Backed cavity frame antenna

Abstract

An electronic device is disclosed that includes a front surface and a metallic back surface, the front surface including a display screen and a non-metallic bezel surrounding the display screen. A cavity is defined along at least a portion of the bezel between the back surface and the bezel of the front surface. The electronic device also includes a conductive radiating element and a conductive ground plane. The conductive radiating element is mounted in or proximate to the cavity so as to face the non-metallic bezel in a first direction toward the front surface and to face the cavity in a second direction toward the back surface. The conductive radiating element is connected to the conductive ground plane and also to the metallic back surface. The conductive radiating element is configured to be excited by an RF feed and the cavity serves as a reflector to direct the RF signal through the bezel.

Description

[0001] The present disclosure relates to an antenna arrangement configured to be incorporated behind a bezel of a portable communication device, such as a laptop or tablet, or a mobile handset, such as a smartphone.

[0002] BACKGROUND

[0003] With the advancement of current mobile telecommunication device (e.g. tablet, laptop and smartphone) technology, there is a trend to support more wireless standards, be thinner and more aesthetically pleasing.

[0004] The desire for thinner devices often requires the use of metal hard shell enclosures that do not provide a good passageway for radio frequency (RF) signals from the antenna. This can be a problem for WLAN frequencies (e.g. 2.4GHz and 5GHz) and is a challenge for any effective antenna design when coupled with an antenna placed in close proximity to the display screen (and associated electronic components).

[0005] It is known to use a plastic window in the metal cover or enclosure so that the RF signals can easily pass through, but this can detract from the aesthetic design of the device and is sometimes associated with less premium models in a range. Other solutions include creating insulated slots around the rim of the housing to create a dipole or monopole antenna element, such as the antenna element on the However, these devices are particularly susceptible to user intervention during use, causing signal attenuation, due to shorting between the elements with a hand or finger.

[0006] Another solution is to use very small antenna arrangements behind the non-metallic bezel of a device screen (e.g. a laptop screen). These types of antenna arrangements are located in a small amount of free space defined by the external metal housing and the internal display screen and manage to pass the signal through slots in the housing behind the screen disguised as non-metallic material with a metallic finish, or through the non-metallic cover forming the screen bezel. Prior art solutions with a relatively large bezel (>10mm) provide good operation in the WLAN bands of 2.4GHz and 5.5GHz. However, performance in these bands can be challenged as the latest models of devices have almost edge-to-edge screens (with typical bezel dimensions <10mm, often <6mm).

[0007] This solution is generally less susceptible to external intervention with a finger or hand blocking any slots or gaps and allows for more complex resonant structure designs to be implemented behind the bezel, which is not feasible when using part of the housing as a radiating element.

[0008] BRIEF SUMMARY OF THE DISCLOSURE

[0009] It is desirable to provide an antenna arrangement suitable for a portable device with wireless capabilities, which has a carrier height of small size (< 6 mm) and which can be placed behind the latest very thin bezel of a screen and which can operate sufficiently in the WLAN frequency bands of 2.4 GHz and 5.5 GHz.

[0010] Viewed from a first aspect, there is provided an electronic device, the electronic device comprising:

[0011] a front surface comprising a display screen and a bezel surrounding the display screen, at least a portion of the bezel being non-metallic;

[0012] a metallic back surface;

[0013] a cavity defined between the back surface and the bezel of the front surface along at least the non-metallic portion of the bezel;

[0014] a conductive radiating element; and

[0015] a conductive ground plane;

[0016] wherein the conductive radiating element is mounted in or adjacent to the cavity so as to face the non-metallic portion of the bezel in a first direction towards the front surface and to face the cavity in a second direction towards the back surface;

[0017] wherein the conductive radiating element is connected to the conductive ground plane;

[0018] wherein the conductive radiating element is further connected to the metallic back surface; and

[0019] wherein the conductive radiating element is configured to be excited by an RF feed.

[0020] Viewed from a second aspect, there is provided an antenna for an electronic device, the antenna comprising:

[0021] a conductive radiating element;

[0022] a conductive ground plane;

[0023] a ground plane extension extending from the conductive ground plane in a direction out of the plane of the conductive ground plane; and

[0024] an RF feed for exciting an RF current in the conductive radiating element;

[0025] wherein the conductive radiating element is connected to the conductive ground plane; and

[0026] The conductive radiating element is further provided with a connector for connection to a metal back cover of the electronic device.

