Patent Publication Number: US-9431768-B1

Title: Electrical connector having resonance control

Description:
BACKGROUND 
     The subject matter herein relates generally to electrical connectors that have pairs of signal conductors configured to convey differential signals and ground conductors that control impedance and reduce crosstalk between the pairs of signal conductors as well as to provide a reliable ground return path. 
     Communication systems exist today that utilize electrical connectors to transmit data. For example, network systems, servers, data centers, and the like may use numerous electrical connectors to interconnect the various devices of the communication system. Many electrical connectors include signal conductors and ground conductors in which the signal conductors are arranged in signal pairs for carrying differential signals. The ground conductors are positioned between the signal pairs to control impedance and reduce crosstalk. Each signal pair may be separated from the adjacent signal pairs by one or more ground conductors. For example, the signal and ground conductors may be arranged in a ground-signal-signal-ground (GSSG) pattern. 
     There has been a general demand to increase the density of signal conductors within the electrical connectors and/or increase the speeds at which data is transmitted through the electrical connectors. As data rates increase and/or distances between the signal pairs decrease, however, it becomes more challenging to maintain a baseline level of signal quality. More specifically, in some cases, electrical energy that flows along the surface of each ground conductor may form a field that propagates between the ground conductors. For example, the ground conductors that flank the signal pair in the GSSG pattern may couple with each other to support an unwanted propagating signal mode. The unwanted electrical propagation mode may then be repeatedly reflected, such as between two PCB ground planes, and form a resonating condition (or standing wave) that causes electrical noise. Depending on the frequency of the data transmission, the electrical noise may increase return loss and/or crosstalk and reduces throughput of the electrical connector. 
     To control resonance between ground conductors and limit the effects of the resulting electrical noise, it has been proposed to electrically common the separate ground conductors using a metal conductor or a lossy plastic material. The effectiveness and/or cost of implementing these techniques is based on a number of variables, such as the geometry of the connector housing and geometries of the signal and ground conductors within the electrical connector. For some applications and/or electrical connector configurations, alternative methods for controlling resonance between the ground conductors may be desired. 
     Accordingly, there is a need for electrical connectors that reduce the electrical noise caused by resonating conditions in ground conductors. 
     BRIEF DESCRIPTION 
     In an embodiment, an electrical connector is provided that includes a connector housing having a front side configured to mate with a mating connector and a mounting side configured to be mounted to a circuit board. The electrical connector also includes signal and ground conductors that extend through the connector housing. The signal conductors form a plurality of signal pairs configured to carry differential signals. The ground conductors are positioned relative to the signal pairs to form a plurality of ground-signal-signal-ground (GSSG) sub-arrays. Each GSSG sub-array includes a corresponding signal pair and first and second ground conductors that separate the corresponding signal pair from adjacent signal pairs. The electrical connector also includes a plurality of resonance-control bridges in which each resonance-control bridge electrically couples the first and second ground conductors of a corresponding GSSG sub-array. Each of the resonance-control bridges includes at least one of a capacitor or a resistor. 
     In some embodiments, the plurality of GSSG sub-arrays includes a first GSSG sub-array and a second GSSG sub-array. The first and second GSSG sub-arrays may have a shared ground conductor that is the second ground conductor of the first GSSG sub-array and the first ground conductor of the second GSSG sub-array. The shared ground conductor may be coupled to two of the resonance-control bridges. Optionally, the two resonance-control bridges are coupled to the shared ground conductor through a shared interconnecting element. The shared interconnecting element may include a base portion that couples to the shared ground conductor and first and second fingers. The first and second fingers are shaped to extend away from each other. Alternatively, the two resonance-control bridges have a respective interconnecting element that is separately coupled to the shared ground conductor. 
     In some embodiments, the first and second ground conductors of each GSSG sub-array are electrically coupled to first and second conductive surfaces, respectively, that are exposed along an exterior of the connector housing. Each resonance-control bridge may include a discrete component that is electrically coupled to the first and second conductive surfaces of the corresponding GSSG sub-array. 
     In some embodiments, the connector housing includes a housing side that faces an exterior of the connector housing. The resonance-control bridges may be positioned along the housing side such that the resonance-control bridges are accessible from the exterior of the connector housing. 
     In some embodiments, the connector housing includes a housing side and the signal and ground conductors form a first conductor row and a second conductor row. The resonance-control bridges are coupled to the first and second ground conductors of the first conductor row through the housing side. The resonance-control bridges are coupled to the first and second ground conductors of the second conductor row through the mounting side. 
     In an embodiment, a circuit board assembly is provided that includes a circuit board having a board surface. The circuit board assembly includes an electrical connector configured to engage a mating connector during a mating operation. The electrical connector includes a connector housing having a front side configured to engage the mating connector and a mounting side mounted to the board surface of the circuit board. The electrical connector also includes signal and ground conductors that extend through the connector housing. The signal conductors form a plurality of signal pairs configured to carry differential signals. The ground conductors are positioned relative to the signal pairs to form a plurality of ground-signal-signal-ground (GSSG) sub-arrays. Each GSSG sub-array includes a corresponding signal pair and first and second ground conductors that separate the corresponding signal pair from adjacent signal pairs. The electrical connector also includes a plurality of resonance-control bridges in which each resonance-control bridge electrically couples the first and second ground conductors of a corresponding GSSG sub-array. Each of the resonance-control bridges includes at least one of a capacitor or a resistor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a circuit board assembly formed in accordance with an embodiment. 
