Abstract:
An antenna module includes an antenna, a number of conductive elements, and a connecting element. The conductive elements and the connecting element are made of conductive material. The conductive elements are adjacent to the antenna, and the connecting element allows for the connection of different numbers of the conductive elements to the antenna depending upon the desired working frequency for the antenna to increase a current length of the antenna.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The disclosure generally relates to antenna modules, particularly to an antenna module having adjustable working frequencies and a wireless communication device using the same. 
         [0003]    2. Description of the Related Art 
         [0004]    Antennas are usually assembled in a wireless communication device to send and/or receive signals. Commonly, frequencies of the antennas are adjusted according to different communication requirements by matching circuits disposed on a circuit board of the wireless communication device. However, the matching circuits make structures of the circuit board more complex and expensive. 
         [0005]    Therefore, there is room for improvement within the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Many aspects of the present embodiments 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 present embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like elements of an embodiment. 
           [0007]      FIG. 1  shows an exploded, schematic view of an exemplary embodiment of a wireless communication device having an antenna module. 
           [0008]      FIG. 2  shows an assembled schematic view of the wireless communication device of  FIG. 1 . 
           [0009]      FIG. 3  is similar to  FIG. 2 , but shown from another angle. 
           [0010]      FIG. 4  is a diagram showing return loss measurements of the antenna module of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    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.” The references “a plurality of” and “a number of” mean “at least two.” 
         [0012]      FIGS. 1-2  show an embodiment of an antenna module  100  mounted on a base board  200  of a wireless communication device  400 , such as a mobile phone or a personal digital assistant (PDA), to receive and/or send signals. In one embodiment, the base board  200  is a printed circuit board and is mounted inside a housing of the wireless communication device  400 . The base board  200  can include a feed point (not shown) and a ground point (not shown) to feed current to the antenna module  100  and provide ground for the antenna module  100 , respectively. 
         [0013]    The antenna module  100  includes an antenna  10 , a plurality of conductive elements  30 , a substrate  50 , and a connecting element  70 . 
         [0014]    The antenna  10  can be a planar inverted-F antenna, a monopole antenna, or other suitable antenna. The antenna  10  is secured on the base board  200  and connected to the feed point and the ground point to send and/or receive signals. 
         [0015]    The plurality of conductive elements  30  is made of conductive material, such as metal. In this exemplary embodiment, the conductive elements  30  are located on the base board  200  and are adjacent to and surround the antenna  10 . 
         [0016]    In one embodiment, the substrate  50  is substantially cuboid and made of plastic. The substrate  50  includes a mounting surface  51  and a side surface  53  substantially perpendicular to the mounting surface  51 . The mounting surface  51  of the substrate  50  defines a plurality of notches  511  arranged in an N×M matrix array. In this exemplary embodiment, both N and M are integers, and the N×M matrix is a 2×14 matrix. The substrate  50  is positioned over the antenna  10  and the conductive elements  30 , such that the antenna  10  and the conductive elements  30  are partially exposed from the notches  511  (see  FIG. 3 ). 
         [0017]    In one embodiment, the connecting element  70  is made of conductive material, such as metal. The connecting element  70  can be received in the notches  511  to electronically connect all or some of the conductive elements  30  to the antenna  10 . In this way, a current length of the antenna  10  can be changed, thereby adjusting a working frequency of the antenna  10 . 
         [0018]    The connecting element  70  includes a plurality of connecting blocks  71 . Referring to  FIG. 3 , in this exemplary embodiment, there are two connecting blocks  71 . One connecting block  71  is received in one corresponding notch  511  to contact the antenna  10  and two adjacent conductive elements  30 . That is, the two conductive elements  30  are electronically connected to the antenna  10  by the connecting block  71 . The other connecting block  71  is received in another notch  511  to contact one of the two conductive elements  30  electronically connected to the antenna  10 . In this way, the two connecting blocks  71  are electronically connected to each other to make the antenna  10  be electronically connected to the two conductive elements  30 , thereby increasing a current length of the antenna  10 . 
         [0019]    In other embodiments, a number of the connecting blocks  71  received in the notches  511  can be adjusted according to a needed working frequency of the antenna  10 . As long as at least one connecting block  71  is electronically connected to one conductive element  30  and the antenna  10 , the other connecting blocks  71  can electronically connect another conductive element  30  to the antenna  10 , or connect another conductive element  30  to the conductive element  30  already electronically connected to the antenna  10 . 
         [0020]    To assemble the antenna module  100  into different wireless communication devices, the substrate  50  is secured on the base board  200 , such that the conductive elements  30  and the antenna  10  are partially exposed from the notches  511  of the substrate  50 . When a working frequency of the antenna  10  needs to be changed, the connecting blocks  71  are received in the corresponding notches  511 . Due to the connecting blocks  71  being made of conductive material, the antenna  10  is electronically connected to the conductive elements  30  by the connecting blocks  71  to increase a current length of the antenna  10 , and adjust a working frequency of the antenna  10 . 
         [0021]      FIG. 4  is a diagram showing a return loss measurement of the antenna module  100 . Curve  1  represents a working frequency of the antenna module  100  when the connecting element  70  is received in the notches  511 . Curve  2  represents a working frequency of the antenna module  100  when the antenna module  100  has no connecting element  70 . As shown in  FIG. 4 , after the connecting element  70  is received in the notches  511 , a central frequency of the antenna  10  can be adjusted from about 1950 megahertz (MHz) to about 1575 MHz. 
         [0022]    In addition, table 1 below shows radiation power measurements of the antenna module  100 . As shown in table 1, when the connecting element  70  is received in the notches  511 , the radiation power of the antenna module  100  is raised to different frequencies. 
         [0000]    
       