[0027] With respect to the first aspect, the cavity is delimited by the metal back surface, metal parts of the display screen and / or electronic components mounted on a main board behind the display screen, etc. Providing the cavity delimited by the metal parts behind the conductive radiating element helps to direct the RF signals excited by the conductive radiating element through the non-metallic bezel on the front surface of the electronic device.

[0028] In some embodiments, the conductive radiating element is self-supporting, e.g. formed from a stamped metal plate, etc. In other embodiments, the conductive radiating element is formed as a conductive antenna pattern on or in an antenna carrier made of a dielectric material. The conductive antenna pattern can be formed on or in the antenna carrier by known processes, e.g. printing, laser direct structuring (LDS), adhesive wrapping, etc.

[0029] In embodiments with an antenna carrier, a conductive ground plane can extend from the antenna carrier. The conductive ground plane can extend in a direction generally parallel to the front surface and the back surface.

[0030] The conductive radiating element can be connected to the metal back surface by direct soldering, conductive foam, pogo pins or any suitable connection.

[0031] The dual grounding of the conductive radiating element to both the metal back surface and the conductive ground plane means that the cavity is delimited by the conductive ground plane surface behind the conductive radiating element, which helps to direct the RF signals excited by the conductive antenna element through the bezel in a direction away from the back surface and out of the front surface.

[0032] The metal back surface is typically a very large (relative to the conductive radiating element) metal part covering most or all of the back of the electronic device, which can be used as a reflector to help direct the radiated RF signals through the bezel of the front surface with improved efficiency and performance.

[0033] The conductive radiating element can have an elongated shape. For example, the conductive radiating element can be substantially rectangular or linear. The conductive radiating element can have a first and a second main edge facing the adjacent edge of the front surface of the electronic device and substantially parallel to the adjacent edge of the front surface of the electronic device, and a second main edge facing the adjacent edge of the display screen and substantially parallel to the adjacent edge of the display screen. One of these main edges, such as the first main edge, is connected to a metal rear surface, while the other main edge, such as the second main edge, is connected to a conductive ground plane. The connection of the first and second main edges, combined with the extent of the metal rear surface and the conductive ground plane, can optionally, along with other conductive components such as the display screen and / or motherboard or battery components, help to define a grounding cavity behind the conductive radiating element.

[0034] Antenna carriers can be shaped or bent to fit a reduced available space in an electronic device in which the front and / or rear surfaces converge toward each other at their edges.

[0035] If the conductive antenna pattern on the antenna carrier does not overlap with the display screen, the antenna carrier can be configured to partially overlap with the display screen. The RF feeder can overlap with the display screen.

[0036] The RF feeder may be located on the ground plane extension. In some embodiments, the RF feeder can excite the conductive radiating element via RF coupling; in other embodiments, the RF feeder may be directly connected to the conductive radiating element.

[0037] The cavity may have a depth of 2 mm to 10 mm, preferably 2 mm to 6 mm, and in some embodiments a depth of 3 mm to 4 mm (e.g., 3.5 mm).

[0038] The cavity may have a height of at least 4 mm, at least 4.2 mm, at least 6 mm, or at least 8 mm.

[0039] The antenna carrier can have a thickness of 1 mm to 5 mm, preferably about 2 mm.

[0040] The antenna carrier may have a height of less than 10 mm, less than 6 mm, and preferably less than 4 mm (e.g., about 3.5 mm).

[0041] The distance between the first main edge and the second main edge of the conductive radiating element can be less than 10 mm, less than 6 mm, and preferably less than 4 mm (e.g., about 3.5 mm). The distance between the first main edge and the second main edge of the conductive radiating element is determined by the width of the frame, which can be as small as 3.5 mm in modern electronic device designs. Brief description of the attached diagram

[0043] Embodiments of the present application are further described below with reference to the accompanying drawings, in which:

[0044] Figure 1 A back elevation of a clamshell notebook computer device is shown;

[0045] Figure 2 A front elevation of a clamshell notebook computer device is shown;

[0046] Figure 3 A front elevation of a notebook computer screen portion is shown with the B lid removed;

[0047] Figure 4 A detailed front elevation of a notebook computer screen portion is shown with the B lid removed;

[0048] Figure 5 A side elevation of an antenna and carrier is shown;

[0049] Figure 6 A detailed front elevation of an antenna and carrier is shown;

[0050] Figure 7 A detailed view of an antenna and feed according to an embodiment is shown;

[0051] Figure 8 A detailed view of an antenna and feed according to an embodiment is shown;

[0052] Figure 9 A detailed view of an antenna and feed according to an embodiment is shown;

[0053] Figure 10 An analog far field main lobe radiation pattern at 2.4 GHz is shown;

[0054] Figure 11 An analog far field main lobe radiation pattern at 5.5 GHz is shown; and

[0055] Figure 12 An analog S parameter plot is shown.