         FIG. 2  is a top perspective cutaway view of an electrical connector formed in accordance with an embodiment. 
         FIG. 3  is another perspective cutaway view of the electrical connector of  FIG. 2 . 
         FIG. 4  is a perspective view of a signal-transmission assembly that may be used with the electrical connector of  FIG. 2 . 
         FIG. 5  is an enlarged cutaway view of the signal-transmission assembly of  FIG. 4  illustrating a single resonance-control bridge. 
         FIG. 6  is an enlarged cross-section of the electrical connector of  FIG. 2  illustrating a plurality of the resonance-control bridges interconnecting ground conductors of the electrical connector. 
         FIG. 7  is a side cross-section of a communication assembly that includes the electrical connector of  FIG. 2  and a mating connector. 
         FIG. 8  is a top perspective cutaway view of an electrical connector formed in accordance with an embodiment. 
         FIG. 9  is a perspective view of a signal-transmission assembly that may be used with the electrical connector of  FIG. 8 . 
         FIG. 10  is an enlarged cross-section of the electrical connector of  FIG. 2  illustrating a plurality of the resonance-control bridges interconnecting ground conductors of the electrical connector. 
         FIG. 11  is an isolated perspective view of an exemplary bridge shoe that may be used with the electrical connector of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments set forth herein may include various electrical connectors that are configured for communicating data signals. The electrical connectors may mate with a corresponding mating connector to communicatively interconnect different components of a communication system. In the illustrated embodiment, the electrical connector is a receptacle connector that is mounted to and electrically coupled to a circuit board. The receptacle connector is configured to mate with a pluggable input/output (I/O) connector during a mating operation. It should be understood, however, that the inventive subject matter set forth herein may be applicable in other types of electrical connectors. Moreover, in various embodiments, the electrical connectors are particularly suitable for high-speed communication systems, such as network systems, servers, data centers, and the like, in which the data rates may be greater than 5 gigabits/second (Gbps). However, one or more embodiments may also be suitable for data rates less than 5 Gbps. 
     The electrical connectors include signal and ground conductors that are positioned relative to each other to form a pattern or array that includes one or more rows (or columns). The signal and ground conductors of a single row (or column) may be substantially co-planar. The signal conductors form signal pairs in which each signal pair is flanked on both sides by ground conductors. The ground conductors electrically separate the signal pairs to reduce electromagnetic interference or crosstalk and to provide a reliable ground return path. The signal and ground conductors in a single row are patterned to form multiple sub-arrays. Each sub-array includes, in order, a ground conductor, a signal conductor, a signal conductor, and a ground conductor. This arrangement is referred to as ground-signal-signal-ground (or GSSG) sub-array. The sub-array may be repeated such that an exemplary row of conductors may form G-S-S-G-G-S-S-G-G-S-S-G, wherein two ground conductors are positioned between two adjacent signal pairs. In the illustrated embodiment, however, adjacent signal pairs share a ground conductor such that the pattern forms G-S-S-G-S-S-G-S-S-G. In both examples above, the sub-array is referred to as a GSSG sub-array. More specifically, the term “GSSG sub-array” includes sub-arrays that share one or more intervening ground conductors. 
       FIG. 1  is a perspective view of a portion of a circuit board assembly  100  formed in accordance with an embodiment. The circuit board assembly  100  includes a circuit board  102  and an electrical connector  104  that is mounted onto a board surface  106  of the circuit board  102 . The circuit board assembly  100  is oriented with respect to mutually perpendicular axes, including a mating axis  191 , a lateral axis  192 , and a vertical or elevation axis  193 . In  FIG. 1 , the vertical axis  193  extends parallel to a gravitational force direction. It should be understood, however, that embodiments described herein are not limited to having a particular orientation with respect to gravity. For example, the lateral axis  192  may extend parallel to the gravitational force direction in other embodiments. 
     In some embodiments, the circuit board assembly  100  may be a daughter card assembly that is configured to engage a backplane or midplane communication system (not shown). In other embodiments, the circuit board assembly  100  may include a plurality of the electrical connectors  104  mounted to the circuit board  102  along an edge of the circuit board  102  in which each of the electrical connectors  104  is configured to engage a corresponding pluggable input/output (I/O) connector. The electrical connectors  104  and pluggable I/O connectors may be configured to satisfy certain industry standards, such as, but not limited to, the small-form factor pluggable (SFP) standard, enhanced SFP (SFP+) standard, quad SFP (QSFP) standard, C form-factor pluggable (CFP) standard, and 10 Gigabit SFP standard, which is often referred to as the XFP standard. In some embodiments, the pluggable I/O connector may be configured to be compliant with a small form factor (SFF) specification, such as SFF-8644 and SFF-8449 HD. In some embodiments, the electrical connectors  104  described herein may be high-speed electrical connectors that are capable of transmitting data at a rate of at least about five (5) gigabits per second (Gbps), at least about 10 Gbps, at least about 20 Gbps, at least about 40 Gbps, or more. 
     Although not shown, each of the electrical connectors  104  may be positioned within a receptacle cage. The receptacle cage may be configured to receive one of the pluggable I/O connectors during a mating operation and direct the pluggable I/O connector toward the corresponding electrical connector  104 . The circuit board assembly  100  may also include other devices that are communicatively coupled to the electrical connectors  104  through the circuit board  102 . The electrical connectors  104  may be positioned proximate to one edge of the circuit board. 
