Abstract:
An interconnection junction for communications cables includes: a first connector; a second connector; and a sealing enclosure having a cavity and formed of a polymeric material, the sealing enclosure comprising an RF-isolating material. The first connector and second connector are joined and reside within the cavity of the sealing enclosure.

Description:
RELATED APPLICATION 
     The present application claims the benefit of and priority from U.S. Provisional Patent Application No. 61/993,116, filed May 14, 2014, the disclosure of which is hereby incorporated herein in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to a device for environmentally sealing and securing the interconnection between electrical cables and/or electrical cables and electronic equipment. 
     BACKGROUND 
     Interconnection junctions, such as the interconnection between two cables or a cable and a piece of electronic equipment, may be subject to mechanical degradation from environmental factors such as moisture, vibration and repeated expansion and contraction from daily temperature changes. Outer sealing enclosures that surround or enclose an electrical interconnection have been used to protect such interconnections. Enclosures often apply rigid clamshell configurations that, once closed, may be difficult to open, especially when installed in exposed or remote locations, such as atop radio towers; gaskets or gel seals may be applied at the enclosure ends and/or along a sealing perimeter of the shell. 
     Elastic interconnection seals are also known. Elastic seals can be advantageous by virtue of being more easily installed over the typically uneven contours of an electrical interconnection. Exemplary configurations are described in U.S. Pat. No. 6,429,373 and in U.S. patent application Ser. No. 13/646,952, filed Oct. 8, 2012; Ser. No. 13/938,475, filed Jul. 10, 2013; and Ser. No. 14/245,443, filed Apr. 4, 2014, the disclosures of each of which are hereby incorporated by reference herein. 
     The development of additional configurations and varieties of connectors can necessitate additional sealing configurations and techniques. 
     SUMMARY 
     As a first aspect, embodiments of the invention are directed to an interconnection junction, comprising: a first connector; a second connector; and a sealing enclosure having a cavity and formed of a polymeric material, the sealing enclosure comprising an RF-isolating material. The first connector and second connector are joined and reside within the cavity of the sealing enclosure. 
     As a second aspect, embodiments of the invention are directed to a sealing enclosure for an interconnection junction of connectors, comprising a body portion having a cavity therein, the cavity configured to house an interconnection junction of a first connector and a second connector. The body portion is formed of a polymeric material that comprises an RF-isolating material. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a partial cross-section of the coaxial cable-connector assembly according to embodiments of the invention, the assembly being shown in a mated condition. 
         FIG. 2  is an enlarged partial section view of the coaxial cable-connector assembly of  FIG. 1 . 
         FIG. 3  is an enlarged partial section view of the coaxial cable-connector assembly of  FIG. 1 . 
         FIG. 4  is a perspective section view of a cover boot to be used in conjunction with the coaxial cable-connector assembly of  FIG. 1  according to embodiments of the invention. 
         FIG. 5  is a section view of the cover boot and coaxial cable-connector assembly of  FIG. 4 . 
         FIG. 6  is an end view of a cover boot according to additional embodiments of the invention. 
         FIG. 7  is a section view of the cover boot of  FIG. 6  and an alternative coaxial cable-connector assembly. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention is described with reference to the accompanying drawings, in which certain embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments that are pictured and described herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. It will also be appreciated that the embodiments disclosed herein can be combined in any way and/or combination to provide many additional embodiments. 
     Unless otherwise defined, all technical and scientific terms that are used in this disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this disclosure, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that when an element (e.g., a device, circuit, etc.) is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. 
     Traditionally, coaxial electrical connectors relied on direct galvanic contact between the respective inner conductors and the respective outer conductors of the connectors to conduct power, signals, etc. However, recently some electrical connectors have been designed that rely on capacitive coupling of conductors rather than direct galvanic connection. Capacitive coupling can assist in reducing and/or eliminating Passive Intermodulation (PIM), the presence of which can negatively impact the performance of joined connectors. Exemplary capacitively coupled connectors are discussed in U.S. patent application Ser. No. 14/102,042, filed Dec. 10, 2013, the disclosure of which is hereby incorporated herein in its entirety. 
     Although their use can be beneficial, capacitively coupled connectors may be subject to additional influences that are less prevalent with traditional galvanic connections. The inventors have recognized that some capacitively coupled connectors may be susceptible to interference from external radio frequency signals. This may be particularly true for connectors that rely on a gap (either filled with a dielectric material, filled with air, or a combination of dielectric and air) between the outer conductors of the two connectors. 
     An exemplary interface of connectors is illustrated in  FIG. 1 . A jack  130 , mounted to a jumper cable  160 , is inserted into a plug  30  that is mounted via a stem  140  on a structure such as a remote radio head, antenna or the like. The plug  30  includes an outer conductor extension  34  that mates with an outer conductor extension  134  of the jack  130 , and an inner conductor extension  32  that mates with an inner conductor extension  132  of the jack  130 . Together, the plug  30  and jack  130  form an interconnection  170 . 
     As can be seen in  FIG. 3 , a gap g 2  is present between the outer conductor extension  34  and the outer conductor extension  134 ; similarly, and as shown in  FIG. 2 , a gap g 1  is present between the inner conductor extension  32  and the inner conductor extension  132 . The gap g 2 , which may include a dielectric layer  144  or may be filled with air, creates a capacitive element between the outer conductor extension  34  and the outer conductor extension  134 , and the gap g 1 , which may include a dielectric layer  44 , creates a capacitive element between the inner conductor extension  32  and the inner conductor extension  132 . However, the presence of the gaps g 1 , g 2  also reduces the ability of the interface to provide RF shielding. 
