Patent Publication Number: US-2010123631-A1

Title: Multi-band Antenna for a Wireless Communication Device

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is related to a multi-band antenna for a wireless communication device, and more particularly, to a multi-band antenna capable of providing extra signal paths with an extra radiating unit on a shorting unit. 
     2. Description of the Prior Art 
     An antenna is utilized for transmitting or receiving radio waves, to transmit or exchange radio signals. An electronic products having a wireless communication function, such as a notebook computer, a personal digital assistant, etc, usually accesses wireless networks via a build-in antenna. Therefore, to realize convenient wireless network access, an ideal antenna should have a wide bandwidth and a small size, to meet a main stream of reducing a size of a portable communication device and integrating an antenna into a notebook computer. In addition, with the advancement of the wireless communication technology, different wireless communication systems may have different operating frequencies. Therefore, an ideal antenna is expected to be a single antenna covering every band used in different wireless communication networks. 
     SUMMARY OF THE INVENTION 
     It is therefore a primary objective of the claimed invention to provide a multi-band antenna for a wireless communication device. 
     The present invention discloses a multi-band antenna for a wireless communication device comprising a grounding unit, coupled to a ground, a first radiating unit, a connecting unit, comprising a first end coupled to the first radiating unit, and a second end, a feeding unit, coupled between the second end of the connecting unit and the grounding unit, for receiving feed signals, a shorting unit, coupled between the second end of the connecting unit and the grounding unit, and a second radiating unit, coupled to the shorting unit. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a schematic diagram of a multi-band antenna according to an embodiment of the present invention. 
         FIG. 1B  is a schematic diagram of signal paths of the multi-band antenna in  FIG. 1A . 
         FIG. 1C  is a schematic diagram of a voltage standing wave ratio of the multi-band antenna shown in  FIG. 1A . 
         FIG. 2A  is a schematic diagram of a multi-band antenna according to an embodiment of the present invention. 
         FIG. 2B  is a schematic diagram of a voltage standing wave ratio of the multi-band antenna shown in  FIG. 2A . 
         FIG. 3A  is a schematic diagram of a multi-band antenna according to an embodiment of the present invention. 
         FIG. 3B  is a schematic diagram of a voltage standing wave ratio of the multi-band antenna shown in  FIG. 3A . 
         FIG. 4A  is a schematic diagram of a multi-band antenna according to an embodiment of the present invention. 
         FIG. 4B  is a schematic diagram of a voltage standing wave ratio of the multi-band antenna shown in  FIG. 4A . 
         FIG. 5A  is a schematic diagram of a multi-band antenna according to an embodiment of the present invention. 
         FIG. 5B  is a schematic diagram of a voltage standing wave ratio of the multi-band antenna shown in  FIG. 5A . 
         FIG. 6A  is a schematic diagram of a multi-band antenna according to an embodiment of the present invention. 
         FIG. 6B  is a schematic diagram of a voltage standing wave ratio of the multi-band antenna shown in  FIG. 6A . 
         FIG. 7A  and  FIG. 7B  are schematic diagrams of multi-band antennas according to embodiments of the present invention. 
         FIG. 8A  is a schematic diagram of a multi-band antenna according to an embodiment of the present invention. 
         FIG. 8B  is a schematic diagram of a voltage standing wave ratio of the multi-band antenna shown in  FIG. 8A . 
         FIG. 9A  is a schematic diagram of a multi-band antenna according to an embodiment of the present invention. 
         FIG. 9B  is a schematic diagram of a voltage standing wave ratio of the multi-band antenna shown in  FIG. 9A . 
         FIG. 10A  to  FIG. 10D  are schematic diagrams of multi-band antennas according to embodiments of the present invention. 
         FIG. 11A  is a schematic diagram of a multi-band antenna according to an embodiment of the present invention. 
         FIG. 11B  is a schematic diagram of a voltage standing wave ratio of the multi-band antenna shown in  FIG. 11A . 
     
    
    
     DETAILED DESCRIPTION 
     Please refer to  FIG.1A , which is a schematic diagram of a multi-band antenna  1  according to an embodiment of the present invention. The multi-band antenna  1  is utilized in a wireless communication device (such as a notebook computer), and comprises a grounding unit  12 , a first radiating unit  14 , a connecting unit  16 , a feeding unit  18 , a shorting unit  20  and a second radiating unit  22 . The grounding unit  12  is coupled to a ground, and utilized for providing grounding. The first radiating unit  14  comprises a first radiating element  140  and a second radiating element  142 , and is utilized for transmitting radio waves. The feeding unit  18  is coupled between the connecting unit  16  and the grounding unit  12 , and utilized for receiving feeding signals, so as to transmit the feeding signals to the first radiating unit  14  via the connecting unit  16 . The shorting unit  20  is coupled between the connecting unit  16  and the grounding unit  12 , and comprises a first shorting element  200  and a second shorting element  202 . An angle between the first shorting element  200  and the second shorting element  202  is preferably 90°. In addition, the second radiating unit  22  is coupled to the shorting unit  20 , and utilized for providing extra signal paths, to reach a goal of multiple bands. The second radiating unit  22  comprises a first radiating element  220  and a second radiating element  222 , and an angle between the first radiating element  220  and the second radiating element  222  is preferably 90°. 