     The electrical connector  104  includes a connector housing  110  having a plurality of housing sides  111 - 116 . The housing sides  111 - 116  include a front side  111 , a top side  112 , a back side  113 , and a mounting side  114 . The housing sides  115 ,  116  extend between the back side  113  and the front side  111 . The front side  111  and the back side  113  face in opposite directions along the mating axis  191 , and the top side  112  and the mounting side  114  face in opposite directions along the vertical axis  193 . The top side  112  faces away from the circuit board  102  and may have the greatest elevation of the housing sides  111 - 116  with respect to the board surface  106 . The front side  111  is configured to mate with a mating connector (not shown), such as the mating connector  266  shown in  FIG. 7 , and the mounting side  114  is configured to be mounted to the board surface  106 . 
     In the illustrated embodiment of  FIG. 1 , the electrical connector  104  is a right-angle connector such that the front side  111  and the mounting side  114  are oriented substantially perpendicular or orthogonal to each other. More specifically, the front side  111  faces in a receiving direction  194  along the mating axis  191 , and the mounting side  114  faces in a mounting direction  195  along the vertical axis  193 . In other embodiments, the front side  111  and the mounting side  114  may face in different directions than those shown in  FIG. 1 . For example, the front side  111  and the mounting side  114  may face in opposite directions. 
     The connector housing  110  includes a receiving cavity  118  that is sized and shaped to receive a portion of the mating connector. For example, in the illustrated embodiment, the receiving cavity  118  is sized and shaped to receive a circuit board (not shown) of the mating connector. The circuit board of the mating connector may include one or more rows of contact pads located along a leading edge of the circuit board. 
     The electrical connector  104  includes signal conductors and ground conductors (not shown) that extend through the connector housing  110  between the front side  111  and the mounting side  114 . Each of the signal and ground conductors may extend between a mating interface and a terminating end. The mating interfaces are configured to slidably engage corresponding contact pads of the mating connector, and the terminating ends are configured to engage the circuit board  102 . For example, the terminating ends may be soldered or welded to traces or contact pads (not shown) along the board surface  106 . Alternatively, the terminating ends may form compliant pins that are inserted into plated thru-holes (PTHs) (not shown) of the circuit board  102 . 
     The signal and ground conductors may be similar or identical to signal and ground conductors  170 ,  172  or the signal and ground conductors  174 ,  176 , which are described below with reference to  FIGS. 2-7 . In particular, the signal and ground conductors may be arranged to form a plurality of ground-signal-signal-ground (GSSG) sub-arrays in which each pair of signal conductors is located between two conductors. The electrical connector  104  may also include a plurality of resonance-control bridges  120 . Each of the resonance-control bridges  120  is configured to electrically couple the two ground conductors that are located on opposite sides of a signal pair of a corresponding GSSG sub-array. The resonance-control bridges  120  may control or limit undesirable resonances that occur within the ground conductors during operation of the electrical connector  104 . Each of the resonance-control bridges  120  may include at least one of a capacitor or a resistor. In particular embodiments, the resonance-control bridges  120  are discrete components that are electrically coupled to the ground conductors. As described herein, the resonance-control bridges  120  may effectively reduce the frequency of energy resonating within the ground conductors. 
     In the illustrated embodiment, the resonance-control bridges  120  are distributed laterally along the top side  112 . The resonance-control bridges  120  may also be positioned laterally along the mounting side  114 . In other embodiments, the resonance-control bridges  120  may be positioned laterally along the back side  113 . In the illustrated embodiment, the resonance-control bridges  120  may have a common axial location relative to the mating axis  191 . In other embodiments, however, the resonance-control bridges  120  may have different axial locations. For example, some of the resonance-control bridges  120  may be located closer to the back side  113  than other resonance-control bridges  120 . 
       FIG. 2  illustrates a top perspective cutaway view of an electrical connector  150  formed in accordance with an embodiment, and  FIG. 3  is another perspective cutaway view through a different section of the electrical connector  150 . The electrical connector  150  may be similar to the electrical connector  104  ( FIG. 1 ) and may replace the electrical connector  104  in the circuit board assembly  100  ( FIG. 1 ). In  FIGS. 2 and 3 , the electrical connector  150  is oriented with respect to mutually perpendicular axes  196 - 198 , including a mating axis  196 , a lateral axis  197 , and a vertical or mounting axis  198 . 
     The electrical connector  150  has a connector housing  152 , which may be similar to the connector housing  110  ( FIG. 1 ). For example, the connector housing  152  includes a front side  153  (shown in  FIG. 7 ), a top side  154 , a back side  155 , and a mounting side  156 . The top side  154  and the mounting side  156  face in opposite directions along the vertical axis  198 . The mounting side  156  is configured to interface with a board surface  267  (shown in  FIG. 7 ) of a circuit board  265  (shown in  FIG. 7 ). The front side  153  faces along the mating axis  196  and is configured to engage a mating connector  264  (shown in  FIG. 7 ), such as a pluggable I/O connector. The connector housing  152  may be molded from a dielectric material to include the various features described herein. 