[0056] DETAILED DESCRIPTION

[0057] Embodiments of the present disclosure can be described with respect to a typical clamshell design notebook computer. Figure 1 Such a notebook computer is illustrated from a back elevation, the housing comprising different lids. In the industry, the lid at the back of the screen is denoted as the A lid (1), and the lid at the bottom of the notebook computer in contact with the surface on which the device is placed is denoted as the D lid (2). Figure 2 The same notebook computer is shown from a front elevation, and comprises the front lid of the screen (including the bezel), which is denoted as the B lid (4). Finally, the lid that encloses the keyboard is denoted as the C lid (3).

[0058] Another embodiment can be described in relation to a typical tablet or convertible tablet that can be docked with a keyboard. In this embodiment, the host device will only have the A cover and B cover in tablet mode. In addition, the motherboard and battery will be housed behind the screen to form an all-in-one unit.

[0059] Figure 3 A closer view of the screen portion of a notebook computer is shown, including the screen back A cover (10), screen unit (11), compact cavity (12), and antenna carrier (14) in place. The cavity is formed where the screen and / or motherboard and battery unit terminate, and the curved portion or remaining length of the housing is folded to complete the A cover shape. This cavity enables a well-designed antenna and antenna carrier to be positioned within this area. The screen and / or motherboard and battery devices are typically both grounded to the metal A cover.

[0060] The cavity area has a maximum height space defined as the gap between the area where the A cover is folded and accepts the B cover and the screen edge, less than 10mm, typically less than 6mm, and for the latest edge-to-edge screens, less than 5mm. In this particular embodiment, the antenna carrier has a height of 3.50mm to fit within the cavity curved portion, and is rectangular, however it should be understood that the carrier can be other shapes, such as curved to fit the curved portion appropriately, or other shapes required by antenna operating parameters.

[0061] Figure 4 Another closer view of the notebook computer screen area is shown, with the B cover also removed. This illustrates the antenna dimensions in more detail, with a height of 3.50mm and a length of 30.00mm. In this embodiment, the carrier is placed towards the left-hand side of the device, however, this can be anywhere along the screen edge depending on the placement of RF noise components, ease of routing other antennas or cables to the RF card in the particular device platform.

[0062] Figure 5 A side elevation of the notebook computer screen portion is shown, with the B cover removed. Figure 5 The available space in the cavity is shown in more detail. The curved portion of the screen (23) and A cover (22) creates a cavity of approximately 3.5mm deep (20) at the midpoint of the curved portion. The cavity can have a height (21) of greater than 8.0mm, preferably greater than 6.0mm, or more preferably greater than 4.2mm. For obvious reasons, the antenna carrier cannot be placed behind the screen unit as the metal back (for a notebook computer) or notebook / motherboard / battery unit (for a tablet or convertible tablet) would block any signal and interfere with the antenna.

[0063] In this particular embodiment, the carrier is designed to be neatly positioned above the screen unit, leaving space by using dimensions of 3.5 mm height and 2.0 mm thickness. In some cases, a portion of the antenna carrier may be placed behind the screen unit, but active radiating elements cannot be placed on the shielded portion of the carrier surface. This would necessitate supporting passive elements, such as non-radiating feeders or passive coupling components.

[0064] Figure 6 A detailed front elevation view of the antenna and carrier (34) in situ on the screen unit (33) is shown, with the device B cover removed. The antenna carrier has metallization in the form of patches or other patterns to form a structure that can be The radiating structure (36) operates in the frequency band. The antenna device also has a feeding structure (37) for supplying RF energy to and from the radiating structure and connecting to a coaxial lead interface from the wireless card in the device. The antenna patch or metallized pattern structure (36) is directly connected to the metal A-cover via a connector (35); this connection can be made by conductive foam, spring pins, or by direct soldering during device assembly.

[0065] Figure 7 A more detailed view of the antenna and carrier assembly according to an embodiment is shown. The carrier (40) is substantially rectangular in shape, but may also be other conformal shapes made to fit the curvature of the A-cover. The carrier is typically an RF-clear plastic material (e.g., ABS), and the antenna pattern (41) includes a metal patch or a zigzag pattern or other patterns to produce 2.4 GHz and 5.5 GHz. The desired resonance. The antenna metal pattern can be fabricated using techniques well-known in the antenna industry, such as laser direct structuring (LDS) or metal stamping. It should also be noted that the antenna pattern is not limited to one side of the carrier; in some cases, depending on performance requirements or the placement of other metal components, the antenna can be formed on more than one side of the carrier.

