Patent Publication Number: US-2021167554-A1

Title: Polarization feature for a receptacle cage

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application U.S. application Ser. No. 16/401,263 filed May 2, 2019, titled “POLARIZATION FEATURE FOR A RECEPTACLE CAGE” (Now U.S. Pat. No. 10,923,856, issued Feb. 16, 2021), which claims benefit to U.S. Provisional Application No. 62/676,338 filed May 25, 2018, titled “POLARIZATION FEATURE FOR A RECEPTACLE CAGE”, the subject matter of which is herein incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     The subject matter herein relates generally to polarization features for receptacle cages. 
     Some communication systems utilize communication connectors to interconnect various components of the system for data communication. Some known communication systems use pluggable modules, such as I/O modules, that are electrically connected to the communication connector. Known communication systems provide electrical shielding, such as in the form of a receptacle cage surrounding the communication connector and the pluggable module to provide electrical shielding. However, there is a desire to increase throughput in communication systems. For example, high speed pluggable modules and corresponding receptacle cages have been proposed having similar geometries as conventional pluggable modules and receptacle cages. However, the pluggable modules are not backwards compatible with older receptacle cages and the pluggable modules have a polarization feature included along the top of the pluggable module in the form of a post or tab extending form the top that restricts the possibility of loading the new high speed pluggable module into one of the older receptacle cages. The new high speed receptacle cages have corresponding polarization features in the form of a channel that receives the tab of the new high speed pluggable modules. The new high speed receptacle cages are backwards compatible with older pluggable modules and will accept older pluggable modules. 
     A need remains for a reliable way of forming the polarization feature on the receptacle cage and providing EMI shielding at the polarization feature on the receptacle cage. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In one embodiment, a receptacle cage is provided including shielding walls forming a module channel configured to receive a pluggable module. The shielding walls include first and second side walls extending from a top wall to form a module channel configured to receive a pluggable module. The top wall is non-planar and has a shroud extending therefrom forming a cage polarization feature. The shroud has a first shroud side wall, a second shroud side wall and a shroud top wall forming a polarization feature channel configured to receive a polarization feature of the pluggable module. 
     Optionally, the shroud may be trapezoidal shaped forming a trapezoidal shaped polarization feature channel. The first shroud side wall may be angled non-perpendicular to the shroud top wall and the second shroud side wall may be angled non-perpendicular to the shroud top wall. The first shroud side wall may be nonparallel to the second shroud side wall. 
     Optionally, the receptacle cage may extend between a front end and a rear end and the top wall may have a front edge at the front end that is continuous between the first side wall and the second side wall and that extends along the shroud over the polarization feature channel. 
     Optionally, the receptacle cage may include a gasket coupled to the top wall having a plurality of spring fingers deflectable relative to the top wall. The gasket may be coupled to the shroud. The gasket may include a base having a complementary shape as the top wall. The base may extend along the first shroud side wall and/or the second shroud side wall and/or the shroud top wall. The base may extend between the shroud and the first side wall and/or between the shroud and the second side wall. Optionally, the gasket may have at least one spring finger extending along the first shroud side wall and/or at least one spring finger extending along the second shroud side wall and/or at least one spring finger extending along the shroud top wall. Optionally, the spring finger along the first shroud side wall may be deflectable in a first deflection direction nonorthogonal to a second deflection direction of the nearest spring finger along the top wall. 
     Optionally, the top wall may include a panel and the shroud may extend upward from the panel. The panel of the top wall may include a first segment between the first shroud side wall and the first side and a second segment between the second shroud side wall and the second side. The first and second segments may be coplanar. Optionally, the top wall may include a first corner connecting the first segment and the first shroud side wall and a second corner connecting the second segment and the second shroud side wall. The top wall may be continuous through the first corner and through the second corner. Optionally, a gasket may be coupled to the top wall having a plurality of spring fingers deflectable relative to the top wall. The gasket may have at least one spring finger extending along the first segment. The gasket may have at least one spring finger extending along the first shroud side wall and/or at least one spring finger extending along the second shroud side wall and/or at least one spring finger extending along the second segment. 
