Patent Publication Number: US-7719476-B2

Title: Complex antenna with protection member

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to an antenna, and more particularly to a complex antenna having desired operating performance. 
   2. Description of the Prior Art 
   Wireless communication devices, such as cellular phones, notebook computers, electronic appliances, and the like, are normally equipped with an antenna that serves as a medium for transmission and reception of electromagnetic signals, such as date, audio, image, and so on. The antenna can be built outside or inside of the devices. Usually, an external antenna is not easily disturbed by inner components of the electrical device and is easily adjusted by user for achieving desired operating performance. Dipole antenna is a kind of traditional external antenna. The length of a radiating element or a grounding element of a traditional dipole antenna substantially equals to ½ wavelength (λ). While, when used in long distance transmission/reception, general dipole antenna generally has weak gain and undesired operating performance. 
   Taiwan Patent No. 560706 disclosed a complex antenna comprising a dipole antenna, a helical antenna, and a rod antenna which connect to one another in series. The complex antenna improves the gain of the antenna and the communication distance of the antenna is fairly increased. However, the connection area between the dipole antenna and the inner conductor of the feeding line has no any additional protection. So, the connection area is not only easy to be broken but also easy to be oxidized. 
   Hence, in this art, a complex antenna to overcome the above-mentioned disadvantages of the prior art will be described in detail in the following embodiment. 
   BRIEF SUMMARY OF THE INVENTION 
   A primary object, therefore, of the present invention is to provide a complex antenna with protection member to protect connection area between feeding line and radiating element. 
   In order to implement the above object and overcome the above-identified deficiencies in the prior art, the complex antenna comprises a rod antenna, a helical antenna, a dipole antenna comprising a radiating element and a grounding element, an insulating tubular element, and a feeding line; the feeding line comprises an inner conductor electrically connecting to the radiating element of the dipole antenna at a first joint position and an outer conductor electrically connecting to the grounding element of the dipole antenna at a second joint position; the rod antenna, the helical antenna, and the dipole antenna are connected in series; the first joint position is covered by the insulating tubular element. 
   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 of a complex antenna in accordance with the present invention; 
       FIG. 2  is an exploded view of  FIG. 1 ; 
       FIG. 3  is a partly exploded view of  FIG. 1 ; and 
       FIG. 4  is a perspective view illustrating using environment of the complex antenna in accordance with the present invention with a shell and an RF connector assembled therewith. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Reference will now be made in detail to a preferred embodiment of the present invention. 
   Referring to  FIG. 1  to  FIG. 4 , a complex antenna  100  according to the present invention comprises three kinds of traditional antennas, a top rod antenna  10 , a middle helical antenna  20 , and a bottom dipole antenna  30 . The three kinds of traditional antennas are connected with one another in series. The dipole antenna  30  comprises a radiating element  31  and a grounding element  32  each having a length substantially equaling to ¼ wavelength. The radiating element  31  of the dipole antenna  30  extends downwardly from a bottom free end of the helical antenna  20  and the rod antenna  10  is extends upwardly from a top free end of the helical antenna  20 . 
   A feeding line  40  connects to the dipole antenna  30 . The feeding line  40  has an inner conductor  41  electrically connecting to the radiating element  31  at a first joint position, an inner insulator  42  covering the inner conductor  41 , an outer conductor  43  connecting to the grounding element  32 , and an outer insulator  44  covering the outer conductor  43 . The grounding element  32  made from sheet metal comprises a column-shape main portion  321  at bottom and a cone-shaped upper portion  322  at top. The upper portion  322  has a hole  33  there rough for permitting the inner conductor  41 , the inner insulator  42 , and the outer conductor  43  protruding beyond the upper portion  322 . The main portion  321  has an aperture (not shown) communicating with the hole  33  of the upper portion  322  just allowing the feeding line  40  protruding through. The diameter of the aperture is slightly large than that of the hole  33 . The outer conductor  43  of the feeding line  40  is electrically soldered at the top edge of the hole  33  at a second joint position or can be turned down to wrap on the outer periphery of upper portion  322  and then soldered on upper portion  322 . An insulating elastic tubular element  60  defines a run-through hole, with upper portion  322  partially received in the run-through hole, thus, the second joint position is covered by insulating elastic tubular element  60 . That is the bottom of the insulating tubular element  60  sits on the grounding element  32  and abuts against the upper portion  322  of the grounding element  32 . The insulating tubular element  60  encloses the first joint position and the second joint position and tightly contacts to the first joint position and the second joint position. So, the first and second joint positions are not easy to be destroyed and broken, and not easy to be oxidized and keeps favorable electrical connection. 
   A metal tubular element  70  is a thin metal sheet and wraps on a lower portion of the insulating tubular element  60  and the upper portion  322  of the grounding element  32 . The bottom of the metal tubular element  70  abuts against the main portion  321  of the grounding element  32 . The metal tubular element  70  and the grounding element  32  together form a capacitance to achieve impedance match for the complex antenna  100 . The second joint position is regarded as a center of the metal tubular element  70  along longitudinal direction. One half part of the metal tubular element  70  extends upwards from the center and the other half part extends downwards from the center. An inner surface of the metal tubular element  70  contacting the insulating tubular element  60  and the grounding element  32  is covered with conductive adhesive. The insulating tubular element  60  is elastic. So, the metal tubular element  70  can be pressed and adhibitted to the insulating tubular element  60 . The metal tubular element  70  is made from aluminum foil, copper foil, or other metals. 
   The rod antenna  10 , the helical antenna  20 , and the radiating element  31  of the dipole antenna  30  are made from folding a whole metal rod or soldering three separate metal rods. The installing process of the complex antenna  100  is as follows. Firstly, protruding the feeding line  40  through the aperture and the hole of the grounding element  32  until the inner conductor  41 , the inner insulator  42 , and the outer conductor  43  partially exposed beyond the edge of the upper portion  322 . Secondly, inserting the radiating element  31  of the dipole antenna  30  through the run-through hole of the insulating tubular element  60 . Thirdly, the inner conductor  41  electrically connects to the radiating element  31  and the outer conductor  43  electrically connects to the edge of the hole  33  to form the first and second joint positions as described above. Fourthly, pulling down the insulating tubular element  60  to abut against the upper portion  322  and cover the first and second joint positions. Fifthly, the metal tubular element  70  is adhibitted to the insulating tubular element  60  and the grounding element  32  with upper portion of the insulating tubular element  60  and the main portion  321  exposed in outside. Thus, the complex antenna  100  is achieved. Referring to the  FIG. 4 , A shell  80  covering the complex antenna  100  connects to the RF connector  900  via a hinge  90 . The complex antenna  100  installs on an electrical device and exposed to the free space. 
   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.