Patent Publication Number: US-2009231230-A1

Title: Multi-band antenna with improved connecting portion

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a multi-band antenna, and more particularly to a low-structure multi-band antenna with a new-structure connecting portion. 
     2. Description of the Prior Art 
     Miniaturization is a trend for portable electric devices. Thus, components inner the portable electric devices become thinner and smaller. Antenna, which is a necessary component in present wireless communicating device, is manufactured to be smaller and lower. Planar Inverted-F Antenna (PIFA) is a type of often-used antennas inner electrical devices. The present PIFA always uses planar three-pieces structure to form its connecting portion. However, the planar three-pieces structure has two pieces extending along the same direction. Thus, the connecting portion with three-pieces structure is not fit for reduce the length along the direction along which the two pieces extends of the antenna. 
     Hence, in this art, a multi-band antenna to overcome the above-mentioned disadvantages of the prior art should be provided. 
     BRIEF SUMMARY OF THE INVENTION 
     A primary object, therefore, of the present invention is to provide a multi-band antenna with low structure. 
     In order to implement the above object, the multi-band antenna includes a grounding element, a connecting element, a first radiating portion and a second radiating portion. The grounding element is located on a first plane. The connecting element extends upwardly from the grounding element to be defined as an L shape and comprises a longer first side and a shorter second side. The first radiating portion includes a first side and a second side. The second radiating portion is connected to the first radiating portion on a first point. The first radiating portion together with the second radiating portion forms a Z shape. The second side of the connecting element is connected to one of the two radiating portions on a second point. 
     Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of a preferred embodiment when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating a first embodiment of a multi-band antenna in according with the present invention; and 
         FIG. 2  is a perspective view illustrating a second embodiment of a multi-band antenna in according with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to a preferred embodiment of the present invention. 
     Reference to  FIG. 1 , a multi-band antenna in according with a first embodiment of the present invention is shown. The multi-band antenna  1  is assembled in a notebook computer (not shown) and comprises a grounding element  100 , a conductive metal sheet  500  and a feeding line  400 . The conductive metal sheet  500  comprises a U-shape first conductive piece  600  and a second linable conductive piece  700  extending from one of the points on the bottom side of the first conductive piece  600  except two terminal points. The grounding element  100  is located on a first plane and the metal sheet  500  is located on a second plane perpendicular to the first plane. In other embodiment, the grounding element  100  is able to be designed to be other configurations and just comprise a part thereof located on the first plane. 
     The first conductive piece  600  of the metal sheet  500  comprises an L-shape first portion to be used as a connecting portion  200 , and an L-shape second portion to be used as a first radiating portion  302 . The second conductive piece  700  is used as a second radiating portion  304 . The first radiating portion  302  together with the second radiating portion  304  forms the radiating element  300 . 
     The connecting element  200  comprises a longer first side  202  and shorter second side  204 . The first side  202  is the lower side arm of the first conductive piece  600  to be connected to the grounding element  100 . The second side  204  is connected to the radiating element  300 . A slot  800  is formed between the first side  202  and the grounding element  100 , which is made by cut a part of the grounding element  100 . 
     The radiating element  300  is of Z shape configuration. The first radiating portion  302  comprises a longer arm  3022  with an end extending along the first direction, and a short arm  3024  connected to the second radiating portion  304  which has an end extending along the second direction. 
     The feeding line  400  comprises an inner conductor  402  connected to a first point P which is the joint point of the first radiating portion  302  and the second radiating portion  304 , and an outer conductor  404  connected to the grounding element  100 . One end of the second side  204  of the connecting portion  200  is connected to the first point P. 
     In other embodiment, the location of the first point P can be moved along vertical direction to be adapted to a radiating element with different length from the radiating element  300  in the first embodiment. 
     Reference to  FIG. 2 , a multi-band antenna  100 ′ according to the second embodiment of the present invention is shown. The difference between the multi-band antenna  100  in according with the first embodiment and the multi-band antenna  100 ′ from the second embodiment is that the first point P of the multi-band antenna  100  is moved rightward to form the first point P′ of the multi-band antenna  100 ′ and the lengths of the first and second radiating portion have been changed. The multi-band antenna  100 ′ comprises a grounding element  100 ′, a connecting element  200 ′ and a radiating element  300 ′ and a feeding line  400 ′. The grounding element  100 ′ is located on a first plane. The connecting element  200 ′ and the radiating element  300 ′ are located on a second plane perpendicular to the first plane. The connecting element  200 ′ is of L-shape configuration and comprises a longer first side  202 ′ connected to the grounding element  100 ′ and a shorter second side  204 ′ connected to the radiating element  300 ′. The radiating element  300 ′ is Z shape and comprises a first radiating portion  302 ′ and a second radiating portion  304 ′ connected to the first radiating portion  302 ′ on the first point P′. The second arm  204 ′ of the connecting element  200 ′ is connected to the second radiating portion  304 ′ on a second point Q′. The first point P′ is separated from the second point Q′ to form a certain distance between the two points. The feeding line  400 ′ comprises an inner conductor  402 ′ connected to the first point P′ and an outer conductor  404 ′ connected to the grounding element  100 ′. Two bending portion  3021 ′,  3023 ′ are defined on the first radiating portion  302 ′ to make the first radiating portion  302 ′ form a Z-shape configuration. The second radiating portion  304 ′ extends along a horizontal direction. 
     While the foregoing description includes details which will enable those skilled in the art to practice the invention, it should be recognized that the description is illustrative in nature and that many modifications and variations thereof will be apparent to those skilled in the art having the benefit of these teachings. It is accordingly intended that the invention herein be defined solely by the claims appended hereto and that the claims be interpreted as broadly as permitted by the prior art.