Abstract:
A coaxial cable connector is provided for interconnecting coaxial cables having center and outer conductors. The coaxial cable connector utilizes a contact and shell arrangement defining a strip line geometry for the electric fields generated by signals passing through the coaxial cable connector. The contacts and shells may be formed with planar conductors aligned parallel to one another with a center conductive strip sandwiched between planar ground strips, all of which are separated by dielectric materials. The widths and thicknesses of the contact and ground planes, the spacing there between and the dielectric materials are manufacturable in an easy, reliable, and cost effective method.

Description:
RELATED APPLICATIONS  
       [0001]    The present application relates to co-pending application Ser. No. ______ (Tyco Docket No. 17712 (MHM Docket No. 13238US02)) filed on ______ and entitled “Coaxial Cable Displacement Contact”. The co-pending application names Michael F. Laub; Richard J. Perko; John P. Huss, Jr.; and Charles R. Malstrom as joint inventors and is assigned to the same assignee as the present application and is incorporated by reference herein in its entirety including the specification, drawings, claims, abstract and the like. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    Certain embodiments of the present invention generally relate to a connector for interconnecting coaxial cables and more particularly to a connector having contacts arranged in a strip line geometry. Certain embodiments of the present invention generally relate to a ground shield and center contact arrangement for a connector.  
           [0003]    In the past, connectors have been proposed for interconnecting coaxial cables. Generally, coaxial cables have a circular geometry formed with a central conductor (of one or more conductive wires) surrounded by a cable dielectric material. The dielectric material is surrounded by a cable braid (of one or more conductive wires), and the cable braid is surrounded by a cable jacket. In most coaxial cable applications, it is preferable to match the impedance between source and destination electrical components located at opposite ends of the coaxial cable. Consequently, when sections of coaxial cable are interconnected, it is preferable that the impedance remain matched through the interconnection.  
           [0004]    Conventional coaxial connectors are formed from generally circular components partly to conform to the circular geometry of the coaxial cable. Circular components are typically manufactured using screw machining and diecast processes that may be difficult to implement. As the difficulty of the manufacturing process increases, the cost to manufacture each individual component similarly increases. Accordingly, conventional coaxial connectors have proven to be somewhat expensive to manufacture. Many of the circular geometries for coaxial connectors were developed based on interface standards derived from military requirements. The more costly manufacturing processes for these circular geometries were satisfactory for low volume, high priced applications, as in military systems and the like.  
           [0005]    Today, however, coaxial cables are becoming more widely used. The wider applicability of coaxial cables demands a high-volume, low-cost manufacturing process for coaxial cable connectors. Recently, demand has arisen for radio frequency (RF) coaxial cables in applications such as the automotive industry. The demand for RF coaxial cables in the automotive industry is due in part to the increased electrical content within automobiles, such as AM/FM radios, cellular phones, GPS, satellite radios, Blue Tooth™ compatibility systems and the like. Also, conventional techniques for assembling coaxial cables and connectors are not suitable for automation, and thus are time consuming and expensive. Conventional assembly techniques involve the following general procedure:  
           [0006]    a) after sliding a ferrule over the cable, stripping the jacket to expose the outer conductive braid,  
           [0007]    b) folding the outer conductive braid back over the ferrule to expose a portion of the dielectric layer,  
           [0008]    c) stripping the exposed portion of the dielectric layer to expose a portion of the inner conductor,  
           [0009]    d) connecting a contact to the inner conductor, and  
           [0010]    e) connecting a contact to the outer conductive braid.  
           [0011]    The above-noted procedure for assembling a connector and coaxial cable is not easily automated and requires several manual steps that render the procedure time consuming and expensive.  
           [0012]    Today&#39;s increased demand for coaxial cables has caused a need to improve the design for coaxial connectors and the methods of manufacture and assembly thereof.  
         BRIEF SUMMARY OF THE INVENTION  
         [0013]    In accordance with an aspect of the present invention, a coaxial cable connector is provided for interconnecting coaxial cables having center and outer conductors. The connector includes first and second insulated housings matably joined with one another and configured to receive first and second coaxial cables. The insulated housings include cavities that receive first and second center contacts configured to securely attach to center conductors of the respective coaxial cables. First and second outer ground contacts are configured to securely attach to outer conductors of the respective coaxial cables and are securable to the first and second insulated housings, respectively. At least one of the first and second center contacts has a planar body section arranged between planar sides of the first and second outer ground contacts.  
           [0014]    In accordance with another aspect of the present invention, the first and second insulated housings include top, bottom and side walls formed in a rectangular shape. The first and second outer ground contacts include a rear wall formed with opposed side walls in a rectangular U-shape and having an open front face inserted over the corresponding insulated housing. The first and second insulated housings, when combined, may define flat opposed walls joining the planar sides of the first and second outer ground contacts. Optionally, the insulated housings may include staggered mating faces.  
           [0015]    In accordance with another aspect of the present invention, the center contacts are formed with a blade contact and a receptacle contact. The blade contact is arranged in a contact plane extending parallel to the planar sides of the first and second outer ground contacts. The first and second outer ground contacts and the center contacts cooperate to form a strip line geometry. Optionally, the planar sides of at least one of the first and second center contacts are sandwiched between planar sides of the first and second outer ground contacts. The center and outer ground contacts produce electric fields concentrated in regions on opposite sides of the planar sides of the blade contact. The electric fields extend along an axis perpendicular to the planar sides of the center and outer ground contacts.  
           [0016]    In accordance with another aspect of the present invention, a connector is provided comprising matable connector housings connectable to coaxial cables having center and outer conductors. The connector includes center and outer contacts securable to the center and outer conductors of the coaxial cable, respectively. The center and outer contacts are securely retained by the connector housings and are arranged in parallel planes with the center contact being sandwiched between the outer contacts.  
           [0017]    Optionally, the outer contacts may be formed with U-shaped rectangular shells joining one another to surround the center contact. The center and outer contacts may cooperate to form a strip line geometry. The electric fields are focused on opposite sides of the center contact and extend in a direction transverse to the parallel planes in which the contacts are arranged.  
           [0018]    In accordance with an alternative aspect of the present invention, a coaxial cable connector is provided that comprises a housing having opposite ends configured to be connectable to a pair of coaxial cables. The connector includes a center contact having a planar body. The center contact is configured to be connected to conductors and the pair of coaxial cables. The connector further includes ground contacts configured to be connected to ground conductors in the pair of coaxial cables. The ground and center contacts are retained by the housing and are arranged parallel to one another.  
           [0019]    Optionally, the ground contacts may have planar bodies and be located on opposite sides of the planar body of the center contact. The planar bodies of the ground contacts are arranged parallel to the planar body of the center contact.  
