Antenna, antenna device, and wireless terminal

Abstract

The present application relates to antennas, antenna arrangements and wireless terminals. An antenna (1) for use in a wireless terminal comprising a ground plane (11) and a metal frame (12) surrounding the ground plane with a gap (13) between the metal frame and the ground plane; wherein the antenna is configured to form a ground connection (15) between the ground plane and the metal frame for operation within a first frequency range (FR1); and wherein the antenna comprises an open cavity structure (100) for a second frequency range (FR2).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of antennas for wireless terminals configured for wireless communication, and in particular to an antenna arrangement for use in at least two frequency ranges. BACKGROUND

[0002] Electronic devices typically comprise wireless communication circuitry, and such electronic devices can be referred to as wireless terminals. For example, cellular telephones, computers and other devices often contain antennas and wireless transceivers for supporting wireless communication.

[0003] A large number of wireless communication systems have been developed and are in use for different purposes. Over the years, various specifications forming standards requirements for wireless communication have been managed through the Third Generation Partnership Project (3GPP). Ever-evolving generations of specifications have been provided for establishing general rules establishing radio interfaces between wireless terminals and base stations for establishing and operating the radio interfaces, as well as various levels of operation of wireless networks. In 3GPP documents, wireless terminals or wireless communication devices are often referred to as User Equipment (UE). A base station defines a cell and is operable to provide radio access to a surrounding area for UEs by providing radio access to UEs within the cell. Base stations are also referred to herein as nodes or access nodes, and various terms are used in 3GPP for different types of systems or specifications. An access network or Radio Access Network (RAN) typically comprises a plurality of access nodes and is connected to a Core Network (CN) that, among other things, provides access to other communication networks. In the so-called 3G specifications, the term NodeB is used to denote an access node, while in the so-called 4G specifications, also referred to as Long Term Evolution (LTE), the term eNodeB (eNB) is used. A further developed set of radio communication specifications is referred to as a 5G-type radio communication system (5GS), including New Radio (NR) technology, where the term gNB is used to denote an access node.

[0004] The stepwise development of wireless communication technology and requirements includes operation in higher frequency bands. For example, it can be desirable to support wireless communication in millimeter wave communication bands. Millimeter wave communication, sometimes referred to as extremely high frequency communication, involves communication at frequencies of about 10-400 GHz. Operation at these frequencies can support high bandwidth and controlled directional communication, such as beam steering, but can also present significant challenges. For example, millimeter wave communication is typically line-of-sight communication, characterized by significant attenuation during signal propagation. In 3GPP, millimeter wave communication is defined under the above-mentioned 5G NR. This can include communication capabilities at different frequencies, including the millimeter wave spectrum above 24 GHz.

[0005] To implement in an electronic device configured as a wireless terminal, new antenna solutions can be needed to accommodate operation in the higher frequency range of the millimeter wave band. At the same time, operation in the lower frequency bands should preferably still be supported to support legacy communication. SUMMARY

[0006] In view of the general object of providing antenna solutions for use in a wireless terminal to provide communication capabilities in different frequency ranges, antennas, antenna arrangements and wireless terminals are provided. These antenna solutions include, inter alia:

[0007] An antenna for use in a wireless terminal, the wireless terminal comprising a ground plane and a metal frame surrounding the ground plane, the metal frame and the ground plane having a gap therebetween;

[0008] wherein the antenna is configured to form a ground connection for a first frequency range between the ground plane and the metal frame; and

[0009] wherein the antenna comprises an open cavity structure for a second frequency range. BRIEF DESCRIPTION OF DRAWINGS

[0010] Various embodiments will be described with reference to the drawings, wherein

[0011] Figure 1 An embodiment of an antenna arrangement is schematically illustrated, the antenna arrangement comprising a ground plane and a metal frame surrounding the ground plane, the metal frame and the ground plane having a gap therebetween, the antenna arrangement comprising an antenna for a first frequency range and an antenna for a second frequency range;

[0012] Figure 2A A perspective view of an antenna comprising an open cavity structure for a second frequency range according to an embodiment is schematically illustrated;

[0013] Figure 2B A cross-sectional view of an open cavity structure according to an embodiment is illustrated;

[0014] Figure 3A A front view of an open cavity structure according to an embodiment is illustrated, seen from a first side;

[0015] Figure 3B A front view of an open cavity structure according to an embodiment is illustrated, seen from an opposite second side;

[0016] Figure 4 A bandwidth obtained by an embodiment of the proposed antenna in a second wavelength range is schematically illustrated;

[0017] Figure 5 An antenna aperture of an antenna without a metal frame is schematically illustrated.

