Grouped element transmission channel link with pedestal aspects

A pedestal connector that incorporates one or more grouped element channel link transmission lines is seen to have a dielectric body and two opposing contact ends that are intended to contact opposing contacts or traces. The dielectric body has an S-shaped configuration such that the transmission lines supported thereon make at least one change in direction, thereby permitting the use of such connector to interconnect elements lying in two different planes. The transmission lines include slots that extend within the frame and which define opposing, conductive surfaces formed on the dielectric body which are separated by an intervening air gap.

BACKGROUND OF THE INVENTION

The present invention pertains to multi-circuit electronic communication systems, and more particularly, to a dedicated transmission channel structure for use in such systems.

Various means of electronic transmission are known in the art. Most, if not all of these means suffer from inherent speed limitations, such as both the upper frequency limit and the actual time a signal requires to move from one point to another within the system, which is commonly referred to as propagation delay. They simply are limited in their electronic performance primarily by their structure, and secondarily by their material composition. One traditional approach utilizes conductive pins, such as those found in an edge card connector, as such as illustrated inFIG. 1. In this type of structure a plurality of conductive pins, or terminals20are arranged within a plastic housing21and this arrangement provides operational speeds of about 800 to 900 MHz. An improvement upon this standard structure is represented by edge card connectors that may be known in the art as “Hi-Spec” and which are illustrated inFIG. 2, in which the system includes large ground contacts25and small signal contacts26disposed within an insulative connector housing27. The signal contacts in these structures are not differential signal contacts, but are merely single-ended signal, meaning that every signal contact is flanked by a ground contact. The operational speeds for this type of system are believed to be about 2.3 Ghz.

Yet another improvement in this field is referred to a “triad” or “triple” connector in which conductive terminals are disposed within a plastic housing28in a triangular pattern, and the terminals include a large ground terminal29, and two smaller differential signal terminals30, as illustrated inFIG. 3, and, as described in greater detail U.S. Pat. No. 6,280,209. This triad/triple structure has an apparent upper limit speed of about 4 Ghz. All three of these approaches utilize, in the most simplest sense, conductive pins in a plastic housing in order to provide a transmission line for electronic signals.

In each of these type constructions, it is desired to maintain a dedicated transmission line through the entire delivery path of the system, including through the circuit board(s), the mating interface and the source and load of the system. It is difficult to achieve the desired uniformity within the system when the transmission system is constructed from individual pins. Discrete point-to-point connections are used in these connectors for signal, ground and power. Each of these conductors was designed as either a conductor or a means of providing electrical continuity and usually did not take into account transmission line effects. Most of the conductors were designed as a standard pinfield so that all the pins, or terminals, were identical, regardless of their designated electrical function and the pins were further arranged at a standard pitch, material type and length. Although satisfactory in performance at low operating speeds, at high operational speeds, these systems would consider the conductors as discontinuities in the system that affect the operation and speed thereof

Many return signal terminals or pins in these systems were commoned to the same ground conductor, and thus created a high signal to ground ratio, which did not lend themselves to high speed signal transmission because large current loops are forced between the signals and the ground, which loops reduce the bandwidth and increase the crosstalk of the system, thereby possibly degrading the system performance.

Bandwidth (“BW”) is proportional to 1√{square root over (L)}C, where L is the inductance of the system components, C is the capacitance of the system components and BW is the bandwidth. The inductive and capacitive components of the signal delivery system work to reduce the bandwidth of the system, even in totally homogeneous systems without discontinuities. These inductive and capacitive components can be minimized by reducing the overall path length through the system, primarily through limiting the area of the current path through the system and reducing the total plate area of the system elements. However, as the transmission frequency increases, the reduction in size creates its own problem in that the effective physical length is reduced to rather small sizes. High frequencies in the 10 Ghz range and above render most of the calculated system path lengths unacceptable.

In addition to aggregate inductance and capacitance across the system being limiting performance factors, any non-homogeneous geometrical and/or material transitions create discontinuities. Using 2.5 Ghz as a minimum cutoff frequency in a low voltage differential signal system operating at around 12.5 Gigabits per second (Gbps), the use of a dielectric with a dielectric constant of about 3.8 will yield a critical path length of about 0.24 inches (6.1 mm), over which length discontinuities may be tolerated. This dimension renders impracticable the ability of one to construct a system that includes a source, transmission load and load within the given quarter-inch. It can thus be seen that the evolution of electronic transmission structures have progressed from uniform structured pin arrangements to functionally dedicated pins arrangements to attempted unitary structured interfaces, yet the path length and other factors still limit these structures.

In order to obtain an effective structure, one must maintain a constant and dedicated transmission line over the entire delivery path: from the source, through the interface and to the load. This would include the matable interconnects and printed circuit boards. This is very difficult to achieve when the delivery system is constructed from individual, conductive pins designed to interconnect with other individual conductive pins because of potential required changes in the size, shape and position of the pins/terminals with respect to each other. For example, in a right angle connector, the relationship between the rows of pins/terminals change in both the length and the electrical coupling. High speed interconnect design principles that include all areas between the source and load of the system including printed circuit boards, board connectors and cable assemblies are being used in transmission systems with sources of up to 2.5 Gbps. One such principle is the principle of ground by design which provides added performance over a standard pin field in that coupling is enhanced between the signal and ground paths and single-ended operation is complimented. Another principle being used in such systems includes impedance tuning to minimize discontinuities. Yet another design principle is pinout optimization where signal and return paths are assigned to specific pins in the pin field to maximize the performance.

These type of systems all are limited with respect to attaining the critical path lengths mentioned above. The present invention is directed to an improved transmission or delivery system that overcomes the aforementioned disadvantages and which operates at higher speeds and in which the transmission line is incorporated into a pedestal connector.