           [0020]    The pair of coaxial cables each form an electric field that is circumferentially symmetrical about the coaxial cables. The center and ground contacts of the coaxial cable connector form an electric field having an asymmetric distribution about center contact with respect to ground contacts, such that the electric field distribution is transferred from a circumferentially symmetric distribution (about the first coaxial cable) to an asymmetric distribution (about center contact with respect to ground contacts) and back to circumferentially symmetric distribution (about the second coaxial cable). The electric field formed by the ground and center contacts may comprise several shapes, but generally is focused or concentrated in areas extending outward perpendicular to the blade contacts in the coaxial cable connector.  
           [0021]    The ground contacts may include body sections arranged parallel to the planar body of the center contact and further include sidewalls arranged perpendicular to the planar body of the center contact, thereby entirely surrounding the center contacts to further control and afford a desirable electric field distribution.  
           [0022]    The housing of the connector may be formed with a rectangular body having a recessed slot therein that receives the center contact. The body portion may also include flat opposed sidewalls engaging the ground contacts. The body portion forms a dielectric layer between the center and ground contacts. More generally, the housing may be formed of the dielectric material and shaped with flat exterior walls engaging the ground contacts and an interior cavity receiving the center contact. The exterior walls and interior cavity of the housing are dimensioned relative to one another in order to space the center and ground contacts apart from one another by a predetermined distance. The interior cavity in the housing may represent a slot extending parallel to the exterior walls of the housing. The slot and walls cooperate to hold the ground and center contacts, respectively, in parallel planes.  
           [0023]    In accordance with another aspect of the present invention, a ground shield is provided for a coaxial cable connector. The ground shield includes contact shells matable with one another to define a shielded chamber extending along a longitudinal axis of the contact shells. Contact shells include walls entirely surrounding a perimeter of the shielded chamber when the contact shells join one another. At least one contact shell is provided with an open end and a cable retention end located at opposite ends of the shielded chamber. The cable retention end is configured to receive and to be connected to a coaxial cable. The contact shell includes at least one wall and at least one adjacent open side extending between the open end and the cable retention end. The open side is subsequently shielded by a wall on the mating contact shell when the contact shells are joined with one another.  
           [0024]    The contact shells may be U-shaped, L-shaped, J-shaped and the like. When formed with a U-shape, each contact shell includes opposed side walls and a connecting wall, with the open side opposing the connecting wall. When the contact shells are joined, the side and connecting walls provide 360° of shielding around a perimeter of the shielded chamber along the length of the shielded chamber from the open end to the cable retention end. The side walls of a single contact shell are located and extend along opposite sides of the shielded chamber and are lined parallel to one another.  
           [0025]    Optionally, a coaxial cable displacement contact may be provided at the cable retention end of at least one contact shell. The coaxial cable displacement contact is configured to engage a conductor of a coaxial cable along a plane extending transverse to, and intersecting, the cable retention end of the corresponding contact shell. 
       
    
    
     BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS  
       [0026]    [0026]FIG. 1 illustrates an exploded isometric view of a connector formed in accordance with at least one embodiment of the present invention.  
         [0027]    [0027]FIG. 2 illustrates an isometric view of an assembled connector formed in accordance with at least one embodiment of the present invention.  
         [0028]    [0028]FIG. 3 illustrates an isometric view of an insulated housing formed in accordance with at least one embodiment of the present invention.  
         [0029]    [0029]FIG. 4 illustrates an isometric view of a contact blade formed in accordance with at least one embodiment of the present invention.  
         [0030]    [0030]FIG. 5 illustrates an isometric view of a receptacle contact formed in accordance with at least one embodiment of the present invention.  
         [0031]    [0031]FIG. 6 illustrates a side view of a contact shell formed in accordance with at least one embodiment of the present invention.  
         [0032]    [0032]FIG. 7 illustrates an end view of a contact shell formed in accordance with at least one embodiment of the present invention.  
         [0033]    [0033]FIG. 8 illustrates a sectional view of a contact shell taken along line  8 - 8  in FIG. 6 in accordance with at least one embodiment of the present invention.  
         [0034]    [0034]FIG. 9 illustrates a coaxial cable displacement contact mounted to a coaxial cable in accordance with at least one embodiment of the present invention.  
         [0035]    [0035]FIG. 10 a  illustrates a coaxial cable geometry for a coaxial cable suited for connection to a connector formed in accordance with at least one embodiment of the present invention.  
         [0036]    [0036]FIG. 10 b  illustrates a strip line geometry for a connector formed in accordance with at least one embodiment of the present invention.  
         [0037]    [0037]FIG. 11 illustrates electric field distributions surrounding a coaxial cable and a connector attached thereto in accordance with at least one embodiment of the present invention.  
         [0038]    [0038]FIG. 12 illustrates an exploded isometric view of a connector formed in accordance with an alternative embodiment of the present invention.  
         [0039]    [0039]FIG. 13 illustrates a receptacle contact formed in accordance with an alternative embodiment of the present invention.  
         [0040]    [0040]FIG. 14 illustrates a connector partially assembled in accordance with an alternative embodiment of the present invention.  
         [0041]    [0041]FIG. 15 illustrates a center contact formed in accordance with at least one embodiment of the present invention.  
         [0042]    [0042]FIG. 16 illustrates at least one center contact formed in accordance with an embodiment of the present invention.  
         [0043]    [0043]FIG. 17 illustrates an isometric view of a shell formed in accordance with at least one embodiment of the present invention.  
         [0044]    [0044]FIG. 18 illustrates an isometric view of a shell formed in accordance with at least one embodiment of the present invention.  
         [0045]    [0045]FIG. 19 illustrates an end view of a shell formed in accordance with at least one embodiment of the present invention.  
         [0046]    [0046]FIG. 20 illustrates an isometric view of an insulated housing formed in accordance with at least one embodiment of the present invention.  
         [0047]    [0047]FIG. 21 illustrates an isometric view of an insulated housing formed in accordance with at least one embodiment of the present invention.  
         [0048]    [0048]FIG. 22 illustrates a partially assembled connector in accordance with one embodiment of the present invention.  
         [0049]    [0049]FIG. 23 illustrates an outer housing and coaxial cable joined in accordance with at least one embodiment of the present invention.  
         [0050]    [0050]FIG. 24 illustrates an outer housing and coaxial cable joined in accordance with at least one embodiment of the present invention.  
         [0051]    [0051]FIG. 25 illustrates an outer housing and coaxial cable joined in accordance with at least one embodiment of the present invention.  
         [0052]    [0052]FIG. 26 illustrates an outer housing and coaxial cable joined in accordance with at least one embodiment of the present invention.  
         [0053]    [0053]FIG. 27 illustrates a coaxial cable displacement contact formed in accordance with an alternative embodiment of the present invention.  
         [0054]    [0054]FIG. 28 illustrates a side view of a contact shell formed in accordance with an alternative embodiment of the present invention.  
         [0055]    [0055]FIG. 29 illustrates a top plan view of a contact shell formed in accordance with an alternative embodiment of the present invention. 