     Optionally, the first shroud side wall, the second shroud side wall and/or the shroud top wall may be curved. Optionally, the shroud may be triangular shaped having the first shroud side wall meeting the second shroud side wall at the shroud top wall with the shroud top wall being a point. 
     In another embodiment, a receptacle cage is provided including shielding walls forming a module channel configured to receive a pluggable module. The shielding walls include first and second side walls extending from a top wall to form a module channel configured to receive a pluggable module. The top wall is non-planar and has a shroud extending therefrom forming a cage polarization feature. The shroud has a first shroud side wall, a second shroud side wall and a shroud top wall forming a polarization feature channel configured to receive a polarization feature of the pluggable module. The receptacle cage includes a gasket having a plurality of deflectable spring fingers extending along the top wall and extending along the shroud. 
     In a further embodiment, a receptacle connector assembly is provided including shielding walls forming a module channel configured to receive a pluggable module. The shielding walls include first and second side walls extending from a top wall to form a module channel configured to receive a pluggable module. The top wall is non-planar and has a shroud extending therefrom forming a cage polarization feature. The shroud has a first shroud side wall, a second shroud side wall and a shroud top wall forming a polarization feature channel configured to receive a polarization feature of the pluggable module. The top wall has a front edge at the front end of the receptacle cage being continuous between the first side and the second side. The front edge is non-planar forming the shroud and the cage polarization feature. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of a communication system formed in accordance with an exemplary embodiment. 
         FIG. 2  is a rear perspective view of pluggable module of the communication system in accordance with an exemplary embodiment. 
         FIG. 3  is a perspective view of a front end of a receptacle cage of the communication system in accordance with an exemplary embodiment. 
         FIG. 4  is a top view of a portion of the receptacle cage at the front end in accordance with an exemplary embodiment. 
         FIG. 5  is a front, partial sectional view of the communication system in accordance with an exemplary embodiment. 
         FIG. 6  is a perspective, partial sectional view of the communication system in accordance with an exemplary embodiment. 
         FIG. 7  is a perspective view of the communication system in accordance with an exemplary embodiment showing the receptacle cage having upper and lower module channels. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a front perspective view of a communication system  100  formed in accordance with an exemplary embodiment. The communication system includes a host circuit board  102  and a receptacle connector assembly  104  mounted to the host circuit board  102 . A pluggable module  106  (fully shown in  FIG. 2 ) is configured to be electrically connected to the receptacle connector assembly  104 . The pluggable module  106  is electrically connected to the host circuit board  102  through the receptacle connector assembly  104 . 
     In an exemplary embodiment, the receptacle connector assembly  104  includes a receptacle cage  110  and a communication connector  112  (shown with phantom lines) adjacent the receptacle cage  110 . For example, in the illustrated embodiment, the communication connector  112  is received in the receptacle cage  110 . In other various embodiments, the communication connector  112  may be located rearward of the receptacle cage  110 . In various embodiments, the receptacle cage  110  is enclosed and provides electrical shielding for the communication connector  112 . The pluggable modules  106  are loaded into the receptacle cage  110  and are at least partially surrounded by the receptacle cage  110 . In an exemplary embodiment, the receptacle cage  110  is a shielding, stamped and formed cage member that includes a plurality of shielding walls  114  that define one or more module channels for receipt of corresponding pluggable modules  106 . In other embodiments, the receptacle cage  110  may be open between frame members to provide cooling airflow for the pluggable modules  106  with the frame members of the receptacle cage  110  defining guide tracks for guiding loading of the pluggable modules  106  into the receptacle cage  110 . 
