Abstract:
An antenna assembly and an electronic device are provided. The antenna assembly includes an antenna; a printed circuit board (PCB) electrically connected with the antenna through a feeding point; and a metal housing electrically connected with the antenna through a ground point.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based on and claims priority to Chinese Patent Application No. 2015107702423, filed Nov. 11, 2015, which is incorporated herein by reference in its entirety. 
       FIELD 
       [0002]    The present disclosure generally relates to the field of antenna technology, and more particularly to an antenna assembly and electronic device. 
       BACKGROUND 
       [0003]    With continuous development of electronic device manufacturing process, more and more electronic devices are provided with a full metal back cover. Compared to a traditional plastic back cover, a full metal back cover looks more beautiful and enables better tactile experience. 
         [0004]    However, the full metal back cover will affect radiation efficiency of an antenna in an electronic device, especially in the case where an electronic device is developed toward thinner and weight lighter, because the distance between the antenna and the full metal back cover is getting smaller, the radiation efficiency of the antenna is more and more affected. 
       SUMMARY 
       [0005]    The present disclosure provides an antenna assembly and electronic device. 
         [0006]    According to a first aspect of embodiments of the present disclosure, an antenna assembly is provided. The antenna assembly includes: an antenna; a PCB (Printed Circuit Board) electrically connected with the antenna through a feeding point; and a metal housing electrically connected with the antenna through a ground point. 
         [0007]    According to a second aspect of embodiments of the present disclosure, an electronic device is provided. The electronic device includes the antenna assembly according to any one embodiment according to the first aspect. 
         [0008]    It is to be understood that both the forgoing general descriptions and the following detailed descriptions are exemplary and explanatory only, and are not restrictive of the present disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the disclosure and, together with the description, serve to explain the principles of the disclosure. 
           [0010]      FIG. 1  is a schematic structural view of an antenna assembly according to an exemplary embodiment of the disclosure. 
           [0011]      FIG. 2  is a schematic structural view of an antenna assembly according to another exemplary embodiment of the disclosure. 
           [0012]      FIG. 3  is a schematic structural view of an antenna assembly according to yet another exemplary embodiment of the disclosure. 
           [0013]      FIG. 4  is a diagram illustrating comparison between radiation efficiency of the present antenna assembly and radiation efficiency of a traditional antenna assembly. 
           [0014]      FIG. 5  is a schematic structural view of an electronic device according to an exemplary embodiment of the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings in which same numbers in different drawings represent same or similar elements unless otherwise described. The implementations set forth in the following description of exemplary embodiments do not represent all implementations consistent with the disclosure. Instead, they are merely examples of devices and methods consistent with aspects related to the disclosure as recited in the appended claims. 
         [0016]    The antenna assembly according to various embodiments of the disclosure can be used in an electronic device configured with a metal housing. The electronic device may be a smart phone, a tablet, a smart TV, an e-book reader, an MP3 (Moving Picture Experts Group Audio Layer III) player or MP4 (Moving Picture Experts Group Audio Layer IV) player, etc. The metal housing may be a seamless housing structure. For example, the metal housing may be a seamless metal back cover of a tablet. For convenience of description, the following embodiments are only illustrated by taking an antenna assembly for a tablet as an example, which is not intended to limit the disclosure. 
         [0017]    Referring to  FIG. 1 , it shows a schematic structural view of an antenna assembly  100  according to an exemplary embodiment of the disclosure. The antenna assembly  100  includes: an antenna  120 , a PCB  140  and a metal housing  160 . 
         [0018]    The antenna  120  and the PCB  140  are electrically connected through a feeding point  142 . 
         [0019]    The antenna  120  may be a loop antenna, an inverted F-type antenna, or a planar inverted-F antenna, etc. Further, the antenna  120  and the PCB  140  are connected through a feeder line. The disclosure does not limit the type of the antenna. 
         [0020]    The feeding point  142  is located on the PCB  140 . The PCB  140  transmits current to the antenna  120  via the feeding point  142  so that the antenna  120  generates electromagnetic radiation based on the current. 
         [0021]    The antenna  120  and the metal housing  160  are electrically connected through a ground point  162 . 
         [0022]    The metal housing  160  may be a seamless housing structure such that current can be conducted between any two points on the metal housing  160 . For example, the metal housing may be a seamless metal back cover of the tablet. 
         [0023]    The ground point  162  is located on the metal housing  160 . The metal housing  160  is electrically connected with the antenna  120  via the ground point  162 , so that current flowing through the antenna  120  go through the metal housing  160 . As such, the metal housing  160  forms a part of the antenna  120 , and will generates resonance under effect of the current, and thereby radiation efficiency of the antenna assembly  100  can be improved. 
