RECONFIGURABLE CASING ANTENNA SYSTEM

Abstract

There is disclosed a reconfigurable antenna device comprising a plurality of antennas disposed about a periphery of a substantially rectangular shape having top, bottom, left and right sides. The antenna device includes a first balanced antenna having first and second radiating arms each having a proximal portion and a distal portion, proximal portions extending along the top side in respectively opposed directions from a substantially central feed point, and the distal portions extending part way down the left and right sides. The antenna device further includes a first unbalanced antenna located generally between the distal portions and adjacent to the proximal portions of the first and second radiating arms. In addition, the antenna device includes a second balanced antenna having a first radiating arm extending up the left side from a feed peed point in a bottom left corner of the periphery and a second radiating arm extending along the bottom side from the feed point in the bottom left corner of the periphery, and a third balanced antenna having a first radiating arm extending up the right side from a feed point in a bottom right corner of the periphery and a second radiating arm extending along the bottom side from the feed point in the bottom right corner of the periphery.

Claims

1. A reconfigurable antenna device comprising a plurality of antennas disposed about a periphery of a substantially rectangular shape having top, bottom, left and right sides, the antennas comprising: i) a first balanced antenna having first and second radiating arms each having a proximal portion and a distal portion, proximal portions extending along the top side in respectively opposed directions from a substantially central feed point, and the distal portions extending part way down the left and right sides; ii) a first unbalanced antenna located generally between the distal portions and adjacent to the proximal portions of the first and second radiating arms; iii) a second balanced antenna having a first radiating arm extending up the left side from a feed point in a bottom left corner of the periphery and a second radiating arm extending along the bottom side from the feed point in the bottom left corner of the periphery; and iv) a third balanced antenna having a first radiating arm extending up the right side from a feed point in a bottom right corner of the periphery and a second radiating arm extending along the bottom side from the feed point in the bottom right corner of the periphery.

2. A device as claimed in claim 1, further comprising a second unbalanced antenna located on the left side between the distal portion of the first radiating arm of the first balanced antenna and the first radiating arm of the second balanced antenna, the second unbalanced antenna having a feed point.

3. A device as claimed in claim 1, further comprising a third unbalanced antenna located on the right side between the distal portion of the second radiating arm of the first balanced antenna and the first radiating arm of the third balanced antenna, the third unbalanced antenna having a feed point.

4. A device as claimed in claim 1, further comprising a fourth unbalanced antenna located along the top side adjacent and substantially parallel to the proximal portion of the first radiating arm of the first balanced antenna.

5. A device as claimed in claim 1, further comprising a fifth unbalanced antenna located along the top side adjacent and substantially parallel to the proximal portion of the second radiating arm of the first balanced antenna.

6. A device as claimed in claim 1, wherein the proximal and distal portions of each radiating arm of the first balanced antenna are disposed substantially at right angles to each other.

7. A device as claimed in claim 1, wherein the first and second radiating arms of each of the second and third balanced antennas are disposed substantially at right angles to each other.

8. A device as claimed in claim 1, configured as a part of a casing or bezel of a mobile phone handset, tablet or laptop computer.

9. A device as claimed in claim 1, further comprising a substrate including a conductive groundplane.

10. A device as claimed in claim 1, wherein the antennas comprise elongate conductive metal strips that are arranged around the periphery.

11. A device as claimed in claim 10, wherein the strips each have a width that is disposed substantially perpendicular to the plane of the substrate.

12. A device as claimed in claim 10, wherein the first unbalanced antenna comprises an elongate metal strip that is disposed in the same plane as or parallel to the substrate at a top edge thereof, adjacent to the proximal portions of the radiating arms of the first balanced antenna and between the distal portions of the radiating arms.

13. A device as claimed in claim 12, wherein the first unbalanced antenna is mounted flat on a surface of the top edge of the substrate, this part of the substrate being free of the conductive groundplane.

14. A device as claimed in claim 13, wherein a floating groundplane in the form of a conductive patch is provided over or under a central portion of the first unbalanced antenna, and a matching circuit for the first balanced antenna is located on the floating groundplane.

15. A device as claimed in claim 1, wherein the feed point of each antenna is connected via a respective matching circuit to at least one respective signal port.

16. A device as claimed in claim 1, wherein the first, second and/or third balanced antennas are configured as dipole antennas.

