Patent Publication Number: US-2015077294-A1

Title: Antenna structure and electronic device using the same

Description:
This application claims the benefit of People&#39;s Republic of China application Serial No. 201320568055.3, filed Sep. 13, 2013, the subject matter of which is incorporated herein by reference. 
     BACKGROUND 
     1. Field of the Invention 
     The disclosure relates in general to an antenna structure, and more particularly to an antenna structure with fixing function. 
     2. Related Art 
     As technology advances, wireless communication has been widely used in our daily life. An antenna is a necessary element in an ordinary communication electronic product. Moreover, the antenna occupies a certain amount of area in the communication electronic product. Thus there is a need for reducing the area the antenna occupies in order to make the communication electronic product small and lightweight. 
     SUMMARY 
     The disclosure is directed to an antenna structure and an electronic device using the same. 
     According to one aspect of the invention, an antenna structure is provided. The antenna structure includes a directional antenna body and a washer body. The directional antenna body includes a first metal sheet and a second metal sheet. The washer body has a screw hole. The washer body is conductive. The first metal sheet and the second metal sheet are connected to the washer body, the first metal sheet is opposite to the second metal sheet, and the first metal sheet and the second metal sheet extend upward from the washer body. 
     According to another aspect of the invention, an antenna structure is provided. The antenna structure includes a directional antenna body and a screw body. The directional antenna body includes a first metal sheet and a second metal sheet. The screw body is conductive. The first metal sheet and the second metal sheet are connected to the screw body, the first metal sheet is opposite to the second metal sheet, and the first metal sheet and the second metal sheet extend upward from the screw body. 
     According to another aspect of the invention, an electronic device is provided. The electronic device includes a circuit board, a case, an antenna structure and a screw. The antenna structure includes a directional antenna body and a washer body. The directional antenna body includes a first metal sheet and a second metal sheet. The washer body has a screw hole. The washer body is conductive. The first metal sheet and the second metal sheet are connected to the washer body, the first metal sheet is opposite to the second metal sheet, and the first metal sheet and the second metal sheet extend upward from the washer body. The screw passes through the screw hole of the washer body, and the screw fixes the antenna structure and the circuit board on the case. 
     According to another aspect of the invention, an electronic device is provided. The electronic device includes a circuit board, a case and an antenna structure. The antenna structure includes a directional antenna body and a screw body. The directional antenna body includes a first metal sheet and a second metal sheet. The screw body is conductive, and the screw body fixes the circuit board on the case. The first metal sheet and the second metal sheet are connected to the screw body, the first metal sheet is opposite to the second metal sheet, and the first metal sheet and the second metal sheet extend upward from the screw body. 
     The invention will become apparent from the following detailed description of the preferred but non-limiting embodiments. The following description is made with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a diagram of an antenna structure according to one embodiment of the invention. 
         FIG. 2A  and  FIG. 2B  show diagrams of an electronic device using the antenna structure according to one embodiment of the invention. 
         FIG. 3  shows a plot of the return loss measured according to one embodiment of the invention. 
         FIG. 4  shows a diagram of an antenna structure according to another embodiment of the invention. 
         FIG. 5A  and  FIG. 5B  show diagrams of an electronic device using the antenna structure according to another embodiment of the invention. 
     
    
    
     In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing. 
     DETAILED DESCRIPTION 
       FIG. 1  shows a diagram of an antenna structure according to one embodiment of the invention. The antenna structure  100  includes a directional antenna body  102  and a washer body  104 . The directional antenna body  102  includes a first metal sheet  106  and a second metal sheet  108 . The washer body  104  has a screw hole  110 . The washer body  104  is conductive. The first metal sheet  106  and the second metal sheet  108  are connected to the washer body  104 , the first metal sheet  106  is opposite to the second metal sheet  108 , and the first metal sheet  106  and the second metal sheet  108  extend upward from the washer body  104 , for example, extending along the direction L1. The extending direction is not limited to the direction L1. It is within the scope of the present invention as long as the metal sheets extend upward from the washer body  104 . 
