Electrical connector configured to reduce resonance

Electrical connector includes a connector body having a front side configured to engage a first electrical component and a mounting side configured to engage a second electrical component. The electrical connector also includes a plurality of signal conductors extending through the connector body. The signal conductors include mating interfaces and mounting interfaces that are positioned for engaging the first and second electrical components, respectively. The electrical connector also includes a ground structure extending generally parallel to and between two of the signal conductors. The connector body has a resonance-control surface that faces the ground structure. The resonance-control surface is shaped to include alternating distal and proximal areas. The proximal areas are closer to the ground structure than the distal areas.

BACKGROUND

The subject matter herein relates generally to electrical connectors that have signal conductors configured to convey data signals and ground structures that provide a ground return path, reduce crosstalk between the signal conductors, and/or control impedance.

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 structures that are positioned between the signal conductors. The ground structures provide return current paths, mitigate crosstalk between the signal conductors, and control impedance. Examples of such ground structures include elongated ground conductors and ground shields.

As one example, a known communication system includes electrical connectors mounted to daughter cards that are configured to engage header connectors mounted to a backplane. The electrical connector includes a plurality of contact modules that are stacked side-by-side. Each contact module includes signal conductors, ground conductors, and at least one ground shield. The signal conductors are arranged in signal pairs and the ground conductors are positioned between adjacent signal pairs. The signal and ground conductors may be arranged in a ground-signal-signal-ground (GSSG) pattern such that the signal and ground conductors are aligned in a common plane. The ground shield electrically shields the signal and ground conductors of one contact module from the signal and ground conductors of another conductor. The ground shield also provides a return path and controls impedance of the electrical connector.

As another example, a known input/output (I/O) connector is configured to receive a pluggable small-form factor (SFF) module. The I/O connector includes a connector housing that forms a slot for receiving a circuit board from the pluggable SFF module. The I/O connector includes one or more rows of conductors in which each conductor engages a corresponding contact pad of the circuit board. The conductors include signal and ground conductors and may be arranged in a ground-signal-signal-ground (GSSG) pattern for each row.

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. For example, the ground structures (e.g., the ground conductors and/or ground shields) may form surface waves that propagate between different points of the ground structures. The surface waves may be repeatedly reflected 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 reduce throughput of the electrical connector.

Although techniques for dampening electrical resonance exist, the effectiveness and/or cost of implementing these techniques is based on a number of variables, such as the geometries of the connector housing, the signal and ground conductors, and the ground shields. For some applications and/or electrical connector configurations, alternative methods for controlling resonance along the ground structures may be desired.

Accordingly, there is a need for electrical connectors that reduce the electrical noise caused by resonating conditions in ground structures.

BRIEF DESCRIPTION

In an embodiment, an electrical connector is provided that includes a connector body having a front side configured to engage a first electrical component and a mounting side configured to engage a second electrical component. The electrical connector also includes a plurality of signal conductors extending through the connector body. The signal conductors include mating interfaces and mounting interfaces that are positioned for engaging the first and second electrical components, respectively. The electrical connector also includes a ground structure extending generally parallel to and between two of the signal conductors. The connector body has a resonance-control surface that faces the ground structure. The resonance-control surface is shaped to include alternating distal and proximal areas. The proximal areas are closer to the ground structure than the distal areas.

In some aspects, the connector body includes a molded dielectric body having the resonance-control surface. Optionally, the ground structure is an elongated ground conductor and is coplanar with the signal conductors. Also optionally, the ground structure is a ground shield having a broad side that faces the distal and proximal areas of the resonance-control surface. The proximal areas and the distal areas may define a recess along the resonance-control surface. The broad side may abut two of the proximal areas and cover an opening to the recess between the two proximal areas.

In some aspects, the proximal areas and the distal areas define a recess along the resonance-control surface. The recess extends across at least two of the signal conductors. Optionally, for at least portions of the at least two signal conductors, the at least two signal conductors extend parallel to one another and an axis. The recess may extend lengthwise perpendicular to the axis.

In some aspects, the signal conductors form at least four signal pairs configured for differential signal transmission. The ground structure includes a plurality of ground shields. Each of the ground shields is positioned between at least two of the signal pairs. At least two of the signal pairs are positioned between adjacent ground shields. The mating interfaces of the signal conductors form a two-dimensional array for engaging the first electrical component at the front side.