SUMMARY OF THE INVENTION

The present directed is therefore directed to an improved transmission structure that overcomes the aforementioned disadvantages and utilizes grouped electrically conductive elements to form a unitary mechanical structure that provides a complete electronic transmission channel that is similar in one sense to a fiber optic system. The focus of the invention is on providing a complete, copper-based electronic transmission channel that may be incorporated into a physical connector structure, as opposed to providing individual inductive pins, separable interfaces with copper conductors, each embedded in the transmission channel yielding more predictable electrical performance and greater control of operational characteristics. Such improved systems of the present invention are believed to offer operating speeds for digital signal transmission of up to 12.5 G at extended path lengths which are greater than 0.24 inch (6.1 mm).

Accordingly, it is a general object of the present invention to provide an engineered waveguide that functions as a grouped element channel link, wherein the link includes a dielectric body portion that is formed into a connector body and at least two conductive elements disposed thereon in a spaced-apart order along an exterior surface thereof.

Another object of the present invention is to provide a high-speed signal transmission line channel link having an elongated body portion of a given cross-section throughout its length, the body portion being formed from a dielectric with a selected dielectric constant, and the link having, in its most basic structure, two conductive elements disposed on the exterior surface thereof, the elements being of similar size and shape and oriented thereon, in opposition to each other, so as to steer the electrical energy wave traveling through the link by establishing particular electrical and magnetic fields.

Yet another object of the present invention is to provide a improved electrical transmission channel incorporated into a pedestal-style connector structure for providing a “stepped” transmission channel between two distinct and spaced-apart levels, the connector structure including a dielectric substrate, and a plurality of grooves formed in the substrate, the grooves having opposing sidewalls, the sidewalls of the grooves having a conductive material deposited thereon, such as by plating, to form distinct electronic transmission channels within the grooves.

A still further object of the present invention is to provide a pre-engineered wave guide in which at least a pair of conductive elements are utilized to provide differential signal transmission, i.e., signal in (“+”) and signal out (“−”), the pair of conductive elements being disposed on the exterior of the dielectric body so as to permit the establishment of capacitance per length, inductance per length, impedance, attenuation and propagation delay per unit length, and establishing these pre-determined performance parameters within the channels formed by the conductive elements.

Yet another object of the present invention is to provide a non-circular transmission line for high speed applications, which includes an elongated rectangular or square dielectric member having an exterior surface with at least four distinct sectors disposed thereon, the dielectric member including a pair of conductive elements aligned with each other and disposed on two of the sectors, while separated by an intervening sector

A further object of the present invention is to provide one or more grouped element channel links in the form of high-speed transmission lines along an elongate body of insulating plastic material with at least one bend in the elongate body to transfer signals along the grouped element channel links in both the vertical and the horizontal directions.

A still further object of the present invention is to provide a frame of a plastic material that may be selectively plated with metal to define one or more grouped element channel links along raised elements in the frame by over-molding the plastic frame with a non-plateable plastic material and plating the exposed raised elements of the frame with metal.

A yet further object of the present invention is to provide one or more grouped element channel links in the form of high-speed transmission lines along a pedestal formed of an insulative material with at least one bend formed in the pedestal in order to transfer signals along the grouped element channel links in both vertical and the horizontal directions.

Another object of the present invention is to provide one or more grouped element channel links in the form of high-speed transmission lines along an insulative support pedestal or along an elongate body of insulating plastic material where the grouped element channel links include a pair of spaced-apart low impedance conductive traces, such as for ground or power, the spaced-apart conductive traces being separated by intervening air gaps and the support structure being configured to provide a trace path in which the traces make at least one change in direction.

Yet another object of the present invention is to provide one or more grouped element channel links in the form of high-speed transmission lines along a pedestal or along an elongate body of insulating plastic material that accommodates both high speed signals along the grouped channel links and slower speed signals along other conductive traces also formed in the pedestal or elongate body.

The present invention accomplishes the above and other objects by virtue of its unique structure. In one principal aspect, the present invention includes a transmission line that is formed from a dielectric with a preselected dielectric constant and a preselected cross-sectional configuration. A pair of conductive surfaces are disposed on the dielectric line, or link, and one preferably aligned with each other and separated from each other. The conductive surfaces serve as wave guides for guiding electrical waves along the transmission link.

In another principal aspect of the present invention, the conductive elements are grouped together as a pair on a single element, thus defining a unitized wave guide that may be run between and among successive printed circuit boards and connected thereto without difficulty. The conductive surfaces may be formed by selectively depositing conductive material thereon, such as by plating, the exterior surface of the dielectric body, or by molding or otherwise attaching an actual conductor to the body. In this manner, the dielectric may be formed with bends and the conductive surfaces that exist on the surface thereof maintains their spaced apart arrangement of grouped channel conductors through the bends.

In yet another principal aspect of the invention, the exterior of the transmission line may be covered by a protective outer jacket, or sleeve. The conductive surfaces may be disposed on the dielectric body in a balanced arrangement with equal widths, or an unbalanced arrangement with a pair of conductive elements of different widths. Three conductive elements may be disposed on the dielectric body to support a differential triple on the transmission line utilizing a pair of differential signal conductors and an associated ground conductor. The number of conductive surfaces is limited only by the size of the dielectric body, and four such discrete conductive elements may be used to support two different signal channels or a single differential pair with dual grounds.

In still another principal aspect of the present invention, a unitary transmission line is formed within one cavity, or a plurality of selectively-sized metallized cavities formed within a substrate. The substrate is grooved to form the cavities and the sidewalls of the grooves may be plated with a conductive material. The air gap between the sidewalls of the cavities, or grooves, in this instance, serves as the dielectric of the transmission channel.

In yet another principal aspect of the present invention, the aforementioned transmission links may be used to carry power. In such circumstances, the underlying transmission line will include a grooved dielectric, with a continuous contact region being formed within the grooves, i.e., covering the sidewalls and bass of the groove. The continuous contact area that is present on these three surfaces for the length of the groove extends the current carrying capability of the structure. A ground plane may be utilized to increase capacitive coupling among the power channels and the ground plane to reduce the source impedance of the overall structure. The transmission line may be formed with projecting ridges, or lands, that serve to define troughs therebetween. The conductive surfaces are formed in the troughs by way of a continuous process, such a selective plating so that a continuous plated trough, i.e., two sidewalls and an interconnecting base are formed which extend for the length of the transmission line. This increases the current carrying capability. A high capacitance may then be created across the dielectric to reduce the source impedance of the system.