     As shown in  FIGS. 2 and 3 , the connector housing  152  defines a receiving cavity  160  that is configured to receive a portion of the mating connector  264 . The receiving cavity  160  includes a board-receiving space  162  and a plurality of conductor slots  164 ,  166  that open to the board-receiving space  162 . In the illustrated embodiment, the conductor slots  164 ,  166  include top conductor slots  164  and bottom conductor slots  166 . The top and bottom conductor slots  164 ,  166  extend lengthwise along the mating axis  196 . With reference to  FIG. 3 , each of the top conductor slots  164  is configured to receive a corresponding portion of a signal conductor  170  or a corresponding portion of a ground conductor  172 . Each of the bottom conductor slots  166  is configured to receive a corresponding portion of a signal conductor  174  or a corresponding portion of a ground conductor  176 . The signal and ground conductors  170 ,  172  and the signal and ground conductors  174 ,  176  of the electrical connector  150  are shown in greater detail in  FIG. 4 . 
     The electrical connector  150  also includes resonance-control bridges  180  (shown in  FIG. 2 ) and resonance-control bridges  182  (shown in  FIG. 3 ). The resonance-control bridges  180 ,  182  may be similar or identical to each other and/or the resonance-control bridges  120  ( FIG. 1 ). The resonance-control bridges  180  are positioned along the top side  154 , and the resonance-control bridges  182  are positioned along the mounting side  156 . As described herein, each of the resonance-control bridges  180  is configured to electrically couple at least two of the ground conductors  172  ( FIG. 3 ), and each of the resonance-control bridges  182  is configured to electrically couple at least two of the ground conductors  176  ( FIG. 3 ). In some embodiments, the connector housing  152  may include a bridge-receiving recess  184  (shown in  FIG. 2 ) and a bridge-receiving recess  186  (shown in  FIG. 3 ). The bridge-receiving recess  184 ,  186  are sized and shaped to receive the resonance-control bridges  180 ,  182 , respectively. 
       FIG. 4  is a perspective view of a signal-transmission assembly  200  that includes the signal and ground conductors  170 ,  172  and the signal and ground conductors  174 ,  176  of the electrical connector  150  ( FIG. 2 ). The signal-transmission assembly  200  also includes the resonance-control bridges  180 ,  182 . The signal and ground conductors  170 ,  172  and the signal and ground conductors  174 ,  176  are configured to extend between the front side  153  ( FIG. 7 ) and the mounting side  156  ( FIG. 2 ) of the connector housing  152  ( FIG. 2 ). The signal conductors  170  form corresponding signal pairs  171  that are configured to carry differential signals, and the signal conductors  174  form corresponding signal pairs  175  that are configured to carry differential signals. The ground conductors  172  are positioned relative to the signal pairs  171  to electrically separate adjacent signal pairs  171  from each other. Likewise, the ground conductors  176  are positioned relative to the signal pairs  175  to electrically separate adjacent signal pairs  175 . 
     The signal and ground conductors  170 ,  172  form a first conductor row  201 . The signal and ground conductors  170 ,  172  of the first conductor row  201  may have identical or essentially identical shapes. For example, the signal and ground conductors  170 ,  172  may be stamped-and-formed from sheet metal using a common press. Likewise, the signal and ground conductors  174 ,  176  form a second conductor row  202 . The signal and ground conductors  174 ,  176  of the second conductor row  202  may have identical or essentially identical shapes. 
     The signal conductors (or signal pairs) and the ground conductors are positioned relative to one another to form a plurality of ground-signal-signal-ground (GSSG) sub-arrays. For example, the signal and ground conductors  170 ,  172  of the first conductor row  201  form three GSSG sub-arrays  204 , which are designated as GSSG sub-arrays  204 A,  204 B,  204 C. The signal and ground conductors  174 ,  176  of the second conductor row  202  form three GSSG sub-arrays  206 , which are designated as GSSG sub-arrays  206 A,  206 B,  206 C. Each of the GSSG sub-arrays  204  includes a corresponding signal pair  171  having two ground conductors  172  on opposite sides of the corresponding signal pair  171 . Each of the GSSG sub-arrays  206  includes a corresponding signal pair  175  having two ground conductors  176  on opposite sides of the corresponding signal pair  175 . It should be understood that the first conductor row  201  may include more than three GSSG sub-arrays  204  and the second conductor row  202  may also include more than three GSSG sub-arrays  204 . 
     In the illustrated embodiment, adjacent GSSG sub-arrays may share a ground conductor. For example, the GSSG sub-array  204 A includes a ground conductor  172 A and a ground conductor  172 B. The GSSG sub-array  204 B includes the ground conductors  172 B and a ground conductor  172 C. The GSSG sub-array  204 C includes the ground conductor  172 C and a ground conductor  172 D. In the GSSG sub-array  204 A, the ground conductor  172 A may be designated as a first ground conductor and the ground conductor  172 B may be designated as a second ground conductor. In the GSSG sub-array  204 B, however, the ground conductor  172 B may be designated as a first ground conductor and the ground conductor  172 C may be designated as the second ground conductor. In such embodiments, the ground conductor  172 B may be a shared ground conductor that separates the corresponding signal pairs  171  of the GSSG sub-arrays  204 A,  204 B. In some embodiments, the shared ground conductor  172 B may be coupled to two of the resonance-control bridges  180 . As shown in  FIG. 4 , the ground conductor  172 C is also a shared ground conductor that separates the corresponding signal pairs  171  of the GSSG sub-arrays  204 B,  204 C. 
     In alternative embodiments, the GSSG sub-arrays  204 A- 204 C may not share a ground conductor. More specifically, each of the GSSG sub-arrays  204 A- 204 C may include two ground conductors without sharing either of the ground conductors. In such embodiments, the pattern of the first conductor row  201  may be ground-signal-signal-ground-ground-signal-signal-ground-ground-signal-signal-ground or (G-S-S-G-G-S-S-G-G-S-S-G). 