     
    
       [0056]    The foregoing summary, as well as the following detailed description of the preferred embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings, embodiments which are presently preferred. It should be understood, however, that the present invention is not limited to the precise arrangements and instrumentality shown in the attached drawings.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0057]    [0057]FIG. 1 illustrates a coaxial cable connector  10  formed in accordance with an embodiment of the present invention. The coaxial cable connector  10  includes insulated housings  12  and  14  that are matable with one another when the coaxial cable connector  10  is fully assembled. Optionally, the insulated housings  12  and  14  may be assembled from more than two pieces, or formed together as one unitary structure. The coaxial cable connector  10  further includes a blade contact  16  and a receptacle contact  18  that are separately securable to center conductors of coaxial cables (not shown in FIG. 1) and engage one another both frictionally and electrically when the coaxial cable connector  10  is fully assembled to form an electrical path between the center conductors. Optionally, only one of the blade contact  16  and the receptacle contact  18  may be securable to a coaxial cable. In this alternative embodiment, the other of the blade contact  16  and the receptacle contact  18  may be connected to a circuit board, an electrical component, a non-coaxial cable and the like. First and second contact shells  20  and  22 , when electrically joined, form a shielded chamber extending along a longitudinal axis of the contact shells  20  and  22 . The contact shells  20  and  22  substantially surround a perimeter of the insulated housings  12  and  14 . The contact shells  20  and  22  are configured to electrically engage outer conductors of the coaxial cable to form an electrical path there between. FIG. 2 illustrates the coaxial cable connector  10  fully assembled, but without the coaxial cables.  
         [0058]    The insulated housings  12  and  14  include mating faces  24  and  26 , respectively, that abut against one another when the coaxial cable connector  10  is fully assembled. In the embodiment of FIG. 1, the mating faces  24  and  26  are formed with notched portions  23  and  25  defining shelves  28  and  30 , respectively, that join one another to ensure proper vertical alignment between the insulated housings  12  and  14 . The insulated housings  12  and  14  include rectangular body sections  32  and  34 , respectively, defined by top walls  36  and  38 , bottom walls  40  and  42 , and side walls  44  and  46 , respectively. The body sections  32  and  34  are surrounded by the contact shells  20  and  22 . The insulated housings  12  and  14  are formed of a dielectric material of a predetermined thickness to afford a desired impedance through the coaxial cable connector  10 .  
         [0059]    The insulated housing  12  includes a slot  48  extending from the mating face  24  rearward along a length of the body section  32 . The slot  48  has an upper edge opening onto the top wall  36 . The slot  48  includes a rear section that flares into a chamber  50  having an upper edge that also opens onto the top wall  36 . The chamber  50  opens into an even wider cavity  52  at a rear end  53  of the body section  32 . The body section  32  is formed integrally with a shroud  54  that is shaped in a rectangular U-shape with bottom and side walls  56  and  58 , respectively. The bottom and side walls  56  and  58  cooperate to define a portion of the cavity  52 .  
         [0060]    The body section  32  and shroud  54  join at an interface that is shaped to accept corresponding features on the contact shell  20  (discussed below in more detail). At the interface, vertical channels  55  are provided between interior surfaces of the leading edges  57  of the side walls  58  and exterior surfaces of the rear ends  53  of the side walls  44 . The channels  55  receive end portions of the contact shell  20 .  
         [0061]    Upper portions of the channels  55  communicate with transverse arm relief slots  59  that are directed toward one another. The arm relief slots  59  are positioned between the rear ends  53  of side walls  44  and the main body portion of the side walls  58  of the shroud  54 . The arm relief slots  59  receive coaxial cable displacement members, such as coaxial cable displacement contacts  138  on the contact shells  20  and  22  to permit the coaxial cable displacement contacts  138  to be inserted and pierce the coaxial cable.  
         [0062]    The blade contact  16  is mounted on an end of the coaxial cable. The cavity  52 , chamber  50 , and slot  48  collectively receive the end of the coaxial cable and the blade contact  16 . The cavity  52 , chamber  50 , and slot  48  have open upper edges to facilitate automated assembly of the coaxial cable connector  10  by permitting the coaxial cable and blade contact  16  mounted thereto to be easily and automatically inserted downward in a transverse direction into the insulated housing  12 . Optionally, the coaxial cable and blade contact  16  may be inserted into the insulated housing  12  through the rear end  60 .  
         [0063]    [0063]FIG. 3 illustrates the insulated housing  14  in more detail. The insulated housing  14  also includes a shroud  62  formed on the rear end of the body section  34 . The shroud  62  includes top and side walls  64  and  66 , respectively, that cooperate to define a U-shaped channel or cavity  68  opening to the rear end  70  of the insulated housing  14 . The cavity  68  receives a coaxial cable with the receptacle contact  18  mounted thereon. The body section  34  includes a chamber  72  having a front end  74  opening onto the mating face  26 . The front end  74  includes beveled edges. The rear end of the chamber  72  communicates with the cavity  68  defined by the shroud  62  and a rear end  63  of the body section  34 .  
         [0064]    The insulated housing  14  also includes vertical channels  65  extending along a rear end  63  of the body section  34  between exterior surfaces of the side walls  46  and interior surfaces of the leading edges  67  of the side walls  66 . The channels  65  are sufficient in depth to receive end portions of the contact shell  22 . The channels  65  communicate with transverse arm relief slots  69  directed toward one another. The arm relief slots  69  are located between rear ends  63  of the side walls  46  and shelves  71  on the side walls  66 . The arm relief slots  69  define guideways that receive coaxial cable displacement contacts  138  on the contact shell  22 .  
         [0065]    [0065]FIG. 4 illustrates a blade contact  16  in more detail. The blade contact  16  includes a flat planar body section  90  having a lead edge  92  that is beveled. The body section  90  includes upper and lower sides  94  and  96  aligned substantially parallel to one another and parallel to a plane of the blade contact. Side edges  98  extend along a length of the body section  90 . A rear end  100  of the body section  90  is formed with a wire crimp  102  having an opening  104  therethrough. The opening  104  receives the center conductor(s) of the coaxial cable. The wire crimp  102  may be compressed to securely, frictionally engage the center conductor(s) of the coaxial cable to mount the blade contact  16  on an end of the coaxial cable.  
         [0066]    [0066]FIG. 5 illustrates the receptacle contact  18  in more detail. The receptacle contact  18  includes a forked body section  106  having a pair of fingers  108  formed in a C-shape. Outer tips of the fingers  108  have contact surfaces  110  spaced apart from one another a distance that is slightly less than a width of the body section  90  of the blade contact  16 . The contact surfaces  110  electrically engage the upper and lower sides  94  and  96  of the blade contact  16  when connected thereto. A rear end of the forked body section  106  is formed with a wire crimp  112  having an opening  114  therethrough. The opening  114  receives the center conductor(s) of a coaxial cable. The center conductors may be securely fixed to the receptacle contact  18  by compressing the wire crimp  112 .  