The power carrying aspect of the invention may be further supplemented by the forming of high density contact sets within the system. In a grooved transmission line the opposing sidewalls of the grooves may be plated with a conductive material to form continuous contacts that extend the length of the transmission line and opposite polarity signals (i.e., “+” and “−”) may be carried along the contacts. A plug assembly may be molded, such as by way of insert molding into the grooves, either individually or as an assembly encompassing two or more such grooves to insulate and isolate the opposed contact pairs, which will result in an increased voltage standoff. A conformal coating may also be used to achieve a similar aim.

The transmission lines of the invention may carry both signals and power and thus may be easily divided into separate signal channels and power channels. The signal channels may be made with conductive strips or paths of a preselected width, while the power channels, in order to carry high currents, may include either wider strips or an enlarged, continues conductor strip. The wider strips are enlarged plate areas as compared to the signal strips and have a high capacitance. The signal and power channels may be separated by a wide, non-conductive area of the transmission line that serves as an isolation region. Because the isolation region may be formed during the forming of the underlying dielectric base, the isolation region may be readily defined to minimize cross-contamination or electrical interference.

In accordance with another aspect of the present invention, and with respect to an ebodiment that pertains to a pedestal-style connector, an over-molded connector may have an elongated frame member formed from a material that can be plated with metal to form conductors for carrying high-frequency electronic signals. The frame member may be formed from a catalyzed resin with a set of raised ribs formed along at least one side of the frame member. Preferably, at least some of the channels defined between the raised ribs are deeper than the other channels, such that the sidewalls of these deeper channels may be plated with metal to provide conductive channel elements with high-frequency electronic signal characteristics, much like a waveguide. The ribs may be disposed on both sides of the frame member and run in the elongated direction of the frame member. One of the sets of the raised ribs may wrap around one end of the frame member from the top surface to the bottom surface to terminate near the other set of raised ribs to provide a contact area on the underside of the frame member. Likewise, the other set of raised ribs may wrap around the other end of the frame member from the bottom side to the top side to provide a second contact area on the top surface of the frame member. Preferably, at least one angular bend is provided across the frame member and across the raised ribs such that the frame member may interface with and conduct electronic signals in both the horizontal and vertical directions.

The over-molded connector may then be formed by selectively over-molding the frame member with an insulative material, such as with a non-catalyzed resin. In this over-molding process, the channels between the raised ribs are filled with the non-catalyzed resin, leaving the tops of the ribs with the catalyzed resin exposed. However, the deeper channels that are to have their sidewalls plated with metal to form the channel links are not filled with the insulative resin. These exposed areas of catalyzed resin left after the over-molding process are then plated with metal. Thus, metallic conductors are formed on the raised ribs and on the sidewalls of the deeper channels. High-frequency differential signals may be conducted along these channel elements. Any metal that accumulates in the bottom of the deeper channels may be removed by known techniques. Preferably, at least one conductor on a raised rib is disposed between each pair of channel elements, with the conductor on the raised rib has a low impedance, such as may be expected for a ground or power source. The channel elements will have an air as their dielectric material and so the differential signals in the channel elements will have a greater affinity for the low impedance conductors located adjacently to the channel elements thereby reducing the impedance of the connector and improving the transmission of the high-frequency signals through the over-molded connector. The over-molded connector may also be fabricated as a pedestal connector.

The present invention also includes the related processes of forming the over-molded connector. Although such over-molding is only the preferred manner of constructing connectors of the invention. The frame member is first molded from a catalyzed resin material with the afore-mentioned characteristics, including the plurality of raised ribs disposed along at least one surface of the frame member with some channels defined by the raised ribs being of greater depth than other channels. One or more angular bends may be provided across the frame member and the raised rib to interface with and conduct electronic signals from different elevations, such as in both the horizontal and vertical directions. The frame member is then selectively over-molded with an electrically insulative compound, such as a non-catalyzed resin, including in the channels between the ribs, but not in the deeper channels that will be used to form high-frequency channel elements. The top surfaces of the ribs and the sidewalls of the deeper channels are next plated with conductive metal to form electrical conductors on the top surfaces of the ribs and to form channel elements in the deeper channels.

These and other objects, features and advantages of the present invention will be clearly understood through a consideration of the following detailed description.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 4illustrates a grouped element channel link50constructed in accordance with the principles of the present invention. It can be seen that the link50includes an elongated, dielectric body51, preferably a cylindrical filament, that is similar to a length of fiber optic material. It differs therefrom in that the link50acts as a pre-engineered wave guide and a dedicated transmission media In this regard, the body51is formed of a dedicated dielectric having a specific dielectric constant and a plurality of conductive elements52applied thereto. InFIGS. 4 and 5, the conductive elements52are illustrated as elongated extents, or strips,52of conductive material and, as such, they may be traditional copper or precious metal extents having a definite cross-section that may be molded or otherwise attached, such as by adhesive or other means to the dielectric body of the link50. They may also be formed on the exterior surface55of the body51such as by a suitable plating process. At least two such conductors are used on each link, typically are used for signal conveyance of differential signals, such as +0.5 volts and −0.5 volts. The use of such a differential signal arrangement permits us to characterize structures of this invention as pre-engineered waveguides that are maintained over the entire length of the signal delivery path. The use of the dielectric body51provides for the reduction and also for preferred coupling to occur within the link. In the simplest embodiment, as illustrated inFIG. 5, the conductive elements are disposed on two opposing faces, so that the electrical affinity of each of the conductive elements is for each other through the dielectric body upon which they are supported, or in the case of a conductive channel as will be explained in greater detail to follow and as illustrated inFIGS. 29-30, the conductive elements are disposed on two or more interior faces of the cavity/cavities to establish the primary coupling mode across the cavity gap and through an air dielectric. In this manner, the links of the present invention may be considered as the electrical equivalent to a fiber optic channel or extent.