     In the illustrated embodiment, the receptacle cage  110  is a single port receptacle cage configured to receive a single pluggable module  106 . In other various embodiments, the receptacle cage  110  may be a ganged cage member having a plurality of ports ganged together in a single row and/or a stacked cage member having multiple ports stacked as an upper port and a lower port. The receptacle cage  110  includes a module channel  116  having a module port  118  open to the module channel  116 . The module channel  116  receives the pluggable module  106  through the module port  118 . In an exemplary embodiment, the receptacle cage  110  extends between a front end  120  and a rear end  122 . The module port  118  is provided at the front end  120 . Any number of module channels  116  may be provided in various embodiments arranged in a single column or in multiple columns (for example, 2X2, 3X2, 4X2, 4X3, 4X1, 2X1, and the like). Optionally, multiple communication connectors  112  may be arranged within the receptacle cage  110 , such as when multiple rows and/or columns of module channels  116  are provided. 
     In an exemplary embodiment, the walls  114  of the receptacle cage  110  include a top wall  130 , a bottom wall  132 , a first side wall  134  and a second side wall  136  extending from the top wall  130 . The bottom wall  132  may rest on the host circuit board  102 . In other various embodiments, the receptacle cage  110  may be provided without the bottom wall  132 . Optionally, the walls  114  of the receptacle cage  110  may include a rear wall  138  at the rear end  122 . The walls  114  define a cavity  140 . For example, the cavity  140  may be defined by the top wall  130 , the bottom wall  132 , the side walls  134 ,  136  and the rear wall  138 . The cavity  140  includes the module channel  116 . In various embodiments, the cavity  140  receives the communication connector  112 , such as at the rear end  122 . Other walls  114  may separate or divide the cavity  140  into additional module channels  116 , such as in embodiments using ganged and/or stacked receptacle cages. For example, the walls  114  may include one or more vertical divider walls between ganged module channels  116 . In various embodiments, the walls  114  may include a separator panel between stacked upper and lower module channels  116 . The separator panel may include an upper panel and a lower panel that form a space between the upper and lower module channels  116 , such as for airflow, for a heat sink, for routing light pipes, or for other purposes. 
     In an exemplary embodiment, the receptacle cage  110  may include one or more gaskets  142  at the front end  120  for providing electrical shielding for the module channels  116 . For example, the gaskets  142  may be provided at the port  118  to electrically connect with the pluggable modules  106  received in the module channel  116 . Optionally, the pluggable module  106  may include a gasket that engages the receptacle cage  110  rather than the receptacle cage  110  having a gasket that engages the pluggable module  106 . In an exemplary embodiment, the gaskets  142  may be provided around the exterior of the receptacle cage  110  for interfacing with a panel  144 , such as when the front end  120  of the receptacle cage  110  extends through a cutout  146  in the panel  144 . The gaskets  142  may include spring fingers  148  or other deflectable features that are configured to be spring biased against the panel  144  to create an electrical connection with the panel  144 . 
     Optionally, the receptacle connector assembly  104  may include one or more heat sinks (not shown) for dissipating heat from the pluggable modules  106 . For example, the heat sink may be coupled to the top wall  130  for engaging the pluggable module  106  received in the module channel  116 . The heat sink may extend through an opening in the top wall  130  to directly engage the pluggable module  106 . Other types of heat sinks may be provided in alternative embodiments. 
     In an exemplary embodiment, the communication connector  112  is received in the cavity  140 , such as proximate to the rear wall  138 . However, in alternative embodiments, the communication connector  112  may be located behind the rear wall  138  exterior of the receptacle cage  110  and extend into the cavity  140  to interface with the pluggable module(s)  106 . In an exemplary embodiment, a single communication connector  112  is provided. In alternative embodiments, the communication system  100  may include multiple communication connectors  112  (for example, for stacked and/or ganged receptacle cages) for mating with corresponding pluggable modules  106 . 
     In an exemplary embodiment, the pluggable modules  106  are loaded through the port  118  at the front end  120  to mate with the communication connector  112 . The shielding walls  114  of the receptacle cage  110  provide electrical shielding around the communication connector  112  and the pluggable module  106 , such as around the mating interface between the communication connector  112  and the pluggable module  106 . 
       FIG. 2  is a rear perspective view of the pluggable module  106  in accordance with an exemplary embodiment. The pluggable module  106  has a pluggable body  170 , which may be defined by one or more shells. The pluggable body may be thermally conductive and/or may be electrically conductive, such as to provide EMI shielding for the pluggable module  106 . The pluggable body  170  includes a mating end  172  and an opposite front end  174 . The mating end  172  is configured to be inserted into the corresponding module channel  116  (shown in  FIG. 1 ). The front end  174  may be a cable end having a cable extending therefrom to another component within the system. 