         [0067]    FIGS.  6 - 8  illustrate the contact shells  20  and  22  in more detail. The contact shells  20  and  22  are similarly constructed; thus, the following discussion is only in connection with the contact shell  20 . The contact shells  20  and  22  may be stamped and formed from sheets of conductive material into a U-shape. The contact shell  20  includes side walls  130  formed parallel to one another and extending along planes parallel to a longitudinal axis of the contact shell  20 . A connecting wall  132  interconnects the side walls  130 . The connecting wall  132  is also planar in design and aligned in a plane extending parallel to the longitudinal axis of the contact shell  20 , but transverse to the planes containing the side walls  130 . An open face  134  (better shown in FIG. 1) extends along the side walls  130  opposite the connecting wall  132 . An open end  136  is provided at one end and a cable retention end  131  is provided at an opposite end of the side and connecting walls  130  and  132 .  
         [0068]    The open face  134  of the contact shell  20  extends along the entire length of the side walls  130  from the cable retention end  131  to the open end  136  to facilitate manufacturability of the contact shell and assembly of the connector. More specifically, the contact shell  20  is easily manufactured, such as by stamping the side and connecting walls  130  and  132  from a common piece of material and then forming/bending the side walls  130  at a right angle to the connecting wall  132 . By leaving the open face  134 , the stamping or forming operations are simplified. During assembly, the open face  134  on each contact shell  20  and  22  permits the coaxial cables, as well as the corresponding blade and receptacle contacts  16  and  18 , to be side loaded. Side loading involves inserting the coaxial cable and corresponding blade or receptacle contact  16  or  18  along a path denoted by arrow A in FIG. 6 in a direction transverse to a longitudinal axis of the contact shell  20 .  
         [0069]    The U-shaped configuration formed by the side and connecting walls  130  and  132  enables the contact shells  20  and  22  to be joined in a manner that provides 360 degrees of shielding around the perimeter of the blade and receptacle contacts  16  and  18 . When joined, the contact shells  20  and  22  also provide 360 degrees of shielding in a plane transverse to a longitudinal axis of the coaxial cable. The 360 degrees of shielding substantially surrounds the portions of the inner conductors of the coaxial cables that are not covered by the outer conductors of the coaxial cables. When the contact shells  20  and  22  are joined, the connecting wall  132  of contact shell  20  covers the open face  134  of contact shell  22 . Similarly, the connecting wall  132  of contact shell  22  covers the open face  134  of contact shell  20 . The side walls  130  of opposite contact shells  20  and  22  overlap one another.  
         [0070]    The coaxial cable displacement contacts  138  are formed on the cable retention ends  131  of the side walls  130 . The coaxial cable displacement contacts  138  are bent inward to face one another. Each pair of coaxial cable displacement contacts  138  lie in a plane perpendicular to the longitudinal axis of the contact shells  20  and  22 . The plane containing the pair of coaxial cable displacement contacts  138  joins the corresponding cable retention end  131 . The coaxial cable displacement contacts  138  are spaced apart by a gap  140 . The gap  140  between the inner edges of the coaxial cable displacement contacts  138  is provided with a width based on the dimensions of the coaxial cable to be joined with the contact shell  20 . The coaxial cable displacement contacts  138  are shorter in height than the side walls  130  to form a shelf  142  that is slidable along rear ends of the side walls  44  of the insulated housing  12 . Optionally, the coaxial cable displacement members, such as coaxial cable displacement contacts  138  may be formed separate from, or stamped integral with, any other portion of the contact shell  20 ,  22  proximate thereto.  
         [0071]    The coaxial cable displacement contacts  138  include bases  139  having support projections  144  that are loosely received in holes  146  formed in the front section of the connecting wall  132 . An assembly tool (not shown) presses against the support projections  144  to mount the coaxial cable displacement contacts  138  onto the cable. Each coaxial cable displacement contact  138  includes a forked section that extends upward from the base  139 .  
         [0072]    The side and connecting walls  130  and  132  extend up to the plane in which the coaxial cable displacement contacts  138  engage the coaxial cable. Hence, the entire length of the coaxial cables outside of the contact shells  20  and  22  shields the inner conductor with outer conductor. The portion of the coaxial cable outside, but leading up to the contact shell is self shielded. The only portion of the inner conductor exposed (e.g., not covered by the outer conductor) is inside the shielded chamber formed by mating contact shells  20  and  22 . The shelves  142  (FIG. 9) join the braid receiving slots  156  at a beveled edge that serves as a lead-in portion to direct the cable onto the displacement beams  154 . The shelves  142  and coaxial cable displacement contacts  138  are received in the transverse arm relief slots  59  and  69  in respective insulated housings  12  and  14 . The displacement beams  154  and the walls  159  induce lateral retention forces on a section of an outer conductor wedged in the braid-receiving slots  156 . The cavity  68  in the shroud  62  and the vertical channels  65  are spaced relative to each other to center the coaxial cable (not shown) between the coaxial cable displacement contacts  138 , thereby properly aligning the displacement beams  154  with respect to the outer conductor of the coaxial cable.  1681  The connecting wall  132  includes a lip section  148  extending forward of the holes  146 . The lip section  148  is tapered inward toward its center and formed with a wire crimp  150  on a distal end thereof. The wire crimp  150  includes step-shaped tips  152  that join one another when folded inward to be clamped onto a coaxial cable. The wire crimp  150  also serves as a strain relief to prevent motion between the coaxial cable and the coaxial cable displacement contacts  138 .  
         [0073]    As shown in FIGS. 7 and 8, the coaxial cable displacement contacts  138  include, proximate inner edges thereof, displacement beams  154  separated from the wall  159  of the coaxial cable displacement contacts  138  by braid-receiving slots  156 . Beam tips  158  of the displacement beams  154  are tapered to facilitate insertion into the coaxial cable when the contact shells  20  and  22  are mounted on the coaxial cables.  
         [0074]    [0074]FIG. 9 illustrates the operation of the coaxial cable displacement contacts  138  when assembled to a coaxial cable  160 . This embodiment includes a pair of coaxial cable displacement contacts  138 . When the contact shells  20  and  22  are mounted to the coaxial cables  160 , the beam tips  158  pierce the cable jacket  162  and outer cable braid  164  and extend into the cable dielectric  166 . The braid-receiving slots  156  securely receive and engage the outer cable braid  164 , through a retention or normal force, to form an electrical connection between the contact shells  20  and  22  and the outer conductors (namely the outer cable braids  164 ) of the coaxial cable  160 . The retention or normal force constitutes a friction force of a magnitude sufficient to provide a long term reliable contact interface.  
         [0075]    The displacement beams  154  are spaced apart by a beam-to-beam distance  170  that is greater than the outer diameter of the center conductor  168 , but less than the inner diameter of the outer cable braid  164  to ensure that the displacement beams  154  do not electrically contact the center conductor  168 , but do pierce the outer cable braids  164 . The displacement beams  154  are formed with a predefined outer beam width  172  and the braid-receiving slots  156  are formed with a predefined slot width  174  based on the inner and outer diameters of the outer cable braid  164  to ensure that the displacement beams  154  pierce the outer cable braid  164 , while the braid-receiving slots  156  have a width sufficient to firmly receive the outer cable braid  164  and form a reliable electrical connection therewith. The cable braid  164  has a radial width defined by the difference between inner and outer diameters of the cable braid  164 , or in other words, a width of the cable braid  164  that is measured in a direction parallel to the radius of the cable braid  164 .  