[0066] As previously described, the antenna pattern (41) is connected to the device A cover via connection point (49). This connection can be conductive foam, spring pins, or direct soldering. Grounding is important for this relatively compact antenna assembly; the grounded bottom and top connections create a cavity formed by the metal A cover, screen unit, and / or motherboard / battery element (24). This cavity, as... Figure 5 As shown, the size is approximately 3.5 mm (20) × 6.0 mm (21), located behind the antenna and carrier device, which produces a cavity-backed antenna effect that further ensures that RF energy is directed to the RF transparent B-cover frame in order to radiate and provide the required performance and efficiency.

[0067] The antenna arrangement has a large ground plane (42) extending from the carrier bottom, where the ground plane extension (45) is connected to the large main ground and extends onto the carrier. The ground plane can be stamped metal or foil extending from the carrier bottom edge, and the ground plane extension can be formed using LDS or metal stamping during normal antenna pattern processing. The ground plane is then connected to the screen / mainboard / battery section in the device, which is the main device ground point.

[0068] The antenna is fed from a feed arrangement (43) located at one end of the carrier and on the ground plane extension (45) to make cabling and connecting coaxial cable by soldering easier. In this particular embodiment, the antenna is directly fed and has passive components (44) placed in the feed to tune the required resonance. Other feed arrangements can include more active arrangements that include passive components and RF switches to actively tune or match the antenna in the required frequency range.

[0069] Figure 8 A detailed view of the antenna and feed is shown according to an embodiment. The arrangement includes a carrier (40), an antenna pattern (41), a ground plane (42), and an associated ground plane extension (45).

[0070] The feed arrangement (43) in this embodiment points from the ground plane extension (45) towards the antenna pattern (41).

[0071] Figure 9 A detailed view of the antenna and feed is shown according to an embodiment. The arrangement includes a carrier (40), an antenna pattern (41), a ground plane (42), and an associated ground plane extension (45).

[0072] The feed arrangement in this embodiment utilizes coupling. The feed arrangement (43) is located close to the extended coupling section (46) of the antenna pattern (41) so that the RF energy presented at the feed can couple with the extended section (46) and induce RF energy in the antenna pattern radiating structure, and vice versa for receive mode.

[0073] Figure 10 Analog far field main lobe radiation pattern at 2.4 GHz is shown. The figure clearly indicates that the main radiation is emitted from the front of the device, through the B cover bezel.

[0074] Figure 11 Analog far field main lobe radiation pattern at 5.5 GHz is shown. The figure also clearly indicates that the main radiation is emitted from the front of the device, through the B cover bezel.

[0075] Figure 12Simulated S-parameter plots showing antenna performance are shown. The plots indicate simulated return loss of the antenna over the operating frequency range. Ideally, one would expect a large drop in return loss due to radiation being transmitted in the system rather than reflected. According to The resonant response is indicated at 2.4 GHz and 5.5 GHz, in accordance with the frequency requirements.

[0076] Throughout the description and claims of this specification, the words "comprise", "contain", "include" and "have" and variations such as "comprises", "contained", "includes" and "has" and negations thereof are to be interpreted to be in an open-ended sense, that is to say, as "including, but not limited to", and are not to be interpreted in an exclusive or exhaustive sense.

[0077] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the application are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features and / or steps disclosed in the specification (including any accompanying claims, abstract and drawings) can be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The application is not restricted to the details of any foregoing embodiments. The application 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 step or any novel combination of steps of any method or process so disclosed.

[0078] The reader's attention is directed to all papers and documents which are filed concurrently with or prior to this specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

Claims

1. An electronic device, comprising: a front surface comprising a display screen and a bezel surrounding the display screen, at least a portion of the bezel being non-metallic; a metallic back surface; a cavity defined between the back surface and the bezel of the front surface along at least the non-metallic portion of the bezel; a conductive radiating element; and a conductive ground plane; wherein the conductive radiating element is mounted in or adjacent to the cavity so as to face the non-metallic portion of the bezel in a first direction towards the front surface and to face the cavity in a second direction towards the back surface; wherein the conductive radiating element is connected to the conductive ground plane; wherein the conductive radiating element is further connected to the metallic back surface; and wherein the conductive radiating element is configured to be excited by an RF feed; wherein the conductive ground plane is a large ground plane to define a front surface of the cavity. The conductive radiating element is self-supporting. 2.The electronic device of claim 1, wherein, The conductive radiating element is formed as a conductive antenna pattern on or in a dielectric antenna carrier. 3.The electronic device of claim 1, wherein, The conductive ground plane extends from the dielectric antenna carrier.