As such, the effectiveness of the links of the present invention are dependent upon the guiding and maintenance of digital signals through the channel link. This will include maintaining the integrity of the signal, controlling the emissions and minimizing loss through the link. The channel links of the present invention contain the electromagnetic fields of the signals transmitted therethrough by controlling the material of the channel link and the geometries of the system components so that preferred field coupling will be provided.

As illustrated better inFIG. 5, the two conductive surfaces52are arranged on the dielectric body51in opposition to each other. This is representative of a balanced link of the invention where the circumferential, or arcuate extent C of the conductive surfaces52is the same, as is the circumferential or arcuate extent C1, of the non-conductive exterior surfaces55of the dielectric body51. This length may be considered to define a gross separation D between the conductive surfaces. As will be explained below, the link may be unbalanced with one of the conductive surfaces having an arc length that is greater than the other. In instances where the dielectric body and link are circular, the link may serve as a contact pin and so be utilized in connector applications. This circular cross-section demonstrates the same type of construction as a conventional round contact pin.

As illustrated inFIG. 6, the links of the present invention may be modified to provide not only multiple conductive elements as part of the overall system transmission media, but may also incorporate a coincident and coaxial fiber optic wave guide therewithin for the transmission of light and optical signals. In this regard, the dielectric body51is cored to create a central opening57through which an optical fiber58extends. Electrical signals may be transmitted through this link as well as light signals60.

FIG. 7schematically illustrates a transmission line70incorporating a link50of the present invention that extends between a source71and a load72. The conductive surfaces52of the link serve to interconnect the source and load together, as well as other secondary loads73intermediate the source and the load. Such secondary loads may be added to the system to control the impedance through the system. A line impedance is established at the source and may be modified by adding secondary loads to the transmission line.

FIG. 8illustrates, schematically, the difference between the links of the present invention and conventional conductors, which are both illustrated in a dielectric block76. Two discrete, conventional conductors77formed from copper or another conductive material extend through the block76. As shown in enlargement “A”, the two discrete conductor presents an open cell structure with a large inductance (L) because of the enlarged current loop. Quite differently, the links of the present invention have a smaller inductance (L) at a constant impedance due to the proximity of the conductive surfaces positioned as the dielectric body51. The dimensions of these links50can be controlled in the manufacturing process and extrusion will be the preferred process of manufacturing with the conductive surfaces being extended with the dielectric body or separately applied of the extrusion, such as by a selective plating process so that the resulting construction is of the plated plastic variety. The volume of the dielectric body51and the spacing between conductive elements disposed thereon may be easily controlled in the extrusion process.

AsFIG. 9illustrates, the dielectric body may have a bend80forward therewith in the form of the 90° right-angle bend illustrated or in any other angular orientation. The dielectric body51and the conductive surfaces52are easily maintained through the bend.

FIG. 10illustrates a transmission line using the links of the invention. The link50is considered as a transmission cable formed from one or more single dielectric bodies51, and one end82of it is terminated to a printed circuit board83. This termination may be direct in order to minimize any discontinuity at the circuit board. A short transfer link84that maintains any discontinuities at a minimum is also provided. These links84maintain the grouped aspect of the transmission link. Termination interfaces85may be provided where the link is terminated to the connector with minimum geometry discontinuity or impedance discontinuity. In this manner, the grouping of the conductive surfaces is maintained over the length of the transmission line resulting in both geometric and electrical uniformity.

FIG. 11illustrates a variety of different cross-sections of the transmission links50of the invention. In the rightmost link90, a central conductor93is encircled by a hollow dielectric body94which in turn, supports multiple conductive surfaces95that are separated by an intervening space, preferably filled with portions of the dielectric body94. This construction is suitable for use in power applications where power is carried by the central conductor. In the middle link91, the central cover96is preferably made of a selected dielectric and has conductive surfaces97supported on it. A protective outer insulative jacket98is preferably provided to protect and or insulate the inner link. The leftmost link92has a protective outer jacket99that enclosed a plateable polymeric ring100that encircles either a conductive or insulative core101. Alternatively, one or the elements surrounding the core or of the link92may be filled with air and may be spaced away from an inner member by way of suitable standoffs or the like.

FIG. 12illustrates an array of links110-113that have their outer regions combined with the dielectric body51to form different types of transmission links. Link110has two conductive surfaces52a,52bof different arc lengths (i.e., unbalanced) disposed on the outer surface of the dielectric body51so that the link110may provide single ended operation. Link111has two equal spaced and sized (or “balanced”) conductive elements52to provide an effective differential signal operation.

Link112has three conductive surfaces115to support a differential triple link operation of two differential signal conductors115aand an assorted ground conductor115b. Link113has four conductive surfaces116disposed on its dielectric body51in which the conductive surfaces116may either include two differential signal channels (or pairs) or a single differential pair with a pair of associated grounds.

FIG. 13illustrates an array of one-type of non-circular links120-122that may have square configurations, as with link120, or rectangular configurations, as with links121-122. The dielectric bodies51may be extended with projecting land portions125that are plated or otherwise covered with conductive material. These land portions125may be used “key” into connector slots in a manner so that contact between the connector terminals (not shown) and the conductive faces125is easily effected.

FIG. 14illustrates some additional dielectric bodies. One body130is shown as convex, which the other two bodies131,132are shown. A circular cross-section of the dielectric bodies has a tendency to concentrate the electrical filed strength at the corners of the conductive surfaces, while a slightly convex form as shown for body131, has a tendency to concentrate the field strength evenly, resulting in a lower and greater convexity, as illustrated in dielectric132may have beneficial cross talk reduction aspects because it focuses the electrical field inwardly.

Importantly, the transmission link may be formed as a single extrusion200(FIGS. 15-16) carrying multiple signal channels thereupon, with each such channel including a pair of conductive surface202-203. These conductive surfaces202,203are separated from each other by intervening body204that supports them, as well as web portions205that interconnect them together. This extrusion200may be used as part of an overall connector assembly220, where the extrusion is received into a complementary shaped opening210formed in a connector housing211. The inner walls of the openings210may be selectively plated, or contacts212may be inserted into the housing211to contact the conductive surfaces and provide, if necessary, surface mount or through hole tail portions.