In some aspects, the electrical connector is a pluggable input/output (I/O) connector in which the ground structure and the signal conductors are elongated conductors.

In some aspects, the alternating distal and proximal areas are designed to cause reflections within surface waves of electrical energy that propagates along the ground structure.

In some aspects, the signal conductors form a plurality of signal pairs configured for differential signal transmission.

In an embodiment, an electrical connector is provided that includes a connector body having a front side configured to engage a first electrical component and a mounting side configured to engage a second electrical component. The connector body includes a plurality of dielectric sections. The electrical connector also includes a plurality of signal conductors extending through or along respective dielectric sections. The signal conductors include mating interfaces and mounting interfaces that are positioned for engaging the first and second electrical components, respectively. The signal conductors form signal pairs in which a plurality of the signal pairs are positioned between adjacent ground shields. The electrical connector also includes a plurality of ground shields interleaved between adjacent dielectric sections. Each of the dielectric sections has a resonance-control surface extending along a broad side of one of the ground shields. The resonance-control surface are shaped to include alternating distal and proximal areas that face the broad side. The proximal areas are closer to the ground structure than the distal areas.

In some aspects, the ground shields are shaped to attach to corresponding dielectric sections of the plurality of dielectric sections to form contact modules. The contact modules are stacked side-by-side.

In some aspects, each of the dielectric sections includes a plurality of the resonance-control surfaces. The proximal areas and the distal areas of each of the dielectric sections form a plurality of recesses that are covered by a common ground shield of the plurality of ground shields.

In some aspects, the proximal areas and the distal areas define a recess along the resonance-control surface that extends across at least two signal conductors. For at least portions of the at least two signal conductors, the at least two signal conductors extend parallel to one another and an axis and the recess extends lengthwise perpendicular to the axis.

In some aspects, the mating interfaces of the signal conductors are arranged in a high-density two-dimensional array for engaging the first electrical component. The electrical connector is designed for backplane or midplane communication systems and designed to operate at data rates greater than 10 gigabits/second (Gbps).

In some aspects, the alternating distal and proximal areas are designed to cause reflections within surface waves of electrical energy that propagates along the ground structure.

In an embodiment, an electrical connector is provided that includes a connector body having a front side configured to engage a first electrical component and a mounting side configured to engage a second electrical component. The connector body includes a plurality of dielectric sections. The electrical connector also includes a plurality of signal conductors extending through or along respective dielectric sections. The signal conductors include mating interfaces and mounting interfaces that are positioned for engaging the first and second electrical components, respectively. The signal conductors form signal pairs. The electrical connector also includes a plurality of ground shields interleaved between adjacent dielectric sections. A plurality of the signal pairs are positioned between adjacent ground shields, wherein each of the dielectric sections has a section side that abuts a broad side of a respective ground shield of the plurality of ground shields. The section side is shaped to include a plurality of recesses that open to the broad side.

In some aspects, the signal conductors form at least ten signal pairs. Each of the ground shields is positioned between at least two of the signal pairs. At least two of the signal pairs are positioned between adjacent ground shields. The mating interfaces of the signal conductors form a high-density two-dimensional array for engaging the first electrical component. Optionally, the electrical connector is designed to operate at data rates greater than 10 gigabits/second (Gbps). The recesses are designed to cause reflections within surface waves of electrical energy that propagates along the ground shields.

DETAILED DESCRIPTION

Embodiments set forth herein include electrical connectors having signal conductors configured to convey data signals and ground structures that provide a ground return path, reduce crosstalk between the signal conductors, and/or control impedance. The ground structures may include, for example, ground shields that are positioned between adjacent signal conductors and/or elongated ground conductors (e.g., stamped and formed contacts) that are positioned between adjacent signal conductors. Embodiments may be configured to improve electrical performance by dampening or impeding the development of electrical resonance that may occur along the ground structures.

