Abstract:
A monopole antenna assembly mounted on a bracket ( 3 ) of an electronic device includes an electronic connector ( 1 ), a printed monopole antenna ( 2 ) mechanically and electrically connecting with a contact ( 12 ) of the electronic connector. The electronic connector is a male connector for complementarily engaging with a female connector of a feeder cable assembly of the electronic device. The electronic connector further comprises at least one mounting leg ( 104 ) cooperating with the contact for firmly retaining the printed monopole antenna.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   The present application is a continuation-in-part application of a copending application Ser. No. 10/841,380 entitled “MONOPOLE ANTENNA ASSEMBLY” filed May 7, 2004, having an unknown serial number, the same inventors and the same assignee. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an antenna assembly, and in particular to a monopole antenna assembly employed in an electronic device. 
   2. Description of the Prior Art or Related Art 
   Today some products applied in Wireless Local Area Network (WLAN), such as WLAN Cards for desktop or laptop computer and WLAN Access Points (APs) under IEEE802.11 a/b standards have been introduced into the market. These communication devices benefit from external antennas or internal antennas. In order to fully utilize the space of the laptop computer, the internal antenna is mostly adopted to be assembled into a hinge or a backplane of a liquid crystal display of the laptop computer. But for the desktop computer, the efficient of utilizing space is not very important. So a simple antenna assembly with a perfect radiating pattern is especially important. 
   U.S. Pat. No. 6,268,836 has disclosed an antenna assembly for a handle electronic device. This antenna assembly comprises a mast, a film, a radiating antenna element disposed on the film, an electrical plug having a contact extending outwardly, a feed line for connecting the contact with the radiating antenna element. The antenna assembly makes an electrical connection with the electronic device when the electrical plug is complementarily connected into an electrical socket of the electrical device. However this antenna assembly has a complex mechanical structure resulting in higher manufacture cost. 
   Monopole antenna assemblies have been adopted for their simple structures. For example, U.S. Pat. No. 6,486,834 discloses an antenna assembly comprising printed meander monopole antenna disposed on a dielectric substrate as an internal antenna for a laptop computer. The dielectric substrate comprises a mounting hole for engaging with a screw to mount the antenna assembly into the laptop computer. However this monopole antenna assembly is not suitable for an external mounting. 
   Hence, an improved antenna assembly is desired to overcome the above-mentioned disadvantages of the prior and related arts. 
   BRIEF SUMMARY OF THE INVENTION 
   A primary object of the present invention is to provide a monopole antenna assembly with simple structure for an electronic device. 
   A monopole antenna assembly in accordance with the present invention mounted onto a bracket of an electronic device comprises an electronic connector having a contact extending outwardly and a monopole antenna having a radiating trace electrically connected with the contact. 
   The antenna assembly connects to the electronic device via a cable assembly. The electronic connector is a male connector. The cable assembly comprises a feeder cable and a female connector connecting to an end of the cable. The male connector complementarily engages with the female connector. Thus this antenna assembly is easy to be made and assembled by engaging or separating between the male and female connectors. 
   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. 1A  is a perspective view of a preferred embodiment of a monopole antenna assembly in accordance with the present invention mounted on a bracket of an electronic device. 
       FIG. 1B  is an enlarged view of the monopole antenna assembly of  FIG. 1A . 
       FIG. 2  is a cross-sectional view of an electronic connector of the monopole antenna assembly of  FIG. 1A  along line  2 — 2  of  FIG. 1A . 
       FIG. 3  is test chart recording for the monopole antenna assembly of  FIG. 1A , showing Voltage Standing Wave Ratio (VSWR) as a function of frequency. 
       FIG. 4  is a recording of a horizontally polarized principle plane radiation pattern in X-Y plane of the monopole antenna assembly of  FIG. 1A  operating at a frequency of 2.5 GHz. 
       FIG. 5  is a recording of a vertically polarized principle plane radiation pattern in X-Y plane of the monopole antenna assembly of  FIG. 1A  operating at a frequency of 2.5 GHz. 
       FIG. 6  is a recording of a horizontally polarized principle plane radiation pattern in Y-Z plane of the monopole antenna assembly of  FIG. 1A  operating at a frequency of 2.5 GHz. 
       FIG. 7  is a recording of a vertically polarized principle plane radiation pattern in Y-Z plane of the monopole antenna assembly of  FIG. 1A  operating at a frequency of 2.5 GHz. 
       FIG. 8  is a cross-sectional view of an another embodiment in accordance with the present invention. 