FIG. 17illustrates the arrangement of two transmission channels50arranged as illustrated and terminated at one end to a connector block180and passing through a right angle block182that includes a series of right angle passages183formed therein which receive the transmission channel links as shown. In arrangements such as that shown in FIG,17, it will be understood that the transmission channel links may be fabricated in a continuous manufacturing process, such as by extrusion, and each such channel may be manufactured with intrinsic or integrated conductive elements52. In the manufacturing of these elements, the geometry of the transmission channel itself may be controlled, as well as the spacing and positioning of the conductive elements upon the dielectric bodies so that the transmission channels will perform as consistent and unitary electronic waveguides which will support a single channel or “lane” of signal (communication) traffic. Because the dielectric bodies of the transmission channel links may be made rather flexible, the systems of the invention are readily conformable to various pathways over extended lengths without significantly sacrificing the electrical performance of the system. The one connector endblock180may maintain the transmission channels in a vertical alignment, while the block182may maintain the ends of the transmission channel links in a right angle orientation for termination to other components.

FIG. 18illustrates a set of convex dielectric blocks or bodies300-302in which separation distance L varies and the curve305of the exterior surfaces306of the blocks raises among the links300-302. In this manner, it should be understood that the shapes of the bodies may be chosen to provide different lens characteristics.

FIG. 19illustrates a multiple channel extrusion400with a series of dielectric bodies or blocks401interconnected by webs402in which the conductive surfaces403are multiple or complex in nature.

The links of the present invention may be terminated into connector and other housings.FIGS. 21-23illustrate one termination interface as a somewhat conical endcap which has a hollow body501with a central openings502. The body may support a pair of terminals504that mate with the conductive surfaces52of the dielectric body51. The endcap500may be inserted into various openings in connector housings and as such, preferably includes a conical insertion end510.

FIG. 24illustrates the endcaps500in place on a series of links520that are terminated to an endblock521that has surface mount terminals522.

FIG. 25illustrates an alternate construction of an end block570. In this arrangement, the transmission lines, or links571, are formed from a dielectric and include a pair of conductive extents572formed on their exterior surfaces (with the extents572shown only on one side for clarity and their corresponding extents being formed on the surfaces of the links571that face the plane of the paper ofFIG. 25). These conductive extents572are connected to traces573on a circuit board574by way of conductive vias575formed on the interior of the circuit board574. Such vias may also be constructed within the body of the end block570, if desired. The vias575are split and their two conductive sections are separated by an intervening gap576to maintain separation of the two conductive transmission channels at the level of the board.

FIG. 26illustrates an end cap600mounted to a printed circuit board601. This style of end cap600serves as a connector and thus includes a housing602, with a central slot603with various key ways604that accept projecting portions of the transmission link. The end cap connector600may have a plurality of windows620for access to soldering the conductive tail portions606of the contacts607. In instances of surface mount tails, the tails may have their horizontal parts609tucked under the body of the endcap housing to reduce the circuit board pad size needed, as well as the capacitance of the system at the circuit board.

FIG. 27Aillustrates a skeletal view of the endcap connector600and shows how the contacts, or terminals607are supported within and extend through the connector housing602. The terminals607may include a dual wire contact end608for redundancy in contact (and for providing a parallel electrical path) and the connector600may include a coupling staple615that has an inverted U-shape and which enhances coupling of the terminals across the housing. The tail portion of these dual wire terminals607enhance the stability of the connector. In this regard, it also provides control for the terminals that constitute a channel (laterally) across the housing slot601.FIG. 27Bis a view of the interior contact assembly that is used in the endcap connector600. The terminals607are arranged on opposite sides of the connector and are mounted within respective support blocks610. These support blocks610are spaced apart from each other a preselected distance that assists in spacing the terminal contacts608apart. A coupling staple615having an overall U-shape, or blade shape, may be provided and may be interposed between the terminals607and support blocks610to enhance the coupling between and among the terminals607.FIG. 28is an end view of the connector600.

FIGS. 29A-Cillustrate another embodiment of a transmission channel link constructed in accordance with the principles of the present invention utilizing air as the dielectric and utilizing broadside coupling between conductive elements. InFIG. 29A, a dielectric substrate700is provided of generally uniform cross-section has body portions701formed at intervals thereon, with conductive elements702disposed on opposite surfaces of the substrate700. In this regard, vertical signal channels are thereby defined in this arrangement, which are identified in the boxes appearing below each of the bodies701inFIG. 29A. The polarity of the conductive elements702may be arranged to provide for differential signal transmission, and as illustrated, one such arrangement locates the positive (“+”) signal conductive surfaces on one side and the negative (“−”) conductive surfaces on the other side of the dielectric substrate. As will be understood in the art, the opposite polarity conductive extents702will constitute pairs or signal channels, that are shown labeled from “1” to “4” underneathFIG. 29A. In this embodiment, the opposite conductive pairs are separated by the volume and extent of the intervening and supporting dielectric substrate. This construction is suitable for mezzanine configurations.

FIG. 29Billustrates a variation in the structure of such a connector with a dielectric body or substrate700′ having a plurality of slots705′ formed therein that are spaced apart from each other along the width of the substrate. Conductive surfaces702′ are disposed on the facing sides (or sidewalls) of the slots and are spaced apart from each by an intervening gap, which is filled with air. In this structure, the polarity of the conductive surfaces may be chosen as shown to have negative and positive signal conductive surfaces facing each other, thereby utilizing the air on the slot705′ as the dielectric between the associated pairs of conductive surfaces. Whereas in the embodiment ofFIG. 29A, the signal pairs or channels were arranged vertically, or through the dielectric body, in the embodiment ofFIGS. 29B and 29C, the arrangement and electrical affinity between the two conductive surfaces thereof is horizontally and extends across through an intervening air gap. In constructing transmission channels of this sort, the entire exterior surface of the substrate may be plated and the upper exterior surfaces706′ may be etched to remove their plating. Any plating that is initially present in the base708′ between the two sidewalls may be removed, such as by etching it away. As a result, a plurality of conductively disassociated vertical plates702′ are formed. In this type of arrangement, the primary field coupling occurs between oppositely charged pairs of conductive surfaces (horizontally inFIG. 29B), and the air gaps, or spacings, are tighter between the oppositely charged pairs of conductive surfaces than is the spacing between the gaps themselves. Thus, the differential pair spacing is “electrically” tighter by way of geometric control to ensure that the primary electrical affinity remains within the differential pair. The spacing and the contour of these conductive surfaces may be controlled by molding the connector and plating the desired surfaces in order to maintain an appropriate size of the connector.