[0018] Figure 6 Schematic illustration of enlarged antenna aperture achieved by connecting an open cavity structure to a metal frame;

[0019] Figure 7 schematically illustrates surface currents obtained by an embodiment of the antenna in a second wavelength range during simulation;

[0020] Figure 8 Schematically illustrates one embodiment of an antenna, wherein the open cavity structure is formed as a substrate-integrated open cavity;

[0021] Figure 9A One embodiment of the antenna is schematically shown, wherein the various open cavity structures of each antenna are integral with the metal frame.

[0022] Figure 9B An open cavity structure integral with the metal frame is schematically shown in a perspective view from a first side;

[0023] Figure 9C An open cavity structure integral with the metal frame is schematically shown in a perspective view from a second side;

[0024] Figure 10 Schematically illustrates an antenna device according to an embodiment, the antenna device comprising four antennas arranged at different positions, which can be used in a beam switching antenna system for a second wavelength range;

[0025] Figure 11 Schematically shows the Figure 10 The simulation power capability of the antenna device during simulation;

[0026] Figure 12A schematically illustrates a wireless terminal according to various embodiments, the wireless terminal comprising an antenna for a second wavelength range; and

[0027] Figure 12B Functional elements of a wireless terminal according to various embodiments are schematically illustrated, the functional elements comprising an antenna for a second wavelength range.

[0028] Figure 12C schematically illustrates antennas for a wireless terminal according to various embodiments, the antennas being arranged as a phased array for use in a second wavelength range;

[0029] Figure 13A Schematically illustrates the incorporation of a lens mounted at an open cavity structure according to one embodiment;

[0030] Figure 13BThe combination of a lens at the display module mounted above the open cavity structure is schematically illustrated in accordance with one embodiment; and

[0031] Figure 14 An antenna device including a curved metal frame that facilitates beam steering of an open cavity structure is schematically illustrated in accordance with one embodiment. DETAILED DESCRIPTION

[0032] The present application will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the application are shown. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the application to those skilled in the art.

[0033] It should be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements can be present. In contrast, when an element is referred to as being "directly connected" to another element, there are no intervening elements present. Like numbers refer to like elements throughout. It will be further understood that, although the terms first, second, etc. can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0034] For clarity and / or conciseness, well-known functions or constructions can not be described in detail. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and will not be interpreted in an overly idealized or overly formal sense unless expressly so defined herein.

[0035] The embodiments of the application are described herein with reference to schematic illustrations of idealized embodiments of the application. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and / or tolerances, are to be expected. Thus, embodiments of the application should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. The

[0036] Various solutions are presented herein related to improvements of edge mounted antenna technology supporting at least two frequency ranges (FRs). The common denominator of such implementations is that a first frequency range FR1 has an associated upper frequency limit, while a second, higher frequency range FR2 has an associated lower frequency limit which is higher than the upper limit of FR1. The implementations are primarily presented for a metal frame antenna arrangement for 3GPP frequency ranges FR1 and FR2, where e.g. for a 5G wireless terminal, FR1 has an associated upper frequency limit of e.g. 7.125 GHz, and FR2 (mmWave) has an associated lower frequency limit of 24 GHz. However, alternative frequency ranges are reasonable within the concept of the described implementations.

[0037] Figure 1 An antenna arrangement 10 according to a general implementation is schematically illustrated. It is also a common solution to integrate an antenna 14 for cellular communication at a lower frequency range FR1 on the metal frame 12 of a wireless terminal. For such antenna designs, it can be necessary to ground / short circuit the metal frame 12 with the ground plane 11 of the main substrate 110 (such as a PCB) of the terminal at at least one location, typically several locations. In the figure, two ground connections 15 are shown. The purpose of the ground connections can be to tune the cellular antenna 14 to correct frequencies with multi-band, and to eliminate parasitic effects from other parts of the metal frame 12. According to the solutions outlined herein, at least one of these ground connections is used as an antenna in a higher frequency range FR2.