         
               
             
               
               
             
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Radiation power table comparing performances of an antenna 
               
               
                 module of the wireless communication device 
               
             
          
           
               
                   
                 Radiation power (dB) 
               
             
          
           
               
                 Frequency 
                 Antenna module without 
                 Antenna module with connecting 
               
               
                 (MHz) 
                 connecting element 
                 element 
               
               
                   
               
               
                 1555 
                 −1.04 
                 −0.82 
               
               
                 1565 
                 −0.99 
                 −0.75 
               
               
                 1575 
                 −0.96 
                 −0.70 
               
               
                 1585 
                 −0.95 
                 −0.66 
               
               
                 1595 
                 −0.95 
                 −0.64 
               
               
                   
               
             
          
         
       
     
         [0023]    Similarly, table 2 below shows radiation efficiency measurements of the antenna module  100 . As shown in table 2, when the connecting element  70  is received in the notches  511 , the radiation efficiency of the antenna module  100  is also raised to different frequencies. 
         [0000]    
       
         
               
             
               
               
             
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Radiation efficiency table comparing performances of 
               
               
                 an antenna module of the wireless communication device 
               
             
          
           
               
                   
                 Radiation efficiency (%) 
               
             
          
           
               
                 Frequency 
                 Antenna module without 
                 Antenna module with connecting 
               
               
                 (MHz) 
                 connecting element 
                 element 
               
               
                   
               
               
                 1555 
                 79 
                 83 
               
               
                 1565 
                 80 
                 84 
               
               
                 1575 
                 80 
                 85 
               
               
                 1585 
                 80 
                 86 
               
               
                 1595 
                 80 
                 86 
               
               
                   
               
             
          
         
       
     
         [0024]    In summary, the wireless communication device  400  includes the conductive elements  30  and the connecting element  70 , and the connecting element  70  electronically connects the conductive elements  30  to the antenna  10  to adjust a current length of the antenna  10 . Thus, working frequencies of the antenna  10  can be easily adjusted, and a matching circuit is not required. Furthermore, a number of the connecting blocks  71  can be changed according to different communication requirements. Thus, a structure or a shape of the antenna  10  does not need to be changed, and a cost of the wireless communication device  400  can be effectively reduced. 
         [0025]    In the present specification and claims, the word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. Further, the word “comprising” does not exclude the presence of elements or steps other than those listed. 
         [0026]    It is to be also understood that even though numerous characteristics and advantages of exemplary embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in the matters of arrangement of parts within the principles of this disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.