     The antenna structure  100  includes the first metal sheet  106 , the second metal sheet  108  and the washer body  104 . The first metal sheet  106  and the second metal sheet  108  have a symmetric bent structure. The first metal sheet  106  bends toward a direction opposite to the second metal sheet  108 , and the second metal sheet  108  bends toward a direction opposite to the first metal  106 , such that the directional antenna body  102  has an outward opening. 
     The first metal sheet  106  and the second metal sheet  108  are both electrically connected to a signal transmission line  112 . The signal transmission line  112  may be for example a radio-frequency (RF) cable, which transmits signals from a circuit board to the antenna structure  100  for signal emission or transmits signals received at the antenna structure  100  to the circuit board. 
     The first metal sheet  106  and the second metal sheet  108  are electrically connected by the signal transmission line  112  to form a dipole antenna. The radiation frequency of the antenna structure  100  can be altered by adjusting the total length of the first metal sheet  106  and the second metal sheet  108 . The total length is roughly equal to half the wavelength of the radiation signal. In addition, the directivity of the antenna structure  100  can be altered by adjusting the bending angle of the first metal sheet  106  and the second metal sheet  108 . The point where the signal transmission line  112  touches the first metal sheet  106  or the second metal sheet  108  serves as a signal feeding point. The location of the feeding point is not limited to the location illustrated in  FIG. 1 , but may also be other locations on the metal sheet. The location of the feeding point affects the impedance matching of the antenna structure  100 . 
     The washer body  104  has a screw hole  110 . The shape of the washer body  104  may be a circle, a square, a triangle, and so on. The design of the antenna structure  100  can be modified according to the shape of the washer body  104 . In addition, the shape of the first metal sheet  106  and the second metal sheet  108  that are connected to the washer body  104  can be modified according to the shape of the washer body  104  as well. The washer body  104  of the antenna structure  100  serves as a washer for a screw. Specifically, when the washer body  104  is used with a screw, it makes the screw attached to the object more tightly and more firmly. 
     The washer body  104  may be conductive so as to make the first metal sheet  106  and the second metal sheet  108  electrically connected to each other. The screw hole  110  can be adjusted according to the screw size and the screw specification adopted. The shape of the screw hole  110  may be a circle, a square, a hexagon and so on. Combined with a screw passing through the screw hole  110 , the antenna structure  100  can be used for fixing and positioning in a communication electronic product. The screw used here may also be a plastic screw as long as it has a fixing function. 
     The antenna structure  100  may also be electrically connected to the ground plane of the circuit board. In addition, the antenna structure  100  may be fixed on other components of an electronic device, such as a case or an iron case. As long as the antenna structure  100  is electrically connected to the signal transmission line  112 , it has a function of an antenna. 
     Because the antenna structure  100  includes the directional antenna body  102  and the washer body  104 , it has both the function of a washer and the function of antenna radiation. The washer body  104  can be used with a screw to fix a first object on a second object, while the directional antenna body  102  can emit or receive wireless signals. In this embodiment, a washer and an antenna are integrated in a single element, thus the total cost and the total volume can be reduced effectively. Conventionally, the washer and the antenna are disposed on different regions of a circuit board, and each element occupies a certain area of the circuit board. Comparing with the conventional approach where a washer and an antenna are independent to each other, the directional antenna body  102  and the washer body  104  are disposed on the same region of the circuit board in this embodiment, and therefore the area of the circuit board can be saved effectively. 
     Furthermore, when installing a component on a circuit board, conventionally a fixing screw and an antenna are installed separately on the circuit board. It must take some work time to install the fixing screw and still some other work time to install the antenna. In this embodiment, however, only the antenna structure  100  has to be installed on the circuit board by a screw, the purpose of disposing the screw and disposing the antenna can be achieved simultaneously. Therefore the work time can be saved as compared with the conventional approach. 
       FIG. 2A  and  FIG. 2B  show diagrams of an electronic device using the antenna structure according to one embodiment of the invention. The electronic device  200  includes a circuit board  202 , a case  204 , the antenna structure  100  and a screw  206 .  FIG. 2A  shows the status before combining the antenna structure  100 , the circuit board  202  and the case  204 . When combining these elements, the screw  206  passes through the screw hole  110  of the washer body  104  to fix the antenna structure  100  and the circuit board  202  on the case  204 .  FIG. 2B  shows the status after combining the antenna structure  100 , the circuit board  202  and the case  204 . After fixing the circuit board  202  on the case  204  by the screw  206  and the washer body  104 , the antenna structure  100  has been disposed on the circuit board  202  as well. The signal transmission line  112  transmits signals from the circuit board  202  to feed in the antenna structure  100  so as to generate radiation signals. The signal transmission line  112  may also transmit signals received at the antenna structure  100  to the circuit board  202 . 
