase efficiency, or they can be tuned to slightly different frequencies (in the same band) in order to widen the frequency response.

[0057] It should also be noted that the additional radiating elements 13, 14 are, in this case, resonant, however they can be non-resonant and have associated matching circuitry, if required by the space and frequency requirements. These elements 13, 14 also have an additional portion 16, 17 on the top edge of the carrier 11 to make a connection to the ground plane 15 constituted by the large back-plate to create a ground point.

[0058] The ground points 18, 19 for the additional radiating elements 13, 14 are preferably at the opposite side of the carrier 1 1 to the feed point 20 of the feed arm 12. The distance between the feed arm feed point 20 and the radiating element ground points 18, 19 defines the size of the ground plane 15, on the back-plate, that the arrangement can utilise to form resonances. A monopole-type radiator 13, 14 is advantageously grounded as close to the edge of the ground plane 15 as possible, such that the radiator 13, 14 has the greatest opportunity to induce RF surface currents in the ground plane 15. This can improve efficiency.

[0059] The feed arm 12 and the additional radiating elements 13, 14 couple to form a grounded loop antenna, with the back-plate ground plane 15. The additional elements 13, 14 are chosen such that a suitable dual resonance is achieved via the grounded-loop to cover the second band as required. As space is often very limited on such a small footprint carrier 1 1 , additional meanders may be required on the radiating elements 13, 14 to remain resonant or cover the required frequencies.

[0060] Figure 7 illustrates an embodiment on a relatively large carrier 11 (height 10mm). This allows the additional radiating elements 13, 14 and the feed arm 12 to occupy relative halves of the carrier 11 to produce acceptable results.

[0061] Figure 8 illustrates another variation of the design, which is used for a relatively small carrier 1 1 (height 8mm). Optimised additional radiators 13, 14, and the feed arm 12, are forced to co-exist in portions of the same halves of the carrier 1 1 in order to maintain electrical length. Such constraints can also mean extra meander arms 21 are also required to define the correct electrical length for frequency operation in the space available.

[0062] It should also be noted that the current designs are based on substantially L- shaped radiating and feed elements 12, 13, 14. However, these could be pi-shapes, or other shapes, dependent on the required frequency response and the level of coupling with the feed arm 12 required to create the grounded loop resonances.

[0063] Figure 9 shows, in schematic form, a flexible PCB 22 on which is formed an exemplary relative arrangement of a feed arm 12 and first and second radiating elements 13, 14 with millimetre scales along vertical and horizontal axes to give an indication of size and scale. The flexible PCB 22 is configured to be wrapped around a dielectric carrier 1 1 so that the lowermost horizontal section 23 of the feed arm 12 extends along a bottom edge face of the carrier 1 1 , and thus serves as a convenient way of connecting to an RF source without itself contributing significantly to coupling with the radiating elements 13, 14.

[0064] Figure 10 shows an S-parameter plot for a hybrid WWAN antenna of an exemplary embodiment of the present disclosure, for example as shown schematically in Figures 6 to 8. The plot shows a resonance at around 1.9GHz, the resonance being relatively wide in the S1 1 plot and more narrow in the S22 plot. Additional resonances are obtained at around 2.3 to 2.69GHz in both the S11 and S22 plots. Looking at the S21 plot, it can be seen that isolation of 15dB or more can be obtained between WWAN antennas.

[0065] Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of them mean "including but not limited to", and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise. [0066] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0067] The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.