Patent Grant
9748681
The subject matter herein relates generally to communication connectors.
Some electrical connector systems utilize communication connectors to interconnect various components of the system for data communication. Some known communication connectors have performance problems, particularly when transmitting at high data rates. For example, the communication connectors typically utilize differential pair signal conductors to transfer high speed signals. Ground conductors improve signal integrity. However, electrical performance of known communication connectors, when transmitting the high data rates, is inhibited by noise from cross-talk and return loss. Such issues are more problematic with small pitch high speed data connectors, which are noisy and exhibit higher than desirable return loss due to the close proximity of signal and ground contacts. Energy from ground contacts on either side of the signal pair may be reflected in the space between the ground contacts and such noise results in reduced connector performance and throughput. The separation of the ground contacts often results in unfavorable resonances supported by the ground contacts at particular frequency bands. Costly methods using complex geometries of the signal and ground contacts have proven effective, but can overly complicate the design of the connector and may be impractical.
A need remains for a high density, high speed electrical connector assembly that reduces unwanted resonances supported by ground contacts in targeted frequency bands.
In an embodiment, a ground contact module is provided including a ground leadframe having ground contacts extending between corresponding mating ends and terminating ends thereof with transition portions between the mating ends and the terminating ends. The transition portions are generally planar between a first side and a second side of the ground leadframe. The ground contact module includes a ground dielectric body holding the ground leadframe. The ground dielectric body has at least one low loss layer overmolded over the ground leadframe and encasing the transition portions of the ground contacts. The at least one low loss layer defines pockets. The ground dielectric body has lossy wings received in corresponding pockets. The lossy wings are electrically coupled to corresponding ground contacts. The lossy wings are manufactured from lossy material capable of absorbing electrical resonance propagating through the contact module stack. The lossy wings are separate and discrete from the at least one low loss layer and being attached to the at least one low loss layer in proximity to the corresponding ground contacts. Each lossy wing is electrically coupled to only one of the ground contacts.
In another embodiment, a contact module stack is provided including first and second signal contact modules each including a corresponding first and second signal leadframe and a corresponding first and second signal dielectric body holding the corresponding first and second signal leadframe. The first and second signal leadframes each have plural signal contacts extending between mating ends and terminating ends with transition portions between the mating and terminating ends. The first and second signal dielectric bodies substantially enclose the transition portions. The contact module stack includes first and second ground contact modules flanking the first and second signal contact modules such that the contact module stack has a ground-signal-signal-ground contact module arrangement. The first and second ground contact modules each include a corresponding first and second ground leadframe and a corresponding first and second ground dielectric body holding the corresponding first and second ground leadframe. The first and second ground leadframes each have ground contacts extending between corresponding mating ends and terminating ends with transition portions between the mating ends and the terminating ends. The first ground dielectric body has a first low loss layer defining pockets and first lossy wings received in corresponding pockets and being electrically coupled to corresponding ground contacts of the first ground leadframe. Each first lossy wing is electrically coupled to only one of the ground contacts of the first ground leadframe. The second ground dielectric body has a second low loss layer having pockets and second lossy wings received in corresponding pockets and being electrically coupled to corresponding ground contacts of the second ground leadframe. Each second lossy wing is electrically coupled to only one of the ground contacts of the second ground leadframe. The first and second lossy wings are manufactured from lossy material capable of absorbing electrical resonance propagating through the contact module stack.
In a further embodiment, a communication connector is provided including a housing having a mating end and a loading end with a cavity open at the loading end and a contact module stack loaded into the cavity of the housing through the loading end. The contact module stack includes at least one signal contact module including a signal leadframe and a dielectric body holding the signal leadframe. The signal leadframe has plural signal contacts extending between mating ends and terminating ends with transition portions between the mating and terminating ends. The dielectric body substantially encloses the transition portions. The contact module stack includes at least one ground contact module stacked adjacent the at least one signal contact module. The at least one ground contact module includes a ground leadframe and a ground dielectric body holding the ground leadframe. The ground leadframe has ground contacts extending between mating ends and terminating ends with transition portions between the mating ends and the terminating ends. The ground dielectric body has at least one low loss layer with pockets and lossy wings received in corresponding pockets and being electrically coupled to corresponding ground contacts. The lossy wings are manufactured from lossy material capable of absorbing electrical resonance propagating through the contact module stack. The lossy wings are separate and discrete from the at least one low loss layer and are attached to the at least one low loss layer in proximity to the corresponding ground contacts. Each lossy wing is electrically coupled to only one of the ground contacts.