     The pluggable module  106  includes a module circuit board  176  that is configured to be communicatively coupled to the communication connector  112  (shown in  FIG. 1 ). The module circuit board  176  may be accessible at the mating end  172 . The module circuit board  176  has a mating edge  178  and mating contacts at the mating edge  178  configured to be mated with the communication connector  112 . The module circuit board  176  may include components, circuits and the like used for operating and or using the pluggable module  106 . For example, the module circuit board  176  may have conductors, traces, pads, electronics, sensors, controllers, switches, inputs, outputs, and the like associated with the module circuit board  176 , which may be mounted to the module circuit board  176 , to form various circuits. 
     The pluggable module  106  includes an outer perimeter defining an exterior of the pluggable body  170 . For example, the outer perimeter may be defined by a top  180 , a bottom  182 , a first side  184  and a second side  186 . The pluggable body  170  may have other shapes in alternative embodiments. In an exemplary embodiment, the pluggable module  106  includes a gasket  188  around the outer perimeter, such as proximate the front end  174 . The gasket  188  may be provided on the top  180  and/or the bottom  182  and/or the sides  184 ,  186 . The gasket  188  includes deflectable spring fingers  190  configured to engage the receptacle cage  110 . The spring fingers  190  may be electrically connected to the interior of the receptacle cage  110  when the pluggable module  106  is plugged into the module channel  116 . The spring fingers  190  may provide electrical shielding (for example, EMI shielding) along the pluggable body  170 , such as at the port  118 . 
     In an exemplary embodiment, the pluggable module  106  includes a polarization feature  192  at the outer perimeter. The polarization feature  192  is used to restrict mating of the pluggable module  106  in an incorrect orientation or with an incorrect receptacle cage  110 . In the illustrated embodiment, the polarization feature  192  is defined by a protrusion  194  extending from the pluggable body  170 . For example, the polarization feature  192  may be a post or tab extending from the top  180 . In an exemplary embodiment, the polarization feature  192  includes a top  196  and sides  198 . Optionally, the polarization feature  192  may be offset, such as closer to the first side  184 . Optionally, multiple polarization features  192  may be provided. In other various embodiments, the polarization feature  192  may be provided at other locations. The polarization feature  192  may be provided at a predetermined depth from the mating end  172  to ensure that the mating end  172  and/or the module circuit board  176  does not mate with the communication connector  112  when plugged into the receptacle cage  110  with the polarization feature  192  and incorrect orientation. 
     In an exemplary embodiment, the pluggable body  170  provides heat transfer for the module circuit board  176 , such as for the electronic components on the module circuit board  176 . For example, the module circuit board  176  is in thermal communication with the pluggable body  170  and the pluggable body  170  transfers heat from the module circuit board  176 . Optionally, the pluggable body  170  may include a plurality of heat transfer fins (not shown) along at least a portion of the outer perimeter of the pluggable module  106  for dissipating heat from the pluggable body  170 . 
       FIG. 3  is a perspective view of the front end  120  of the receptacle cage  110  in accordance with an exemplary embodiment.  FIG. 3  shows the module port  118  to the module channel  116  open at the front end  120  configured to receive the pluggable module  106  therein. In the illustrated embodiment, the module channel  116  is surrounded by the top wall  130 , the bottom wall  132 , and the side walls  134 ,  136 . 
     In an exemplary embodiment, the receptacle cage  110  includes a cage polarization feature  200  configured to interface with the polarization feature  192  of the pluggable module  106 . In the illustrated embodiment, the cage polarization feature  200  is provided along the top wall  130 ; however, in alternative embodiments, the cage polarization feature  200  may be provided along one or more additional or alternative walls  114  of the receptacle cage  110 . In an exemplary embodiment, the cage polarization feature  200  includes a polarization feature channel  202  open to the module channel  116 . The polarization feature channel  202  receives the polarization feature  192  of the pluggable module  106 . For example, the polarization feature channel  202  may be sized and shaped to receive the polarization feature  192  and may be positioned along the top wall  130  to receive the polarization feature  192 . 