       FIG. 3  shows a plot of the return loss measured according to one embodiment of the invention. Take −10 dB as the threshold value of the return loss, as shown in  FIG. 3 , the radiation frequency of the antenna in this embodiment is in the range of 2.4 GHz-2.5 GHz. 
       FIG. 4  shows a diagram of an antenna structure according to another embodiment of the invention. The antenna structure  400  includes a directional antenna body  402  and a screw body  404 . The directional antenna body  402  includes a first metal sheet  406  and a second metal sheet  408 . The screw body  404  is conductive. The first metal sheet  406  and the second metal sheet  408  are connected to the screw body  404 , the first metal sheet  406  is opposite to the second metal sheet  408 , and the first metal sheet  406  and the second metal sheet  408  extend upward from the screw body  404 , for example, extending along the direction L2. The extending direction is not limited to the direction L2. It is within the scope of the present invention as long as the metal sheets extend upward from the screw body  404 . 
     The difference between this embodiment and the antenna structure  100  in the previous embodiment is that the washer body  104  is replaced by the screw body  404 , so that the antenna structure  400  includes the first metal sheet  406 , the second metal sheet  408  and the screw body  404 . The bent structure of the first metal sheet  406  and the second metal sheet  408  is the same as that in the previous embodiment. The first metal sheet  406  and the second metal sheet  408  are both electrically connected to a signal transmission line  412 . The signal transmission line  412  may be for example a RF cable. The structure of the directional antenna body  402  is the same as that in the previous embodiment, and hence the related antenna characteristics are the same, which will not be repeated here. 
     Due to the screw body  404 , the antenna structure  400  serves as a screw that is capable of fixing objects. The screw body  404  may be conductive so as to make the first metal sheet  406  and the second metal sheet  408  electrically connected to each other. The screw drive of the screw body  404  may be single slot, cross-recess, square, and so-on. The screw drive allows the user to use a corresponding screwdriver to turn the screw body  404 , which means turning the entire antenna structure  400 . The antenna structure  400 , serving as a screw, can be used for fixing and positioning in a communication electronic product. 
       FIG. 5A  and  FIG. 5B  show diagrams of an electronic device using the antenna structure according to another embodiment of the invention. The electronic device  500  includes a circuit board  502 , a case  504  and the antenna structure  400 .  FIG. 5A  shows the status before combining the antenna structure  400 , the circuit board  502  and the case  504 . The circuit board can be fixed on the case  504  by the screw body  404 .  FIG. 5B  shows the status after combining the antenna structure  400 , the circuit board  502  and the case  504 . After fixing the circuit board  502  on the case  504  by the screw body  104 , the antenna structure  400  has been disposed on the circuit board  502  as well. The signal transmission line  412  transmits signals from the circuit board  502  to feed in the antenna structure  400  so as to generate radiation signals. The signal transmission line  412  may also transmit signals received at the antenna structure  400  to the circuit board  502 . In this embodiment, the screw body  404  may be electrically connected to the ground plane of the circuit board  502 . 
     In summary, in this invention an antenna and a washer are designed as a single element such that the single element possesses both functions. Alternatively, an antenna and a screw are designed as a single element such that the single element possesses both functions. Compared with the conventional approach where a screw is used for fixing a circuit board, the antenna structure proposed in this invention possesses the characteristics of both an antenna and a washer (or a screw), and therefore the total cost and total volume of the antenna and the washer (or the screw) can be saved effectively. In addition, since the antenna and the washer (or the screw) are disposed in the same region on the circuit board, the area used on the circuit board can be further reduced. During the assembling process, after the antenna structure is combined with the circuit board and the case, the purpose of disposing the screw and disposing the antenna can be achieved simultaneously. Therefore the work time can be saved as compared with the conventional approach. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.