         [0076]    As illustrated in FIG. 6, at least one side wall  130  may include a protrusion  176  therein to frictionally mate with the interior of the side wall  130  of the opposite contact shell  20  and  22  to ensure adequate normal force between the contacts shells  20  and  22  to ensure a reliable electrical interface.  
         [0077]    Optionally, both coaxial cable displacement contacts  138  may be formed integrally with one another and attached (integrally or otherwise) to only one of the side walls  130  and/or connecting wall  132 . When formed integrally with one another, the coaxial cable displacement contacts  138  would still include a partial notch (resembling the upper end of gap  140 ) between the upper ends of the displacement beams  154  to form an area to accept the portion of the coaxial cable that is not pierced by the displacement beams  154 . Hence, the gap  140  need not extend along the entire length of the displacement beams  154 , but instead may only be provided near the upper ends thereof.  
         [0078]    [0078]FIG. 10 a  illustrates a graphical representation of a coaxial cable geometry  180  including a center conductor  181 . The center conductor  181  is centered within an intermediate dielectric material  183  that is surrounded by a cylindrical outer conductor  182 , thereby centering the inner conductor  181  in the outer conductor  182 . The outer conductor  182  may be formed as a braid type conductor and the like. The center conductor  181  has a radius r i , while the outer conductor  182  has an inner radius r O . The dielectric material  183  has a relative dielectric constant of ε r . The general formula defining the impedance produced by the coaxial cable geometry  180  is represented by the following equation:  
               Z   o     =       60       ɛ   r                         ln        (       r   o       r   i       )                     Ohms             Equation                   (   1   )                                 
 
         [0079]    [0079]FIG. 10 b  illustrates a graphical representation of a cross-section of a strip line geometry  186  that is formed by the coaxial cable connector  10 . In the strip line geometry  186 , a center conductor  187  is sandwiched between two wider ground conductors  188 . The center and ground conductors  187  and  188  are planar in shape and aligned in planes extending parallel to one another. The center conductor  187  is formed with a width (W) and a thickness (T). The ground conductors  188  are spaced from the center conductor  187  by spacings H and H1. The center conductor  187  is surrounded by a dielectric material  189  filling the void between the ground conductors  188 . The dielectric material  189  has a relative dielectric constant of ε r . The general formula defining the impedance produced by the strip line geometry  186  is represented by the following equation:  
               Z   0     =       80       ɛ   r                         ln        (       1.9        (       2      H     +   T     )           0.8      W     +   T       )            (     1   -     H     4   ×   H1         )        Ohms             Equation                   (   2   )                                 
 
         [0080]    The strip line geometry  186  is more easily manufactured and the design parameters are more readily controlled during production as compared to connectors maintaining circular geometries or other geometries that produce symmetric electric field distribution. By way of example, during the manufacture of the coaxial cable connector  10  having the strip line geometry  186 , the manufacturing process more easily controls the spacings H and H1, thickness (T), width (W) and relative dielectric ε r . The structures forming the strip line geometry  186  enables the impedance of the coaxial cable connector  10  to be easily controlled. This ability translates to reduced manufacturing costs.  
         [0081]    [0081]FIG. 11 illustrates electric field distributions formed about a coaxial cable and about a coaxial cable connector  10  connected to the coaxial cable. A series of parallel lines  190  denote the geometry of the coaxial cable. A large rectangular box  192  denotes a general geometry for the coaxial cable connector  10 . A smaller shadow box  193  denotes the general geometry of a contact blade, such as contact blades  16  and  216 . The shadow box  193  may also represent a receptacle contact, such as formed by receptacle contact  18  or  218 .  
         [0082]    An electric field distribution  191  is produced by the coaxial cable. The electric field distribution  191  is distributed symmetrically about a circumference of the coaxial cable and decreases in intensity at greater radial distances from the center conductor of the coaxial cable. A representative magnitude distribution for the electric field distribution  191  is illustrated as a series of concentric shaded rings that are aligned in one plane traversing the coaxial cable (e.g., perpendicular to the cable axis). A feature of electric fields formed about a coaxial cable geometry is that the magnitude/intensity distribution of the electric fields are circumferentially uniform and vary only in the radial direction.  
         [0083]    An electric field  195  is formed by the coaxial cable connector  10 . The electric field  195  is distributed asymmetrically about the coaxial cable connector  10  and is oriented with a particular relation to the strip line geometry  186  created between the blade contacts  16  and  216  and the corresponding side walls  130 ,  237  and  239  (as discussed above with FIG. 10 b ). The distribution of the magnitude or intensity for the electric field  195  is denoted by asymmetric shaded areas surrounding the shadow box  193 . The electric field  195  is oriented proximate opposite sides of the shadow box  193  along a transverse axis  197  extending perpendicularly to the plane of the shadow box  193 . As shown by the shaded areas in the electric field  195 , the magnitude or flux density is primarily concentrated in major areas  198  centered about the transverse axis  197  and extending in opposite directions. The magnitude or flux density of the electric field  195  is secondarily concentrated to a much lesser extent in lateral areas  199  near side edges of the shadow box  193  (representing the side edges of the blade contacts  16  and  216 ). Stated another way, the magnitude or flux density of the electric field  195  is focused primarily in major areas  198 , while being focused in lateral areas  199  to a lesser degree.  
         [0084]    In the embodiment of FIG. 1, the blade contact  16  represents the center conductor  187 . The thickness and width of the blade contact  16  is easily controlled when stamping the blade contact  16  from a flat planar metal sheet of known thickness. The side walls  130  of the contact shells  20  and  22  represent ground conductors  188 . The width of the top walls  36  define the spacings H and H1 between blade contact  16  and side walls  130 . The distances between the blade contact  16  and the connecting walls  132  in each contact shell  20  and  22  may be formed sufficiently wide such that the connecting walls  132  have a minimal impact on the impedance of the coaxial cable connector  10 .  
         [0085]    In accordance with at least one embodiment, the contact shells  20  and  22  afford a one-piece contact system that utilizes the insulated housings  12  and  14  as “stuffers” to retain the coaxial cables (e.g., cable  160 ) intact during a crimping process. The insulated housings  12  and  14  also assist in locating the coaxial cables  160 . The width of the braid-receiving slot is dependent upon the diameter of the conductive braid. By way of example only, the braid-receiving slot width may be slightly larger (e.g., a few thousandths of an inch) than the diameter of the conductive braid with multiple conductors of the braid in each braid-receiving slot. This permits a significant amount of plastic deformation during the assembly process. Deformation of the conductive braid along with the wiping action that occurs during assembly ensures that clean metallic surfaces on the multiple conductors of the conductive braid come into contact with the coaxial cable displacement contacts  138  while retaining a desired amount of residual spring force between the multiple conductors and the coaxial cable displacement contacts  138 . Retaining a desired residual spring force between the braid conductors and the coaxial cable displacement contacts  138  provides a stable long term, low resistance contact interface.  