         [0024]    It should be noted that, the antenna  120  includes an antenna feeding point  122  and an antenna ground point  124 , and the antenna  120  is electrically connected with the feeding point  142  of the PCB  140  via the antenna feeding point  122 , and is electrically connected with the ground point  162  of the metal housing  160  via the antenna ground point  124 . 
         [0025]    Thus, the antenna is electrically connected with a feeding point of the PCB and also is electrically connected with the metal housing through ground points such that the metal housing forms a part of the antenna. In this way, it avoids that the radiation efficiency of the antenna will be affected greatly as the antenna is placed closer to the full metal back cover in the case where an electronic device is developed toward thinner and weight lighter. Accordingly, radiation efficiency of the antenna is increased by directing current flowing through the antenna back to the ground via the metal housing and causing resonance of the metal housing. 
         [0026]    Referring to  FIG. 2 , it shows a schematic structural view of an antenna assembly  200  according to another exemplary embodiment of the disclosure. The antenna assembly  200  includes: an antenna  220 , a PCB  240  and a metal housing  260 . 
         [0027]    The antenna  220  and the PCB  240  are electrically connected through a feeding point  242 . 
         [0028]    As shown in  FIG. 2 , the antenna  220  is electrically connected with the feeding point  242  of the PCB  240  via an antenna feeding point  222 . 
         [0029]    The antenna  220  and the metal housing  260  are electrically connected through a ground point  262 . 
         [0030]    As shown in  FIG. 2 , the antenna  220  is electrically connected with the ground point  262  of the metal housing  260  via an antenna ground point  224 . 
         [0031]    The ground point  244  of the PCB  240  is electrically connected to the metal housing  260 . 
         [0032]    Unlike the antenna assembly shown in  FIG. 1 , the PCB  240  is also provided with a ground point  244 , through which the PCB  240  is electrically connected with the metal housing  260 . The metal housing  260  directs current flowing through the antenna  220  and the metal housing  260  back to the PCB  240 . 
         [0033]    With the above described connections, when the antenna assembly  200  works, the PCB  240  transmits current to the antenna feeding point  222  of the antenna  220  via the feeding point  242 . As the current flows through the antenna  220 , electromagnetic radiation is generated. Since the antenna ground point  224  of the antenna  220  and the ground point  262  of the metal housing  260  are electrically connected, the current flowing through the antenna  220  flows to the metal housing  260 , and then flows back to the PCB  240  through the ground point  244  connecting the metal housing  260  and PCB  240 . A transmission path for the current is shown in a dotted line of  FIG. 2 . 
         [0034]    Typically, an antenna ground point of the antenna and a ground point of the PCB are directly connected such that the current flowing through the antenna directly flows back to the PCB without flowing through the metal housing, and, thus the metal housing is not involved in radiation of the antenna assembly. Therefore, the radiation efficiency of the antenna is only related to the distance between the antenna and the metal housing, the smaller the distance is, the lower the radiation efficiency of the antenna is. 
         [0035]    In the antenna assembly according to the present embodiment, however, the metal housing  260  forms a part of the antenna  220  such that radiation area of the antenna  220  is greatly increased. Under the effect of the current, the metal housing  260  generates resonance, and thereby the radiation efficiency of the antenna assembly  200  is improved significantly. 
         [0036]    Thus, in the antenna assembly according to the present embodiment, the antenna is electrically connected with a feeding point of the PCB and also is electrically connected with the metal housing through ground points such that the metal housing forms a part of the antenna. In this way, it avoids that the radiation efficiency of the antenna will be affected greatly as the antenna is placed closer to the full metal back cover in the case where an electronic device is developed toward thinner and weight lighter. Accordingly, radiation efficiency of the antenna is increased by directing current flowing through the antenna back to the ground via the metal housing and causing resonance of the metal housing. 
         [0037]    Referring to  FIG. 3 , it shows a schematic structural view of an antenna assembly  300  according to yet another exemplary embodiment of the disclosure. The antenna assembly  300  includes: an antenna  320 , a PCB  340  and a metal housing  360 . 
         [0038]    The antenna  320  and the PCB  340  are electrically connected through a feeding point  342 . 
         [0039]    As shown in  FIG. 3 , the antenna  320  is electrically connected with the feeding point  342  of the PCB  340  via an antenna feeding point  322 . 
         [0040]    The antenna  320  and the metal housing  360  are electrically connected through a ground point  362 . 
         [0041]    As shown in  FIG. 3 , the antenna  320  is electrically connected with the ground point  362  of the metal housing  360  via an antenna ground point  324 . 
         [0042]    In order to improve stability of the antenna assembly  300  in an electronic device, the PCB  340  is fixed on an intermediary metal frame  380  and electrically connected with the intermediary metal frame  380  through a ground point  344 , as shown in  FIG. 3 . 