To reduce the unwanted effects of electrical resonance, embodiments described herein include resonance-control surfaces that are shaped to include a plurality of proximal areas and a plurality of distal areas. A proximal area is a local area of the resonance-control surface that abuts the ground structure. As set forth herein, a local area of the resonance-control surface may “abut” the ground structure if a nominal gap exists between the local area and the ground structure, if the local area is part of a discrete structure that presses against the ground structure, or if the local area is defined by material that encases (e.g., through molding) the ground structure. A distal area is a local area of the resonance-control surface that is positioned further away from the ground structure than an adjoining proximal area. In other words, the proximal area of the resonance-control surface is closer to the ground structure than the adjoining distal area. The proximal areas and the distal areas are arranged in series and in an alternating manner such that each of the distal areas may extend between adjacent proximal areas and each of the proximal areas may extend between adjacent distal areas. The alternating proximal and distal areas define a series of recesses that open to the ground structure.

The series of proximal and distal areas change a distance between the ground structure and the resonance-control surface. The series of proximal and distal areas may change a surface wave of electrical energy that propagates between different points of the ground structure. Without being bound to a particular theory, the series of proximal and distal areas (or the series of recesses along the ground structure) may cause fluctuations in the impedance experienced by the surface wave. These fluctuations may cause reflections in the surface wave that destructively interfere with one another to dampen the surface wave. Particular embodiments may reduce the likelihood that electrical noise generated by one ground structure may couple to and affect an adjacent ground structure.

A shape of the resonance-control surface may be selected to achieve a target performance. More specifically, dimensions of the proximal areas, dimensions of the distal areas, dimensions of the recesses, and/or depths of the recesses may be selected to achieve a target performance. As such, the recesses may be positioned in a regular or irregular pattern. In some embodiments, the recesses have a cubed or parallelepiped volume. Yet in other embodiments, the recesses may be rounded or wave-like.

In some embodiments, the electrical connectors are configured to mate with other electrical connectors during a mating operation. During the mating operation, a first conductor of one connector may engage and slide (or wipe) along a second conductor of the other connector. The first and second conductors may engage each other at mating zones. The mating zones typically have smooth surfaces to create a sufficient number of contact points between the first and second conductors. The first and second conductors may be signal conductors or ground conductors.

Although the illustrated embodiment includes electrical connectors that are used in high-speed communication systems, such as backplane or midplane communication systems or input/output (I/O) systems, it should be understood that embodiments may be used in other communication systems or in other systems/devices that utilize ground structures. Accordingly, the inventive subject matter is not limited to the illustrated embodiments.

For example, the electrical connectors shown in the drawings have a front side that is configured to mate with another connector and a mounting side that is configured to be mounted to a printed circuit board. It should be understood, however, that electrical connectors set forth herein may be configured to interconnect a different combination of electrical components (e.g., other electrical connectors, circuit boards, or other components having conductive pathways). For instance, in some embodiments, the electrical connector may have a front side that is configured to mate with a first electrical component and a mounting side that is configured to mate with a second electrical component. Alternatively, the front side may be configured to mate with the second electrical component or the mounting side may be configured to mate with the second electrical component.

Embodiments may be particularly suitable for communication systems, such as network systems, servers, data centers, and the like, in which the data rates may be greater than ten (10) gigabits/second (Gbps) or greater than five (5) gigahertz (GHz). One or more embodiments may be configured to transmit data at a rate of at least 20 Gbps, at least 40 Gbps, at least 56 Gbps, or more. One or more embodiments may be configured to transmit data at a frequency of at least 10 GHz, at least 20 GHz, at least 28 GHz, or more. It is contemplated, however, that other embodiments may be configured to operate at data rates that are less than 10 Gbps or operate at frequencies that are less than 5 GHz.

As used herein with respect to data transfer, the term “configured to” does not mean mere capability in a hypothetical or theoretical sense, but means that the embodiment is designed to transmit data at the designated rate or frequency for an extended period of time (e.g., expected time periods for commercial use) and at a signal quality that is sufficient for its intended commercial use. The phrase “designed to” may be replaced by “configured to” and vice versa.

Various embodiments may be configured for certain applications. One or more embodiments may be configured for backplane or midplane communication systems. For example, one or more of the electrical connectors described herein may be similar to electrical connectors of the STRADA Whisper or Z-PACK TinMan product lines developed by TE Connectivity. The electrical connectors may include high-density arrays of electrical contacts. A high-density array may have, for example, at least 12 signal contacts per 100 mm2along the front side or the mounting side of the electrical connector. In more particular embodiments, the high-density array may have at least 20 signal contacts per 100 mm2.