[0038] Figure 2A and Figure 2B How such an implementation of an antenna 1 is configured is explained in more detail. The antenna 1 is designed for a wireless terminal comprising a ground plane 11 and a metal frame 12 surrounding the ground plane. In particular, the metal frame 12 has a gap or clearance 13 with the ground plane 11 provided on the substrate 110. The antenna 1 is configured to form a ground connection 15 between the ground plane 11 and the metal frame 12 for operation within a first frequency range FR1. In addition, the antenna 1 comprises an open cavity structure 100 for a second frequency range FR2. That is, the open cavity structure 100 is adapted or configured for emitting radio frequency (RF) energy within the second frequency range FR2. Figure 2A A feed point 108 of the antenna 1 for FR2 operation is also indicated.

[0039] In various embodiments, the open cavity structure 100 is a waveguide structure that is at least partially open-ended in the gap 13. In other words, the ground connection 15 is designed as an open cavity structure or open-ended waveguide structure, wherein the first surface 101 (e.g. the top surface) is partially open-ended. Thereby, an open surface portion 104 is provided at the gap 13 between the metal frame 12 and the ground plane 11. At least another surface or portion of the open cavity structure 100 is directly connected to the metal frame 12 to ensure that the antenna 1 is grounded at FR1. The at least one other surface can include an edge or side surface 107 connected to the first surface 101 and / or a second surface 102 of the open cavity structure 100 opposite to the first surface 101.

[0040] In some embodiments, the open cavity structure 100 comprises a dielectric member 103 and an electrically conductive member configured to connect the ground plane and the metal frame. That is, in these embodiments, the electrically conductive member forms the ground connection 15 between the ground plane and the metal frame for operation in the first frequency range FR1. The dielectric member 103 can for example comprise a ceramic, a plastic or other dielectric material. The electrically conductive member can comprise a surface coating on the dielectric member, such as a metal cover 102, 105, 107 or a metalized surface 102, 105, 107 of the dielectric member 103. In alternative embodiments, the dielectric member can be air (such as an air gap) shaped and confined within the metal surface portion 102, 105, 107.

[0041] The electrically conductive member providing the ground connection 15 can be arranged to partially cover the dielectric member 103, thereby presenting an open surface portion 104 of the dielectric member at the gap 13 in the first surface 101 of the open cavity structure 100.

[0042] It can be noted that, Figure 2B It is shown that the electrically conductive member comprises a portion 106 at the second lower surface 102 of the open cavity structure 100, which is connected to the metal frame 12 to form the ground position 15 for FR1 operation. However, in alternative embodiments, the second surface 102 is also partially or completely open, wherein the electrically conductive member is provided as an electrically conductive edge surface 107.

[0043] Figure 3A It is schematically shown that the open surface portion 104 is directed towards the first surface 101 (i.e., Figure 2A and Figure 2BThe dashed surfaces are electrically conductive, including the ground plane 11 and surface portions 105 of the electrically conductive member. However, the open surface portion 104 is arranged at the gap 13, at least partly between the inner circumference of the metal frame 12 and the outer edge of the ground plane 11. It is noted that the ground plane 11 can be formed by inner and / or outer layers on a substrate 110, onto which various further components can be mounted (not shown).

[0044] In another aspect, Figure 3B A view towards the opposite, second surface 102 of the open cavity structure 100 is shown. Here, an embodiment according to Figure 2B is shown, wherein the electrically conductive member comprises a second surface member 106 covering the second surface 102 in the gap 13.

[0045] The dimensions of the open surface portion 104 affect the frequencies and bandwidth of the frequency range FR2 at which the antenna 1 is configured to operate. As Figure 3A indicated, the ground element 15 (formed by the electrically conductive member configured to be connected to the metal frame 12 across the gap 13) has a width W in a plane parallel to the ground plane 11. In some embodiments, the width W is half a wavelength λ / 2 of a center frequency of the intended FR2, where the wavelength λ is an effective wavelength taking into account the dielectric constant of the surrounding material. In other words, the width is about the λ / 2 half wavelength of the center frequency. For an example of FR2 operation at 28 GHz, W can be about 5 mm, or in the range of 4-6 mm depending on influences from other components. Regarding the depth L of the open portion 104, the greater the depth, the greater the width the proposed antenna can be configured to achieve. In one embodiment where the depth L is 2 mm, a bandwidth of about 4 GHz is achievable at FR2. In various embodiments, the antenna 1 can be configured to have a depth in the range of 1.5 mm to 2.5 mm.