     Also shown in  FIG. 4 , the signal and ground conductors  170 ,  172  may include interference features  283 ,  284 ,  285 ,  286 , and the signal and ground conductors  174 ,  176  may include interference features  294 ,  295 ,  296 ,  297 . As described below, the interference features  283 - 286  and  294 - 297  are configured to engage portions of the connector housing  152  ( FIG. 2 ) to hold the corresponding conductor relative to the connector housing  152 . 
       FIG. 5  is a perspective view that illustrates a resonance-control bridge  180 C in greater detail. The resonance-control bridge  180 C is coupled to the first and second ground conductors  172 C,  172 D of the GSSG sub-array  204 C. The first and second ground conductors  172 C,  172 D flank the corresponding signal pair  171  of the signal conductors  170 . The resonance-control bridge  180 C includes a discrete component  210 . The discrete component  210  may include at least one of a capacitor or resistor. For example, in the illustrated embodiment, the discrete component  210  is a capacitor, such as a multilayer ceramic chip capacitor. 
     In the illustrated embodiment, the discrete component  210  is substantially box-shaped and extends between opposite first and second terminals  216 ,  218 . The first and second terminals  216 ,  218  are mechanically and electrically coupled to the first and second interconnecting elements  212 ,  214 , respectively. The interconnecting elements  212 ,  214  are hereinafter referred to as bridge shoes  212 ,  214 , respectively. The first and second terminals  216 ,  218  may be soldered or welded to the first and second bridge shoes  212 ,  214 , respectively. The first bridge shoe  212  interconnects the first terminal  216  and the ground conductor  172 C. The second bridge shoe  214  interconnects the second terminal  218  and the ground conductor  172 D. In the illustrated embodiment, the first bridge shoe is T-shaped, and the second bridge shoe  214  is L-shaped, but other shapes may be used. The other resonance-control bridges  180  and the resonance-control bridges  182  ( FIG. 4 ) may be similar or identical to the resonance-control bridge  180  shown in  FIG. 5 . 
       FIG. 6  is an enlarged cross-section of a portion of the electrical connector  150  taken along the line  6 - 6  in  FIG. 2 . The connector housing  152  has a receiving surface  220  that defines a portion of the top side  154 . More specifically, the receiving surface  220  defines a portion of the bridge-receiving recess  184 . The receiving surface  220  is located a depth from a top surface  222  of the top side  154 . Each of the receiving and top surfaces  220 ,  222  faces an exterior of the connector housing  152 . Also shown, the connector housing  152  may include coupling cavities  224  that open to the bridge-receiving recess  184  and the exterior of the connector housing  152 . In  FIG. 6 , the coupling cavities  224  extend from the receiving surface  220  toward the corresponding ground conductors  172 A,  172 B,  172 C. 
       FIG. 6  illustrates two resonance-control bridges  180 A,  180 B and a portion of the resonance-control bridge  180 C. As shown, the signal conductors  170  and the ground conductors  172  of the first connector row  201  are co-planar. More specifically, flex segments  280  of the signal and ground conductors  170 ,  172  coincide with a conductor plane  230  that extends parallel to the mating and lateral axes  196 ,  197 . The flex segments  280  are configured to engage the mating connector  264  ( FIG. 7 ). A side view of the flex segments  280  is shown in  FIG. 7 . 
     The connector housing  152  includes platform portions  232 A,  232 B,  232 C that are configured to support the resonance-control bridges  180 A,  180 B, and  180 C, respectively. Each of the platform portions  232 A- 232 C is positioned between the corresponding resonance-control bridge and one of the signal pairs  171  and is defined laterally between two of the coupling cavities  224 . For example, the platform portion  232 A is positioned between the resonance-control bridge  180 A and the signal pair  171  of the GSSG sub-array  204 A. The platform portion  232 A separates the resonance-control bridge  180 A from the corresponding signal pair  171 . The adjacent platform portions  232 A,  232 B are separated by one of the coupling cavities  224 , and the adjacent platform portions  232 B,  232 C are separated by another of the coupling cavities  224 . 
     The resonance-control bridge  180 A is coupled to the ground conductors  172 A,  172 B through bridge shoes  214 ,  212 , respectively. The resonance-control bridge  180 B is coupled to the ground conductors  172 B,  172 C through corresponding bridge shoes  212 . In the illustrated embodiment, each of the bridge shoes  212  is a shared bridge shoe that electrically couples a shared ground conductor to two of the resonance-control bridges  180 . For example, one of the bridge shoes  212  electrically couples the resonance-control bridge  180 A and the resonance-control bridge  180 B to the shared ground conductor  172 B. The other bridge shoe  212  shown in  FIG. 6  electrically couples the resonance-control bridge  180 B and the resonance-control bridge  180 C to the shared ground conductor  172 C. 
       FIG. 11  is an isolated perspective view of an exemplary bridge shoe  212 . The bridge shoe  212  includes a base portion  234  and first and second fingers  236 ,  238  that are directly coupled to the base portion  234 . In the illustrated embodiment, the base portion  234  includes a planar body that extends parallel to the vertical axis  198 . The first and second fingers  236 ,  238  are shaped to extend away from each other and parallel to the lateral axis  197 . The first and second fingers  236 ,  238  include respective conductive surfaces  237 ,  239 . In the illustrated embodiment, the bridge shoe  212  is stamped-and-formed from sheet metal. For example, a blank of material may be stamped to form the base portion  234  and another portion that include the first and second fingers  236 ,  238 . The other portion may be split and shaped to form the first and second fingers  236 ,  238  as shown in  FIG. 11 . 