In an exemplary embodiment, the first communication connector 12 and the second communication connector 14 are configured to be electrically connected to respective first and second circuit boards 16, 18. The first and second communication connectors 12, 14 are utilized to provide a signal transmission path to electrically connect the circuit boards 16, 18 to one another at a separable mating interface.
The communication connector 12 includes a housing 20 holding a contact module stack 22 comprising a plurality of signal contact modules 24 and a plurality of ground contact modules 26 in a stacked arrangement. The contact modules 24, 26 may be wafers. In an exemplary embodiment, the signal and ground contact modules 24, 26 are arranged in a ground-signal-signal-ground (GSSG) arrangement with pairs of signal contact modules 24 flanked by ground contact modules 26. The signal contact modules 24 have pairs of contacts (for example, arranged in differential pairs) and the ground contact modules 26 provide shielding for the signal contact modules 24. Optionally, the signal contact modules 24 are high-speed signal contact modules transmitting high speed data signals. Optionally, at least some of the signal contact modules 24 may be low-speed signal contact modules transmitting lower speed signals, such as control signals. The housing 20 includes multiple walls that define a cavity 30 that receives the contact module stack 22. The housing 20 extends between a mating end 32 and a loading end 36. The cavity 30 is open at the loading end 36 to receive the contact module stack 22. The contact module stack 22 defines a mounting end 34 which is mounted to the circuit board 16.
In an exemplary embodiment, the contact module stack 22 includes lossy material configured to absorb at least some resonance that propagates along the current paths defined by the signal contacts and/or the ground contacts through the communication connector 12. For example, the lossy material may be provided in the ground contact modules 26. The lossy material provides electric and/or magnetic lossiness through a portion of the communication connector 12. The lossy material is able to conduct electrical energy at very low levels. The lossy material is less conductive than traditional conductive material, such as the conductive material of the contacts, and more conductive than the low loss dielectrics. The lossy material may be designed to provide electrical loss in a certain, targeted frequency range. The lossy material may include conductive particles (or fillers) dispersed within a dielectric (binder) material. The dielectric material, such as a polymer or epoxy, is used as a binder to hold the conductive particle filler elements in place. These conductive particle filler elements then impart loss that converts the dielectric material to a lossy material. In some embodiments, the lossy material is formed by mixing binder with filler that includes conductive particles. Examples of conductive particles that may be used as a filler to form electrically lossy materials include but are not limited to carbon or graphite formed as fibers, flakes, or other particles. Metal in the form of powder, flakes, fibers, or other conductive particles may also be used to provide suitable lossy properties. Alternatively, combinations of fillers may be used. For example, metal plated (or coated) particles may be used. Silver and nickel may also be used to plate particles. Plated (or coated) particles may be used alone or in combination with other fillers, such as carbon flakes. In some embodiments, the fillers may be present in a sufficient volume percentage to allow conducting paths to be created from particle to particle. For example when metal fiber is used, the fiber may be present at an amount up to 40% by volume or more. The lossy material may be magnetically lossy and/or electrically lossy. For example, the lossy material may be formed of a binder material with magnetic particles dispersed therein to provide magnetic properties. The magnetic particles may be in the form of flakes, fibers, or the like. Materials such as magnesium ferrite, nickel ferrite, lithium ferrite, yttrium garnet and/or aluminum garnet may be used as magnetic particles. In some embodiments, the lossy material may simultaneously be an electrically-lossy material and a magnetically-lossy material. Such lossy materials may be formed, for example, by using magnetically-lossy filler particles that are partially conductive or by using a combination of magnetically-lossy and electrically-lossy filler particles.
As used herein, the term “binder” encompasses material that encapsulates the filler or is impregnated with the filler. The binder material may be any material that will set, cure, or can otherwise be used to position the filler material. In some embodiments, the binder may be a thermoplastic material such as those traditionally used in the manufacture of communication connectors. The thermoplastic material may be molded, such as molding of the ground contact modules 26 into the desired shape and/or location. However, many alternative forms of binder materials may be used. Curable materials, such as epoxies, can serve as a binder. Alternatively, materials such as thermosetting resins or adhesives may be used.
Optionally, the communication connector 14 may be similar to the communication connector 12. For example, the communication connector 14 may include a contact module stack similar to the contact module stack 22 and may include ground contact modules with lossy material. In other various embodiments, the communication connector 14 may be another type of connector. For example, the communication connector 14 may be a high speed transceiver module having a circuit card configured to mate with the communication connector 12. In such embodiments, the communication connector 14 does not include a contact module stack.
