Abstract:
An electrical connector for mounting to a print circuit board includes an insulative housing, a metal shell shielding around the housing and a plurality of terminals received in the housing. Each terminal having a body section and a contact section extending from the body section, the housing includes a first housing and a second housing, the body section being received in the second housing and the contact section extending from the second housing to the first housing. The first housing has a first dielectric constant and the second housing has a second dielectric constant higher than the first dielectric constant so as to prevent the characteristic impedance change.

Description:
FIELD OF THE INVENTION 
     The present invention relates to an electrical connector, and more particularly to an electrical connector having a housing with different dielectric constant to prevent characteristic impedance change. 
     DESCRIPTION OF THE RELATED ART 
     An electrical connector is disclosed in U.S. Pat. No. 7,955,137 issued to Ko et al. on Jun. 7, 2011. Said connector includes an insulative housing and a number of terminals received in the housing. The terminal includes a body section, a contact section and a soldering section extending from opposite side of the body section, all sections of the terminal have a same thickness. 
     However, the contact section should contact with another connector and the soldering section solder with a cable, respectively, then the thickness of the contact section and soldering section will increase to change the characteristic impedance of the terminal. 
     In view of the above, a new electrical connector that overcomes the above-mentioned disadvantages is desired. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an electrical connector with the same characteristic impedance. 
     In order to achieve the above-mentioned object, an electrical connector includes an insulative housing having a first housing and a second housing received in the first housing; a metal shell shielding the insulative housing; a plurality of terminals received in the insulative housing and each having a body section and a contact section extending from the body section, the body section being received in the second housing and the contact section extending from the second housing to the first housing; said first housing has a first dielectric constant and the second housing has a second dielectric higher than the first dielectric constant. 
     Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of the present embodiment when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an electrical connector of the present invention; 
         FIG. 2  is a partly exploded view of the electrical connector; 
         FIG. 3  is an exploded view of the electrical connector except a shell; 
         FIG. 4  is another exploded perspective view of the electrical connector shown in  FIG. 3 ; 
         FIG. 5  is an enlarged cross sectional view of the electrical connector; 
         FIG. 6  is a perspective view showing terminals connecting with a mating terminal and cable. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made to the drawing figures to describe the preferred embodiments of the present invention in detail. 
     Referring to  FIG. 1  to  FIG. 3 , disclosed here is an electrical connector  100  made in accordance with the present invention. The electrical connector  100  is a Diiva cable connector and used for mating a receptacle connector (not shown), said connector  100  includes an insulative housing  1 , a metal shell  2  shielding around the insulative housing and a plurality of terminals  3  received in the insulative housing  1 , the electrical connector also has a cable  4  which connects with the terminal  3  and a supporting block  5  used for setting and separating the cable  4 . 
     Referring to  FIG. 6 , each terminal  3  has an average thickness C, the terminal  3  includes a body section  31  and a contact section  32  extending from the body section  31 , the terminal  3  also includes a soldering section  33  extending from the body section  31 . The soldering section  33  and the contact section  32  are formed on opposite ends of the body section  31 . Said contact section  32  mates with a contact portion  91  of the receptacle connector (not shown) and the soldering section  33  is soldered to the soldering portion  41  of the cable  4 . A thickness A of the contact position is the thickness of the contact portion  91  plus the thickness of the contact section  32  and a thickness B of the soldering position is the thickness of the soldering section  33  plus the thickness of the soldering portion  41  of the cable  4 . Said thickness A of the contact position and the thickness B of the soldering position are thicker than the thickness C of the body section  31 , therefore, the contact position and the soldering section has a low impedance and the body section  31  has a high impedance, so the impedance of terminal  3  changes obviously. Said soldering portion  41  is thicker than the contact portion  91  in present invention, in other words, said thickness B of the soldering position is thicker than the thickness A of the contact position, therefore, the soldering position defines lower characteristic impedance than the contact position. 
