Patent Publication Number: US-7215286-B2

Title: Notebook and antenna thereof

Description:
BACKGROUND 
   The invention relates to an antenna, and more particularly to an antenna for receiving a wireless digital television signal. 
     FIG. 1   a  shows a conventional flat antenna  1  utilized in a notebook, which comprises a signal receiving element  2 , a signal line  3  and a ground element  4 . The signal receiving element  2  is connected to the ground element  4 . The signal line  3  is coupled to the signal receiving element  2 .  FIG. 1   b  shows signal reception of the conventional flat antenna  1 , wherein when a wireless signal to be received comprises a center frequency of 575 MHz, a bandwidth thereof (bandwidth is defined as signals having voltage with standing wave ratios lower than 3) is between 40–50 MHz. 
   Improvement in digital television technology has lead to a demand for notebooks to receive wireless digital television signals. Thus, notebook antennas must have a wide bandwidth to receive television signals in different frequencies to provide different television channels. The frequencies of wireless digital television signals are between 400–800 MHz, and an antenna for receiving wireless digital television signals must have a bandwidth of at least 200 MHz. Thus, a convention flat antenna cannot be utilized for receiving wireless digital television signals. 
   SUMMARY 
   Antennas are provided. An exemplar embodiment of an antenna comprises: an antenna body; a cable; a substrate; a ground element and a conductive element. The antenna body, which is U-shaped, comprises a first portion, a second portion and a third portion, wherein the first portion is planar, the second portion is connected to an end of the first portion, the third portion is connected to an end of the second portion, and the first portion is parallel to the third portion. The ground element and the conductive element are disposed on the substrate. An isolation gap is formed between the ground element and the conductive element. The first portion is coupled to the conductive element. The cable comprises a signal line coupled to the conductive element. 
   The invention provides wider bandwidth enabling reception of wireless digital television signals. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be more fully understood from the following detailed description and the accompanying drawings, given by the way of illustration only and thus not intended to limit the disclosure. 
       FIG. 1   a  shows a conventional flat antenna; 
       FIG. 1   b  shows signal reception of the conventional flat antenna; 
       FIG. 2   a  shows an antenna of a first embodiment of the invention; 
       FIG. 2   b  is an enlarged view of portion A of  FIG. 2   a;    
       FIG. 2   c  shows a path of a wireless signal in the first embodiment of the invention; 
       FIG. 2   d  shows signal reception of the antenna of the first embodiment of the invention; 
       FIG. 3  shows a notebook utilizing the antenna of the invention; 
       FIG. 4   a  shows an antenna of a second embodiment of the invention; 
       FIG. 4   b  shows an antenna of a third embodiment of the invention. 
   

   DETAILED DESCRIPTION 
   First Embodiment 
     FIG. 2   a  shows an antenna  100  of a first embodiment of the invention, which comprises an antenna body  10 , a cable  20 , a substrate  30 , a ground element  31  and a conductive element  32 . The antenna body  10  is substantially U-shaped, and comprises a first portion  11 , a second portion  12  and a third portion  13 . The first portion  11 , the second portion  12  and the third portion  13  are planar. The second portion  12  is connected to an end of the first portion  11 . The third portion  13  is connected to an end of the second portion  12 . The first portion  11  is parallel to the third portion  13 . The ground element  31  is oblong. The ground element  31  and the conductive element  32  are disposed on the substrate  30 . An isolation gap  33  is formed between the ground element  31  and the conductive element  32 . The first portion  11  is coupled to the conductive element  32 . The cable  20  comprises a signal line  21 , and the signal line  21  is coupled to the conductive element  32 . 
   In a modified example of the invention (not shown), the conductive element  32  is omitted, and the signal line  21  is directly coupled to another end of the first portion  11  opposite to the second portion  12 . 
     FIG. 2   b  is an enlarged view of portion A of  FIG. 2   a , wherein the cable  20  is a coaxial cable, and comprises the signal line  21  and a ground line  22 . The ground line  22  is near the signal line  21 . The ground line  22  is welded to the ground element  31  by solder  23 . 
   With reference to  FIG. 2   c , when the antenna  100  receives a wireless signal  40 , the wireless signal  40  passes through the third portion  13 , the second portion  12  and the first portion  11  following a U-shaped path, and is transmitted to the conductive element  32  and the signal line  21 . A length of the U-shaped path (the sum of a length L 1  of the first portion  11 , a length L 2  of the second portion  12  and a length L 3  of the third portion  13 ) is substantially equal to λ/4, wherein λ is a wave length of the wireless signal  40 . A length L 4  of the ground element  31  is λ/8. 
     FIG. 2   d  shows signal reception of the invention. When the antenna  100  receives the wireless signal comprising a center frequency 575 MHz, a bandwidth thereof (bandwidth is defined as signals having voltage with standing wave ratios lower than 3) is wider than 200 MHz. The invention thus provides wider bandwidth and enables reception of wireless digital television signals. 
     FIG. 3  shows a notebook  200  utilizing the antenna  100  of the invention. The notebook  200  comprises a housing  210 , a liquid crystal display  220 , a back plate  221 , a connection element  230 , a control interface  240  and the antenna  100 . The back plate  221 , the connection element  230  and the antenna  100  are disposed in the housing  210 . The back plate  221  is a metal plate and connected to the liquid crystal display  220 . The connection element  230  is sheet metal and straddles a ground element of the antenna  100  and the back plate  221 . A ground area of the antenna  100  is therefore increased, and bandwidth and impedance of the antenna  100  are more easily modified. 
   Second Embodiment 
     FIG. 4   a  shows a second embodiment of the invention, wherein an oblong opening  14  is formed on the third portion  13  of the antenna body  10 . A resonance length of the antenna body  10  is therefore increased, and a size of the antenna  10  is reduced. 
   Third Embodiment 
     FIG. 4   b  shows a third embodiment of the invention, wherein a triangular opening  15  is formed on the third portion  13  of the antenna body  10 . A resonance length of the antenna body  10  is therefore increased, and a size of the antenna  10  is reduced. 
   While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation to encompass all such modifications and similar arrangements.