Electrical connector with improved impedance continuity

1. Field of the Invention

The present invention relates to an electrical connector, and more particularly to an electrical connector for communication applications.

2. Description of Related Arts

In communication applications, a header mated with a receptacle is widely used for transmitting high speed signal. U.S. Pat. No. 5,522,730, issued on Jun. 4, 1996, discloses a header. According to the disclosure, the header connector comprises a middle board, a first U-shaped insulative housing mounted on a surface of the middle board, a U-shaped second insulative housing mounted on an opposite surface of the middle board, and a plurality of contacts mounted on the first and the second insulative housings. The first insulative housing defines a first receiving room, and the second insulative housing defines a second receiving room. Each of the contacts comprises a first mating portion received in the first receiving room, a second mating portion received in the second receiving room, and a middle portion connecting between the first mating portion and the second portion. Each of the middle portions comprises a compliant pin portion for interference fitting with the middle board to retain the contacts on the middle board. The compliant pin portions will cause signal contact impedance discontinuity to thereby deteroirate high speed signal transmission.

Hence, an improved electrical connector is desired to offer advantages over the related art.

An object of the present invention is to provide an electrical connector having signal contacts with improved impendence continuity, and grounding contact stably mounted.

To achieve the above-mentioned object, an electrical connector, comprises a middle board defining a plurality of receiving holes, a first insulative housing mounted on one side of the middle board and defining a first receiving room for receiving a first mating connector, and a plurality of contacts mounted on the first insulative housing. The contacts comprise a plurality of signal contacts and a plurality of grounding contacts. Each of the signal contacts and the grounding contacts comprises a first mating portion, a second mating portion opposite to the first mating portion, and a middle portion between the first and the second mating portions. The middle portions extend beyond the first insulative housing and are received in the receiving holes of the middle board. Each of the middle portions of the signal contacts is solid. Each of the middle portions of the grounding contacts has a through hole and has an outer profile wider than that of middle portion of the signal contact.

According to the present invention, the middle portions of the signal contacts have a rigid structure to ensure the signal contacts having continuity impendence. The middle portions of the grounding contacts have a flexible structure to ensure the grounding contacts stably mounted on the first insulative housing.

FIG. 1 is a perspective view of an electrical connector in accordance with the present invention;

FIG. 2 is a partly exploded view of the electrical connector as shown in FIG. 1 showing the second insulative housing separated from the middle board;

FIG. 3 is a partly exploded view of the electrical connector as shown in FIG. 2 further showing the first insulative housing separated from the middle board;

FIG. 4 is an exploded view of the electrical connector as shown in FIG. 1 ; and

FIG. 5 is a cross-sectional view of the electrical connector taken along line 5 - 5 of FIG. 1 .

Reference will now be made in detail to a preferred embodiment of the present invention.

Referring to FIGS. 1 to 3 , an electrical connector 100 comprises a middle board 4 , a first insulative housing 1 mounted on a first surface of the middle board, and a second insulative housing 2 mounted on an second surface of the middle board opposite to the first surface, and a plurality of contacts mounted on the first and the second insulative housings 1 , 2 .

The first insulative housing 1 having an U shape comprises a first mounting wall 11 having opposite edges, a pair of first side walls 12 vertically extending from the opposite edges of the first mounting wall 11 along a first direction respectively, and a first receiving room 13 defined between the pair of first side walls 12 for receiving a first mating connector. The first mounting wall 11 comprises a plurality of first mounting holes 110 extending through the first mounting wall 11 .

The second insulative housing 2 having a structure similar to the first insulative housing 1 , comprises a second mounting wall 21 parallel to the first mounting wall 11 having opposite edges, a pair of second side walls 22 vertically extending from the opposite edges of the second mounting wall 21 along a second direction opposite to the first direction respectively, and a second receiving room 23 defined between the pair of the second side walls 22 for receiving a second mating connector. The first receiving room 13 has a first opening facing to the first direction, and the second receiving room 23 has a second opening facing to a second direction. The second mounting wall 21 comprises a plurality of second mounting holes 210 extending through the second mounting wall 21 . The first side walls 12 are aligned with the pair second side walls 22 respectively.

The middle board 4 is sandwiched between the first insulative housing 1 and the second insulative housing 2 , and defines a plurality of first and second receiving hole 41 , 42 extending through the middle board 4 for receiving the contacts 3 . The first receiving holes 41 don't coat any conductive material, and the second receiving holes 42 are coated with conductive layer 421 .

The contacts 3 are arranged in matrix and comprise a plurality of signal contacts S and a plurality of grounding contacts G. Each of the signal contacts S and the grounding contacts comprises a first mating portion 31 received in the first receiving room 13 , a second mating portion 32 received in the second receiving room 23 , a middle portion 33 disposed between the first and the second mating portions 31 , 32 , a first mounting portion 34 connecting between the first mating portion 31 and the middle portion 33 and received in the first mounting wall 11 , and a second mounting portion 35 connecting between the second mating portion 32 and the middle portion 33 and received in the second mounting wall 21 . The first mating portions 31 extend through the first mounting holes 110 and are received in the first receiving room 13 . The second mating portions 32 extend through the second mounting holes 210 and are received in the second receiving room 23 . The first insulative housing 1 is separated apart from the second insulative housing 2 . The middle portions 33 of the signal contacts S and the grounding contacts G are disposed between the first insulative housing 1 and the second insulative housing 2 .

Referring to FIGS. 4 and 5 , the middle portions 33 of the grounding contacts G have a width larger than a width of the middle portions 33 of the signal contacts S. The signal contacts S and the grounding contacts G are configured to have retention between each of the signal contacts S and the middle board 4 is weaker than that between each of the grounding contacts G and the middle board 4 . In this embodiment, each of the middle portions 33 of the grounding contacts G defines a through hole 331 to make the middle portion 33 of the grounding contact G compliant. The middle portions 33 of the grounding contacts G can be press fitted into the second receiving holes 42 of the middle board 4 to electrically connect with the conductive layer 421 . Therefore, the grounding contacts G have an improved grounding performance, and are stably retained in the middle board 4 . The middle portions 33 of the signal contacts S have a rigid structure and are received in the first receiving holes 41 of the middle board 4 . The signal contacts S have a flat shape without any through hole. The middle portions 33 of the signal contacts S have a radial dimension smaller than a radial dimension of the first receiving hole 41 . The signal contacts S loose fit with the first receiving holes 41 , and insulate with the first receiving holes 41 . Therefore, the signal contacts S can keep impedance continuity. The first mounting portions 34 of the contacts 3 have an interference with the first mounting holes 110 to retain the contacts 3 on the first insulative housing 1 , and the second mounting portions 35 of the contacts 3 have an interference fit with the second mounting holes 210 to retain the contacts 3 on the second insulative housing 2 .

Referring to FIGS. 4 and 5 , the middle portions 33 of the signal contacts S are thinner than the first and the second mating portions 31 , 32 of the signal contacts S to make the impedance of the signal contacts S matching the impedance of the system. The first mating portions 31 of the signal contacts S are shorter than the first mating portions 31 of the grounding contacts G, and the second mating portions 32 of the signal contacts S are shorter than the second mating portions 32 of the grounding contacts G to improve the shielding performance.

It is to be understood, however, that even though numerous characteristics and advanarmes 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.