         [0086]    Optionally, the shape of the displacement beams and displacement beam tips may be varied. The displacement beam tip may be provided with a double edge used to ensure that when the displacement beam is inserted into the dielectric material of the coaxial cable, the displacement beams travel along a straight line. Tapering the displacement beam provides added strength, while reducing unwanted deflection of the displacement beam during installation.  
         [0087]    During assembly of the coaxial cable connector and two cables, the following steps may be carried out. Initially, the ends of the two coaxial cables to be interconnected are stripped to expose an end portion of their respective center conductors. The exposed end portion of the center conductors are then inserted into the openings  104  and  114  in the blade contact  16  and receptacle contact  18 , respectively. The wire crimps  102  and  112  are compressed to securely retain the exposed end portions of the center conductors. Next, the coaxial cables and the blade and receptacle contacts  16  and  18  are inserted into respective insulated housings  12  and  14 . With reference to FIG. 1, the body section  90  of the blade contact  16  is inserted (laterally or longitudinally) into the slot  48 , and the wire crimp  102  is inserted into the chamber  50 . An unstripped portion of the coaxial cable behind the exposed center conductor is inserted into the cavity  52  until leading edges of the dielectric material, cable braid and cable jacket abut against shelves  51  near the rear ends  53  of the side walls  44 . Once inserted, a leading tip portion of the body section  90  of the blade contact  16  projects forward from the notched portion  23  of the mating face  24 . The blade contact  16  and receptacle contact  18  are joined when the insulated housing  12  and  14  are combined.  
         [0088]    Each of the contact shells  20  and  22  are separately mounted on a corresponding one of the insulated housings  12  and  14 . During mounting, the contact shells  20  and  22  are separately inserted along an axis  11  (FIG. 1) aligned perpendicularly to the longitudinal axis  13  of the coaxial cable connector  10 . As the contact shells  20  and  22  are inserted, the coaxial cable displacement contacts  138  pierce the corresponding coaxial cables  160  and the displacement beams  154  engage the outer cable braids  164  (as illustrated in FIG. 9). Next, an outer housing is assembled to the coaxial cable connector  10 .  
         [0089]    Once assembled, the insulated housings  12  and  14 , blade and receptacle contacts  16  and  18 , and contact shells  20  and  22  cooperate (as illustrated in FIG. 2) to define a strip line contact configuration as discussed above in connection with FIG. 10 b  to afford a desired impedance for signals carried through the coaxial cable connector  10 . The process of assembling the coaxial cable connector  10  is easily automated, reliable and cost effective.  
         [0090]    [0090]FIG. 12 illustrates a coaxial cable connector  200  formed in accordance with an alternative embodiment. The coaxial cable connector  200  includes insulated housing  212  and  214 , a blade contact  216 , a receptacle contact  218 , and contact shells  220  and  222 . The contact shells  220  and  222  include side walls  237  and  239 , respectively, and connecting walls  233  and  235 , respectively. The blade contact  216  functionally replaces blade contact  16 , while the receptacle contact  218  functionally replaces receptacle contact  18 . The first and second insulated housings  212  and  214  include mating faces  224  and  226 , respectively, that have even more pronounced notched portions  223  and  225  and shelves  228  and  230 , respectively. The shelf  228  includes a notch  229  that accepts a body section  290  of the receptacle contact  218 . The shelf  228  also includes a slot  231  that accepts a finger  219  of the blade contact  216 .  
         [0091]    The side walls  237  and  239 , and corresponding connecting walls  233  and  235 , are formed in U-shapes and have open faces  201  and  207 , respectively. The side walls  237  and  239  include contact retention ends  203  and  209 , and open ends  205  and  211 , respectively, opposite one another. The open faces  201  and  207  extend from the contact retention ends  203  and  209  to the open ends  205  and  211 , respectively, to afford the advantages discussed above in connection with contact shells  20  and  22 .  
         [0092]    The blade contact  216  is illustrated in more detail in FIG. 13. The blade contact  216  includes a body section  215  with fingers  217  and  219  extending therefrom. The fingers  217  and  219  are separated by a slot  221  extending partially along a length of the body section  215  rearward from a leading edge  213 . A rear end of the body section  215  is secured to a wire crimp  223  having an opening  225  therethrough to receive the center conductor of a coaxial cable connected thereto.  
         [0093]    The blade contact  216  and receptacle contact  218 , when joined, are aligned in perpendicular planes. The plane containing the fingers  217 ,  219  of the blade contact  216  is aligned parallel to the side walls  237  and  239  of the contact shells  220  and  222 , respectively. The plane containing the body section of the receptacle contact  218  is aligned parallel to the connecting walls  233  and  235  of the contact shells  220  and  222 , respectively. As shown in FIGS. 12 and 13, the body section  290  of the contact  218  is formed with a width that is greater than a width of an adjoining crimp  291 .  
         [0094]    Optionally, the body section  290  may be different than shown in FIG. 12. The body section  290  may be dimensioned to cooperate with the connecting walls  233  and  235  to produce a second strip line geometry. The second strip line geometry is perpendicular to the strip line geometry formed by the blade contact  216  and the side walls  237  and  239  to form a dual strip line geometry. In this dual strip line geometry, the blade and receptacle contacts  216  and  218  form a cross arrangement. Optionally, one or more of the blade contacts  16 ,  216  and receptacle contacts  18 ,  218  may include multiple contacts that are similarly shaped and oriented parallel or perpendicular to one another. By way of example, two contacts may be stacked parallel to one another or two contacts may be oriented perpendicular to one another.  
         [0095]    The connecting walls  132 ,  233  and  235  and side walls  130 ,  237  and  239 , individually and collectively, constitute ground contacts. In other words, each connecting wall  132 ,  233  and  235  constitutes an individual ground contact. The combination of opposed connecting walls  132 ,  233  and  235  may be considered to constitute a ground contact. The combination of opposed side walls  130 ,  237  and  237  may be considered to constitute a ground contact. As a further example, each connecting wall  132 ,  233  and  235  in combination with one or more adjoining side walls  130 ,  237  and  239  may be considered a ground contact.  
         [0096]    The insulated housing  214  includes a latch  241  projecting upward from the top wall  264 . The latch  241  enables the coaxial cable connector  200  to be mounted to another structure. Channels  243  are also provided in the top wall  264  on either side of the latch  241  to provide an even wall thickness to improve moldability and to reduce the amount of material used.  
         [0097]    [0097]FIG. 14 illustrates the contact shells  220  and  222  assembled with corresponding housings  212  and  214 . As illustrated in FIG. 14, during assembly, the contact shells  220  and  222  may be connected with corresponding coaxial cables and insulated housings  212  and  214  before the insulated housings  212  and  214  are mated with one another.  
