Abstract:
An integrated antenna for worldwide interoperability for microwave access (WiMax) and wireless local area network (WLAN), includes a substrate, a grounding metal strip, and first and second radiating metal strips. The first radiating metal strip is disposed on the substrate and is not connected to the grounding metal strip. The first radiating metal strip has a first portion and a second portion on two ends thereof. The first and second portions are used to induce first and second resonance modes, respectively. The second radiating metal strip is disposed on the substrate and is connected to the grounding metal strip. The second radiating metal strip is not connected to the first radiating metal strip. The energy is coupled from the second radiating metal strip to the first radiating metal strip to induce a third resonance mode. The antenna is adapted to the frequencies of WiMax and WLAN.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an antenna for wireless networks, and more particularly, to an integrated antenna for Worldwide Interoperability for Microwave Access (WiMax) and Wireless Local Area Networks (WLAN). 
   2. Description of the Related Art 
   Along with the boom in wireless communication technology, various multi-frequency communication products are emerging, and thus the wireless communication products have become a normal part of human life. Almost all of the new products are provided with the wireless transmission function in order to meet the requirements of the public, for example, a data transmission function is required in a notebook computer or a multimedia device. In order to eliminate the trouble in wiring and setting, a wireless transmission antenna setting that achieves wireless transmission has become necessary. 
   However, the conventional antenna used in wireless communication products may only be operated at a single frequency of 2.4 GHz or a dual-frequency (2.4 GHz and 5 GHz) which fail to cover the frequencies (2.5 GHz and 3.5 GHz) required in WiMax and the frequency required in WLAN. 
   Therefore, it is necessary to provide an innovative and progressive integrated antenna for WiMax and WLAN to solve the above problem. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to an integrated antenna for WiMax and WLAN which comprises a substrate, a grounding metal strip, a first radiating metal strip, and a second radiating metal strip. The substrate has a first surface. The first radiating metal strip is disposed on the first surface of the substrate and is not connected to the grounding metal strip. The first radiating metal strip has a first portion for inducing a first resonance mode and a second portion for inducing a second resonance mode on two ends thereof. The second radiating metal strip is disposed on the first surface of the substrate and is connected to the grounding metal strip. The second radiating metal strip is not connected to the first radiating metal strip. The energy is coupled from the second radiating metal strip to the first radiating metal strip to induce a third resonance mode. 
   Therefore, the integrated antenna is adapted to the frequencies (2.5 GHz and 3.5 GHz) of WiMax and the frequency of WLAN. Also, the substrate is used in the present invention as a medium having the function of reducing frequency. Moreover, the integrated antenna in the present invention is a flat planar structure, which may greatly save the space for assembling. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic view of an antenna disposed in a screen-housing frame of a notebook computer according to the present invention; 
       FIG. 2  is a partially enlarged schematic view of the antenna disposed in the screen-housing frame of the notebook computer according to the present invention; 
       FIG. 3  is a schematic view of an integrated antenna for WiMax and WLAN according to a first embodiment of the present invention; 
       FIG. 4  is a schematic view of an integrated antenna for WiMax and WLAN according to a second embodiment of the present invention; 
       FIG. 5  is a schematic view of an integrated antenna for WiMax and WLAN according to a third embodiment of the present invention; 
       FIG. 6  is a schematic view of an integrated antenna for WiMax and WLAN according to a fourth embodiment of the present invention; and 
       FIG. 7  is a schematic view of an integrated antenna for WiMax and WLAN according to a fifth embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 1 and 2  show a schematic view and a partially enlarged schematic view of an antenna disposed in a screen-housing frame of a notebook computer according to the present invention respectively. The antenna of the present invention is adapted to various wireless electronic devices, including but not limited to a notebook computer, and other electronic products such as a personal digital assistant (PDA) may utilize the integrated antenna of the present invention, so as to achieve the function of wireless communication. The notebook computer  1  has a screen  11  and a screen-housing frame  12 . The integrated antenna  2  of the present invention (e.g., the first embodiment, as shown in  FIG. 3 ) is disposed on the screen-housing frame  12  of the notebook computer  1 , and a coaxial cable  29  connects the integrated antenna  2  to a control circuit (not shown) of the notebook computer  1 , so as to transmit data through the integrated antenna  2 . 
   The integrated antenna  2  has at least one connecting structure for fixing the integrated antenna  2  to the screen-housing frame  12 . In this embodiment, the connecting structure is an adhesive layer (not shown) located on the backside of the integrated antenna  2  for adhering the integrated antenna  2  to the screen-housing frame  12 . 
     FIG. 3  shows a schematic view of an integrated antenna for WiMax and WLAN according to a first embodiment of the present invention. The integrated antenna  2  comprises a substrate  20 , a grounding metal strip  21 , a first radiating metal strip  22  and a second radiating metal strip  23 . The substrate  20  has a first surface  201 , and the material of the substrate  20  may be selected from a group consisting of plastic, foamed plastic, ceramic, FR-4, printed circuit board (PCB) and Flexible PCB. A dielectric constant of the substrate  20  is preferably higher than those of the first radiating metal strip  22  and the second radiating metal strip  23 , so as to achieve the function of reducing the frequency. 
   The grounding metal strip  21  is used to ground. In this embodiment, an auxiliary grounding metal strip  24  adhered to the grounding metal strip  21  is further provided. The auxiliary grounding metal strip  24  may be made of aluminum foil. 
   The first radiating metal strip  22  is disposed on the first surface  201  of the substrate  20 . The first radiating metal strip  22  is not connected to the grounding metal strip  21  and not connected to the second radiating metal strip  23 . The first radiating metal strip  22  has a first portion  25  and a second portion  26  on two ends thereof. The first portion  25  is used for inducing a first resonance mode, and the second portion  26  is used for inducing a second resonance mode. 
