Patent Publication Number: US-11025010-B2

Title: High frequency electrical connector

Description:
BACKGROUND OF THE DISCLOSURE 
     1. Field of the Disclosure 
     The present disclosure relates to an electrical connector, and more particularly to an electrical connector for high frequency signal transmission. 
     2. Description of Related Arts 
     Signal transmission in the electrical connection system requires a consistent impedance along the transmission path. Anyhow, impedance may inevitably dropped at the mating regions between the mated plug and receptacle connector, thus resulting in an unstable transmission with improper losses.  FIG. 8  is a diagram showing the impedance curve of the traditional contact with a width/thickness ratio of 1.8 
     An improved arrangement is desired to have the electrical connector with the properly contact arrangement for maintaining a relatively consistent impedance along the transmission path including in the mating region. 
     SUMMARY OF THE DISCLOSURE 
     An object of the invention is to provide an electrical connector with an insulative housing and a plurality of contacts retained therein. The housing forms a central slot along a longitudinal direction, and includes a base, opposite first wall and second wall extending from the base and located by two sides of the central slot. The contact includes a retaining section retained to the corresponding first or second wall, and a spring arm, with a contacting section at a free end thereof, extending from the retaining section and into the central slot wherein a width/thickness ratio in the contacting section is in a range between 0.8˜1.28. Understandably, such a ratio may efficiently lower the capacitive effect, thus improving impedance matching. 
     The first wall forms a first mating region, a second mating region and a third mating region between the first mating region and the second mating region in the longitudinal direction. The second wall forms a fourth mating region. The contacts includes first contacts, second contacts, the third contacts and the fourth contacts respectively disposed in the corresponding first mating region, second mating region, third mating region and fourth mating region. The width/thickness ratio of the contacting can be 1 wherein both the width and thickness of each of the first contacts and the second contacts are 0.25 mm while both those of each of the third contacts and the fourth contacts are 0.20 mm Alternately, the width/thickness ratio can be 0.8 wherein the width is 0.2 mm and the thickness is 0.25 mm for both the first contact and the second contact while the width is 0.16 mm and the thickness is 0.20 mm for both the third contact and the fourth contact. Alternately, the width/thickness ratio can be 1.28 wherein the width is 0.32 mm and the thickness is 0.25 for both the first contact and the second contact while the width is 0.256 mm and the thickness is 0.2 mm for both the third contact and the fourth contact. Moreover, for enhancing the grounding effect, the second wall forms a groove to receive the grounding bar having fingers mechanically and electrically connecting the retaining sections of the corresponding fourth contacts. 
     Other objects, advantages and novel features of the disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an electrical connector mounted upon a printed circuit board according to the invention; 
         FIG. 2  is a perspective view of the electrical connector removed away from the printed circuit board of  FIG. 1 ; 
         FIG. 3  is another perspective view of the electrical connector removed away from the printed circuit board of  FIG. 1 ; 
         FIG. 4  is an exploded perspective view of the electrical connector of  FIG. 3 ; 
         FIG. 5  is another exploded perspective view of the electrical connector of  FIG. 4 ; 
         FIG. 6  is a perspective view of the grounding bar contacting the fourth contacts of the electrical connector of  FIG. 1 ; 
         FIG. 7  is a cross-sectional view of the electrical connector of  FIG. 1 ; 
         FIG. 8  is a diagram showing the impedance curve of the traditional contact; and 
         FIG. 9  is a diagram showing the impedance curve of the instant invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1-7 , an electrical connector  100  includes an insulative housing  1  and a plurality of contacts  2  retained to the housing  1 . The housing  1  forms a central slot  3  extending along the longitudinal direction, and includes a base  10  with opposite first wall  11  and second wall  12  extending therefrom by two sides of the central slot  3 . Along the front-to-back direction perpendicular to both the longitudinal direction and the transverse direction, the contact  2  includes a middle retaining section  21  retained to the base  10 , a front spring arm (not labeled) extending from the retaining section  21  with a contacting section  22  at a free end which extends into the central slot  3 , and a rear solder leg  23  extending from the retaining section  21  and out of the base  10 . The ratio of the width to the thickness in the contacting section  22  is in a range between 0.8˜1.28. The first wall  11  includes a first mating region  101 , a second mating region  102  and a third mating region  103  located in a groove  110  between the first mating region  101  and the second mating region  102 . The contacts  2  includes first contacts  201 , the second contacts  202  and the third contacts  203  respectively disposed within the corresponding first mating region  101 , second mating region  102  and third mating region  103 . The second wall  12  forms a fourth mating region  104  corresponding to all the first mating region  101 , the second mating region  102  and the third mating region  103  in a transverse direction perpendicular to the longitudinal direction. The fourth contacts are disposed in the fourth mating region  104 . 