     Returning to  FIG. 6 , the conductive surfaces  237 ,  239  of the first and second fingers  236 ,  238 , respectively, may be exposed to the exterior of the connector housing  152  when the conductive surfaces  237 ,  239  are not coupled to the corresponding resonance-control bridges  180 . The resonance-control bridge  180 A is mechanically and electrically coupled to the conductive surface  237  of the first finger  236 , and the resonance-control bridge  180 B is mechanically and electrically coupled to the conductive surface  239  of the second finger  238 . The base portion  234  may be mechanically and electrically coupled to the corresponding ground conductor  172 B. As such, one of the shared bridge shoes  212  may electrically couple the shared ground conductor  172 B to the resonance-control bridges  180 A,  180 B and electrically couple the resonance-control bridges  180 A,  180 B to each other. The other shared bridge shoes  212  shown in  FIG. 6  may electrically couple the shared ground conductor  172 C to the resonance-control bridges  180 B,  180 C and electrically couple the resonance-control bridges  180 B,  180 C to each other. 
     The bridge shoe  214  includes a base portion  240  and a finger  242 . The base portion  240  engages the ground conductor  172 A. The finger  242  includes a conductive surface  243  that may be exposed along the exterior of the connector housing  152  when the conductive surface  243  is not coupled to the resonance-control bridge  180 A. The terminal  216  of the resonance-control bridge  180 A is mechanically and electrically coupled to the finger  242  and, more specifically, to the conductive surface  243 . As described herein, the terminal  216  may be soldered or welded to the finger  242 . In alternative embodiments, the bridge shoe  212  and the resonance-control bridge  180 A are not discrete elements. For example, the terminal  216  may be shaped to include a finger and/or base portion that extends toward and engages the ground conductor  172 A. 
     As shown, each of the first and second fingers  236 ,  238  and the finger  243  extends substantially parallel to the conductor plane  230 . Each of the first and second fingers  236 ,  238  and the finger  243  includes a respective underside  244  that faces the corresponding platform portion. In some embodiments, the underside  244  may interface with the corresponding platform portion such that the underside  244  engages the platform portion or has a nominal gap therebetween. 
     In the illustrated embodiment, the coupling cavities  224  may enable electrical coupling of the resonance-control bridges  180 A- 180 C to the corresponding ground conductors  172  after the signal-transmission assembly  200  ( FIG. 4 ) is positioned within the connector housing  152 . For example, the resonance-control bridges  180 A- 180 C may be soldered or welded to the corresponding bridge shoes to form a resonance-control assembly  250  that includes each of the resonance-control bridges  180 A- 180 C and each of the bridge shoes  212 ,  214 . The resonance-control assembly  250  may then be mounted onto the top side  154  such that the base portions  234 ,  240  are inserted into the corresponding coupling cavities  224  and engage the corresponding ground conductors  172 . In other embodiments, the bridge shoes  212 ,  214 , prior to being attached to the corresponding resonance-control bridges  180 A- 180 C, may be mounted onto the top side  154  such that the base portions  234 ,  240  are inserted into the corresponding coupling cavities  224  and engage the corresponding ground conductors  172 . After the bridge shoes  212 ,  214  are mounted onto the top side  154 , the resonance-control bridges  180 A- 180 C may be soldered or welded to the corresponding bridge shoes as shown in  FIG. 6 . 
     In the illustrated embodiment, the resonance-control bridges  180 A- 180 C are positioned along the top side  154  such that the resonance-control bridges  180 A- 180 C are accessible from the exterior of the connector housing  152 . Such embodiments may enable easier manufacturing and/or inspection of the electrical connector  150 . In alternative embodiments, the bridge shoes  212 ,  214  and/or the resonance-control bridges  180 A- 180 C are not exposed to the exterior of the connector housing  152 . For example, the bridge shoes  212 ,  214  may be soldered or welded to the corresponding ground conductors  172  prior to the connector housing  152  being molded around the signal-transmission assembly  200  ( FIG. 4 ). In such embodiments, the bridge shoes  212 ,  214  and/or the resonance-control bridges  180 A- 180 C may not be viewable and/or accessible to an individual from the exterior of the connector housing  152 . 
       FIG. 7  is a side cross-section of a communication assembly  260  that includes a circuit board assembly  262  and a mating connector  264  that is communicatively coupled to the circuit board assembly  262 . The circuit board assembly  262  includes a circuit board  265  having a board surface  267  and the electrical connector  150  mounted to the board surface  267 . As shown, the electrical connector  150  is a right-angle connector such that the front side  153  and the mounting side  156  are oriented substantially perpendicular or orthogonal to each other. More specifically, the front side  153  faces in a forward direction  275  along the mating axis  196 , and the mounting side  156  faces in a mounting direction  277  along the vertical axis  198 . 