     Referring to  FIG. 3  and  FIG. 4 , said terminals  3  are retained in the insulative housing  1 , the insulative housing  1  defining a first housing  11 , a second housing  12  received in the first housing  11  and a third housing  13  adjacent to the second housing  12 . Said first housing  11  defines a mating face  111  and a rear face  112  opposite to the mating face  111 , the first housing  11  runs through the mating face  111  and the rear face  112 , and formed a cavity  113 . Said cavity  113  defines a pair of guide slots  1141  formed on opposite sidewalls  114  thereof and the guide slots  1141  define a pair of stopping portion  1142  adjacent to the rear face  112 , said second housing  12  defines a pair of guide ribs  1211  on opposite sidewalls  121  to be retained in the guide slot  1141 . Each guide rib  1211  defines a protrusion portion adjacent to a rear face of the second housing  12  to match with the stopping portion  1142 . Said guide slots  1141  are used for the guide rib  1211  slipping therein and said protrusion portions are used for the first housing  11  retaining behind the second housing  12 . 
     Combining with  FIG. 5 , said second housing  12  defines a plurality of second passageways  122  and the body section  31  of terminals  3  are received in the second passageways  122 . The contact sections  32  extend to the first housing  11  from the body sections  31 , said first housing  11  defines first passageways  115  which communicate with the second passageways  122  for receiving the contact sections  32 . The soldering sections  33  extend to the third housing  13  from the body sections  31 , said third housing defines a plurality of receiving slots  131  for receiving the soldering sections  33 . The first housing  11 , second housing  12  and third housing  13  are made of different materials, said first housing  11  has a first dielectric constant and the third housing  13  has a third dielectric constant, said second housing  12  has a second dielectric constant higher than both the first dielectric constant and the third dielectric constant. Understandably, the low dielectric constant of a housing can result in high characteristic impedance of a terminal and the high dielectric constant of a housing can result in low characteristic impedance of a terminal. The contact sections  32  are arranged in the first housing  11  in order to pull high characteristic impedance and the soldering sections  33  are arranged in the third housing  13  for obtaining high characteristic impedance, while the body sections  31  are arranged in the second housing  12  in order to obtain low characteristic impedance. Therefore, the characteristic impedance of everywhere of the terminal  3  could get balance. 
     Referring to  FIG. 3  and  FIG. 4 , said metal shell  2  includes a mating shell  21  which mates with the receptacle connector and a base shell  22  which is mounted on a rear end of the mating shell  21 . The mating shell  21  defines two surfaces opposite to each other, one of the surface outwardly tears out of a pair of openings  211  and formed a pair of tabs  212  which are perpendicular to the openings  211 . The base shell  22  comprises a first shell  221  and a second shell  222  assembled to the first shell  221 . The first shell  21  has a vertical portion  2211  bending downwardly from an upper face thereof and a horizontal portion  2212  extending horizontally from the vertical portion  2211 . Said horizontal portion  2212  defines a pair of grooves  2213  matching with the tab  212 . Following the presentation of the insulative housing  1  and the metal shell  2  assembly, said first shell  221  and the second shell  222  form the base shell  22 , the mating shell  21  and the base shell  22  are assembled together via the cooperation of through the tabs  212  of the mating shell  21  and the grooves  2213  of the base shell  22 . Said mating shell  21  is located at the front end of the base shell  22 , the front end of the first housing  11  is received in the mating shell  21 , and the rear end of the first housing  11  is supported at the mating shell  21  and received in the base shell  22 . The second housing  12  is retained behind the first housing  11  through the guide slot  1141 , and the second housing  12  includes a pair of flanges  123  for matching with the openings  211 , said first housing  11  and the second housing  12  are stably retained in the mating shell  21 . Said third housing  13  which is retained behind the second housing  11  and the supporting block  5  which is retained behind the third housing are received in the base shell  22 . The cable  4  is arranged on the supporting block  5  so that the soldering portion  41  can be stably welded with the soldering section  33 . 
     Referring to  FIG. 2 , said vertical portion  2211  and the horizontal portion  2212  of the base shell  22  form a hollow portion  2214 . The outwall of the metal shell  2  is overmolded with a insulative shell  6  and plastic of the insulative shell  6  enters the hollow portion  2214  so as to facilitate stable combination of the metal shell  2  and the insulative shell  6 . 
     While a preferred embodiment in accordance with the present invention has been shown and described, equivalent modifications and changes known to persons skilled in the art according to the spirit of the present invention are considered within the scope of the present invention as described in the appended claims.