4. The electronic device of claim 3, wherein, The antenna carrier is arranged to overlap the display screen by a portion in case the conductive antenna pattern on the antenna carrier does not overlap the display screen.

5. The electronic device of claim 3 or 4, wherein, The RF feed is arranged on a portion of the antenna carrier that overlaps the display screen.

6. The electronic device of claim 5, wherein, The dielectric antenna carrier has a thickness of 1 mm to 5 mm, or substantially 2 mm.

7. The electronic device of any of claims 3-4 and 6, wherein, The dielectric antenna carrier has a height of less than 10 mm, less than 6 mm, less than 4 mm, or substantially 3.5 mm.

8. The electronic device of any of claims 3-4 and 6, wherein, The conductive radiating element has an elongated shape, or is substantially rectangular or linear.

9. The electronic device according to any one of claims 1 to 4 and 6, wherein, The conductive radiating element has a first major edge facing and substantially parallel to an adjacent edge of the front surface of the electronic device and a second major edge facing and substantially parallel to an adjacent edge of the display screen.

10. The electronic device according to any one of claims 1 to 4 and 6, wherein, One of the first and second major edges is connected to the metallic back surface and the other of the first and second major edges is connected to the conductive ground plane.

11. The electronic device of claim 10, wherein, The connections of the first and second major edges to the metallic back surface and the conductive ground plane, together with the metallic back surface and the conductive ground plane, define the cavity as a grounded cavity between the conductive radiating element and the metallic back surface, the grounded cavity being configured to guide RF signals through the non-metallic portion of the bezel.

12. The electronic device of claim 11, wherein, A distance between the first and second major edges of the conductive radiating element is less than 10 mm, less than 6 mm, less than 4 mm, or substantially 3.5 mm.

13. The electronic device of claim 10, wherein, The conductive ground plane extends substantially parallel to the front and back surfaces.

14. The electronic device according to any one of claims 1 to 4, 6, and 11 to 13, wherein, The conductive ground plane is provided with a ground plane extension extending in a direction out of the plane of the conductive ground plane.

15. The electronic device according to any one of claims 1 to 4, 6, and 11 to 13, wherein, ​ 16. The electronic device of claim 15, wherein, The RF feed is arranged on the ground plane extension.

17. The electronic device of any of claims 1-4, 6, 11-13, and 16, wherein, The cavity has a depth of 2 mm to 10 mm, or 2 mm to 6 mm, or 3 mm to 4 mm, or substantially 3.5 mm.

18. The electronic device of any of claims 1-4, 6, 11-13, and 16, wherein, The cavity has a height of at least 4 mm, at least 4.2 mm, at least 6 mm, or at least 8 mm.

19. An antenna for an electronic device, the antenna comprising: a conductive radiating element; a conductive ground plane; a ground plane extension extending from the conductive ground plane in a direction out of the plane of the conductive ground plane; and an RF feed for exciting an RF current in the conductive radiating element; wherein the conductive radiating element is connected to the conductive ground plane; and wherein the conductive radiating element is further provided with a connector for connection to a metal back cover of an electronic device; wherein the conductive ground plane is a large ground plane to define a front surface of a cavity between the metal back cover and a bezel of a front surface of the electronic device.

20. The antenna of claim 19, wherein, The conductive radiating element is self-supporting.

21. The antenna of claim 19, wherein, The conductive radiating element is formed as a conductive antenna pattern on or in a dielectric antenna carrier.

22. The antenna of claim 21, wherein, The conductive ground plane extends from the dielectric antenna carrier.

23. The antenna according to claim 21 or 22, wherein, The dielectric antenna carrier has a thickness of 1 mm to 5 mm, or substantially 2 mm.

24. The antenna of claim 21 or 22, wherein, The dielectric antenna carrier has a height of less than 10 mm, less than 6 mm, less than 4 mm, or substantially 3.5 mm.

25. The antenna of any one of claims 19-22, wherein, The conductive radiating element has an elongated shape, or is substantially rectangular or linear.

26. The antenna of any one of claims 19-22, wherein, The conductive radiating element has opposite and substantially parallel first and second major edges.

27. The antenna according to claim 26, wherein, One of the first and second major edges is provided with the connector for connection to the metal back cover, and the other of the first and second major edges is connected to the conductive ground plane.

28. The antenna of any of claims 19-22 and 27, wherein, The RF feed is arranged on the ground plane extension.

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