     In an exemplary embodiment, the top wall  130  is nonplanar including a shroud  204  extending therefrom forming the cage polarization feature  200 . The shroud  204  is provided at a front edge  206  of the top wall  130  and extends rearward from the front edge  206 . In an exemplary embodiment, the shroud  204  is integral with the top wall  130 . For example, the shroud  204  is formed with the top wall  130 , such as being stamped and formed or extruded with the top wall  130 . The shroud  204  is a continuous part of the top wall  130 . 
     The shroud  204  includes a first shroud side wall  210 , a second shroud side wall  212  and a shroud top wall  214  extending between the first shroud side wall  210  and the second shroud side wall  212 . In various embodiments, the shroud walls  210 ,  212 ,  214  are planar walls, however; the shroud walls may be curved in other various embodiments. For example, at least one of the first shroud side wall  210  and/or the second shroud side wall  212  and/or the shroud top wall  214  may be curved. In an exemplary embodiment, the shroud  204  is trapezoidal shaped forming a trapezoidal shaped polarization feature channel  202 . For example, the first shroud side wall  210  is angled non-perpendicular to the shroud top wall  214  and the second shroud side wall  212  is angled non-perpendicular to the shroud top wall  214 . The first shroud side wall  210  is angled nonparallel to the second shroud wall  212 . The shroud  204  may have other shapes in alternative embodiments. The shroud  204  may include greater or fewer walls in alternative embodiments. For example, the shroud top wall  214  may be eliminated and the shroud  204  may be triangular-shaped in alternative embodiments. For example, the shroud  204  may be triangular shaped having the first shroud side wall  210  meeting the second shroud side wall  212  at the shroud top wall  214  with the shroud top wall  216  being a point or having a near zero width. 
     In an exemplary embodiment, the top wall  130  includes a panel  208  defined by a first segment  216  and a second segment  218  with the shroud  204  being formed out of the panel  208  and extending upward from the panel  208 . The first segment  216  extends between the first shroud side wall  210  and the first side wall  134  of the receptacle cage  110 . The second segment  218  extends between the second shroud side wall  212  and the second side wall  136  of the receptacle cage  110 . In the illustrated embodiment, the first and second segments  216 ,  218  are coplanar and the shroud  204  extends above the first and second segments  216 ,  218 . Optionally, the first segment  216  may be narrower than the second segment  218  (and the second segment  218  may be wider than the first segment  216 ) such that the shroud  204  is offset and positioned closer to the first side wall  134  and further from the second side wall  136 . In other various embodiments, the first and second segments  216 ,  218  may have equal widths with the shroud  204  centered between the first and second side walls  134 ,  136 . 
     The top wall  130  includes a first corner  220  connecting the first segment  216  and the first shroud side wall  210  and a second corner  222  connecting the second segment  218  and the second shroud side wall  212 . The top wall  130  is continuous through the first corner  220  and through the second corner  222 . For example, the first segment  216  is continuous with the first shroud side wall  210  and the second segment  218  is continuous with the second shroud side wall  212 . The top wall  130  includes a third corner  224  connecting the first shroud side wall  210  and the shroud top wall  214  and a fourth corner  226  connecting the second shroud side wall  212  and the shroud top wall  214 . The top wall  130  is continuous through the third corner  224  and through the fourth corner  226 . For example, the first shroud side wall  210  is continuous with the shroud top wall  214  and the second shroud side wall  212  is continuous with the shroud top wall  214 . In an alternative embodiment, the shroud  204  may be provided at the first side wall  134  or the second side wall  136  such that the top wall  130  does not include the first segment  216  and corresponding first corner  220  and/or the second segment  218  and corresponding second corner  222 . 