Non-limiting examples of some applications that may use embodiments set forth herein include host bus adapters (HBAs), redundant arrays of inexpensive disks (RAIDs), workstations, servers, storage racks, high performance computers, or switches. Embodiments may also include electrical connectors that are pluggable input/output (I/O) connectors. For example, the electrical connectors may be configured to be compliant with certain 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.

As used herein, phrases such as “a plurality of [elements]” and “an array of [elements]” and the like, when used in the detailed description and claims, do not necessarily include each and every element that a component may have. The component may have other elements that are similar to the plurality of elements. For example, the phrase “a plurality of dielectric sections [being/having a recited feature]” does not necessarily mean that each and every dielectric section of the component has the recited feature. Other dielectric sections may not include the recited feature. Accordingly, unless explicitly stated otherwise (e.g., “each and every dielectric section of the electrical connector [being/having a recited feature]”), embodiments may include similar elements that do not have the recited features.

In order to distinguish similar elements in the detailed description and claims, various labels may be used. For example, an electrical connector may be referred to as a header connector, an electrical connector, or a mating connector. Electrical contacts may be referred to as header contacts, receptacle contacts, or mating contacts. When similar elements are labeled differently (e.g., receptacle contacts and mating contacts), the different labels do not necessarily require structural differences.

FIG. 1is a perspective view of a partially assembled communication system100. The communication system100includes an electrical connector102and a first electrical component104. For reference, the communication system100is oriented with respect to mutually perpendicular X, Y, and Z axes. In some embodiments, the electrical connector102and the first electrical component104are a receptacle connector and a header connector, respectively, and the communication system100is a backplane communication system. For example, the electrical connector102may be similar to receptacle connectors of the Z-PACK TinMan product lines developed by TE Connectivity. The electrical connector102is mounted to a second electrical component103(e.g., a daughter card) and the first electrical component104is mounted to a backplane circuit board105.

In other embodiments, the communication system100may be a midplane communication system. Embodiments, however, are not limited to backplane or midplane communication systems and may be suitable for other applications. For example, one or more embodiments may be a pluggable I/O connector. Embodiments may be designed to engage different types of electrical components. For example, an electrical component may be another electrical connector (or mating connector) or may be a printed circuit. The first electrical component104is hereinafter referred to as the mating connector104, and the second electrical component103is hereinafter referred to as the printed circuit (or circuit board)103.

In the illustrated embodiment, the electrical connector102includes a plurality of discrete contact modules106and a front housing108that is coupled to the plurality of contact modules106. Each of the contact modules106includes a dielectric section or body110and at least one ground structure112(shown inFIG. 3). The ground structures112may be interleaved between the dielectric sections110of adjacent contact modules106. The contact modules106are stacked side-by-side. The contact modules106and the front housing108collectively form a connector body114of the electrical connector102.

The connector body114has a front side116that faces in a mating direction118along the Z axis. The front side116defines the front or forward-most portion of the electrical connector102. In the illustrated embodiment, the front housing108includes the front side116of the connector body114. The connector body114also has a mounting side120that faces in a mounting direction122along the Y axis. In the illustrated embodiment, the contact modules106collectively define the mounting side120. The front side116is configured to engage the mating connector104, and the mounting side120is configured to engage the printed circuit103. In alternative embodiments, the mounting side120may face in a mounting direction along the X axis or in a mounting direction along the Z axis that is opposite the mating direction118.

The front housing108has passages124that extend between the front side116and a loading side126of the front housing108. The loading side126engages the contact modules106. The passages124align with and are configured to receive signal conductors130and ground extensions132(shown inFIG. 3) from corresponding contact modules106. The passages124are also configured to receive signal contacts134and ground contacts136of the mating connector104. In the illustrated embodiment, the signal contacts134are signal pins and the ground contacts136are ground walls or shields.