     The inventors have recognized that a sealing enclosure, such as the cover boot described in U.S. Pat. No. 6,429,373 and the two-piece boot and cover described in U.S. patent application Ser. No. 14/245,443, supra, can provide RF shielding of either a capacitively coupled interface or a traditional galvanic interface. Thus, pursuant to embodiments of the invention, sealing enclosures that include an RF-isolating material (such as an RF-absorbent material or an RF-reflective material) are discussed below. 
     In one embodiment, the sealing enclosure may be formed of a conductive polymer. As used herein, a “polymeric” material includes elastomeric materials, such as rubbers, as well as harder polymeric materials. The conductivity of the polymeric material may provide shielding of RF signals. Exemplary conductive elastomeric materials may include silicone, fluorosilicone, ethylene propylene diene monomer (EPDM), and nitrile rubbers filled with silver-plated aluminum, nickel-plated graphite, and silver-plated copper. Other exemplary polymeric materials include acrylonitrile-butadiene-styrene (ABS) and polypropylene. 
     As an alternative, the sealing enclosure may be formed of a material that has been impregnated or doped with an RF-isolating material. Exemplary RF-absorbing materials include silver-plated aluminum, nickel-plated graphite, silver-plated copper, and ferrite- or iron-based alloys. 
     As another alternative, the sealing enclosure may be formed of a material that has been coated with an RF-isolating material. Exemplary coating materials include conductive paints (typically infused with copper, aluminum and/or silver) or a thin film/sheets of an RF-absorbing material. This embodiment may be particularly suitable for clamshell-style sealing enclosures. 
     In embodiments of sealing enclosures in which interconnection junctions of capacitively coupled connectors are housed, care should be taken so that no more than one DC conductive path exists between either of the outer conductors of the connectors and the RF-absorbent material of the sealing enclosure. Put differently, either one or the other of the outer conductors may contact the RF-isolating material of the sealing enclosure, but not both: otherwise, a DC connection will be present between the outer conductors of the two connectors, thus destroying the capacitive coupling between the conductors and the benefits conveyed thereby. 
     Referring now to  FIG. 4 , a cover boot for an interconnection junction of coaxial connectors, designated broadly at  200 , is illustrated therein. The cover boot  200  includes a generally cylindrical interconnection section  232 . An end wall  234  with an opening  236  partially covers one end of the interconnection section  232 . A tapered transition section  240  merges with the interconnection section  232 ; in turn, a generally cylindrical cable section  242  merges with the transition section  240 . Thus, the hollow, generally coaxial sections of the cover boot  200  define a continuous bore  246 . 
     As can be seen in  FIG. 5 , the cover boot  200  can then be applied such that the interconnection section  232  of the cover boot  200  fits over the interconnection  170 , with the end wall  234  positioned adjacent the end of the plug  30  adjacent the mounting structure and the stem  140  snugly held within the opening  236 . The cable section  242  fits over the jumper cable  160 . Because the interconnection  170  resides within the cover boot  200 , with the opening  236  fitting tightly over the stem  140  and the cable section  242  fitting tightly over the cable  160 , a seal is formed over the interconnection  170  that can help to protect it from moisture and other environmental agents. 
     Because the interconnection  170  is a capacitively coupled interconnection, care should be taken to avoid making direct contact between any conductive portions of the cover boot  200  and both of the outer conductor extensions  34 ,  134 . One manner of achieving this configuration would be to coat the outer surface of the cover boot  200  with an RF-isolating coating, such that the coating is shielded from the outer conductor extensions  34 ,  134  by the remainder of the cover boot  200  and, therefore, contacts neither of the outer conductor extensions  34 ,  134 . In another embodiment, the cover boot  200  may include a coating band, strip or ring on its inner surface that contacts only the outer conductor  34  of the plug  30  near or at its free end and is spaced apart from the outer conductor  134  of the jack  130 . As another alternative, the cover boot  200  may be formed of a conductive elastomer and shaped such that the interconnection section  232  and transition section  240  are spaced from the outer conductor  134  of the jack  130 , so as to avoid contact therewith. As still another alternative, an adapter for the sealing enclosure, such as that discussed in U.S. Provisional Patent Application No. 61/908,977, filed Nov. 26, 2013, the disclosure of which is hereby incorporated herein in its entirety, may be employed to space the cover boot  200  away from one of the outer conductor extensions. Other alternatives will be apparent to those of skill in this art. 
     Referring now to  FIGS. 6 and 7 , a galvanic connector interface, designated broadly at  370 , is shown therein. The interface  370  includes a connector  410  configured to be attached to the end of a coaxial cable and a connector  420  configured to be mounted on a piece of electronic equipment, such as a remote radio head. The interface  370  is enclosed within a sealing cover  400  that includes a generally cylindrical interconnection section  432 . A diamond-shaped flange  434  is mounted to the interconnection section  432  via a short trunk  436 . A generally cylindrical main section  438  merges with the interconnection section  432  opposite the trunk  436 . The main section  438  is smaller in diameter than the interconnection section  432 . A tapered transition section  440  merges with the main section  438 ; in turn, a generally cylindrical cable section  442  merges with the transition section  440 . The cover  400  also includes two opposed axially-extending fins  445  that project radially outwardly and three axial ribs between the fins  445  on each side. Thus, the hollow, generally coaxial sections of the cover  400  define a continuous bore  446 . The cover  400  is described in greater detail in U.S. patent application Ser. No. 14/245,443, filed Apr. 4, 2014, supra. The cover  400  may be formed of any of the materials discussed above and/or be rendered RF-isolating in any of the ways discussed above. 
     The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.