Patent Publication Number: US-9893425-B2

Title: Antenna structure and wireless communication device using the same

Description:
FIELD 
     The disclosure generally relates to antenna structures, and particularly to a multiband antenna structure, and a wireless communication device using the same. 
     BACKGROUND 
     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, such as wireless signals operated in a long term evolution (LTE) band. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Implementations of the present technology will now be described, by way of example only, with reference to the attached figures. 
         FIG. 1  is an isometric view of a wireless communication device employing an antenna structure, according to an exemplary embodiment. 
         FIG. 2  is similar to  FIG. 1 , but shown from another angle. 
         FIG. 3  is a return loss (RL) graph of the antenna structure of  FIG. 1 . 
         FIG. 4  is an antenna efficiency graph of the antenna structure of  FIG. 1 . 
         FIG. 5  is an isometric view of the antenna structure of  FIG. 1 , showing an orthogonal projection of an third radiator plate on a first surface. 
     
    
    
     DETAILED DESCRIPTION 
     It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts have been exaggerated to better illustrate details and features of the present disclosure. 
     Several definitions that apply throughout this disclosure will now be presented. 
     The term “coupled” is defined as connected, whether directly or indirectly through intervening components, and is not necessarily limited to physical connections. The connection can be such that the objects are permanently connected or releasably connected. The term “substantially” is defined to be essentially conforming to the particular dimension, shape, or other feature that the term modifies, such that the component need not be exact. For example, substantially cylindrical means that the object resembles a cylinder, but can have one or more deviations from a true cylinder. The term “comprising,” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, group, series and the like. 
     The present disclosure is described in relation to an antenna structure and a wireless communication device using same. 
       FIG. 1  illustrates an embodiment of 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, a tablet, or an intelligent watch, for example (details not shown). The wireless communication device  200  further includes a printed circuit board (PCB)  220 , the PCB  220  forms a feed pin  222  and a ground pin  224 . The antenna structure  100  receives current from the feed pin  222 , and is grounded by the ground pin  224 . 
     The antenna structure  100  includes a baseplate  10 , a first radiator plate  20 , a second radiator plate  30 , and a third radiator plate  40 . The baseplate  10  carries the first radiator plate  20 , the second radiator plate  30 , and the third radiator plate  40 . The second radiator plate  30  is coupled to the first radiator plate  20  and the third radiator plate  40 . 
     In at least one embodiment, the baseplate  10  is made of composite materials, such as glass epoxy phenolic, for example. The baseplate  10  is located adjacent to the PCB  220 , and includes a first surface  12  and a second surface  14  opposite to the first surface  12 . The first radiator plate  20  and the second radiator plate  30  are disposed on the first surface  12 , and the third radiator plate  40  is disposed on the second surface  14 . 
     The first radiator plate  20  is substantially an L-shaped sheet, and includes a feed section  22  and an extending section  24 . The feed section  22  extends towards the PCB  220  to coupled to the feed pin  222 . The extending section  24  is perpendicularly connected to the feed section  22 , and extends towards a side of the baseplate  10 . 
     The second radiator plate  30  is substantially a U-shaped sheet, and includes a first coupling section  32 , a second coupling section  34 , and a third coupling section  36 . The first coupling section  32  can be a rectangular sheet, and is spaced from and parallel to the extending section  24 . Thus, a slot S is defined between the first coupling section  32  and the extending section  24  to allow the extending section  24  to be electronically coupled to the first coupling section  32 . The second coupling section  34  and the third coupling section  36  are symmetrically and perpendicularly connected to two opposite ends of the first coupling section  32 . 
     Also referring to  FIGS. 2 and 5 , the third radiator plate  40  is substantially a T-shaped sheet, and includes a connection section  42  and a ground section  44 . The connection section  42  can be a rectangular sheet, and is coupled to the first coupling section  32 . In at least one embodiment, lengths of the connection section  42  and the first coupling section  32  are the same. An orthogonal projection  420  of the connection section  42  on the first surface  12  and the second radiator plate  30  jointly define a rectangle  430 . That is, the orthogonal projection  420  of the connection section  42  on the first surface  12 , the second coupling section  34 , the first coupling section  32 , and the third coupling section  36  are connected in turn. The ground section  44  is perpendicularly connected to a middle portion of the connection section  42 , and extends towards the PCB  220  to coupled to the ground pin  224 . An orthogonal projection  440  of the ground section  44  on the first surface  12  is perpendicular to the first coupling section  32 . Thus, current from the second radiator plate  30  can be coupled to the connection section  42  via the second coupling section  34  and the third coupling section  36 , and the current can also be coupled from the first coupling section  32  to the ground section  44 . 
     When current is input to the feed pin  22  from the PCB  200 , the current flows to the extending section  24 , and then is coupled to the second radiator plate  30  and the third radiator plate  40 . The current is grounded by the ground section  44  to form at least three current paths. Specifically, the first radiator plate  20 , the second radiator plate  30 , and the third radiator plate  40  cooperatively form a first current path for resonating a first mode to receive and transmit wireless signals at a first bandwidth which can be for example about 2400-2484 MHz. In addition, the second radiator plate  30  and the third radiator plate  40  jointly form a second current path for resonating a second mode to receive and transmit wireless signals at a second bandwidth which can be for example about 3410-3590 MHz. Furthermore, the first radiator plate  20  forms a third current path for resonating a third mode to receive and transmit wireless signals at a third bandwidth which can be for example about 5200-6500 MHz. 
       FIG. 3  illustrates a return loss (RL) graph of the antenna structure  100 . The antenna structure  100  has good performance when operating at 2400-2484 MHz, 3410-3590 MHz, and 5200-6500 MHz, for receiving and transmitting wireless signals, such as BLUETOOTH signals, LTE signals, or WIFI signals. 
       FIG. 4  illustrates an antenna efficiency of the antenna structure  100 . When the antenna structure  100  operates at 2400-2484 MHz, the antenna efficiency can be about 60%-70%. When the antenna structure  100  operates at 3410-3590 MHz, the antenna efficiency can be about 75%-80%. When the antenna structure  100  operates at 5200-6500 MHz, the antenna efficiency can be about 60%-80%. 
     In summary, the second radiator plate  30  is coupled to the first radiator plate  20  and the third radiator plate  40 , and jointly form a closed current circuit with the third radiator plate  40 . Thus, the antenna structure  100  has good communication quality at a plurality of frequency bands used in wireless communications, which allows further size reductions of the wireless communication device  200  employing the antenna structure  100 . 
     The embodiments shown and described above are only examples. Many details are often found in the art such as the other features of the antenna structure and the wireless communication device. Therefore, many such details are neither shown nor described. Even though numerous characteristics and advantages of the present technology have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in the details, especially in matters of shape, size and arrangement of the parts within the principles of the present disclosure up to, and including the full extent established by the broad general meaning of the terms used in the claims. It will therefore be appreciated that the embodiments described above may be modified within the scope of the claims.