FIG. 2is a perspective view of the dielectric section110of a contact module106(shown inFIG. 1). In the illustrated embodiment, the dielectric section110is a molded dielectric body in which the dielectric material that is molded around the signal conductors130. The signal conductors130extend through the dielectric section110. Each of the signal conductors130includes a mating interface140and mounting interface142that are configured to be positioned along the front side116(FIG. 1) and the mounting side120(FIG. 1), respectively, of the connector body114(FIG. 1). The mating interfaces140are configured to engage the signal contacts134(FIG. 1), and the mounting interfaces142are configured to engage the printed circuit103(FIG. 1).

The signal conductors130may be formed from a common lead frame (not shown) that is stamped from conductive sheet material. The conductive sheet material may include one or more metal layers. For example, a base layer of the stamped sheet material may be a phosphor bronze, beryllium copper, brass, or other metal material. The stamped sheet material may be plated with one or more other metal materials. For instance, a diffusion layer may be plated over the base layer and may comprise, for example, nickel and/or tin. The diffusion layer may be plated with one or more other metal materials, such as a precious metal (e.g., gold).

As part of the lead frame, the signal conductors130may be interconnected through bridges (not shown). After the dielectric section110is molded around the lead frame, the bridges may be broken to electrically separate the signal conductors130. However, other methods of manufacturing the dielectric section110exist. For example, in other embodiments, the signal conductors130may be sandwiched between two dielectric sub-sections. Yet in other embodiments, the ground shields125(FIG. 3) or other ground structures may form part of the lead frame.

The dielectric section110has opposite section sides146,148. The dielectric section110also includes a mounting edge150, a front or mating edge152, a body edge154, and a rear edge156. The mounting edges150of the contact modules106(FIG. 1) collectively form the mounting side120(FIG. 1).

Also shown inFIG. 2, the section side148includes a plurality of recesses160. The recesses160open to the section side148and are positioned along respective signal paths135(shown inFIG. 6). In the illustrated embodiment, the recesses160extend only partially between the section sides146,148. As described herein, the recesses160are designed and positioned to achieve a target electrical performance.

FIG. 3is an isolated perspective view of the ground shield125. The ground shield125may be stamped-and-formed from conductive sheet material. The ground shield125has opposite broad sides162,164and an outer shield edge166that defines a profile or perimeter of the ground shield125. Optionally, the ground shield125may include a plurality of inner shield edges168that define openings170through the ground shield125.

The ground shield125is configured to be positioned between adjacent dielectric sections110(FIG. 1) and may include a plurality of shield sections that are coupled to one another. For example, the ground shield125includes a body section172, the ground extension132, and a mounting section174. The body section172is configured to be positioned between the adjacent dielectric sections110. The ground extension132is configured to electrically shield the mating interfaces140(FIG. 2) of the signal conductors130(FIG. 1) from the mating interfaces140of an adjacent contact module106(FIG. 1). The mounting section174is configured to be mechanically and electrically coupled to the printed circuit103(FIG. 1). For example, the mounting section174may include mounting interfaces176that are designed to be inserted into corresponding plated thru-holes (PTHs) of the printed circuit103.

FIG. 4illustrates how a contact module106of the electrical connector102(FIG. 1) is formed. As shown, the section side146of the dielectric section110includes a plurality of channels or openings180. The channels180expose portions of the signal conductors130to air and are designed to achieve a target electrical performance of the electrical connector102(FIG. 1). Also shown, the dielectric section110may include an overhanging portion178that projects laterally beyond the section side146.

To assemble the contact module106, the broad side164of the ground shield125may be positioned to abut the section side146of the dielectric section110. The shield edge166may engage the overhanging portion178. The overhanging portion178may clear the section side146by at least a thickness of the ground shield125. The body section172is sized and shaped to cover essentially an entirety of the section side146. The ground extension132clears the front edge152of the dielectric section110and is positioned along the mating interfaces140. Optionally, the dielectric section110may engage portions of the ground shield125. For example, one or more of the openings170may receive a portion of the dielectric section110and form an interference fit therewith.

FIG. 5illustrates how the electrical connector102may be assembled from a plurality of the contact modules106and a front housing108. The contact modules106are stacked side-by-side. In the illustrated embodiment, the ground shield125of one contact module106is configured to cover the recesses160of the adjacent contact module106. In other embodiments, however, the ground shield125of a contact module106may cover the recesses160of the same contact module106.