     In an exemplary embodiment, the front edge  206  of the top wall  130  is continuous between the first side wall  134  and the second side wall  136 . For example, the top wall  130  extends along the shroud  204  over the polarization feature channel  202 . The front edge  206  is continuous from the first side wall  134  along the first segment  216 , through the first corner  220  along the first shroud side wall  210 , through the third corner  224  along the shroud top wall  214 , through the fourth corner  226  along the second shroud side wall  212 , through the second corner  222  along the second segment  218  to the second side wall  136 . The top wall  130  is a continuous piece of metal along such segments and walls. There are no gaps or slits in the top wall  130  along the front edge  206 . The top wall  130  provides rigid, mechanical stability across the width of the receptacle cage  110  between the first side wall  134  and the second side wall  136 . The top wall  130  includes an interior surface  230  facing the module channel  116  and the polarization feature channel  202  and an exterior surface  232  facing the exterior of the receptacle cage  110 . In an exemplary embodiment, there are no breaks or gaps along the interior surface  230  or the exterior surface  232  at the front edge  206  even as the top wall  130  forms the cage polarization feature  200 . 
       FIG. 4  is a top view of a portion of the receptacle cage  110  at the front end  120 .  FIG. 4  shows the gasket  142  coupled to the top wall  130 . The gasket  142  includes a base  150  coupled to the top wall  130 . The spring fingers  148  extend from the base  150  of the gasket  142 . In an exemplary embodiment, the base  150  has a complementary shape as the top wall  130 . For example, the base  150  has a complementary shape as, and extends along, the front edge  206  of the top wall  130 . 
     The gasket  142  extends along the cage polarization feature  200 . The base  150  has a shroud segment  152  extending along the shroud  204  and a panel segment  154  extending along the panel  208 . For example, the panel segment  154  may include a first segment  156  extending along the first segment  216  and a second segment  158  extending along the second segment  218 . The shroud segment  152  includes a first shroud side wall segment  160 , a second shroud side wall segment  162  and a shroud top wall segment  164 . The shroud segment  152  and the panel segment  154  may be continuous along the top wall  130 . Optionally, the gasket  142  may be continuous along the top wall  130  and/or the first wall  134  and/or the second wall  136  and/or the bottom wall  132 . 
     The spring fingers  148  of the gasket  142  include shroud spring fingers  166  that extend along the shroud  204  and panel spring fingers  168  that extend along the panel  208 . In an exemplary embodiment, the gasket  142  includes at least one shroud spring finger  166  extending along the first shroud side wall  210 , at least one shroud spring finger  166  extending along the second shroud side wall  212  and at least one shroud spring finger  166  extending along the shroud top wall  214 . In an exemplary embodiment, the gasket  142  includes at least one panel spring finger  168  extending from the first segment  156  and at least one panel spring finger  168  extending from the second segment  158 . The spring fingers  148  are configured to engage the panel  144  (shown in  FIG. 1 ). 
     In an exemplary embodiment, the shroud  204  extends to a rear  240 . The top wall  130  may continue rearward of the rear  240  of the shroud  204 . In various embodiments, the polarization feature channel  202  may be closed or bridged at the rear  240  to limit or restrict EMI leakage at the rear  240 . 
       FIG. 5  is a front, partial sectional view of the communication system  100  in accordance with an exemplary embodiment.  FIG. 6  is a perspective, partial sectional view of the communication system  100  in accordance with an exemplary embodiment.  FIGS. 5 and 6  illustrate the receptacle connector assembly  104  mounted in the cutout  146  in the panel  144  with the receptacle cage  110  extending through the cutout  146  and the gaskets  142  between the receptacle cage  110  and the panel  144 .  FIGS. 5 and 6  illustrate the pluggable module  106  in the receptacle cage  110  showing the gaskets  188  of the pluggable module  106  engaging the receptacle cage  110 .  FIGS. 5 and 6  illustrate the polarization feature  192  of the pluggable module  106  received in the cage polarization feature  200  of the receptacle cage  110 . 