[0046] Figure 4 A chart of simulated bandwidth measurements is schematically shown for an embodiment using an embodiment according to the embodiments discussed with reference to Figure 2A , Figure 2B and Figure 3A , Figure 3B The open cavity structure 100 of the proposed antenna 1 can achieve a very large bandwidth, such as 10 GHz with -6 dB impedance match and 4 GHz with -10 dB impedance match. The antenna gain in this embodiment is about 10 dBi.

[0047] Figure 5 An antenna aperture 50 for the described open cavity structure 100 is schematically shown, without connection to the metal frame. In another aspect, Figure 6An antenna aperture 60 for the described open cavity structure 100 is schematically illustrated when connected to the metal frame 12 at the grounding location 15. The effect is to enlarge the antenna aperture by introducing the metal frame 12.

[0048] Thus, the proposed antenna device achieves high gain since the proposed structure feeds energy onto the metal frame, which enlarges the antenna aperture to a larger radiator. Figure 7 A simulation of the surface currents at 28 GHz on the antenna device 10 is schematically illustrated, including the antenna 1, the ground plane 11, and the metal frame 12. The achieved peak gain is sufficient to meet the 3GPP spherical coverage requirement for mobile handheld devices, with an input power of about 12.5 dBm.

[0049] Figure 8 An embodiment of the antenna 1 is schematically illustrated, where the open cavity structure 100 is a substrate integrated open cavity (SIW). The SIW is an alternative to the metallization of one or more surfaces of the dielectric member 103 and provides the benefit of easy manufacturing.

[0050] As Figure 2A , Figure 2B , Figure 3A , Figure 3B and Figure 8 illustrated by the embodiments, the open cavity structure 100 can be attached to the ground plane 11, i.e. to the substrate 110 incorporating the ground plane 11. The open cavity structure 100 can be joined to the ground plane 11 or the substrate 110 by soldering, gluing, or other means. Furthermore, the open cavity structure protrudes laterally from the ground plane 11, i.e. beyond the side edges of the substrate 110, such that the open portion 104 is located in the gap 13 when the open cavity structure is connected to the metal frame 12. In a variant of the present embodiment (not illustrated), the dielectric member 103 is integral with the substrate 110 of the ground plane 11, forming a protrusion beyond the side edges of the substrate 110.

[0051] Figures 9A to 9C An alternative embodiment is schematically illustrated, where the open cavity structure 120 is integral with the metal frame 12. Figure 9A An arrangement with four open cavity structures is illustrated, but fewer or more open cavity structures 120 can be included.

[0052] Figure 9B It is illustrated how the open cavity structure 120, which is suitable for FR2, includes a conductive member 121 that is integral with the metal frame 12 and configured to be connected to the ground plane 11 of the substrate 110, e.g. as indicated in Figure 2A but in Figure 9BThe opening cavity structure 120 comprises a dielectric member 121 attached or inserted to the conductive member 121. In the illustrated embodiment, the dielectric member preferably extends to the inner periphery of the metal frame 12, so that when the substrate 110 comprising the ground plane 11 is connected to the metal frame 12, the dielectric member will be arranged to the ground plane 11 in the gap 13, e.g. as illustrated in Figure 2A The attachment can be achieved by soldering, gluing or e.g. by means of screws provided in the apertures 123, so that the connectors 124 are placed in contact with the feed locations of the opening cavity structure 120.

[0053] Figure 10 The antenna arrangement 10 is schematically illustrated, wherein four antennas 1A-D are arranged in different sections. This is similar to the embodiment of Figure 9A but here the opening cavity structures 100, 120 of the respective antennas 1A-D are located in different corners of the ground plane 11. Typically, a cellular antenna 14 requires multiple ground connections for FR1. Therefore, in some embodiments, multiple ground locations 15 are integrated with the proposed opening cavity structures 100, 120 at multiple locations on the metal frame 12 to form antennas 1A-D for FR2.