17. A device as claimed in claim 1, wherein the first, second and/or third balanced antennas are configured as centre feed slot antennas.

18. A device as claimed in claim 1, wherein the first, second, third, fourth and/or fifth balanced antennas are configured as offset feed slot antennas.

19. A device as claimed in claim 1, wherein ends of the radiating arms of the antennas are spaced from each other around the periphery by air gaps or solid dielectric spacer elements.

20. A device as claimed in claim 1, wherein at least some of the antennas are wholly or partially provided with a dielectric coating.

21. A device as claimed in claim 1, wherein the antennas are wholly or partially provided with a dielectric coating.

22. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:

[0058] FIG. 1 shows a first embodiment in schematic form;

[0059] FIG. 2 shows a close up of the top of the embodiment of FIG. 1;

[0060] FIG. 3 is a plot showing the return loss of the embodiment of FIG. 1;

[0061] FIG. 4 shows a second embodiment in schematic form;

[0062] FIG. 5 is a plot showing the return loss of the embodiment of FIG. 4;

[0063] FIG. 6 shows a third embodiment in schematic form;

[0064] FIG. 7 shows a system block illustrating how the embodiment of FIG. 6 may be used to drive 13 ports; and

[0065] FIG. 8 is a plot showing the return loss of the embodiment of FIG. 6.

DETAILED DESCRIPTION

[0066] A first embodiment is shown in FIGS. 1 and 2. There is provided a substrate 1, which may be a PCB of a mobile telephone handset, the substrate 1 including a conductive groundplane over a majority of its area. The antenna device forms a generally rectangular frame around the substrate 1, and may be incorporated into a casing (not shown) of the mobile handset (not shown), for example as a bezel or the like. Alternatively, the antenna device may be mounted to an interior surface of the casing of the mobile handset, as required by design and aesthetic considerations.

[0067] The antenna device of this embodiment comprises six distinct antennas, each of which is provided with a matching circuit connected to a signal port, the matching circuits and signal ports being mounted on the substrate 1.

[0068] A first balanced antenna 2 is provided at the top edge of the substrate 1, and comprises first and second radiating arms 3, 3′. Each radiating arm 3, 3′ has a proximal portion 4, 4′ extending parallel to the top edge of the substrate 1 away from a central feed point 5, and a distal portion 6, 6′ extending part way along and parallel to the left and right sides respectively of the substrate 1.

[0069] A first unbalanced antenna 7 is also provided at the top edge of the substrate 1, extending parallel to the proximal portions 4, 4′ of first balanced antenna 2. In the embodiment of FIG. 1, the first unbalanced antenna 7 is located on the side of the first balanced antenna 2 that faces towards the substrate 1 and spaced a small distance therefrom. The first unbalanced antenna 7 has a central feed point 8, which may take the form of a central stub 80 extending from the first unbalanced antenna 7. It can be seen that the first unbalanced antenna 7 is located between the distal portions 6, 6′ of the first balanced antenna 2. A notch or cut-out 9, 9′ is provided at the end of each distal portion 6, 6′ of the first balanced antenna 2 where it meets the proximal portion 4, 4′. The notches or cut-outs 9, 9′ expose the ends of the first unbalanced antenna 7 at the top left and top right corners of the frame. The notches 9, 9′ may help to reduce unwanted coupling between the antennas 2, 7.

[0070] Second and third unbalanced antennas 100, 200 (best seen in FIG. 2) are provided at the top edge of the substrate 1, respectively extending parallel to the proximal portions 4, 4′ of the first balanced antenna 2. The second and third unbalanced antennas 100, 200 are each provided with a feed 102, 202.

[0071] Each of the first balanced antenna 2 and first to third unbalanced antennas 7, 100, 200 is provided with a respective matching circuit and signal port 10, 11, 101, 201 on the substrate 1.

[0072] A second balanced antenna 12 is provided at the bottom left corner of the substrate 1. The second balanced antenna 12 is configured as a dipole and comprises a first radiating arm 13 extending up the left side of the substrate 1 and a second radiating arm 14 extending along the bottom edge of the substrate 1 at a right angle to the first radiating arm 13. The second balanced antenna 12 is fed at a feed point 15 between the first 13 and second 14 radiating arms. A matching circuit and signal port 16 is provided on the bottom left corner of the substrate 1.

