Patent Publication Number: US-2011057850-A1

Title: Printed antenna

Description:
BACKGROUND 
     1. Technical Field 
     Embodiments of the present disclosure relate to antennas, and especially to a printed antenna. 
     2. Description of Related Art 
     Inner printed antennas are traditionally designed as a monopole antenna  1 , as shown in  FIG. 5 , and need a large area to be a ground area  3  and a clearance zone  2 . Therefore, design of a printed antenna to meet good performance and miniature demands has proven a significant challenge in the industry. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of one embodiment of a printed antenna according to the present disclosure; 
         FIG. 2  is a graph showing one exemplary embodiment of a return loss of the printed antenna of  FIG. 1 ; 
         FIG. 3  is a horizontal radiation pattern of the printed antenna of  FIG. 1 ; 
         FIG. 4  is a perpendicular radiation pattern of the printed antenna of  FIG. 1 ; and 
         FIG. 5  is a schematic diagram of another embodiment of a printed antenna according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a schematic diagram of one embodiment of a printed antenna  100  according to the present disclosure is shown. The printed antenna  100  comprises a feed portion  10 , a radiating portion  20 , a clearance zone  40 , and a ground portion  50 . 
     The ground portion  50  is “L” shape surrounding the radiating portion  20 . In one embodiment, the ground portion  50  positions the printed antenna  100  to a corner of a substrate  200 , to save space for a substrate  200 . The ground portion  50  defines a feed via  51 . 
     The feed portion  10  is shaped as a bent taper, to feed electromagnetic signals. In one embodiment, the feed portion  10  comprises a feed end  11  and a connection end  12 . A width of the feed portion  10  is gradually increased from the feed end  11  to the connection end  12 . The feed end  11  passes through the feed via  51 , and the connection end  12  is connected to the radiating portion  20 . In one embodiment, the connection end  12  is substantially vertical to the feed end  11  of the feed portion  10 , and the feed portion  10  forms an asymmetrical structure of the feed portion  10 , to match impedance. The tapered shape of the feed portion  10  can reduce return loss, and broaden the frequency bands for the printed antenna  100 . 
     The radiating portion  20  transceives electromagnetic signals, and comprises a first radiator  21  and a second radiator  22 . 
     The first radiator  21  is connected to the feed portion  10 . In one embodiment, the first radiator  21  is elongated. A width of the first radiator  21  is the same as a width of the connection end  12  of the feed portion  10 . 
     The second radiator  22  with one end connects to the first radiator  21 , and the other end is a free end. The free end of the second radiator  22  is bent along the feeding portion  10 , and defines a slot  30  between the second radiator  22  and the first radiator  21  and the feeding portion  10 . In one embodiment, shapes of the second radiator can be adjusted according to residual of the substrate  200  or the clearance zone  40 . The slot  30  is substantially elongated, to increase coupling between the first radiator  21  and the second radiator  22 . 
     The clearance zone  40  is between the ground portion  50  and the radiating portion  20 . In one embodiment, the printed antenna  100  is positioned on a corner of the substrate  200 , to save space of the clearance zone  40 , and therefore to reduce a dimension of the printed antenna  100 . 
     Referring to  FIG. 2 , an exemplary return loss of the printed antenna  1000  is shown. In test point  1 , frequency band is 1.8 GHz, return loss is 13.4990 dB. In test point  2 , the frequency band is 1.92 GHz, the return loss is −7.8990 dB. In test point  3 , the frequency band is 2.17 GHz, the return loss is −8.8270 dB. In test point  4 , the frequency band is 2.45 GHz, the return loss is −8.5900 dB. That is, the return loss is less than −7 dBm when the printed antenna  100  operates in frequency bands 1.92 GHz to 2.17 GHz, and 2.412 to 2.484 GHz, which complies with inner antenna standards, to cover WCDMA and WIFI frequency bands. 
       FIG. 3  and  FIG. 4  are radiation patterns of the printed antenna  100 . As shown, the printed antenna  100  comprises directional radiation patterns, without significant dead area. 
     Although the features and elements of the present disclosure are described as embodiments in particular combinations, each feature or element can be used alone or in other various combinations within the principles of the present disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.