The passages124of the front housing108are sized and shaped to receive the mating interfaces140of the signal conductors130and the ground extensions132of the ground shields125. After assembly, the mating interfaces140and the ground extensions132are disposed entirely within the front housing108such that the signal contacts134(FIG. 1) and the ground contacts136(FIG. 1) engage the mating interfaces140and the ground extensions132, respectively, within the front housing108. In alternative embodiments, the mating interfaces140and the ground extensions132may clear the front side116.

FIG. 6is a sectional view of a portion of the electrical connector102taken along the line6-6inFIG. 5.FIG. 7is a cross-section of a portion of the electrical connector102taken along the line7-7inFIG. 5.FIG. 6includes four contact modules1061,1062,1063, and1064.FIG. 7shows the contact modules1062,1063, and1064. Each of the contact modules1061,1062,1063, and1064includes a ground shield125, a dielectric section110having recesses160, and a plurality of signal conductors130. The recesses160have openings230that open to the corresponding section side148. The ground shields125are interleaved between adjacent dielectric sections110.

As shown inFIG. 6, the signal conductors130are arranged in signal pairs135. The signal conductors130of a single signal pair135have essentially identical paths through the dielectric section110. The signal pairs135are configured for differential signal transmission and, as such, may be referred to as differential pairs.

Also shown inFIG. 6, each of the ground shields125is positioned between signal conductors130. For example, the ground shield125of the contact module1061is positioned between the signal conductors130of the contact module1061and the signal conductors130of the contact module1062. More specifically, the ground shield125of the contact module1061is positioned between signal pairs135of the contact module1061and signal pairs135of the contact module1062. Moreover, a plurality of signal conductors130are positioned between two adjacent ground shields125. Multiple signal pairs135of the contact module1062are positioned between the ground shield125of the contact module1061and the ground shield125of the contact module1062. In the illustrated embodiment, the signal conductors130of the contact module1062are closer to the ground shield125of the contact module1062than the ground shield125of the contact module1061.

With respect toFIGS. 6 and 7, each of the dielectric sections110has one or more resonance-control surfaces200. The resonance-control surfaces200have non-planar contours (e.g., corrugated or wavy contours). When the electrical connector102(FIG. 1) is fully assembled, the resonance-control surfaces200are positioned to extend along the broad side162of one of the ground shields125. InFIG. 6, a ground shield125is not shown along the section side148of the dielectric section110of the contact module1061. It should be understood, however, that a ground shield125may be positioned along the section side148and cover recesses160of the dielectric section110of the contact module1061when the electrical connector102is fully assembled.

Each of the resonance-control surfaces200is shaped to impede the development of electrical resonance that may occur along the ground shields125. In certain embodiments, the resonance-control surface200may dampen electrical noise generated by one ground shield125and reduce coupling of the electrical noise with an adjacent ground shield125.

Each of the resonance-control surfaces200is shaped to include distal areas204and proximal areas206that face the broad side162of one of the ground shields125. For example, the dielectric section110may be molded to include the distal and proximal areas204,206. Alternatively, the dielectric section110may be provided and portions of the dielectric section110may be removed to form the resonance-control surface200. The proximal areas206are closer to the broad side162of the ground shield125than the distal areas204. The distal areas204and the proximal areas206alternate such that a distal area204extends between adjacent proximal areas206of the resonance-control surface200.

Dimensions of the distal areas204, the proximal areas206, and the recesses160may be selected to achieve a target performance of the electrical connector102(FIG. 1). For example, the distal area204is located a depth210away from the adjacent proximal areas206. The distal areas204and the proximal areas206form the recesses160. Each of the recesses160is defined by the distal area204and respective interior surfaces212,213(shown inFIG. 6),214, and215. The interior surfaces212-215extend the depth210between the distal area204and the proximal areas206. In the illustrated embodiment, the interior surfaces212-215are planar surfaces that are perpendicular to the distal area204and the proximal areas206. In other embodiments, however, the interior surfaces212-215may have a non-planar shape and/or may be non-orthogonal with respect to the distal area204and the proximal areas206. Other dimensions that may be selected to achieve the target performance include a length216of the recesses160, a width218of the recesses160, and a separation distance220between adjacent recesses160.