         [0098]    [0098]FIGS. 15 and 16 illustrate blade and receptacle contacts  316  and  318 , respectively. In FIG. 15, the blade contact  316  is illustrated having a planar body section  317  with a slot  319  cut in an outer end thereof to form a fork having fingers  321  and  322 . At the outer ends of the fingers  321  and  322 , rounded projections  323  are provided in the opening to the slot  319  and are oriented to face one another. The projections  323  ensure a secure frictional and electrical interconnection between the blade contact  316  and a joining receptacle contact  318  when the receptacle contact  318  is inserted into the slot  319 . An opposite end of the body section  317  includes a crimp  324  having an opening  325  that receives a center conductor of a coaxial cable. The crimp  324  is securely clasped to the center conductor of the coaxial cable.  
         [0099]    [0099]FIG. 16 illustrates a receptacle contact  318  having a planar body section  326  with a beveled outer end  328  for insertion between the projections  323  on the blade contact  316 . An opposite end of the body section  326  includes a crimp  330  having an opening  332  that receives a center conductor of the corresponding coaxial cable. The crimp  330  is formed to securely attach to the center conductor of the coaxial cable.  
         [0100]    [0100]FIGS. 17 and 18 illustrate opposite views of an alternative configuration for a contact shell. Each contact shell  340  includes side walls  344  and a connecting wall  348 . A projection  352  is provided on at least one side wall  344  to ensure a proper electrical connection between mating contact shells  340 .  
         [0101]    The connecting walls  348  includes a transition region  356  at a rear end thereof that is formed integrally with a laterally extending separation plate  360 . The separation plate  360  includes a slot  363  to facilitate cutting of the separation plate  360  during assembly. The separation plate  360  is in turn formed integrally with a strain relief crimp  364 . During assembly, the strain relief crimp  364  is physically separated from the transition region  356 , such as through a stamping operation, and then secured to the coaxial cable.  
         [0102]    The strain relief crimp  364  is U-shaped and includes a laterally extending body portion  361  joining the separation plate  360 . The body portion  361  is secured at opposite ends to arms  365  that extend parallel to one another and in a direction perpendicular to the body portion  361 . The arms  365  include ribs  367  along both side edges thereof. The body portion  361  includes a cable grip  369  centered between the arms  365 . The cable grip  369  includes teeth  371  directed inward to face the coaxial cable. The teeth  371  pierce the jacket of the coaxial cable and engage the outer conductor when the strain relief crimp  364  is secured to the coaxial cable. The cable grip  369  may be formed in a punched star pattern with a plurality of teeth  371  being stamped, and bent to face inward. Alternatively, the teeth  371  may be replaced with a single tooth or, with one or more barbs. Optionally, the cable grip  369  need not engage the outer conductor, but instead may only pierce a surface of the jacket sufficiently to resist any anticipated cable stresses.  
         [0103]    [0103]FIG. 19 illustrates an end view of contact shell  340 . The coaxial cable displacement contacts  368  include support projections  370  formed on lower ends thereof to be loosely received in openings in the connecting wall  348 . The displacement beams  372  extend upward and are separated from one another by a gap  374 . The displacement beams  372  include pointed tips  376  that facilitate penetration of the jacket and outer conductor of the corresponding coaxial cable. Braid receiving slots  378  extend downward and are flared outward away from the gap  374  at base wells  373  to form a hooked shape.  
         [0104]    The contact walls  375  include tapered undercut edges  377  extending along the top of the coaxial cable displacement contacts  368 . The undercut edges  377  end at lead tips  379  which face one another and are located at mouths  381  of the braid receiving slots  378 . The contact walls  375  shear the cable jacket away from the outer conductor as the coaxial cable displacement contacts  368  engage and pierce the coaxial cable. The undercut edges  377  form an acute angle with the central longitudinal axis of the displacement beams  372 . The undercut edges  377  are tapered downward and away from the lead tips  379  at an acute angle  383  to horizontal (denoted by a dashed line) to form a collection area for the excess cable jacket material displaced as the outer conductor is wedged into the braid receiving slots  378 , as well as to facilitate shearing. By shearing the cable jacket away from the outer conductor before entering the mouth  381 , the coaxial cable displacement contacts  368  prevent the cable jacket from becoming wedged in the braid receiving slots  378 . If the cable jacket becomes wedged in the braid receiving slots  378 , it may interfere with the electrical connection between the outer conductor and the braid receiving slots  378 .  
         [0105]    [0105]FIGS. 20 and 21 illustrate opposite views of an alternative embodiment for an insulated housing that may be used in one or both halves of a connector. The insulated housing  400  includes a mating face  402  on a front end of a rectangular body section  404 . A rear end of the body section  404  is formed with a shroud  406  through a joining section  408 . The shroud  406  includes opposed side walls  410  and  412  cooperating to define a U-shaped chamber  414  therebetween that receives the coaxial cable. Interior surfaces of the side walls  410  and  412  include notches  416  and  418  facing one another and extending vertically in a direction transverse to a length of the insulated housing  400 . At least one of the notches  416  and  418  includes a pair of parallel ribs  420  that extend along the length of the corresponding notch  416  or  418 .  
         [0106]    The body section  404  includes a chamber  405  adapted to receive a leading end of the coaxial cable and a crimp on a blade or receptacle contact  316  or  318  attached thereto. A front end of the body section  402  includes a slot  407  that accepts an associated one of the blade and receptacle contacts  316  and  318 .  
         [0107]    A rear end  424  of the shroud  406  is joined with a strain relief member  426  having a base  419  with a U-shaped notch  428  therein. The notch  428  in the strain relief member  426  includes an inner surface  421  having transverse arcuate grooves  423 . Opposite ends of the notch  428  form ledges  425 . Side walls  427  extend upward from the ledges  425  along opposite sides of the notch  428 . Channels  430  are formed in each ledge  425  and extend through the strain relief member  426  to a rear side  431 . The channels  430  are spaced apart to align with and receive the arms  365  when the contact shell  340  is laterally joined with insulated housing  400  in the direction of arrow  434  (FIG. 21). The length of each channel  430  is slightly less than an outer dimension of the ribs  367  such that, as the arms  365  are pressed into channels  430 , the ribs  367  engage ledge  425  to hold the strain relief crimp  364  and strain relief member  426 .  
         [0108]    As the strain relief crimp  364  and strain relief member  426  are pressed together, the teeth  371  of the cable grip  369  pierce the jacket and engages the outer conductor of the coaxial cable. The cable grip  369  secures the strain relief crimp  364  to the coaxial cable and prevents relative axial motion therebetween.  
         [0109]    The cable grip  369  resists axial movement between the coaxial cable and the insulated housing  400  without deforming the circular cross-section of the coaxial cable. The strain relief crimp  364  and member  426  minimize compression of the coaxial cable into a compressed geometry which may otherwise interfere with the impedance and signal performance. The channels  430  and arms  365  need not have a rectangular cross-section, but instead may be circular, square, arcuate, triangular and the like. Optionally, the number of channels  430  and arms  365  may be fewer or greater than two.  
