1.  Field of the Invention
The present invention relates generally to a multi-band antenna, and more particularly to a multi-band antenna suitable for being built into an electronic device, such as a notebook. 
2.  Description of the Prior Art
A present electric device always needs more than one type of antennas for wireless communication.  To make design of the electric device more beautiful, theses antennas are assembled in the inner space of the electric device.  Thus, antennas used on different frequency bands are always integrated together to reduce their volume for the limited inner space. 
US Patent Application Publication No.  2007/0040754 discloses an antenna structure integrating a first antenna of wireless wide area network (WWAN) and a second antenna of wireless local area network (WLAN), the same as U.S. Pat.  No.  7,289,071, US Patent Application Publication No.  2007/0060222, US Patent Application Publication No.  2007/0096999, and so on.  The first and second antennas respectively work as a single antenna but not influence to each other.  However, the antenna structure has two feeding line to support the two separated antennas, so that the structure is complex. 
Hence, in this art, a multi-band antenna to overcome the above-mentioned disadvantages of the prior art should be provided.