FIG. 29Cillustrates a similar structure, but one which utilizes a conductive ground plane710′ applied to the lower surface of the dielectric substrate700′.

Such structures may be used to form dense matrices of transmission channel links as is illustrated inFIG. 30wherein a plurality of substrates700′ are stacked together on their side. Each substrate may include a ground plane710′ and three communication or signal lanes, as illustrated or other arrangements may be chosen.

FIG. 31illustrates the use of such a structure within a right angle context, with a dielectric block800with a plurality of grooves804formed therein. The opposite walls of the grooves804may be plated with conductive surfaces803that extend from one end806to a bellmouth802at the other end807. The conductive surfaces803end short of the bellmouths802to electrically decouple the channel from the next transmission channel link section.

FIGS. 32-34illustrate another construction of a waveguide media constructed in accordance with the principles of the present invention. As shown inFIG. 32, a dielectric substrate900is provided with a plurality of slots902formed thereon. The slots902are formed in opposing surfaces of the dielectric body904to define a series of raised lands that support plated or otherwise conductive surfaces903. The slots902may be considered as forming a series of thin webs that reduce the cross-section of the dielectric and reduce capacitive coupling between alternate channels. The width of the conductive surface may be controlled within each signal channel or lane in order to control the impedance of the channels. As shown best inFIG. 34, surface mount members, such as feet910may be formed with the substrate and may include the conductive surfaces disposed on their exterior surfaces in order to establish a conductive interface for connecting with a circuit board, such as by soldering.

FIG. 35illustrates a transmission line420of the invention that extends between two circuit boards421,422. The transmission line420mates with a connector424, similar to the type shown inFIG. 26and extends outwardly therefrom to a surface mount connection arrangement425disposed on the circuit board422(or formed as surface mounting “feet” that are molded or otherwise formed with the transmission line that may be attached to opposing contact pads or traces on the surface of the circuit board422). Such a connection may include a plurality of contact members426that extend upwardly from the surface427and the contact members preferably includes conductive surfaces428that are arranged in opposition to the conductive strips430so that they will make direct contact with the strips430of the transmission element. They may be soldered, or otherwise attached or may rely solely upon frictional contact to make an electrical connection. The arrangement illustrated also includes an exterior protective jacket431formed of a plastic or metal (provided that the interior side thereof which opposes the transmission element is protected with an insulator) to protect the transmission channel from damage and exterior contact.

InFIG. 36, the transmission link420is illustrated in a right angle configuration extending between two circuit boards. The transmission link may be molded into such a shape with the desired physical dimensions of thickness, spacing, etc. so as to maintain the waveguide parameter through the turning radius. In the application shown, the transmission link interconnects a surface mount connector424with a circuit board427by way of a surface mount arrangement425directly positioned on the surface of board427.

FIGS. 37 and 38illustrate another embodiment of a grouped element channel transmission line, or link650, that is particularly suitable for carrying high voltages and currents at high density contact spacings. The body of the transmission line650is formed from a dielectric and it has a series of grooves, or slots651, formed therein that extend into the body portion thereof from one surface652thereof. The sidewalls654of these slots are conductively coated with a conductive material, such as by plating, and in effect define a series of “plates”655that are opposed to each other and are separated by the intervening space, or air, that will typically occupy the slots651. In the left ofFIGS. 37 and 38, an insert molded plug658is shown and this plug includes a cap portion659and one or more tongues, or fillers660that depend from the cap portion659and which extend into and completely occupy the space of the slots651. A ground plane659may be deposited on the lower surface of the transmission line ofFIGS. 37 & 38to provide increased capacitive coupling.

In this manner, and as shown best schematically inFIG. 38, the opposed polarity (i.e., “+” or “−”) conductive pairs of contacts are electrically isolated from each other, but nevertheless define a complete circuit. The sizes involved with the transmission elements of the present invention permit very high densities to be achieved with a low inductance delivery mode, especially due to the large number of common parallel current paths. To the right ofFIGS. 37 and 38is shown another means for accomplishing this isolation, namely the use of a conformal coating that conforms to the overall slot and land configuration but which provides electrical insulation or isolation between the two conductive surfaces. The use of opposed pairs in the transmission lines, over which is traversed current across and possibly on two opposing surfaces thereof, will lead to a lower loop inductance of the transmission line system.

As shown inFIG. 39, the transmission lines of the present invention may also be used to conduct power at very low impedance. In the transmission line750illustrated, a dielectric body portion751is provided with a series of grooves752formed in its outer surfaces753. In a departure from some of the previous embodiments, more than just the exterior surfaces of the land portions of the dielectric body are plated with a conductive material. Two such lands755are continuously plated for the length of the transmission line750and they are interconnected by plating in the groove, or trough752, that separates them, so that five distinct surfaces are plated. these include the two lands755, the two sidewalls756of the grooves752and the base757of the groove, which all cooperate to form a single power terminal of the transmission line. In this arrangement there is an increased surface area which will provide an increased capacitance between the power terminal and an associated ground terminal. The low inductance and increased capacitance will serve to lower the impedance of the overall system, so that the transmission lines of the present invention may be used for low impedance power delivery.

