Patent Publication Number: US-2010123637-A1

Title: Antenna

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates to an antenna, and more particularly to an antenna with dipole antennas connected in parallel thereto. 
     2. Related Art 
     Since the wireless communication technology that uses electromagnetic waves to transmit signals can achieve the effect of communicating with a remote device without a connection by wires in use, the products employing the wireless communication technology, such as mobile phones and notebooks, are increasingly diversified. Since these products use electromagnetic waves to transmit signals, antennas for receiving/transmitting the electromagnetic wave signals become indispensable. Currently, the antennas are mainly divided into antennas exposed outside a device and antennas built in the device. However, the antenna exposed outside the device not only influences the volume, size, and beauty of the product, but also tends to be bent and broken due to external force impacts. Therefore, the built-in antenna has become a trend. 
     The antenna applied to a bridge node of a wireless local area network in an early period is mainly a dipole antenna or a monopole antenna, but the dipole antenna and the monopole antenna are complex in manufacturing and require high costs and expenses. Therefore, currently the manufacturing of the dipole antenna in a printed circuit board (PCB) manner is favored by manufacturers and has the advantages of easy manufacturing and low cost. The printed dipole antenna is achieved by manufacturing the dipole antenna on a PCB, and thus can be combined with the circuit wiring on the PCB in manufacturing, which not only omits multi-process complex steps to save the cost, but also reduces the volume of the product. 
     In the past, when a single dipole antenna is manufactured on a small substrate, a zero point may occur on a radiation pattern thereof in a pointing direction, such that when the single dipole antenna radiates signals, abnormal signal attenuation occurs at a certain angle in the antenna radiation scope. 
     SUMMARY OF THE INVENTION 
     In view of the above problems, the present invention is directed to an antenna with at least one dipole antenna connected in parallel thereto. The at least one dipole antenna is connected in parallel to a signal feed point of a single dipole antenna, so as to alleviate the disadvantage that a zero point may be generated on the single dipole antenna. 
     The antenna disclosed according to the present invention includes a substrate, a signal feed portion, and a plurality of radiation units. The substrate has a first surface and a second surface. The signal feed portion is located on the substrate to feed in or feed out a signal. The plurality of radiation units is located on the substrate, connected to the signal feed portion, and arranged in a radial shape. 
     Each of the radiation units includes a radiation portion and a ground portion. The radiation portion is located on the first surface with one end connected to the signal feed portion. The ground portion is located on the second surface in symmetry with the radiation portion, with one end connected to the signal feed portion. 
     The antenna disclosed according to the present invention further includes a signal line and a base seat. The signal line includes a core, an insulating layer, and a ground layer. The core is connected to the radiation portion to transmit the signal. The insulating layer wraps the core. The ground layer wraps the insulating layer and is connected to the ground portion, so as to serve as a signal ground. The base seat is located at one side of the substrate and corresponds to the second surface, and includes a base plate and a frame. The base plate is located at one side of the substrate and corresponds to the second surface, and has a third surface corresponding to the second surface. The frame is disposed on the third surface and corresponds to and covers the plurality of radiation units. 
     The antenna disclosed according to the present invention has a plurality of dipole antennas connected in parallel to the signal feed portion, so as to alleviate the disadvantage that the zero point may be generated on the single dipole antenna and achieve the effect of a large half-power beam width angle. Meanwhile, the base seat is used to reflect signals radiated by the radiation units in a direction towards the second surface, i.e., to reflect and concentrate backward radiation of the antenna in a direction of forward radiation, so as to enhance a front-to-back ratio and suppress a side lobe. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given herein below for illustration only, and thus are not limitative of the present invention, and wherein: 
         FIG. 1  is a schematic view of a first embodiment of the present invention; 
         FIG. 2  is an exploded view of a second embodiment of the present invention; 
         FIG. 3  is a schematic assembled view of the second embodiment of the present invention; 
         FIG. 4  is an assembled side view of the second embodiment of the present invention; 
         FIG. 5  is a simulated diagram illustrating a radiation pattern at different angles at a frequency of 9.9 GHz according to the first embodiment of the present invention; 
         FIG. 6  is a simulated diagram illustrating a radiation pattern at different angles at the frequency of 9.9 GHz according to the second embodiment of the present invention; and 
         FIG. 7  is a diagram illustrating a radiation pattern measured at different angles at the frequency of 9.9 GHz according to the second embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The features and implementations of the present invention are described below in detail with the accompanying drawings. 
     Referring to  FIG. 1 , a schematic view of a first embodiment of the present invention is shown. In this embodiment, an antenna  100  includes a substrate  21 , a signal feed portion, and a plurality of radiation units. 
     The substrate  21  has a first surface  21   a  and a second surface  21   b . The signal feed portion is located on the substrate  21  to feed in or feed out a signal. The plurality of radiation units is located on the substrate  21 , connected to the signal feed portion, and arranged in a radial shape. 
     The plurality of radiation units includes a first radiation unit, a second radiation unit, and a third radiation unit. 