     The receiving cavity  160  is sized and shaped to receive a portion of the mating connector  264 . In the illustrated embodiment, the mating connector  264  includes a connector card (or circuit board)  266  that is sized and shaped for inserting into the receiving cavity  160 . The mating connector  264  may include other elements, such as a connector housing (not shown) and signal-processing units (not shown) that are mounted to the connector card  266 . The connector card  266  includes first and second board surfaces  268 ,  269  that face in opposite directions and a leading edge  270  that extends between the board surfaces  268 ,  269 . Each of the board surfaces  268 ,  269  includes a corresponding row of contact pads  272  located along the leading edge  270 . The contact pads  272  are configured to engage the signal conductors  170 ,  174  ( FIG. 3 ) and the ground conductors  172 ,  176 . In  FIG. 7 , only the ground conductors  172 ,  176  are shown, but it should be understood that the signal conductors  170 ,  174  engage corresponding contact pads  272  when the mating connector  264  and the electrical connector  150  are fully mated. 
     In the illustrated embodiment, each of the ground conductors  172  extends between a distal tip  276  and a terminating end  278 . The terminating ends  278  are terminated (e.g., soldered or welded) to corresponding conductive elements of the circuit board  265 . Each of the ground conductors  172  includes the flex segment  280  and a base segment  282 . The base segment  282  includes the terminating end  278  and the interference features  283 ,  284 ,  285 ,  286 . The interference features  283 - 286  are points or regions along the base segment  282  of the corresponding ground conductor  172  that are shaped to engage the connector housing  152  to hold the base segment  282  in a fixed position relative to the connector housing  152 . In the illustrated embodiment, the ground conductor  172  includes four interference features  283 - 286 , but may include fewer or more interference features in other embodiments. The interference features  283 - 286  and the terminating end  278 , which is secured to the circuit board  265 , operate to hold the base segment  282  in a fixed position relative to the connector housing  152 . 
     In  FIG. 7 , the base segment  282  extends from the terminating end  278  to the interference feature  283 . The flex segment  280  extends from the interference feature  283  to the distal tip  276 . The flex segment  280  may flex when the connector card  266  engages the ground conductors  172  during a mating operation. To this end, the flex segment  280  includes a mating interface  288 . The mating interface  288  is shaped to engage the connector card  266  and slide or wipe along the board surface  268  until the mating interface  288  is in a final position engaged to a corresponding contact pad  272  as shown in  FIG. 7 . 
     The ground conductors  176  may include similar features as the ground conductors  172 . For example, each of the ground conductors  176  extends between a distal tip  290  and a terminating end  291 . The terminating ends  291  are terminated (e.g., soldered or welded) to corresponding conductive elements of the circuit board  265 . In the illustrated embodiment, the terminating ends  291  are proximate to the front side  153 . The terminating ends  278  of the ground conductors  172  are proximate to the back side  155 . The terminating ends  276 ,  278 , however, may have different positions in other embodiments. 
     The ground conductors  176  also include a flex segment  292  and a base segment  293 . The base segment  293  includes the terminating end  291  and one or more interference features  294 ,  295 ,  296 ,  297 . Like the interference features  283 - 286 , the interference features  294 - 297  engage the connector housing  152  to hold the base segment  293  in a fixed position relative to the connector housing  152 . 
     In  FIG. 7 , the base segment  293  extends from the terminating end  291  to the interference feature  294 . The flex segment  292  extends from the interference feature  294  to the distal tip  290 . The flex segment  292  may flex when the connector card  266  engages the ground conductors  176  during a mating operation. The flex segment  292  also includes a mating interface  298  that is shaped to engage the connector card  266 . As shown, the mating interfaces  288 ,  298  oppose each other and are configured to receive the connector card  266  therebetween. 
     Each of the ground conductors  172  has an electrical path length that is measured between the mating interface  288  of the corresponding ground conductor  172  and the terminating end  278  of the corresponding ground conductor  172 . Each of the ground conductors  176  has an electrical path length that is measured between the mating interface  298  of the corresponding ground conductor  176  and the terminating end  291  of the corresponding ground conductor  176 . 
     The resonance-control bridges  180 ,  182  are electrically coupled to the ground conductors  172 ,  176 , respectively, at designated locations along the electrical path length. The designated locations are based on a desired electrical performance of the electrical connector  150 . For example, in some embodiments, it may be desirable to electrically couple the resonance-control bridge  180  at a path location that is within a middle one-half of the electrical path length of the corresponding ground conductor  172 . The middle one-half extends half of the electrical path length between about Point  1  and Point  4  in FIG.  7 . In certain embodiments, it may be desirable to electrically couple the resonance-control bridge  180  at a path location that is within a middle one-third of the electrical path length of the corresponding ground conductor  172 . The middle one-third extends between Point  2  and Point  3  in  FIG. 7 . In more particular embodiments, it may be desirable to electrically couple the resonance-control bridge  180  at a path location that is about one-half of the electrical path length of the corresponding ground conductor  172 . It is noted that the above examples were described with reference to the resonance-control bridge  180  and the corresponding ground conductor  172 . The resonance-control bridge  182  may be coupled to similar path locations of the corresponding ground conductor  176 . 
     In other embodiments, however, the resonance-control bridges  180 ,  182  may electrically couple to the ground conductors  172 ,  176 , respectively, at other path locations. For example, the resonance-control bridge  180  may electrically couple to the ground conductors  172  at an end-quarter of the corresponding ground conductor  172 . The end-quarter represents a quarter of the electrical path length of the corresponding ground conductor  172  that extends between Point  4  and the terminating end  278 . 