FIGS. 40 & 41illustrate possible executions of the use of a mixed signal and power transmission line. InFIG. 40, it can be seen that the transmission line950has two signal traces, or extents951and a single, wide power trace, or extent952formed on at least one, and preferably both (opposing) surfaces955of the transmission line. The power extents define a large power channel with an enlarged continuous conductor for increased current handling and high capacitance with the enlarged plate areas. The power and signal regions of this type of structure may be separated by a wide “isolation” region956that is molded or formed as part of the transmission line. In manufacturing processes such as extrusion, the tolerances and dimensions of the isolation region may be controlled with high reliability to obtain the maximum electrical benefit and minimize cross-contamination or shorting contact between the power and signal extents.

FIG. 41illustrates a similar structure except that the power region includes a plurality of power extents952athat are separated by intervening isolation regions.

FIGS. 42-50illustrate a pedestal-type arrangement which incorporates the principles of the present invention, and is preferably intended for use in applications where a transition is required between two levels. InFIG. 42, the pedestal-style connector as illustrated takes the form of a frame, generally designated1000, for a grouped element channel link (GECL) connector. The frame1000has a plurality of raised rib-like elements running in generally parallel relationship along the contoured surfaces thereof. Frame1000may be described as being elongated in the longitudinal direction of the rib-like elements, as compared to the width of frame1000. A first group of raised elements1006runs from one side of an aperture1008disposed in abase portion1010of the frame1000, and runs up a front side of a generally vertical portion1012, and then runs across the top side of a top portion1014, and further wraps around a back end1016(FIG. 45) of frame1000, and finally terminates on the underside of top portion1014in the vicinity of a pair of centering and support pins1018and1020(FIG. 50). The general configuration of this frame is similar to an S-shape and it provides a torturous path between two levels in which the transmission lines supported on the frame change direction at least once.

A second group of raised elements1022runs from an opposite side of aperture1008, wraps around a front edge1024of the frame1000, runs along the underside of base portion1010, runs up the backside of vertical portion1012, then runs along the underside of top portion1014, and also terminates on the underside of top portion1014in the vicinity of the centering and support pins1018and1020, but short of the terminal ends of first group of raised elements1006. Thus, frame1000provides two groups of raised elements1006and1022that run in opposite directions from near aperture1008on the top side of base portion1010to the underside of top portion1014of frame1000. As seen inFIG. 50, the raised elements1006and1022, including the terminal ends thereof, may be in staggered relationship to each other, rather than in aligned relationship. Terminal ends1028of raised elements1006and terminal ends1030of raised elements1022may also be arranged in parallel rows, and may also project from the underside surface of top portion1014for suitable surface mount to, and for electrical contact with a corresponding conductive pattern on a printed circuit board or the like.

The frame1000is preferably formed with at least one bend so that the conductive traces will make at least one change of direction in their extent therealong. In the illustrated embodiment of frame1000, and as seen in the side view ofFIG. 43, frame1000may be provided with two approximately 90° bends1002and1004to accommodate positional translation of electronic signals between different vertical positions, as well as between different horizontal positions. Of course, the bends1002and1004may be provided at any desired angle. For example, bends1002and1004could be less than, or more than, 90° and achieve the desired results. These bends in effect define a torturous path for the conductors and permit the connectors of the present invention to be used in applications in order to interconnect together circuits at two different levels within an electronic device, such as a server or router or the like.

The frame1000may be formed from a catalyzed resin, such as a liquid crystal polymer (LCP), by known molding techniques. The frame1000may then be over-molded, such as with a non-catalyzed resin, to provide the GECL connector illustrated inFIG. 51. In the over-molding process, certain features of frame1000are left exposed, such as the top surfaces of raised elements1006and1022. Such exposed features can then be plated with a metal, such as for example with by an electroless plating process to form electrical conductors along the top surfaces of the raised elements1006and1022. Of course, the over-molding process may be reversed with a non-catalyzed resin being molded first, and a catalyzed resin then molded to form traces for the metal plating of the desired conductors. A third technique is to mold the connector and then select the areas for metallization with a laser or with lithographic techniques. The connector may be molded as a single piece and the plating applied thereto either selectively or grossly and then etched away.

A pair of apertures that are defined in the base portion1010may be utilized, if desired, in the over-molding process to position or index frame1000during the molding process. Disposed between each raised element1006and1022is a recess or channel, such as channels1026shown inFIG. 50. The aperture1008, also defined in the base portion1010, will enhance the flow of the resin about the frame1000, including filling of recesses or channels1026with resin to electrically insulate the metallization formed on the plurality of separate raised elements1006and1022to provide separate electrical conductors thereon.

In accordance with one aspect of the present invention, at least some of the channels disposed between raised elements1006and/or1022are of greater depth than channels1026. For example, inFIG. 48, three channels1032are provided with greater depth. Channels1032are not filled with resin during the over-molding process. Thus, during the electroless metallization plating process, channels1032also have metallization formed on the sidewalls1036of channels1032to form metal conductors in the channels1032. This can best be seen inFIG. 50where metallization is formed on the sidewalls1036of three pairs of the raised ribs1006that form three channels1032. The thickness of the metallization inFIG. 50is enlarged for illustration purposes. These metallized channels1032are also shown inFIG. 46. Any metallization formed in the bottoms of channels1032can be removed by known techniques to provide two separate and opposed electrical conductors on the sidewalls1036in each channel1032. Since channels1032are not over-molded, there is air dielectric between the metal sidewalls1036. The channels1032with the plated sidewalls act as a transmission line for high frequency signals therein. For example, high speed differential electronic signals, such as about +5 volts and −5 volts, at frequencies of 10 Gigabits or higher, may be conducted along the opposed metallized sidewalls1036. In this respect, the channels1032also act as waveguides which extend for the length of the transmission line that is defined by the two conductive trace portions. The intervening air gap has a dielectric constant of approximately or equal to 1.0 which enhances coupling between the two conductors.