[0054] In some embodiments, each antenna 1A-D can be selectively used to implement a beam switching antenna system for FR2 in a wireless terminal incorporating the antenna arrangement 10. The benefit of such a beam switching antenna system is that it can achieve a large spherical coverage, which is one of the fundamental aspects of the 3GPP requirements for an antenna system. Figure 11 A graph representing the simulated coverage of the antenna arrangement 10 as in Figure 10 is illustrated, showing the cumulative distribution function (CDF) of the effective isotropic radiated power (EIRP). Tests have shown that the proposed beam switching array can meet the 3GPP requirements of 12 dBm input power at the antenna port, where the 12 dBm input power can be achieved by any type of mainstream power amplifier type as a front-end technology, such as CMOS, GaAs, GAN, etc.

[0055] By the various embodiments of the proposed antennas 1 employed in the antenna arrangement 10, the antennas 1 are configured to conveniently radiate or receive at the gap 13 arranged inside the metal frame. This is beneficial as it provides a convenient way of obtaining coverage even if a display module or other conductive member is placed on the ground plane 11.

[0056] Figure 12AThe wireless terminal 200 is schematically illustrated as seen towards a first surface representing the front face of the terminal. The metal frame 12 forms the perimeter of the terminal 200 and it also forms part of the antenna arrangement 10 together with one or more antennas 1A, 1B for FR2 operation, as described. Each of these antennas 1A, 1B comprises an open cavity and open cavity structure 100A, 100B, also forming the ground connection 15 for antennas for FR1 operation. The front face of the terminal holds a display 210, which is arranged to at least partly cover the ground plane 11 (not shown). The antennas 1A, 1B can be open ended outside the display 210 in the gap 13, providing wireless coverage from the front face.

[0057] Figure 12B The wireless terminal 200 is schematically illustrated. The wireless terminal 200 can be configured for communication with an access network and comprises a transceiver 204, such as a radio receiver and transmitter for communication with the access network over at least an air interface. The terminal 1 further comprises a logic unit 201. The logic unit 201 can comprise, for example, a controller or microprocessor 202. The logic unit can also comprise or be connected to a data storage device 203 configured to comprise a computer-readable storage medium. The data storage device 203 can comprise memory and can be, for example, one or more of a buffer, a flash memory, a hard drive, a removable media, a volatile memory, a non-volatile memory, a random access memory (RAM), or other suitable device. In a typical arrangement, the data storage device 203 comprises non-volatile memory for long-term data storage and volatile memory used as system memory for the controller 202. The data storage device 203 can exchange data with the processor 202 of the logic unit 201 over a data bus. The data storage device 203 is considered a non-transitory computer-readable medium. One or more processors of the logic unit 201 can execute instructions stored in the data storage device or a separate memory in order to perform the operations of the wireless terminal 200, as described herein. The wireless terminal 200 further comprises at least one antenna 1 according to the embodiments presented herein, configured to operate in FR1 and form a ground connector for FR1 operation between the ground plane 11 and the metal frame 12 (not shown). The wireless terminal 200 can also comprise a display 210 as part of the user interface. It can be noted that the wireless terminal 200 can obviously comprise other features and functionalities than those identified, such as, for example, a power supply, but these components are not shown in the drawings for the sake of clarity. Figure 12B