[0073] A third balanced antenna 17 is provided at the bottom right corner of the substrate 1. The third balanced antenna 17 is configured as a dipole and comprises a first radiating arm 18 extending up the right side of the substrate 1 and a second radiating arm 19 extending along the bottom edge of the substrate 1 at a right angle to the first radiating arm 18. The second balanced antenna 17 is fed at a feed point 20 between the first 18 and second 19 radiating arms. A matching circuit and signal port 21 is provided on the bottom right corner of the substrate 1.

[0074] The ends of the second radiating arms 14, 19 are separated from each other at the bottom edge of the substrate 1 by an air gap 22, or alternatively by a solid dielectric spacer.

[0075] The ends of the first radiating arms 13, 18 of the second and third balanced antennas 12, 17 in this embodiment are separated from the ends of the distal portions 6, 6′ of the first balanced antenna 2 at the left and right edges of the substrate 1 by air gaps/dielectric spacers 23. Additional metal or non-metal spacers 300 may be provided as required, the spacers 300 optionally helping to reduce unwanted coupling.

[0076] The return loss for the antenna device of FIGS. 1 and 2 is shown FIG. 3, demonstrating that the antenna device can operate in six frequency bands (MIMO LTE low-band, GPS, MIMO LTE mid-band, 2.4 GHz WiFi, MIMO LTE high-band and 5.5 GHz WiFi). Isolation at 700 MHz is below −30 dB, and at 2700 MHz is below −15 dB.

[0077] FIG. 4 shows a second embodiment, with the various components labelled as in FIG. 1. In this embodiment, the first unbalanced antenna 7 is disposed in the same plane as the substrate 1, or in a parallel plane. The first unbalanced antenna 7 may be mounted directly on a groundplane-free region at the top edge of the substrate 1, or may be formed as a separate element above the top edge of the substrate 1 as shown in FIG. 3. The matching circuit and signal port 10 for the first balanced antenna 2 may be mounted on a floating groundplane provided on a central part of the first unbalanced antenna 7.

[0078] The embodiment of FIG. 4 also includes a second unbalanced antenna 24 at the left side of the substrate 1 and a third unbalanced antenna 25 at the right side of the substrate 1. The second and third unbalanced antennas 24, 25 are respectively located between the ends of the first radiating arms 13, 18 of the second and third balanced antennas 12, 17 and the ends of the distal portions 6, 6′ of the first balanced antenna 2 at the left and right edges of the substrate 1. Air gaps/dielectric spacers 23 are provided to prevent conductive electrical contact. The second and third unbalanced antennas 24, 25 each have a feed point connected to a respective matching circuit and signal port 26, 27.

[0079] The return loss for the antenna device of FIG. 4 is shown FIG. 5, demonstrating that the antenna device can operate in six frequency bands (MIMO LTE low-band, GPS, MIMO LTE mid-band, 2.4 GHz WiFi, MIMO LTE high-band and 5.5 GHz WiFi). Isolation at 700 MHz is below −30 dB, and at 2700 MHz is below −10 dB.

[0080] FIG. 6 shows a third embodiment, which is similar to that of FIG. 1, but includes the unbalanced antennas 24, 25 of the FIG. 4 embodiment as fourth and fifth unbalanced antennas in addition to the second and third unbalanced antennas 100, 200. The embodiment of FIG. 6 thus has three balanced antennas 2, 12, 17 and five unbalanced antennas 7, 100, 200, 24, 25 distributed around the periphery. An additional metal or non-metal spacer 300 may be provided on the bottom edge for cosmetic reasons and optionally to help reduce unwanted coupling between balanced antennas 12 and 17.

[0081] FIG. 7 is a system block showing how the antenna device of the FIG. 6 embodiment, comprising eight separate antennas, can be provided with suitable matching circuitry to drive 13 signal ports. Using high pass and low pass filters 400, 401 and matching circuits 402, 402′, it is possible for a single antenna element to handle two independently tuneable RF signals, as described in more detail in the present Applicant's co-pending UK patent application no GB1415780.4.

[0082] The return loss for the antenna device of FIGS. 6 and 7 is shown FIG. 8, demonstrating that the antenna device can operate in six frequency bands (MIMO LTE low-band, GPS, MIMO LTE mid-band, 2.4 GHz WiFi, MIMO LTE high-band and 5.5 GHz WiFi).

[0083] 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.

[0084] 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.

[0085] 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.