Patent Publication Number: US-9425509-B2

Title: Antenna structure and wireless communication device using the same

Description:
BACKGROUND 
     1. Technical Field 
     The disclosure generally relates to antenna structures, and particularly to an antenna structure for receiving/transmitting dual-band wireless signals or multiband wireless signals and a wireless communication device using the same. 
     2. Description of Related Art 
     Antennas are used in wireless communication devices such as mobile phones. The wireless communication device uses a multiband antenna to receive/transmit wireless signals at different frequencies. However, many multiband antennas have complicated structures and are large, thereby making it difficult to miniaturize the wireless communication devices. 
     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 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 views. 
         FIG. 1  is an isometric view of a wireless communication device employing an antenna structure, according to an exemplary embodiment. 
         FIG. 2  is a return loss (RL) graph of the antenna structure of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     The disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean “at least one.” 
       FIG. 1  shows a wireless communication device  200  employing an antenna structure  100 , according to an exemplary embodiment. The wireless communication device  200  can be a mobile phone or a personal digital assistant, for example. 
     The wireless communication device  200  includes a printed circuit board (PCB)  220 . The PCB  220  has a feed pin  221 , a first ground pin  222 , and a second ground pin  223  formed on one surface of the PCB  220 . The feed pin  221  is configured to provide current to the antenna structure  100 . The antenna structure  100  is located above the PCB  220 , and is grounded through the first ground pin  222  and the second ground pin  223 . 
     The antenna structure  100  includes a feed portion  10 , a first ground portion  21 , a second ground portion  22 , a first antenna  30 , and a second antenna  50 . The feed portion  10  is connected to the feed pin  221 , the first ground portion  21  is parallel to the second ground portion  22 , the first ground portion  21  is connected to the first ground pin  222 , and the second ground portion  22  is connected to the second ground pin  223 . 
     The first antenna  30  includes a first radiator  31  and a second radiator  32  substantially positioned coplanar with the first radiator  31 . The first radiator  31  is a rectangular sheet. The first radiator  31  is connected to the feed portion  10 , and extends towards the first ground portion  21 . The second radiator  32  is a substantially bent L-shaped sheet, and includes a first extending sheet  321  and a second extending sheet  322 . The first extending sheet  321  is connected to the feed portion  10 , and extends away from the first radiator  31 . The second extending sheet  322  is connected substantially perpendicularly to the first extending sheet  321 . 
     The second antenna  50  is made of metal, and two distal ends of the second antenna  50  are connected to the first ground portion  21  and the second ground portion  22 , respectively. The second antenna  50  includes a first radiation portion  51 , a second radiation portion  52 , a third radiation portion  53 , and a fourth radiation portion  54 . The first radiation portion  51  is connected to the first ground portion  21 , the fourth radiation portion  54  is connected to the second ground portion  22 , and the first radiation portion  51 , the second radiation portion  52 , the third radiation portion  53 , and the fourth radiation portion  54  are connected in turn. Thus, the second antenna  50  substantially forms a loop structure. 
     The first radiation portion  51  is parallel to the first radiator  31 , and a length of the first radiation portion  51  is greater than the first radiator  31 . The second radiation portion  52  includes a first sheet  521  and a second sheet  522 . The first sheet  521  is connected to the first radiation portion  51 , and is parallel to the first extending sheet  321 . The second sheet  522  is connected substantially perpendicularly to the first sheet  521 , and is parallel to the second extending sheet  322 . 
     The third radiation portion  53  is positioned on a plane that is substantially perpendicular to a plane in which the second radiation portion  52  is positioned. The third radiation portion  53  includes a first extending section  531 , a second extending section  532 , a third extending section  533 , a fourth extending section  534 , a fifth extending section  535 , and a sixth extending section  536 . The first extending section  531  is connected to the second sheet  522 . The second extending section  532  is connected substantially perpendicularly to the first extending section  531 . The third extending section  533  is a rectangular sheet, and is perpendicularly connected between the second extending section  532  and the fourth extending section  534 . The fourth extending section  534  and the second extending section  532  are positioned parallel to each other and extend along two opposite directions to define a first gap S 1 . The fifth extending section  535  is perpendicularly connected between the fourth extending section  534  and the sixth extending section  536 . The sixth extending section  536  and the fourth extending section  534  are positioned parallel to each other and extend along two opposite directions to define a second gap S 2 . 