     The first radiation unit is located on the substrate  21 , connected to the signal feed portion, and arranged in a radial shape. The first radiation unit includes a first radiation portion  24   a  and a first ground portion  24   b . The first radiation portion  24   a  is located on the first surface  21   a  with one end connected to the signal feed portion. The first radiation portion  24   a  is in a geometric shape of a rectangle, a polygon, or the like. The first ground portion  24   b  is located on the second surface  21   b  in symmetry with the first radiation portion  24   a , with one end connected to the signal feed portion. 
     The second radiation unit is located on the substrate  21 , connected to the signal feed portion, and arranged in a radial shape. The second radiation unit includes a second radiation portion  25   a  and a second ground portion  25   b . The second radiation portion  25   a  is located on the first surface  21   a , with one end connected to the signal feed portion and the other end extended in a direction perpendicular to that of the other end of the first radiation portion  24   a . The second radiation portion  25   a  is in a geometric shape of a rectangle, a polygon, or the like. The second ground portion  25   b  is located on the second surface  21   b  in symmetry with the second radiation portion  25   a , with one end connected to the signal feed portion and the other end extended in a direction perpendicular to that of the other end of the first ground portion  24   b.    
     The third radiation unit is located on the substrate  21 , connected to the signal feed portion, and arranged in a radial shape. The third radiation unit includes a third radiation portion  26   a  and a third ground portion  26   b . The third radiation portion  26   a  is located on the first surface  21   a , with one end connected to the signal feed portion and the other end extended in a direction parallel to that of the other end of the second radiation portion  25   a . The third radiation portion  26   a  is in a geometric shape of a rectangle, a polygon, or the like. The third ground portion  26   b  is located on the second surface  21   b  in symmetry with the third radiation portion  26   a , with one end connected to the signal feed portion and the other end extended in a direction parallel to that of the other end of the second ground portion  25   b.    
     In this embodiment, a plurality of dipole antennas is connected in parallel to the signal feed portion, so as to alleviate the disadvantage that a zero point may be generated on a single dipole antenna and achieve the effect of a large half-power beam width angle. 
     Referring to  FIG. 2 , an exploded view of a second embodiment of the present invention is shown. This embodiment is approximately the same as the first embodiment. In this embodiment, the antenna  100  includes a base seat  27 . The base seat  27  is located at one side of the substrate  21  and corresponds to the second surface  21   b,  and includes a base plate  27   a  and a frame  27   b . The base plate  27   a  is located at one side of the substrate  21  and corresponds to the second surface  21   b , and has a third surface  270   a  corresponding to the second surface  21   b . The frame  27   b  is disposed on the third surface and corresponds to and covers the first radiation unit, the second radiation unit, and the third radiation unit. The base plate  27   a  and the frame  27   b  are made of a metal material such as copper and aluminum. A signal line  23  may penetrate through the base plate  27   a.    
     Referring to  FIG. 3 , a schematic assembled view of the second embodiment of the present invention is shown. The antenna  100  further includes the signal line  23 . The signal line  23  includes a core, an insulating layer, and a ground layer. The core is electrically connected to the signal feed portion on the first surface  21   a  to transmit a signal. The insulating layer wraps the core. The ground layer wraps the insulating layer, and is electrically connected to the signal feed portion on the second surface  21   b , so as to serve as a signal ground. The signal line  23  may penetrate through the base plate  27   a.  Referring to  FIG. 4 , an assembled side view of the second embodiment of the present invention is shown. 
     In this embodiment, the first radiation unit, the second radiation unit, and the third radiation unit are connected in parallel to the signal feed portion, so as to alleviate the disadvantage that a zero point may be generated on a single dipole antenna and achieve the effect of a large half-power beam width angle. Meanwhile, the base seat  27  is used to reflect signals radiated by the first radiation unit, the second radiation unit, and the third radiation unit in a direction towards the second surface  21   b , i.e., to reflect and concentrate backward radiation of the antenna in a direction of forward radiation, so as to enhance a front-to-back ratio and suppress a side lobe. 
       FIG. 5  is a simulated diagram illustrating a radiation pattern at different angles at a frequency of 9.9 GHz according to the first embodiment of the present invention, and  FIG. 6  is a simulated diagram illustrating a radiation pattern at different angles at the frequency of 9.9 GHz according to the second embodiment of the present invention. As can be seen from  FIGS. 5 and 6 , the second embodiment of the present invention can obtain a larger radiation angle than the first embodiment of the present invention. Therefore, the antenna and the base seat disclosed in the present invention have the effect of increasing a half-power radiation angle. 
     Referring to  FIG. 7  and Table 1,  FIG. 7  is a diagram illustrating a radiation pattern measured at different angles on a vertical plane at the frequency of 9.9 GHz according to the second embodiment of the present invention, and Table 1 is a table illustrating maximum gains and wave widths measured at different angles at the frequency of 9.9 GHz according to the second embodiment of the present invention. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Table illustrating maximum gains and wave widths measured 
               
               
                 at different angles at the frequency of 9.9 GHz 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Tangent plane (degree) 
                 0 
                 45 
                 90 
                 135 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Maximum gain (dBi) 
                 3.98 
                 3.41 
                 3.86 
                 3.61 
               
               
                   
                 Wave width (degree) 
                 95.0 
                 98.4 
                 112.3 
                 125.9