     Please continue to refer to  FIG. 1B , which is a schematic diagram of signal paths of the multi-band antenna  1 . As illustrated in  FIG. 1B , the multi-band antenna  1  generates three signal paths: R 1 , R 2  and R 3  respectively. The signal paths R 1  and R 2  start from the feeding unit  18 , and pass through the connecting unit  16 , the first radiating element  140  and the second radiating element  142 , which are well known by those skilled in the art. The signal path R 3  starts from the feeding unit  18 , via a part of the shorting unit  20 , and finally passes through the second radiating unit  22 . That is, in addition to the signal paths R 1  and R 2 , the present invention further provides the extra signal path R 3 , to achieve three bands. 
     Therefore, via the second radiating unit  22 , the multi-band antenna  1  can provide the extra signal path R 3 , so as to generate three transmitting bands. In this case, the present invention can generate VSWR (voltage standing wave ratio) as shown in  FIG. 1C  by adjusting lengths, widths or materials of the first radiating unit  14  and the second radiating unit  22 . 
     The present invention adds the extra second radiating unit  22  to the shorting unit  20 , so as to provide the signal path R 3 . Note that, a shape, material, etc. of the second radiating unit  22  are not limited in any certain condition. Certainly, the present invention can further add other radiating units to the shorting unit  20 , or can branch an extra radiating element over the second radiating unit  22 , to provide more bands. Similarly, other units or elements can have similar changes, which are not limited. The following description respectively introduces variations of the second radiating unit  22 , the shorting unit  20 , and the first radiating unit  14 , and note that, the present invention is not limited to the examples. 
     In  FIG. 1A , the second radiating element  22  is composed of the first radiating element  220  and the second radiating element  222 , perpendicular to each other. Practically, the angle between the first radiating element  220  and the second radiating element  222  is not limited to 90°, and can be greater than or smaller than 90° according to different requirements. In addition, a shape of the second radiating unit  22  is not limited to an “L” shape formed by the first radiating element  220  and the second radiation  222 , and can be arc-shaped or an inclined plane formed by a single metal arm. 
     For example, please refer to  FIG. 2A , which is a schematic diagram of a multi-band antenna  2  according to an embodiment of the present invention. A structure of the multi-band antenna  2  is similar to that of the multi-band antenna  1 , while the difference is that the second radiating unit  22  of the multi-band antenna  1  is replaced by an arc-shaped second radiating unit  22 A in the multi-band antenna  2 . In this case, VSWR of the multi-band antenna  2  is shown in  FIG. 2B , which can generate three bands. 
     Similarly, please refer to  FIG. 3A , which is a schematic diagram of a multi-band antenna  3  according to an embodiment of the present invention. A structure of the multi-band antenna  3  is similar to that of the multi-band antenna  1 , while the difference is that the second radiating unit  22  of the multi-band antenna  1  is replaced by a second radiating unit  22 B having an inclined plane in the multi-band antenna  3 . In this case, VSWR of the multi-band antenna  3  is shown in  FIG. 3B , which can generate three bands. 
     Except changing the shape of the second radiating unit  22 , the present invention can further change a position connected between the second radiating unit  22  and the shorting unit  20 . 
     For example, please refer to  FIG. 4A , which is a schematic diagram of a multi-band antenna  4  according to an embodiment of the present invention. A structure of the multi-band antenna  4  is similar to that of the multi-band antenna  1 , while the difference is that the second radiating unit  22  of the multi-band antenna  1  is replaced by a second radiating unit  22 C, composed of three radiating elements, in the multi-band antenna  4 . Meanwhile, the second radiating unit  22 C is coupled to the second shorting element  202  of the shorting unit  20 . In this case, VSWR of the multi-band antenna  4  is shown in  FIG. 4B , which can generate three bands. 
     Moreover, when realizing the multi-band antenna of the present invention, the present invention can use multi-layer printed circuit board other than iron sheets, to realize the multi-band antenna according to different requirements. For example, please refer to  FIG.5A , which is a schematic diagram of a multi-band antenna  5  according to an embodiment of the present invention. A structure of the multi-band antenna  5  is similar to that of the multi-band antenna  1 , while the difference is that the multi-band antenna  5  is formed on a substrate  50 , the grounding unit  12 , the first radiating unit  14 , the connecting unit  16 , the feeding unit  18  and the shorting unit  20  are formed on a front plane of the substrate  50 , and the second radiating unit  22  is formed on a rear plane of the substrate  50 . In addition, the second radiating unit  22  and the shorting unit  20  are connected by a via  52 . In this case, VSWR of the multi-band antenna  5  is shown in  FIG. 5B , which can generate three bands. 