   The length of the first portion  25  is smaller than that of the second portion  26 , and thus the frequency of the first resonance mode is higher than that of the second resonance mode. The frequency of the first resonance mode ranges from 4.9 GHz to 6 GHz, the frequency of the second resonance mode ranges from 3.3 GHz to 3.9 GHz. 
   In this embodiment, the first radiating metal strip  22  has an opening  221  for distinguishing the first portion  25  from the second portion  26 . The first portion  25  is rectangular-shaped and has a first extension portion  251  extending in a first direction (to the right in the figure). The second portion  26  has a first end  261  and a second end  262 . The first end  261  is connected to the first portion  25 . The width of the second end  262  is larger than that of the first end  261 . The second end  262  is rectangular-shaped and has a second end face  2621 . 
   The second radiating metal strip  23  is disposed on the first surface  201  of the substrate  20  and connected to the grounding metal strip  21 . The second radiating metal strip  23  is not connected to the first radiating metal strip  22 , and the energy is coupled from the second radiating metal strip  23  to the first radiating metal strip  22  to induce a third resonance mode. The frequency of the third resonance mode ranges from 2.3 GHz to 2.7 GHz, which covers the frequency of WiMax and the frequency of 2.4 GHz of WLAN. 
   In this embodiment, the second radiating metal strip  23  has a third end  231  and a fourth end  232 , and the third end  231  is connected to the is grounding metal strip  21 . The fourth end  232  is perpendicular to the third end  231  and has a fourth end face  2321 . The fourth end face  2321  faces the second end face  2621  of the second end  262 , and is spaced from the other by a first pitch. 
   In this embodiment, the first end  261  of the second portion  26  of the first radiating metal strip  22  further comprises a feed-in point  27 . The grounding metal strip  21  further comprises a ground point  28 , and the feed-in point  27  and the ground point  28  are electrically connected to a signal end and a ground end of the coaxial cable  29  respectively. 
   In this embodiment, the first radiating metal strip  22  and the second radiating metal strip  23  are adhered to the first surface  201  of the substrate  20 . 
   Therefore, the integrated antenna  2  of the present invention is adapted to the frequencies (2.5 GHz and 3.5 GHz) of WiMax and the frequency (2.4 GHz or 5 GHz) of WLAN. Also, the substrate  20  is used in the present invention as a medium having the function of reducing frequency. Moreover, the integrated antenna  2  in the present invention is a flat planar structure, which may greatly save the space for assembling. 
     FIG. 4  shows a schematic view of an integrated antenna for WiMax and WLAN according to a second embodiment of the present invention. The integrated antenna  3  comprises a substrate  30 , a grounding metal strip  31 , a first radiating metal strip  32 , and a second radiating metal strip  33 . The first radiating metal strip  32  has a first portion  35  and a second portion  36  on two ends thereof. The second portion  36  has a first end  361  and a second end  362 . The second end  362  is rectangular shaped, and has a second end face  3621 . The second radiating metal strip  33  has a third end  331  and a fourth end  332 , and the fourth end  332  has a fourth end face  3321 . 
   The difference between the integrated antenna  3  in this embodiment and the integrated antenna  2  in the first embodiment ( FIG. 3 ) lies in the fact that the second end  362  has a second extension portion  363  extending to a first direction (to the right in the figure) and facing the fourth end face  3321 . The width W 1  of the second end  362  is greater than the width W 2  of the second extension portion  363 . The fourth end  332  has a third extension portion  333  extending to a second direction (to the left in the figure) and facing the second end face  3621 . The third extension portion  333  is perpendicular to the fourth end face  3321 . The width W 3  of the fourth end  332  is greater than the width W 4  of the third extension portion  333 . The second direction is opposite the first direction. The second extension portion  363  is parallel to the third extension portion  333 , and is spaced from the other by a second pitch. In this embodiment, the second extension portion  363  is disposed below the third extension portion  333 . The second pitch ranges from 0.1 mm to 5 mm. 
     FIG. 5  shows a schematic view of an integrated antenna for WiMax and WLAN according to a third embodiment of the present invention. The integrated antenna  4  in this embodiment is substantially the same as the integrated antenna  3  in the second embodiment ( FIG. 4 ), except that a second end face  4621  of a second end  462  is an inclined plane, i.e., an angle between the second end face  4621  and a second extension portion  463  is not 90°, and the inclined plane (the second end face  4621 ) faces a third extension portion  433 . 
     FIG. 6  shows a schematic view of an integrated antenna for WiMax and WLAN according to a fourth embodiment of the present invention. The integrated antenna  5  in this embodiment is substantially the same as the integrated antenna  3  in the second embodiment ( FIG. 4 ), except that in this embodiment, a second extension portion  563  is disposed above a third extension portion  533 . 
     FIG. 7  shows a schematic view of an integrated antenna for WiMax and WLAN according to a fifth embodiment of the present invention. The integrated antenna  6  in this embodiment is substantially the same as the integrated antenna  5  in the fourth embodiment ( FIG. 6 ), except that a second end face  6621  of a second end  662  is an inclined plane, i.e., an angle between the second end face  6621  and a second extension portion  663  is not 90°, and the inclined plane (the second end face  6621 ) faces a third extension portion  633 . 
   While several embodiments of the present invention have been illustrated and described, various modifications and improvements can be made by those skilled in the art. The embodiments of the present invention are therefore described in an illustrative but not restrictive sense. It is intended that the present invention should not be limited to the particular forms as illustrated, and that all modifications which maintain the spirit and scope of the present invention are within the scope defined in the appended claims.