         [0043]    The intermediary metal frame  380  is fixed on the metal housing  360  and is electrically connected with the metal housing  360 . The intermediary metal frame  380  may be made of an aluminum alloy material. 
         [0044]    It should be noted that, the present embodiment is only illustrated by taking a PCB fixed on an intermediary metal frame as an example. In practice, the battery and other components of the electronic device may also be fixed on the intermediary metal frame in order to improve stability of the various components of the electronic device, which is not limited in the disclosure. 
         [0045]    The PCB  340  transmits current to the antenna feeding point  322  of the antenna  320  via the feeding point  342 , and as current flows through the antenna  320 , electromagnetic radiation is generated. Since the antenna ground point  324  of the antenna  320  and the ground point  362  of the metal housing  360  are electrically connected, the current flows to the metal housing  360  after flowing through the antenna  320 . The current flows through the metal housing  360 , and then flows to the intermediary metal frame  380  which is electrically connected to the metal housing  360 , and then flows back to the PCB  340  via the ground point  344 . 
         [0046]    Similar with the operation principle of the antenna assembly shown in  FIG. 2 , the metal housing  360  forms a part of the antenna  320  such that radiating area of the antenna  320  is greatly increased. Under the effect of the current, the metal housing  360  generates resonance, and thereby the radiation efficiency of the antenna assembly  300  is improved significantly. 
         [0047]    Thus, in the antenna assembly according to the present embodiment, the antenna is electrically connected with a feeding point of the PCB and also is electrically connected with the metal housing through ground points such that the metal housing forms a part of the antenna. In this way, it avoids that the radiation efficiency of the antenna will be affected greatly as the antenna is placed closer to the full metal back cover in the case where an electronic device is developed toward thinner and weight lighter. Accordingly, radiation efficiency of the antenna is increased by directing current flowing through the antenna back to the ground via the metal housing and causing resonance of the metal housing. 
         [0048]    Further, in the present embodiment, by fixing the PCB on the intermediary metal frame and placing the intermediary metal frame on the metal housing, not only the antenna radiation efficiency can be improved, but also stability of the PCB and other components can be ensured. 
         [0049]      FIG. 4  illustrates comparison between radiation efficiency of the present antenna assembly and radiation efficiency of a traditional antenna assembly under the same condition (i.e. the same distance between the antenna and the metal housing), by taking WI-FI (Wireless-Fidelity) at dual-frequency of 2.4 GHz/5 GHz as an example. The X-axis in  FIG. 4  represents the radiation frequency and the Y-axis in  FIG. 4  represents the radiation efficiency. 
         [0050]    In a low frequency band, since wavelength in the low frequency band is longer, the radiation efficiency of the antenna will be very low if the distance between the antenna and the metal housing is small. For example, the traditional antenna assembly has an antenna radiation efficiency of 7.5% at 2.4 GHz. With the antenna assembly according to the embodiments of the disclosure, since the metal housing forms a part of the antenna and thus is involved in radiation of the antenna due to generation of resonance, the radiation efficiency of the antenna is improved. The antenna radiation efficiency at 2.4 GHz reaches around 20%. Obviously, by using the antenna assembly according to the embodiments of the disclosure, the radiation efficiency of the antenna can be significantly improved, especially in the low frequency band. 
         [0051]    Referring to  FIG. 5 , it shows a schematic structural view of an electronic device  500  according to an exemplary embodiment of the present disclosure. The electronic device  500  includes the antenna assembly shown in any one of the  FIG. 1 ,  FIG. 2  and  FIG. 3 . The antenna assembly includes an antenna  510 , a PCB  520 , and a metal housing  530 . 
         [0052]    The metal housing  530  may be a metal housing of the electronic device  500 .  FIG. 5  is illustrated by taking the metal housing  530  being the seamless metal back cover of the electronic device  500  as an example. 
         [0053]    It should be noted that the electronic device  500  also include other components. For example, as shown in  FIG. 5 , the electronic device  500 , when it is a tablet, also includes a display module  540  and a battery  550 . In other possible implementations, the electronic device  500  may also include components such as sensors, physical buttons, etc, which will not be described redundantly. 
         [0054]    Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the embodiments disclosed here. This application is intended to cover any variations, uses, or adaptations of the disclosure following the general principles thereof and including such departures from the present disclosure as come within known or customary practice in the art. The specification and embodiments are merely considered to be exemplary and the substantive scope and spirit of the disclosure is limited only by the appended claims. 
         [0055]    It should be understood that the disclosure is not limited to the precise structure as described above and shown in the figures, but can have various modification and alternations without departing from the scope of the disclosure. The scope of the disclosure is limited only by the appended claims.