[0058] Figure 12C The wireless terminal 200 is schematically illustrated. The wireless terminal 200 can be configured for communication with an access network and comprises a transceiver 204, such as a radio receiver and transmitter for communication with the access network over at least an air interface. The terminal 1 further comprises a logic unit 201. The logic unit 201 can comprise, for example, a controller or microprocessor 202. The logic unit can also comprise or be connected to a data storage device 203 configured to comprise a computer-readable storage medium. The data storage device 203 can comprise memory and can be, for example, one or more of a buffer, a flash memory, a hard drive, a removable media, a volatile memory, a non-volatile memory, a random access memory (RAM), or other suitable device. In a typical arrangement, the data storage device 203 comprises non-volatile memory for long-term data storage and volatile memory used as system memory for the controller 202. The data storage device 203 can exchange data with the processor 202 of the logic unit 201 over a data bus. The data storage device 203 is considered a non-transitory computer-readable medium. One or more processors of the logic unit 201 can execute instructions stored in the data storage device or a separate memory in order to perform the operations of the wireless terminal 200, as described herein. The wireless terminal 200 further comprises at least one antenna 1 according to the embodiments presented herein, configured to operate in FR1 and form a ground connector for FR1 operation between the ground plane 11 and the metal frame 12 (not shown). The wireless terminal 200 can also comprise a display 210 as part of the user interface. It can be noted that the wireless terminal 200 can obviously comprise other features and functionalities than those identified, such as, for example, a power supply, but these components are not shown in the drawings for the sake of clarity. Figure 12A ​part of the implementation of variants of the embodiment where a plurality of antennas 1A, 1B, 1C, 1D configured for FR2 according to the solution presented herein are placed to form a phased array 122. The phased array antenna 122 can be operated by the transceiver 204 under the control of the logic unit 201 to obtain spatially different radio transmission and / or reception in the wireless terminal 200 in the FR2 frequency range.

[0059] Figure 13A and Figure 13B schematically shown Figure 12A and Figure 12B cross-sectional view of an implementation of a terminal of the embodiment. In these figures, an open cavity structure 100 is shown, which is provided at the gap 13 between the ground plane 11 and the metal frame 12. Further, a display 210 is provided above the ground plane 11. The display 210 is a module comprising at least one electrically conductive layer, which can act as a radiation shielding layer, severely reducing the wireless communication capabilities. However, by applying the FR2 antenna 1 at the gap 13, which forms a ground connection for FR1 operation, the corresponding gap between the display 210 and the metal frame 12 is used to obtain the communication capabilities to and from the front face of the terminal 200.

[0060] As Figure 13A and Figure 13B various embodiments can comprise a lens 130, which is provided for optimizing the radiation pattern of the antenna 1 at the gap 13. The lens 130 is arranged above the antenna 1 and is configured to focus or collimate radio waves of the second frequency range FR2. Such an arrangement can for example be used to control or concentrate the radiation pattern in a direction substantially perpendicular to the ground plane 11 and the display 210. The lens 130 can for example be attached by means of glue, which is transparent for the desired wavelength region of FR2.

[0061] In one embodiment, as Figure 13A shown, such a lens can be provided on the open cavity structure 100, above the open surface portion 104.

[0062] In an alternative embodiment, as Figure 13B shown, the lens can be provided on the display module 210, above the open surface portion 104.

[0063] In order to focus and collimate the radiation to and from the antenna 1, the lens can take any suitable shape. This includes wedge-shaped, trapezoidal and convex. The lens 130 can be manufactured from a material that is highly transmissive for the desired wavelength region of FR2 and has a suitable refractive index.

[0064] Figure 14An antenna device comprising a curved metal frame 12 according to embodiments is schematically illustrated, which facilitates beam steering of the open cavity structure. With such a design, the side lobes from the open cavity structure 100 can be reduced upwards in the figure, while the forward facing lobe is increased. In various embodiments, the lens 130 and the curved metal frame 12 can be combined to optimize the radiation pattern of the antenna 1.

[0065] Thus, the foregoing disclosure proposes various antenna designs implemented by feeding energy from an open cavity waveguide-like structure 100 into a metal frame 12 for use in a wireless terminal. The large aperture on the metal frame facilitates high gain at FR2, such as the millimeter wave band, and also facilitates beam shaping. For an antenna system, the larger its aperture, the higher gain it can achieve. The metal frame 12 serves as a reflector, reflecting energy towards a certain desired direction. The proposed open cavity structure 100 further acts as a ground connection in FR1, which provides a convenient solution for integration of a multi-band antenna system. Furthermore, the open surface portion 104 on the open cavity structure 100 occupies very little space and is arranged in a small gap just inside the metal frame 12. In this way, the antenna of the proposed solution can be integrated on a full display wireless terminal.