With continuing reference toFIG. 50, other raised ribs1038of the set of raised elements1006have adjacent channels filled during the over-molding process such that only the top surface of ribs1038become plated with metal to form conductors during the plating process. Preferably, at least one of the ribs1038is disposed between the high frequency transmission lines formed in each of channels1032. In use, the conductors formed on ribs1038are preferably used for low impedance sources, such as ground and power, to provide affinity for the differential signals in the transmission lines in channels1032. To this end, it is further preferable to dispose a low impedance conductor on ribs1038aat both sides of the channels1032. Thus, a preferred assignment of the conductors formed on the raised ribs1038and1038aand in channel elements1032across frame1000and across the corresponding connector1050is, for example, ground, differential signal pair, power, differential signal pair, ground, differential signal pair and power. Of course, assignment of the ground or power conductors1038or1038amay be changed since any power sources are considered to be low impedance, and similar in impedance to ground.

It may be noted that the raised elements1022are not provided with any channels1032in the embodiment shown inFIGS. 48 and 50. However, some of the elements1022may also be provided with transmission lines in channels1032, if desired. In this embodiment it is assumed that conductors formed on top of elements1022may be utilized to conduct lower frequency signals, or for additional power and ground lines.

FIG. 51illustrates a grouped element channel link connector, generally designated1050, after the frame1000is over-molded. Various features of frame1000are shown in phantom lines. Connector1050therefore retains the attributes of frame1000such as its elongate shape in the direction of the raised elements or ribs and one or more bends to translate signals between vertical as well as horizontal positions.

An alternate embodiment of connector1050is generally designated1060inFIG. 52. Connector1060is generally similar to connector1050except that channels1062that are partially interposed between signal channel transmission conductive surfaces are wider than the channels1032in the connector1050. The connector1060may typically be a connector that mates with a circuit card or board edge of a transceiver or adapter module that is inserted into and held within a conductive shielding cage1070,1082. The forward edge at1022would support a connector1062as shown inFIG. 53, while the rear edge to which the channels1062extend would contact the upper surface of a circuit board1052. (FIG. 53.) In this embodiment of connector1060, no low impedance conductors, such as on ribs1038inFIG. 50, are provided between the transmission lines formed in channels1062. However, a low impedance conductor may be provided to either side of channels1062, such as on ribs1064. Again, channels1062are not filled during the over-molding process, such that the sidewalls of channels1062are plated with conductive metal during the plating process in a manner already described for channels1032of connector1050.

An example of the use of the GECL connector1050, or the alternate embodiment GECL connector1060, is illustrated inFIGS. 53 and 54. A printed circuit board (“PCB”)1052may be provided with a plurality of connector surface mounting areas1054, each including a plurality of electrical contacts for mating to corresponding contacts on the underside of connectors1050or1060. Apertures1056may be provided at the mounting areas1054to engage the centering and mounting pins1618and1020and align the connector1050to PCB1052.

The card edge connector1062has downwardly depending pins1064that mate with apertures1036and1038in GECL connectors1050and1060. Edge connector1062has a plurality of contacts on its underside that make electrical connection with the metal conductors on the raised elements1006and1022of connectors1050and1060when attached thereto. A generally rectangular opening1066is defined in the face of edge connector1062to receive an edge of a mating connector with a plurality of electrical contacts. Thus, all, or any select portion, of the signals present on the conductors formed on raised elements1006and1022, including the channel elements1032and1062, may be made available at opening1066of edge connector1062.

A connector tray, or shielding cage1070may optionally engage PCB1052and it may be divided into a plurality of chambers; one for each connector1050or1060. A plurality of round bosses1072defined on sides of connector tray1070fit into correspondingly shaped recesses1074defined in the edges of PCB1052, and vertically oriented pins1078on tray1070fit into apertures1080disposed between the mounting areas1054to lock tray1070to PCB1052. A lip1076of tray1070rests on the upper surface of PCB1052. A plurality of tray, or cage covers1082, are preferably provided with downwardly depending pins1084which may be inserted in apertures1086defined in the connector tray1070. Connector tray1070and tray covers1082may be plated with a metal to reduce EMI, RF or other electrical interference about the connectors1050and1060.

Another frame member embodiment is shown inFIG. 55at1102. This frame1102has a plurality of elements1104and1106(and which are plated with a conductive material) that are supported on a base portion and which extend upwardly therefrom so that they are “raised” with respect to the base. The frame1102also has one or more bends, such as at1108and1110in which the conductive traces of the connector make two changes of direction, for the same reasons and purposes as in the earlier-described frame1000. Rows of contacts1112and1114are disposed at the ends of these elements1106and1104, respectively, are adapted to make contact with corresponding rows of contacts, such as at the mounting area1054on the circuit board1052inFIGS. 53 and 54. The free ends1106of these conductive elements permit another connector to be soldered to the connector1100. As seen inFIGS. 55 & 56, the two free ends are spaced apart from each other in the vertical direction and they further preferably lie in two different, but generally parallel planes.

Frame1002is adapted to be over-molded into another style of pedestal connector1100that is shown inFIGS. 56-58. At least some channels between the raised elements1104, as shown inFIG. 56, such as the three channels1122, are preferably left open during the over-molding process so that sidewalls of channels1122may be metallized to operate as channel elements or transmission lines, as previously described above for connectors1050and1060. This plating with a conductive material may also be done prior to the overmolding of the outer portions of the connector.

The frame member1102is formed with an outer portion, preferably over molded about selected portions thereof and this outer portion has a pair of support walls1199that extend vertically as shown inFIG. 56to create a cavity, or receptacle1200underneath the one end1106and adjacent to the other end so that the pedestal connector mat be placed on a circuit board over another connector. This connector has a greater width of the slots between its sidewalls and these wider channel elements1124are otherwise similar in construction, arrangement and operation to the already described wider channel elements1062utilized in connector1060inFIG. 52. Metal plating1132is disposed on the opposing sidewalls of channel elements112. Any metal formed in the bottom of channels1124during the metallization process may be removed by various techniques known to the prior art. In the embodiments of the pedestal connector1100illustrated inFIGS. 55-58, raised elements1106are not provided with any narrow or wide channel elements1122or1124, but may be if so desired A pair of apertures1128and1130in the top surface of pedestal connector1100is adapted to receive the edge connector1062shown inFIGS. 53 and 54, in similar fashion and for the same purposes as described above for connectors1050and1060.