       FIG. 9  shows a monopole antenna assembly of the first embodiment in accordance with the present invention assembled in a desktop computer. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Reference will now be made in detail to a preferred embodiment of the present invention. 
   Referring to  FIG. 1A , a monopole antenna assembly assembled on a bracket  3  of an electronic device such as a desktop computer (not shown) comprises an electronic connector  1  and a printed monopole antenna  2 . 
   Referring to  FIG. 1B  and  FIG. 2 , the electronic connector  1  comprises a metal shield  10  divided into an upper portion  103  and a lower portion  102  by a baffle  101 , a dielectric housing  11  received in the upper portion  103 , a receiving room  105  defined in the lower portion  102  and a contact  12  getting through the receiving room  105 . Four mounting legs  104  are parallel to the contact  12  and respectively set on four corners of a top surface of the upper portion  103 . The contact  12  comprises an insert end  121  for complementarily engaging with another electronic connector (not show) of the electronic device, a retaining part  122  surrounded by the dielectric housing  11  and a connecting portion  123  for connecting with the printed monopole antenna. A pair of barbs  124  protrude from the surface of the retaining portion  122  and are fully inserted into the dielectric housing  11 . 
   The printed monopole antenna  2  comprises an elongate dielectric substrate  21  and a straight printed radiating trace  22  disposed on the substrate  21 . In this embodiment, the length of the radiating trace is 27 mm for operating at 2.4 GHZ frequency band. When the monopole antenna  2  is mounted onto the electronic connector  1 , the connecting portion  123  of the electronic connector  1  is soldered onto an end of the radiating trace  22 . Each two adjacent mounting legs  104  in one side can be selected to engage on a first surface of the substrate  21 . The contact  12  engages on a second surface of the substrate  21 . Thus the substrate  21  is clamped by the mounting legs  104  and the contact  12 . 
   The bracket  3  is a metal sheet mounted on a panel of the electronic device (such as a desktop computer). The bracket  3  comprises a hole  31  and a mounting portion  32  for mounting the bracket  3  onto the electronic device. The mounted monopole antenna assembly gets through the hole  31  with part of the electronic connector  1  below a bottom surface of the bracket  3  and the printed monopole antenna  2  on a top surface of the bracket  3 . The shield  10  of the electronic connector  1  is soldered to the bracket  3 . 
   The printed monopole antenna  2  is perpendicular to the bracket  3  to achieve a best radiating pattern. The shield  10  is soldered onto the bracket  3  to obtain a larger grounding area for the monopole antenna  2 . In this embodiment the electronic connector  1  is a male connector for engaging a female connector (not shown) of a feeder cable assembly (not shown). The feeder cable has a signal line making electrical connection with radiating trace through the contacts of the male and female connectors. The feeder cable also has a ground line founding an electrical connection path between the shields of the male and female connectors and the bracket  3 . 
   In assembling, this monopole antenna assembly utilizes the electronic connector  1  as a plug for complementarily engaging or separating with the cable assembly of the electronic device. This monopole antenna assembly is especially suitable to be an external antenna assembly for the electronic device. 
     FIG. 3  shows a test chart recording of Voltage Standing Wave Ratio (VSWR) of the monopole antenna assembly as a function of frequency. Note that VSWR drops below the desirable maximum value “2” in the 2.4–2.5 GHz frequency band, indicating acceptably efficient operation in the frequency band. 
     FIGS. 4–7  show horizontally and vertically polarized principle plane radiation patterns of the monopole antenna assembly operating at frequencies of 2.5 GHz. Note that each radiation pattern is close to a corresponding optimal radiation pattern and there is no obvious radiating blind area. 
   In another embodiment,  FIG. 8 , the radiating trace  21  of the monopole antenna assembly is a meander radiating trace which is a rectangular-wave shape. The other elements are same with the first embodiment. 
   In assembly, further referring to  FIG. 9 , the monopole antenna assembly of the first embodiment in accordance with the present invention is mounted in an expansion slot  52  in a back panel  51  of a desktop computer  5  by fixing the bracket  3  to the back panel  51 . The bracket  3  and the printed monopole antenna  2  is exposed to an exterior side  510  of the computer  5  or the bracket  3 , so the communication of the printed monopole antenna  2  is not affected by the back panel  51 . The connecting portion  123  of the contact  12  is exposed to the exterior side  510  of the computer  5  or the bracket  3  for connecting with the printed monopole antenna  2 , and the insert end  121  of the contact  12  faces an interior of the computer  15  for mating with the complementary electrical connector. 
   It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. For example, the printed circuit board may be arranged in a parallel relation with the bracket instead of the perpendicular relation.