     The fourth radiation portion  54  includes a first connection section  541 , a second connection section  542 , a third connection section  543 , a fourth connection section  544 , a fifth connection section  545 , a sixth connection section  546 , a seventh connection section  547 , and a eighth connection section  548 . The first connection section  541  is connected to the sixth extending section  536 . The second connection section  542  is perpendicularly connected between the first connection section  541  and the third connection section  543 , and is parallel to the fifth extending section  535 . A third gap S 3  is defined between the first connection section  541  and the third connection section  543 . The fourth connection section  544  is perpendicularly connected between the third connection section  543  and the fifth connection section  545 , and is opposite to the third extending section  533 . The fifth connection section  545  and the third connection section  543  are positioned parallel to each other and extend along two opposite directions to define a fourth gap S 4 . The sixth connection section  546  is connected substantially perpendicularly to the fifth connection section  545 , and is parallel to the third extending section  533 . The seventh connection section  547  is connected substantially perpendicularly to the sixth connection section  546 , and is substantially coplanar with the first radiation portion  51 . The eighth connection section  548  extends towards the first radiation portion  51 , and a distal end of the eight connection section  548  is connected to the second ground portion  22 . 
     When current is input to the feed portion  10  from the feed pin  221 , the current flows to the first radiator  31  and the second radiator  32 . A first proportion of the current is coupled from the first radiator  31  to the first radiation portion  51 , and is grounded via the first ground portion  21 . Thus, the first radiator  31  and the first radiation portion  51  are activated to receive/transmit first wireless signals at a first central frequency of about 1710 MHz. A second proportion of the current is coupled from the second radiator  32  to the second antenna  50 , and flows to the second radiation portion  52 , the third radiation portion  53 , and the fourth radiation portion  54 . Thus, the second radiator  32 , the second radiation portion  52 , the third radiation portion  53 , and the fourth radiation portion  54  are activated to receive/transmit second wireless signals at a second central frequency of about 800 MHz. A third proportion of the current is coupled from the second radiator  32  to the second radiation portion  52 . Thus, the second radiator  32  and the second radiation portion  52  are activated to receive/transmit third wireless signals at a third central frequency of about 2650 MHz. In addition, the current is coupled from the second radiation portion  52  to the third radiation portion  53 , and flows to the first extending section  531 , the second extending section  532 , the third extending section  533 , the fourth extending section  534 , the fifth extending section  535 , and the sixth extending section  536 . Thus, the third radiation portion  53  is activated to receive/transmit fourth wireless signals at a fourth central frequency of about 2110 MHz. Furthermore, the current is also coupled from the sixth extending section  536  to the fourth radiation portion  54 , and is grounded via the second ground portion  22 . Thus, the fourth radiation portion  54  is activated to receive/transmit fifth wireless signals at a fifth central frequency of about 2330 MHz.  FIG. 2  is a return loss (RL) graph of the antenna structure  100  of  FIG. 1 . The antenna structure  100  has good performance when operating at central frequencies of about 704-960 MHz and 1710-2690 MHz. 
     In summary, the first antenna  30  receives the current, and the current is coupled from the first antenna  30  to the second antenna  50 . Additionally, the first radiation portion  51 , the second radiation portion  52 , the third radiation portion  53 , and the fourth radiation portion  54  substantially form a loop structure to receive/transmit dual-band wireless signals or multiband wireless signals. Thus, the wireless communication device  200  does not require any additional antennas, which effectively reduces a required size of the wireless communication device  200 . 
     It is to be understood, however, that even through numerous characteristics and advantages of the present disclosure have been set forth in the foregoing description, together with details of assembly and function, the disclosure is illustrative only, and changes may be made in detail, especially in the matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.