Claims

1. An antenna for use in a wireless terminal comprising a ground plane and a metal frame, the metal frame enclosing the ground plane, the metal frame and the ground plane having a gap therebetween; wherein the antenna comprising an open cavity structure, wherein at least one surface or portion of the open cavity structure is directly connected with the metal frame to ensure a ground connection between the ground plane and the metal frame when the antenna communicates at a first frequency range, wherein the open cavity structure is configured to emit radio frequency energy in a second frequency range, wherein the open cavity structure comprises a dielectric member and an electrically conductive member configured to connect the ground plane with the metal frame and arranged to partially cover the dielectric member, thereby presenting an open surface portion of the dielectric member at the gap and a partial surface of the dielectric member not covering the electrically conductive member at the gap, thereby being directly connected with the metal frame.

2. The antenna of claim 1, wherein, the open surface portion is configured at a first surface of the open cavity structure.

3. The antenna of claim 2, wherein, the electrically conductive member at least partially covers the dielectric member at a second surface of the open cavity structure opposite to the first surface.

4. The antenna of claim 2 or 3, wherein, the electrically conductive member at least partially covers an edge surface of the open cavity structure, the edge surface being connected to the first surface.

5. The antenna of claim 1, wherein, the electrically conductive member comprises a surface coating on the dielectric member.

6. The antenna of claim 1, wherein, the open cavity structure is a substrate integrated open cavity.

7. The antenna of claim 1, wherein, the open cavity structure is integral with the metal frame.

8. The antenna of claim 1, wherein, the open cavity structure is attached to a substrate of the ground plane and protrudes laterally from the substrate.

9. The antenna of claim 1, wherein, the dielectric member is integral with a substrate of the ground plane.

10. The antenna of claim 9, wherein, the dielectric member comprises a laterally protruding portion of the substrate of the ground plane.

11. The antenna according to claim 1, wherein, the electrically conductive member has a width of half a wavelength of a center frequency of the second frequency range in a plane parallel to the ground plane.

12. The antenna according to claim 1, wherein, the second frequency range is a millimeter wave range.

13. The antenna according to claim 1, wherein, the gap is at least 1.5 mm at the ground connection.

14. The antenna of claim 1, comprising a lens configured to focus radio waves of the second frequency range, the lens being arranged above the antenna.

15. The antenna of claim 14, wherein, the lens is disposed on the open surface portion of the dielectric member.

16. An antenna arrangement comprising an antenna according to any of claims 1 to 15; a ground plane; and a metal frame surrounding the ground plane, the metal frame and the ground plane having a gap therebetween, wherein the antenna connects the ground plane to the metal frame at a ground point.

17. The antenna arrangement of claim 16, comprising a first antenna for the first frequency range.

18. The antenna arrangement of claim 16 or 17, comprising a plurality of ground connections between the ground plane and the metal frame, the plurality of ground connections being configured as a plurality of antennas for the first frequency range. ​ 19. A wireless terminal comprising the antenna device according to any one of claims 16 to 18.

20. The wireless terminal according to claim 19, comprising a display module attached on top of the ground plane.

21. The wireless terminal of claim 20, wherein, A lens is provided on the display module.

22. The wireless terminal according to any one of claims 19 to 21, when comprising the antenna device according to claim 18, comprising: a transceiver connected to the plurality of antennas; and a logic unit configured to control the transceiver to transmit radio signals by beam switching operation with selective use of one or more of the plurality of antennas.

23. The wireless terminal according to any one of claims 19 to 22, wherein the display module comprises a liquid crystal display.

24. The wireless terminal according to any one of claims 19 to 23, wherein the display module comprises an organic light emitting diode display.

25. The wireless terminal according to any one of claims 19 to 24, wherein the display module comprises a touch screen.

26. The wireless terminal according to any one of claims 19 to 25, wherein the display module comprises a flexible display.

27. The wireless terminal according to any one of claims 19 to 26, wherein the display module comprises a transparent display.

28. The wireless terminal according to any one of claims 19 to 27, wherein the display module comprises a curved display.

29. The wireless terminal according to any one of claims 19 to 28, wherein the display module comprises a foldable display.

30. The wireless terminal according to any one of claims 19 to 29, wherein the display module comprises a rollable display.

31. The wireless terminal according to any one of claims 19 to 30, wherein the display module comprises a stretchable display.

32. The wireless terminal according to any one of claims 19 to 31, wherein the display module comprises a transparent conductive layer.

33. The wireless terminal according to any one of claims 19 to 32, wherein the display module comprises a

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