     Except the via  52 , the present invention can use various connecting units to connect the second radiating unit  22  and the shorting unit  20 . For example, please refer to  FIG. 6A , which is a schematic diagram of a multi-band antenna  6  according to an embodiment of the present invention. A structure of the multi-band antenna  6  is similar to that of the multi-band antenna  5 , while the difference is that a coupling element  52 A is used in the multi-band antenna  6  to connect the second radiating unit  22  and the shorting unit  20 . In this case, VSWR of the multi-band antenna  6  is shown in  FIG. 6B , which can generate three bands. 
     As shown in  FIG. 2A ,  2 B to  FIG. 6A ,  6 B, shape, position, connecting method of the second radiating unit  22  can be varied, and are not limited to these embodiments. In addition, the present invention can further add other radiating units to the shorting unit  20  or add other radiating elements to the second radiating unit  22 , to achieve the goal of multiple bands. For example, please refer to  FIG. 7A  and  FIG. 7B , which are schematic diagrams of multi-band antennas  71 ,  72  according to embodiments of the present invention. Structures of the multi-band antennas  71 ,  72  are similar to the structure of the multi-band antenna  1 , while the difference is that an extra third radiating unit  24  is added to the shorting unit  20  of the multi-band antenna  71 , and an extra third radiating element  224  is added to the second radiating unit  22  of the multi-band antenna  72 . Note that,  FIG. 7A  and  FIG. 7B  are only utilized for illustrating variations of the present invention, and those skilled in the art can adjust an amount of the radiating units in the shorting unit  20  or an amount of the radiating elements in the second radiating unit  22  according to different requirements. 
     The following starts to introduce variation of the shorting unit  20 . Please refer to  FIG. 8A , which is a schematic diagram of a multi-band antenna  8  according to an embodiment of the present invention. A structure of the multi-band antenna  8  is similar to that of the multi-band antenna  1 , while the difference is that the shorting unit  20  of the multi-band antenna  1  is replaced by an arc-shaped shorting unit  20 A in the multi-band antenna  8 . In this case, VSWR of the multi-band antenna  8  is shown in  FIG. 8B , which can generate three bands. 
     Similarly, please refer to  FIG. 9A , which is a schematic diagram of a multi-band antenna  9  according to an embodiment of the present invention. A structure of the multi-band antenna  9  is similar to that of the multi-band antenna  1 , while the difference is that the shorting unit  20  of the multi-band antenna  1  is replaced by a shorting unit  20 B having an inclined plane in the multi-band antenna  9 . In this case, VSWR of the multi-band antenna  9  is shown in  FIG. 9B , which can generate three bands. 
     Finally, introduce variation of the first radiating unit  14 . Please refer to  FIG. 10A  to  FIG. 10D , which are schematic diagrams of multi-band antennas  101 ,  102 ,  103  and  104  according to embodiments of the present invention. Structures of the multi-band antennas  101 ,  102 ,  103  and  104  are similar to the structure of the multi-band antenna  1 , while the difference is that extra radiating elements are added to the first radiating unit  14  in the multi-band antennas  101 ,  102 ,  103  and  104 . In the multi-band antenna  101 , a third radiating element  144  is added to the first radiating element  140  of the first radiating unit  14 . In the multi-band antenna  102 , a third radiating element  146  added to a boundary between the first radiating element  140  and the second radiating element  142  of the first radiating unit  14 . In the multi-band antenna  103 , a third radiating element  148  is added to the second radiating element  142  of the first radiating unit  14 . In the multi-band antenna  104 , except the third radiating element  148 , a fourth radiating element  150  is added to the boundary between the first radiating element  140  and the second radiating element  142 . Note that,  FIG. 10A  to  FIG. 10D  are utilized for illustrating the embodiments of the present invention, and those skilled in the art can adjust an amount of the radiating elements included in the first radiating unit  14  according to different requirements, which is not limited to these embodiments. 
     In addition, a shape of the first radiating unit  14  is not limited to a certain category. For example, please refer to  FIG. 11A , which is a schematic diagram of a multi-band antenna  11  according to an embodiment of the present invention. A structure of the multi-band antenna  11  is similar to that of the multi-band antenna  1 , while the difference is that the first radiation  14  of the multi-band antenna  1  is replaced by a first radiating unit  14 A in the multi-band antenna  11 . The first radiating unit  14 A comprises a first radiating element  140 A and a second radiating element  140 B, and both have bending structures. In this case, VSWR of the multi-band antenna  11  is shown in  FIG. 11B , which can generate three bands. 
     Note that, the aforementioned embodiments are utilized for illustrating merits of the present invention. Those skilled in the art can make modification and variation according to different requirements. Meanwhile, the embodiments are not applied independently, and can be cooperated. 
     To sum up, the present invention adds extra radiating units to the shorting unit of the multi-band antenna, to provide extra signal paths, so as to reach the goal of multiple bands. Therefore, through adjusting shape, scale, material, etc., of each element, the present invention can achieve a single antenna covering every band used in different wireless communication networks, to meet a main stream of reducing a size of a portable communication device. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention.