Patent Abstract:
The metal housing of a miniaturized electronic device is shaped to function as a multiband antenna assembly. The antenna assembly includes a feeding terminal, a radiator connecting to the feeding terminal, and a metal element. The metal element is part of a housing of the electronic device. The metal element includes two antenna units, both of which are adjacent to and spaced from the radiator. An electronic device using the antenna assembly is also described.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is related to co-pending U.S. Patent Application Ser. No. 14/014,633 entitled “ANTENNA ASSEMBLY AND ELECTRONIC DEVICE USING THE ANTENNA ASSEMBLY”. Such application has the same assignee as the present application. The above-identified applications are incorporated herein by reference. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to antenna assemblies, especially to an antenna assembly integral with metal housing and an electronic device using the antenna assembly. 
     2. Description of Related Art 
     Miniaturization of electronic devices applies as well to antennas as for the electronic devices. At the same time, electronic devices having metal housings are popular since the metal housings have high strength, high heat dissipation, tactile satisfaction, and attractive appearance. However, when the electronic devices having metal housings are miniaturized, the keep-out zones of the antennas may be reduced. As a result, the sending/receiving efficiency for signals of the antennas is adversely affected. 
     Therefore, there is room for improvement within the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is an isometric view of partial of an electronic device having an antenna assembly in accordance with an exemplary embodiment. 
         FIG. 2  is a return loss diagram for the antenna assembly of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows an antenna assembly  100  which is used in an electronic device  200  having a metal housing. The electronic device  200  may be a mobile phone, a tablet computer, or a radio communication device, for example. 
     The electronic device  200  includes a circuit board  220 . The circuit board  220  defines a feeding point  222 , through which the circuit board  220  feeds electrical signals to the antenna assembly  100 . The circuit board  220  also defines a grounding point (not shown). 
     The antenna assembly  100  includes a feeding terminal  10 , a radiator  30 , and a metal element  70 . The feeding terminal  10  electrically connects to the feeding point  222 . The radiator  30  connects to the feeding terminal  10 . The metal element  70  is spaced from the radiator  30 . 
     In the exemplary embodiment, the radiator  30  includes a first radiator  31  and a second radiator  33 . The first radiator  31  is substantially perpendicularly connected to the feeding terminal  10 . The second radiator  33  is substantially perpendicularly connected to the first radiator  33 , and on a same plane as the first radiator  31 . The length of the second radiator  33  is greater than the length of the first radiator  31 . 
     The metal element  70  is metal and part of the metal housing of the electronic device  200 . The metal element  70  includes a frame  71 , a first antenna unit  72  and a second antenna unit  74 , both of which extend from the frame  71 . The frame  71  is connected to the grounding point of the circuit board  220  by screws or metallic flexible sheet (not shown). 
     The first antenna unit  72  is substantially perpendicularly connected to the frame  71 . The first antenna unit  72  is on a first plane, the frame  71  is on a second plane, and the radiator  30  is on a third plane. The first plane, the second plane, and the third plane are vertical to each other. In the exemplary embodiment, the first antenna unit  72  is a sheet extending towards the radiator  30 , and spaced from the second radiator  33 . The second antenna unit  74  is also on the first plane. The second antenna unit  74  includes a first extending sheet  741 , a second extending sheet  743 , and a third extending sheet  745 . The first extending sheet  741  extends towards a direction as the same as the first antenna unit  72 . The first extending sheet  741  is parallel to and spaced from the first antenna unit  72 , and has a length greater than the length of the first antenna unit  72 . The second extending sheet  743  extends perpendicularly towards the radiator  30 , and substantially perpendicularly connects to the first extending sheet  741  and the third extending sheet  745 . The third extending sheet  745  extends towards the feeding terminal  10 , and is spaced from the second radiator  33  and the first antenna unit  72 . In the exemplary embodiment, the vertical distance between the third extending sheet  745  and the first extending sheet  741  is equal to the vertical distance between the first antenna unit  72  and the first extending sheet  741 . The first antenna unit  72  and the first extending sheet  741  cooperatively define a first slot. The third extending sheet  745  and the first extending sheet  741  cooperatively define a second slot. 
     When the feeding terminal  10  passes electrical signals from the electronic device  200 , the electricity flows through the first radiator  31  and the second radiator  33  to excite a first mode to receive or send a first signal, such as a WCDMA band2 signal. Since the first antenna unit  72  and the second antenna unit  74  both are parallel and adjacent to the second radiator  33 , the electricity of the second radiator  33  can flow to the first antenna unit  72  and the second antenna unit  74 . The electricity flowing to the first antenna unit  72  flows through the frame  71  and then to ground, allowing a second mode to be excited, to receive or send a second signal, such as a WCDMA band1 signal. The electricity flowing to the second antenna unit  74  flows through the third extending sheet  745 , the second extending sheet  743 , and the first extending sheet  741 , in that order, to the frame  71  and then to ground, allowing a third mode to be excited, to receive or send a third signal, such as GSM 850  signal and GSM 900  signal.  FIG. 2  shows that the antenna assembly  100  has a low return loss at a first bandwidth between about 800 MHz to about 900 MHz, at a second bandwidth between about 1800 MHz to about 1900 MHz, and at a third bandwidth between about 1900 MHz to about 2100 MHz. 
     The exemplary antenna assembly  100  utilizes the metal element  70  of the electronic device  200  to form both a first antenna unit  72  and a second antenna unit  74 , which reduces the keep-out zone of the antenna assembly  100  without adversely affecting the efficiency of the antenna assembly  100 . As a result, the size of the antenna assembly  100  and the electronic device  200  are reduced. 
     It is believed that the exemplary embodiment and its advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the disclosure or sacrificing all of its advantages, the examples hereinbefore described merely being preferred or exemplary embodiment of the disclosure.

Technology Classification (CPC): 7