The cage member 102 is a shielding, stamped and formed cage member that includes a plurality of shielding walls 108 that define multiple ports 110, 112 for receipt of the pluggable modules 106. In the illustrated embodiment, the cage member 102 constitutes a stacked cage member having the ports 110, 112 in a stacked configuration. Any number of ports may be provided in alternative embodiments. In the illustrated embodiment, the cage member 102 includes the ports 110, 112 arranged in a single column, however, the cage member 102 may include multiple columns of ganged ports 110, 112 in alternative embodiments (for example, 2×2, 3×2, 4×2, 4×3, etc.). The communication connector 104 is configured to mate with the pluggable modules 106 in both stacked ports 110, 112. Optionally, multiple communication connectors 104 may be arranged within the cage member 102, such as when multiple ports are provided.
Upper and lower extension portions 132 and 134 extend from the body portion 122 to define a stepped mating face. A recessed face 136 is provided between the extension portions 132, 134. For a single port cage member, the communication connector 104 may only include a single extension portion. Mating slots 140 and 142, such as circuit card receiving slots, extend inwardly from the mating face of the respective upper and lower extension portions 132, 134, and extend inwardly to the body portion 122. The mating slots 140, 142 are configured to receive mating components, such as plug connectors, card edges of circuit cards of the corresponding pluggable modules 106 (shown in
The contact module stack 150 includes signal contact modules 152 (shown in
In an exemplary embodiment, each ground dielectric body 172 includes lossy material configured to absorb at least some electrical resonance that propagates along the signal leadframe 160 and/or the ground leadframe 170. For example, the lossy material may form part of the ground dielectric body 172. In an exemplary embodiment, the ground dielectric body 172 includes lossy wings extending from one or more edges of the ground conductors and that are attached to other portions of the ground dielectric body 172. The lossy material provides electric and/or magnetic lossiness through a portion of the ground contact module 154. The lossy material is able to conduct electrical energy at very low levels. The lossy material is less conductive than conductive material, such as the conductive material of the ground leadframe 170. The lossy material may be designed to provide electrical loss in a certain, targeted frequency range. The lossy material may include conductive particles (or fillers) dispersed within a dielectric (binder) material. The dielectric material, such as a polymer or epoxy, is used as a binder to hold the conductive particle filler elements in place. These conductive particle filler elements then impart loss that converts the dielectric material to lossy material. In some embodiments, the lossy material is formed by mixing binder with filler that includes conductive particles. Examples of conductive particles that may be used as a filler to form electrically lossy materials include carbon or graphite formed as fibers, flakes, or other particles. Metal in the form of powder, flakes, fibers, or other conductive particles may also be used to provide suitable lossy properties. Alternatively, combinations of fillers may be used. For example, metal plated (or coated) particles may be used. Silver and nickel may also be used to plate particles. Plated (or coated) particles may be used alone or in combination with other fillers, such as carbon flakes. In some embodiments, the fillers may be present in a sufficient volume percentage to allow conducting paths to be created from particle to particle. For example when metal fiber is used, the fiber may be present at an amount up to 40% by volume or more. The lossy material may be magnetically lossy and/or electrically lossy. For example, the lossy material may be formed of a binder material with magnetic particles dispersed therein to provide magnetic properties. The magnetic particles may be in the form of flakes, fibers, or the like. Materials such as magnesium ferrite, nickel ferrite, lithium ferrite, yttrium garnet and/or aluminum garnet may be used as magnetic particles. In some embodiments, the lossy material may simultaneously be an electrically-lossy material and a magnetically-lossy material. Such lossy materials may be formed, for example, by using magnetically-lossy filler particles that are partially conductive or by using a combination of magnetically-lossy and electrically-lossy filler particles.
The ground dielectric body 172 encases the ground leadframe 170, such as the transition portions 177. In an exemplary embodiment, the mating ends 176 extend forward of the ground dielectric body 172 and the terminating ends 178 extend below the ground dielectric body 172. The ground dielectric body 172 may be an overmolded dielectric body overmolded over the ground leadframe 170. Alternatively, the ground dielectric body 172 may be pre-molded pieces coupled together around the ground leadframe 170.
In an exemplary embodiment, the ground dielectric body 172 includes lossy material. For example, the ground dielectric body 172 includes at least one low loss layer 180 (
The low loss layer(s) 180 are provided on a first side 184 and on a second side 186 (shown in
In an exemplary embodiment, the low loss layer(s) 180 define pockets 188 between the first and second sides 184, 186. The pockets 188 receive corresponding lossy wings 182. The pockets 188 may expose portions of the ground contacts 174, such as the edges 179 of the transition portions 177. The low loss layer(s) 180 includes a plurality of windows 190 that expose the ground contact(s) 174 to air and define exposed surfaces 192 of the ground contact(s) 174. The windows 190 may be formed by pinch-points of the ground leadframe 170 during overmolding. The windows 190 may be sized and shaped to affect the electrical characteristics of the ground contact(s) 174 by exposing such portions to air.