         [0110]    [0110]FIG. 22 illustrates the shell  340  mated to a corresponding insulated housing  400 .  
         [0111]    [0111]FIGS. 23 and 24 illustrate an outer housing  450  provided over one of the shells  340  once mounted to an insulated housing  400 . The outer housing  450  is formed of an insulated material. The outer housing  450  includes a latch beam  452  on one exterior surface thereof. The latch beam  452  includes a latch projection  451 . A secondary lock member  454  is provided on one end of the outer housing  450 .  
         [0112]    [0112]FIGS. 25 and 26 illustrate an outer housing  460  provided over another of the shells  340  once mounted to an insulated housing  400 . The outer housing  460  is configured to mate with the outer housing  450 . The outer housing  460  includes a mating end  462  adapted to receive the end  453  of the outer housing  450 . A slot  464  is provided in one side of the outer housing  460  to accept the latch projection  451  on the latch beam  452  of the outer housing  450 . FIG. 26 illustrates an interior chamber  466  within the outer housing  460 , in which is viewable a shell  340  securely retained therein. An opposite end  468  of the outer housing  460  is formed with a secondary lock member  470 .  
         [0113]    [0113]FIG. 27 illustrates an alternative embodiment of a coaxial cable displacement contact. The coaxial cable displacement contact  538  may be formed on either one of the side walls or a connecting wall, such as one of side walls  130  or connecting wall  132  (FIG. 1). The coaxial cable displacement contact  538  is aligned in a plane perpendicular to the longitudinal axis of a corresponding contact shell, such as contact shell  20  (FIG. 1). In the example of FIG. 27, the coaxial cable displacement contact  538  is joined with the connecting wall, such as connecting wall  132 , along edge  539 .  
         [0114]    The coaxial cable displacement contact  538  includes a gap  540  defining a channel between forked displacement sections  541  and  543 . Each displacement section  541  and  543  includes a displacement beam  544  and a contact wall  546  separated by a slot  548 . Upper ends of the contact walls  546  include lead-in edges  550  formed to slope inward and downward from outer edges  552  of the coaxial cable displacement contact  538 . The lead-in edges  550  slope inward and downward to join mouths  554  of the slots  548  proximate tips  556  on upper ends of the displacement beams  544 . The lead-in edges  550  direct the cable jacket onto the displacement beams  544 . Lower ends of the slots  548  include wells  558  configured to receive an outer conductor of the coaxial cable when the displacement beams  544  pierce the outer jacket and the outer cable. The spacing between the displacement beams  544  and the slots  548  is determined based upon the dimensions of a coaxial cable to be secured therein.  
         [0115]    [0115]FIGS. 28 and 29 illustrate an alternative embodiment for a contact shell. The contact shell  560  includes side walls  562  and a connecting wall  564 . A contact retention end  566  of the side walls  562  includes coaxial cable displacement contacts  568 . The connecting wall  564  is joined with a separation plate  570  through a transition region  572 . The separation plate  570  is in turn connected to a strain relief crimp  574  through a transition region  590 . The separation plate  570  includes a slot  576  to facilitate cutting of the separation plate  570 .  
         [0116]    The strain relief crimp  574  is U-shaped and includes a body portion  577  having arms  578  on opposite sides thereof and extending upward therefrom. The arms  578  include ribs  580  on opposite sides thereof. The strain relief crimp  574  operates in the same manner as the strain relief crimps  364  (discussed above in connection with FIGS. 17 and 18) to frictionally engage channels in a mating strain relief member (such as channels  430  in strain relief member  426  in FIGS. 20 and 21).  
         [0117]    The strain relief crimp  574  includes multiple cable gripping features, such as cable grips  582  and  584  and barbs  586 - 588 . Cable grips  582  and  584  are provided along the length of the body portion  577  and are formed by punching a star pattern in the body portion  577  and bending the star pattern to provide a circular ring of teeth extending upward from the body portion  577 . The barbs  586 - 588  are provided on opposite ends of the body portion  577 . In the example of FIGS. 28 and 29, a single barb  586  is stamped in, and bent upward proximate, the lead edge of the body portion  577  within the transition region  590  connecting the strain relief crimp  574  to the separation plate  570 . A pair of barbs  587  and  588  are provided proximate the rear edge of the body portion  577  next to one another. The cable grips  582  and  584 , and barbs  586 - 588  pierce the coaxial cable when the strain relief crimp  574  is securely joined with a corresponding strain relief member. The cable grips  582  and  584 , and barbs  586 - 588  may extend so far into the coaxial cable as to completely pierce the outer jacket and engage and/or also pierce the outer conductor to afford a secure connection between the strain relief crimp  574  and the coaxial cable.  
         [0118]    Optionally, the coaxial cable connector  10  may only be connected to a coaxial cable at one end, while being connected at the opposite end to a structure other than a coaxial cable. For example, the coaxial cable connector may have one end adapted to be connected to discrete components, a printed circuit board, a circuit board, a flex circuit, a differential pair, a twisted pair of wires, two wires, a back plane, and the like. Accordingly, the end of the coaxial cable connector  10  connected to the non-coaxial structure need not include a shell or coaxial cable displacement crimp as discussed above.  
         [0119]    Optionally, the contact shells  20 ,  22 ,  220  and  222  may be formed in configurations other than a U-shape. Instead, both contact shells in a pair (e.g., contact shells  20  and  22 ) may be L-shaped and configured such that, when joined the two L-shaped contact shells form a shielding box that surrounds and provides 360 degrees of shielding in a plane transverse to the axis of the cable axis. The 360 degrees of shielding substantially surrounds the inner contacts (including the crimps attaching the inner coaxial cable conductor to the inner contacts). When L-shaped, each contact shell includes two walls that may be different or equal length. Alternatively, the contact shells may have a modified J-shape, namely an L-shape with a flange bent on the outer end of the lower wall of the L-shape. The flange on the lower wall of each contact shell overlaps an adjoining upper a wall on the mating contact shell.  
         [0120]    Optionally, both contact shells in a pair need not have the same cross-sectional shape, so long as the two contact shells, when mated, surround and provide 360 degrees of shielding in a plane transverse to the axis of the cable axis. The 360 degrees of shielding substantially surrounds the perimeter of the inner contacts and over the exposed inner conductors. Instead, one contact shell may provide shielding for three sides of the inner contacts/conductors, while the other contact shell may provide shielding for less than three sides. For example, one contact shell may be U-shaped while the other contact shell may be L-shaped, a modified J-shape or simply a flat wall covering the open face in the U-shaped contact shell mated thereto. The contact shells each may be formed with up to three walls.  
         [0121]    While particular elements, embodiments and applications of the present invention have been shown and described, it will be understood, of course, that the invention is not limited thereto since modifications may be made by those skilled in the art, particularly in light of the foregoing teachings. It is therefore contemplated by the appended claims to cover such modifications that incorporate those features which come within the spirit and scope of the invention.