Turning toFIG. 7, the ground shields125are configured to cover the openings230of the recesses160and abut the proximal areas206. As shown, a small gap232exists between the proximal areas206and the ground shield125. The gap232may be determined by the size and shape of the overhanging portion178(FIG. 4).

FIG. 8is a side view of one of the contact modules106. The signal conductors130and signal pairs135are shown in phantom. Each of the signal pairs135extends along a signal path234, which is represented by a center line extending between the two signal conductors130of the signal pair135. The recesses160may be oriented orthogonal to the signal paths234. For example,FIG. 8shows a first axis (or signal axis)291and a second axis (or elevation axis)292that is perpendicular to the first axis291. Each of the signal paths234extends parallel to the first axis291for a portion of the signal path234. The recesses160, however, extend lengthwise in a direction along the second axis292or in a direction that is perpendicular to the first axis291.

In some embodiments, the recesses160extend across at least two of the signal conductors130. For example, each of the recesses160extends across the two signal conductors of a signal pair135. Optionally, a single recess160may extend across more than two signal conductors130. For example, the recesses160′ and160″ may form a single recess that extends across four signal conductors.

FIG. 9is a perspective view of a portion of a circuit board assembly300formed in accordance with an embodiment. The circuit board assembly300includes a circuit board302and an electrical connector304that is mounted onto a board surface306of the circuit board302. The circuit board assembly300is oriented with respect to mutually perpendicular X, Y, and Z axes.

In some embodiments, the circuit board assembly300may be a daughter card assembly that is configured to engage a backplane or midplane communication system (not shown). In other embodiments, the circuit board assembly300may include a plurality of the electrical connectors304mounted to the circuit board302along an edge of the circuit board302in which each of the electrical connectors304is configured to engage a corresponding pluggable input/output (I/O) connector. The electrical connectors304and 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 connectors304described herein may be high-speed electrical connectors.

Although not shown, each of the electrical connectors304may 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 connector304. The circuit board assembly300may also include other devices that are communicatively coupled to the electrical connectors304through the circuit board302. The electrical connectors304may be positioned proximate to one edge of the circuit board.

The electrical connector304includes a connector body310having a plurality of sides. The sides include a front side311and a mounting side314. The front side311is configured to engage an electrical component (not shown), such as a pluggable transceiver, and the mounting side314is mounted to the board surface306. In the illustrated embodiment ofFIG. 9, the electrical connector304is a right-angle connector such that the front side311and the mounting side314are oriented substantially perpendicular or orthogonal to each other. In other embodiments, the front side311and the mounting side314may face in different directions than those shown inFIG. 9. For example, the front side311and the mounting side314may face in opposite directions.

The connector body310includes a receiving cavity318that is sized and shaped to receive a portion of the other connector. For example, in the illustrated embodiment, the receiving cavity318is sized and shaped to receive a circuit board (not shown) of the other connector. The circuit board of the other connector may include one or more rows of contact pads (not shown) located along a leading edge of the circuit board.

FIG. 10illustrates signal conductors322and ground structures324that may be used with the electrical connector304(FIG. 9). The signal conductors322are elongated signal conductors322. The ground structures324are also elongated ground conductors324. In some embodiments, the signal conductors322and the ground conductors324have identical shapes such that either conductor can be used to transmit data signals and either conductor can be used as a ground structure. The ground conductors324and the signal conductors322may have similar or identical cross-sections. The signal and ground conductors322,324are positioned within the receiving cavity318(FIG. 9) for engaging contact pads of a circuit board.

InFIG. 10, the ground conductors324and the signal conductors322are coplanar and form a portion of a row of conductors. The signal conductors322are arranged in signal pairs325with one or more ground conductors324disposed between adjacent signal pairs325. Optionally, the electrical connector304may include another row of conductors.

The connector body310may be molded with a dielectric material. As shown, the connector body310may be shaped to include resonance-control surfaces330that include alternating proximal areas332and distal areas334. The proximal areas332and distal areas334form recesses340. The recesses340are coplanar with edges of the signal and ground conductors322,324. As described above with respect to the resonance-control surfaces200(FIG. 6), the alternating proximal areas332and distal areas334are designed to cause reflections within surface waves of electrical energy that propagates along the ground conductors324.

It should 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.

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, sixth paragraph, unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.