In the illustrated embodiment, the ground dielectric body 172 includes a plurality of the lossy wings 182. Each lossy wing 182 is a separate and discrete piece from the low loss layer 180. The lossy wings 182 may be molded in situ in the pockets 188. For example, the lossy wings 182 may be formed with the low loss layer 180 in a multistage overmolding process (for example, a two shot overmolding process). Alternatively, the lossy wings 182 may be pre-molded and inserted into the pockets 188 and coupled to the low loss layer 180. For example, the lossy wings 182 may be secured to the low loss layer 180, such as by a friction fit, by being laminated or adhered to the low loss layer 180, by securing features (for example, posts and holes) formed in or on the lossy wings 182 and the low loss layer 180, by using separate securing features such as clips, or by other securing means.
The lossy wings 182 are electrically coupled to the corresponding ground contacts 174. Each lossy wing 182 may be directly electrically coupled to the corresponding ground contact 174. Alternatively, the lossy wing 182 may be indirectly electrically coupled to the corresponding ground contact 174, such as by capacitive coupling. The lossy wing 182 may be coupled to the ground contact 174 at one of the edges 179 and may extend from the edge 179 into the gap between the ground contact 174 and the adjacent ground contact 174. The lossy wing 182 may extend outward from the edge 179 of the ground contact 174 into, and optionally entirely through, the ground leadframe plane of the corresponding ground contact 174. Optionally, one or more of the ground contacts 174 may have lossy wings 182 electrically coupled to opposite edges 179 thereof extending in opposite directions.
In an exemplary embodiment, each lossy wing 182 is coupled to only one ground contact 174. Bridges 194 of the low loss layer 180 are provided between the lossy wings 182 to isolate the lossy wings 182 from each other. The bridges 194 may be coupled to corresponding ground contacts 174, or alternatively, may be provided in the gaps between the ground contacts 174. The bridges 194 extend between first and second lands 195, 196 to enclose the pockets 188. For example, the first land 195 may be at the front of the ground dielectric body 172 proximate to the mating ends 176 of the ground contacts 174, while the second land 196 may be at the bottom of the ground dielectric body 172 proximate to the terminating ends 178. The pockets 188 between the lands 195, 196 and the bridges 194 allow the lossy wings 182 to be recessed into the ground dielectric body 172. In an exemplary embodiment, outer surfaces 198 of the lossy wings 182 may be generally coplanar with outer surfaces 199 of the low loss layer 180 at the first side 184 and/or the second side 186.
Electrical performance of the communication connector 104 is enhanced by the inclusion of the lossy material in the ground contact modules 154. For example, at various data rates, including high data rates, return loss is inhibited by the lossy wings 182. For example, the return loss of the small pitch, high speed data of the contact module stack 150 due to the close proximity of signal and ground contacts 164, 174 is reduced by the lossy wings 182. For example, energy from the ground contacts 174 on either side of the signal pair reflected in the space between the ground contacts 174 is absorbed, and thus connector performance and throughput are enhanced.
The signal leadframe 160 includes at least one signal contact 164 extending between a mating end 166 and terminating end 168 with a transition portion between the mating and terminating ends 166, 168. In the illustrated embodiment, the mating end 166 is at the front of the signal contact module 152 and the terminating end 168 is at the bottom of the signal contact module 152. The transition portion transitions 90° between the mating and terminating ends 166, 168. Other configurations are possible in alternative embodiments. The signal leadframes 160 may be stacked adjacent the ground leadframes 170 with the mating ends 166 aligned with the mating ends 176 for mating with the pluggable module 106 (shown in
The signal dielectric body 162 encases the transition portions of the signal leadframe 160. The signal dielectric body 162 may be an overmolded dielectric body overmolded over the signal leadframe 160. Alternatively, the signal dielectric body 162 may be pre-molded pieces coupled together around the signal leadframe 160. The signal dielectric body 162 may be manufactured entirely from low loss dielectric material. The signal dielectric body 162 may abut against the adjacent ground dielectric body 172.
When the contact module stack 150 is assembled, the ground contact modules 154 provide electrical shielding for the signal contact modules 152. The conductive ground contacts 174 provide electrical shielding to shield the pairs of signal contacts 164 from other pairs of signal contacts 164, such as signal contacts in another part of the contact module stack 150. The electrical shielding improves electrical performance of the communication connector 104 (shown in
It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Dimensions, types of materials, orientations of the various components, and the number and positions of the various components described herein are intended to define parameters of certain embodiments, and are by no means limiting and are merely exemplary embodiments. Many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. §112(f), unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.
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