Patent Publication Number: US-2011050539-A1

Title: Monopole antenna

Description:
BACKGROUND 
     1. Technical Field 
     Embodiments of the present disclosure relate to antennas, and especially to a monopole antenna. 
     2. Description of Related Art 
     Monopole antennas are gaining popularity, due to easy production and good performance. However, monopole antennas also have disadvantages, such as having frequency bands that may be offset by length or height of the position point, or dimensions of the monopole antennas. 
     A positioning method of the monopole antenna is by assistant devices, or other external structures. Thus, overcoming the above-described disadvantaged is desired. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a monopole antenna according to the present disclosure; and 
         FIG. 2  is a graph showing return loss of the monopole antenna of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a schematic diagram of a monopole antenna  100  as disclosed is shown. The monopole antenna  100  comprises a feed portion  10 , a radiating portion  20 , a position portion  30 , and a substrate  40 . 
     The substrate  40  defines a via hole  41 . 
     The feed portion  10  feeds electromagnetic signals by way of the via hole  41 . 
     The radiating portion  20  is L shaped, to transceive the electromagnetic signals. The radiating portion  20  comprises a first radiator  21  and a second radiator  22 . One end of the first radiator  21  is connected to the feed portion  10 . One end of the second radiator  22  is perpendicularly connected to other end of the first radiator  21 , and the other end of the second radiator  22  is free. The first radiator  21  is perpendicular to the substrate  40 . 
     In one embodiment, the first radiator  21  and the second radiator  22  are columnar. The first radiator  21  and the second radiator  22  are sectionally designed with different radii having gradually matched impedance, and broaden frequency bands of the monopole antenna  100 . 
     The position ring  30  is configured between the feed portion  10  and the radiating portion  20 , and positioned on the substrate  40 . In one embodiment, a radius of the position ring  30  is larger than that of the via hole  41 , and a radius of the feed portion  10  is approximately the same as the radius of the via hole  41 . In one embodiment, the radiating portion  20  is securely positioned on the substrate  40  by the position ring  30 , requiring no external device, making assembly more convenient. 
     Referring to  FIG. 2 , return loss of the monopole antenna  100  is shown. When the radiating portion  20  operates at approximately 2.5 GHz, the return loss is less than −10 dB, which complies with WIFI standards. 
     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.