     During operation of the communication assembly  260 , unwanted electrical energy may propagate between the ground conductors  172 ,  176 . The electrical energy may be repeatedly reflected and form a resonating condition (or standing wave). For example, the electrical energy may be reflected by a ground plane of the circuit board  265  and a ground plane of the connector card  266 . Without the resonance-control bridges  180 , the electrical energy may resonate at a frequency and magnitude that is based, in part, on the electrical path length between the mating interface  288  and the terminating end  278 . Under certain circumstances, the electrical resonance may negatively affect data transmission. When the resonance-control bridges  180  are present, however, the frequency at which the electrical energy resonates may be changed and the magnitude may be reduced. In such embodiments, the negative effects on the electrical resonance may be reduced and, accordingly, signal quality may be improved. As such, the resonance-control bridges  180  may effectively change the frequency at which the electrical energy resonates between the ground conductors  172  such that electrical noise generated by the electrical energy does not significantly degrade signal quality of the data transmission. The resonance-control bridges  182  may have a similar effect as the resonance-control bridges  180 . 
       FIG. 8  is a top perspective cutaway view of an electrical connector  300  formed in accordance with an embodiment, and  FIG. 9  is a perspective view of a signal-transmission assembly  302  that may be used with the electrical connector  300  of  FIG. 8 . The electrical connector  300  ( FIG. 8 ) may be similar to the electrical connector  150  ( FIG. 2 ). For example, the electrical connector  300  includes a connector housing  304  that may be similar or identical to the connector housing  152  ( FIG. 2 ). The electrical connector  300  also includes resonance-control bridges  306  that are positioned along a top side  308  of the connector housing  304  and resonance-control bridges  307  (shown in  FIG. 9 ) that are positioned along a mounting side  309  of the connector housing  304 . 
     With respect to  FIG. 9 , the signal-transmission assembly  302  may be similar to the signal-transmission assembly  200  ( FIG. 4 ). For example, the signal-transmission assembly  302  includes signal and ground conductors  310 ,  312  and signal and ground conductors  314 ,  316 . The signal-transmission assembly  302  also includes the resonance-control bridges  306 ,  307 . The signal and ground conductors  310 ,  312  and the signal and ground conductors  314 ,  316  are configured to extend between the front side (not shown) and the mounting side  309  ( FIG. 8 ) of the connector housing  304  ( FIG. 8 ). The signal conductors  310  form corresponding signal pairs  311  that are configured to carry differential signals, and the signal conductors  314  form corresponding signal pairs  315  that are configured to carry differential signals. The ground conductors  312  are interleaved between the signal pairs  311  to electrically separate adjacent signal pairs  311  from each other. Likewise, the ground conductors  316  are interleaved between the signal pairs  315  to electrically separate adjacent signal pairs  315 . In the illustrated embodiment, the ground conductors  312  form interconnecting elements  320  that are configured to mechanically and electrically couple to corresponding resonance-control bridges  306 . The interconnecting elements  320  are hereinafter referred to as ground tabs  320 . 
       FIG. 10  is an enlarged cross-section of the electrical connector  300  taken along the line  10 - 10  in  FIG. 8  and illustrates resonance-control bridges  306 A,  306 B and a portion of a resonance-control bridge  306 C. The portion of the connector housing  304  shown in  FIG. 10  is similar or identical to the portion of the connector housing  152  shown in  FIG. 6 . For example, the connector housing  304  includes coupling cavities  324  that open to a bridge-receiving recess  326  along the top side  308  and the exterior of the connector housing  304 . In the illustrated embodiment, the coupling cavities  324  extend from a receiving surface  328  toward respective ground channels  330 . The ground channels  330  have the ground conductors  312  disposed therein. 
     As shown in  FIG. 10 , the ground tabs  320  extend through corresponding coupling cavities  324 . The ground tabs  320  include a ground tab  320 A and ground tabs  320 B. The ground tabs  320 B are shared ground tabs. For example, each of the ground tabs  320 B includes a base portion  334  and first and second fingers  336 ,  338  that are directly coupled to the base portion  334 . The first and second fingers  336 ,  338  are shaped to extend away from each other and along the top side  308 . The first and second fingers  336 ,  338  include respective conductive surfaces  337 ,  339  that are positioned within the bridge-receiving recess  326  of the connector housing  304 . 
     As shown, the resonance-control bridge  306 A is mechanically and electrically coupled to the conductive surface  337  of the first finger  336 , and the resonance-control bridge  306 B is mechanically and electrically coupled to the conductive surface  339  of the second finger  338 . As such, the ground tab  320 B is a shared ground tab that electrically couples each of the resonance-control bridges  306 A,  306 B to the same ground conductor  312 . The ground conductor  312  that includes the ground tab  320 B may also be a shared ground conductor that is positioned between two signal pairs  311 . The ground tab  320 A also includes a base portion  340  and a finger  342 . The finger  342  is mechanically and electrically coupled to the resonance-control bridge  306 A. 
     Accordingly, embodiments described herein include interconnecting elements that extend through a housing side, such as a top side, to electrically couple the ground conductors and the resonance-control bridges. Particular examples of interconnecting elements that may be used include the bridge shoes  212 ,  214  ( FIG. 5 ) and the ground tabs  320  ( FIG. 9 ). It should be understood, however, that other interconnecting elements may extend through a housing side to electrically couple the resonance-control bridges to corresponding ground conductors. 
     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 various embodiments 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 patentable scope should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. 
     As used in the description, the phrase “in an exemplary embodiment” and the like means that the described embodiment is just one example. The phrase is not intended to limit the inventive subject matter to that embodiment. Other embodiments of the inventive subject matter may not include the recited feature or structure. 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.