     In an exemplary embodiment, the gaskets  142  are provided circumferentially around the exterior of the receptacle cage  110 , such as along the top wall  130 , the bottom wall  132 , the first side wall  134  and the second side wall  136 . The spring fingers  148  of the gaskets  142  are compressed against the panel  144  within the cutout  146 . The cutout  146  includes a notch  147  for the cage polarization feature  200 . In the illustrated embodiment, the notch  147  has a complementary shape as the cage polarization feature  200 . For example, the notch  147  may have a trapezoidal shape having angled side walls and a top wall. The shroud spring fingers  166  engage the edges of the panel  144  defining the notch  147 . 
     In an exemplary embodiment, the first and second shroud side walls  210 ,  212  are angled relative to the first and second segments  216 ,  218  to angle the shroud spring fingers  166  upward and outward toward the panel  144 . If the shroud side walls  210 ,  212  were at right angles to the shroud top wall  214 , the shroud spring fingers  166  would be biased straight outward therefrom making it difficult to interface with the panel  144 . For example, due to the clearance gap defined by the cutout between the exterior surface  232  of the receptacle cage  110  and the edge of the panel  144  defining the cutout  146 , there would be very little overlap between the panel  144  and the shroud side walls  210 ,  212  and thus very little surface area for the shroud spring fingers  166  to engage. The shroud side walls  210 ,  212  could be made taller and the notch  147  correspondingly made taller to increase the amount of overlap, but that would increase the size of the polarization feature channel  202 , which could negatively impact the electrical performance by creating an EMI leakage location. 
     In an exemplary embodiment, the first and second shroud side walls  210 ,  212  are angled relative to the first and second segments  216 ,  218  to angle the shroud spring fingers  166  away from the panel spring fingers  168 . For example, if the shroud side walls  210 ,  212  were at right angles to the shroud top wall  214 , the shroud spring fingers  166  would be biased straight outward therefrom directly toward the immediately adjacent panel spring fingers  168 . This would cause the shroud spring fingers  166  to interfere with the immediately adjacent panel spring fingers  168  or would require the panel spring fingers  168  to be moved further away decreasing the shielding performance by moving the contact points between the receptacle connector assembly  104  and the panel  144  further apart. 
     In an exemplary embodiment, the first and second shroud side walls  210 ,  212  are angled to provide stability for the shroud  204 . For example, having the shroud side walls  210 ,  212  angled provide a more rigid structure than if the shroud side walls  210 ,  212  are parallel. However, the shroud  204  may have other shapes in alternative embodiments, including shapes having the shroud side walls  210 ,  212  parallel to each other, with the shroud  204  being integral with the top wall  130 . 
     The pluggable module  106  is received in the module channel  116  and is electrically connected to the communication connector  112  when plugged therein. During mating, the polarization feature  192  is aligned with the cage polarization feature  200 . The protrusion  194  is received in the polarization feature channel  202 . The top  196  may face the shroud top wall  214  and the sides  198  may face the shroud side walls  210 ,  212 . Optionally, there may be clearance between the protrusion  194  and the shroud  204  such that the shroud  204  does not interfere with loading of the pluggable module  106  into the receptacle cage  110 . However, if the pluggable module  106  were improperly oriented relative to the receptacle cage  110 , such as if the polarization feature  192  or misaligned with the cage polarization feature  200 , the polarization features  192 ,  200  would restrict mating. In an exemplary embodiment, the receptacle cage  110  provides electrical shielding for the pluggable module  106 . In an exemplary embodiment, the gasket  188  of the pluggable module  106  provides EMI shielding at the front end  120  of the receptacle cage  110 . For example, the spring fingers  190  may engage the interior surfaces of the walls  114 . 
       FIG. 7  is a perspective view of the communication system  100  in accordance with an exemplary embodiment showing the receptacle cage  110  having upper and lower module channels  116 . The receptacle cage  110  includes a separator panel  124  between the upper and lower module channels  116 . The separator panel  124  includes a first wall  126  and a second wall  128 . The first wall  126  defines a bottom wall of the upper module channel  116  and the second wall  128  defines a top wall of the lower module channel  116 . The second wall  128  includes a cage polarization feature  200  having a polarization feature channel  202  in the form of a shroud  204 . 
     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.