     The contacts  2  includes the differential pair contacts  25  and the grounding contacts  24 . In the instant invention, the ratio between the width and the thickness in the contacting section is set in a range between 0.8˜1.28, compared with the value of 1.8 disclosed in the traditional contact. For example, when the ratio is equal to 1, both the width and the thickness of the first contact  201  and the second contact  202  are 0.25 mm while both the width and thickness of the third contact and the fourth contact are 0.20 mm.  FIG. 9  shows the impedance curve under the instant invention, wherein the impedance of the contacting section around the mating region can be raised up, compared with that shown in  FIG. 8 , thus improving the impedance matching. 
     Alternately, when the ratio is set at 0.8, the width of the first contact  201  and that of the second contact  202  are 0.20 mm and the thicknesses thereof are 0.25 while the width of the third contact  203  and that of the fourth contact  204  are 0.16 mm and the thicknesses thereof are 0.20 mm Alternately, when the ratio is set at 1.28, the width of the first contact  201  and that of the second contact  202  are 0.32 mm and the thicknesses thereof are 0.25 mm while the width of the third contact  203  and that the fourth contact are 0.256 mm and the thicknesses thereof are 0.20 mm. In general, disregarding which value of the ratio is selected, the width of the first contact  201  and that of the second contact  202  should be five fourths of those of the third contact  203  and the fourth contact  204 . Similarly, the thickness of the first contact  201  and that of the second contact  202  are also five fourths of those of the third contact  203  and the fourth contact  204 . As noted, such a difference result from the different basic structure of the first contact  201  and the second contact  202  and those of the third contact  203  and the fourth contact  204  wherein the dimension and the pitch of the first contact  201  and those of the second contact  202  are significantly larger than those of the third contact  203  and the fourth contact  204 . Notably, in this embodiment, the first contacts  201  are same with the second contacts  202 , and the third contacts  203  are same with the fourth contacts  204 . In addition, in this embodiment such a ratio in the spring arm is about 1.85 for the third contact and the fourth contact, and 2.85 for the first contact and the second contact. 
     To enhance the grounding effect, the second wall  12  forms a slit  120  to communicate with the fourth mating region  104 . A grounding bar  4  is received within the slit  120 , and includes a main body  41  and a plurality of spring tangs  42  mechanically and electrically connecting to the corresponding grounding contacts  24  of the fourth contacts  204 . The spring tang  42  includes a contacting section  420  resiliently contacting a retaining section  21  of the corresponding grounding contacts  24  of the fourth contacts  204  so as to reduce resonance during transmission. Understandably, the slit  120  extends from the front mating face of the housing  1  and along an interior surface of the second wall  12  so as to allow the grounding bar  4  to be inserted into the housing from the front mating opening wherein the second wall  12  further forms a plurality of openings (not labeled) to receive the corresponding tangs  42   
     While a preferred embodiment in accordance with the present disclosure has been shown and described, equivalent modifications and changes known to persons skilled in the art according to the spirit of the present disclosure are considered within the scope of the present disclosure as described in the appended claims.