Patent Publication Number: US-2016226202-A1

Title: Right angle coaxial cable and connector assembly

Description:
The present application claims the benefit of and priority from U.S. Provisional Application No. 62/111,300, filed Feb. 3, 2015, the disclosure of which is hereby incorporated herein in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention is directed generally to electrical cable connectors, and more particularly to coaxial connectors for electrical cable. 
     BACKGROUND OF THE INVENTION 
     Coaxial cables are commonly utilized in RF communications systems. A typical coaxial cable includes an inner conductor, an outer conductor, a dielectric layer that separates the inner and outer conductors, and a jacket that covers the outer conductor. Coaxial cable connectors may be applied to terminate coaxial cables, for example, in communication systems requiring a high level of precision and reliability. 
     Coaxial connector interfaces provide a connect/disconnect functionality between (a) a cable terminated with a connector bearing the desired connector interface and (b) a corresponding connector with a mating connector interface mounted on an apparatus or on another cable. Typically, one connector will include an inner contact, such as a pin or post connected to an inner conductor and an outer conductor connector body connected to the outer conductor; these are mated with a mating sleeve (for the pin or post of the inner conductor) and another outer conductor connector body of a second connector. Coaxial connector interfaces often utilize a threaded coupling nut or other retainer that draws the connector interface pair into secure electro-mechanical engagement when the coupling nut (which is captured by one of the connectors) is threaded onto the other connector. 
     Although many coaxial connectors are configured to be oriented “in line” with their attached cables (i.e., such that the inner contact is generally coaxial with the inner conductor of the cable), some coaxial connectors are configured such that the inner contact is oriented generally perpendicular to the attached cable. These so-called “right angle” connectors can raise different issues than inline connectors when being attached to a cable due to their geometry. 
     Passive Intermodulation Distortion (PIM) is a form of electrical interference/signal transmission degradation that may occur with less than symmetrical interconnections and/or as electro-mechanical interconnections shift or degrade over time. Interconnections may shift due to mechanical stress, vibration, thermal cycling, and/or material degradation. PIM can be an important interconnection quality characteristic, as PIM generated by a single low quality interconnection may degrade the electrical performance of an entire RF system. Thus, the reduction of PIM via connector design is typically desirable. 
     SUMMARY 
     As a first aspect, embodiments of the invention are directed to a coaxial cable-connector assembly. The assembly comprises a coaxial cable and a right angle coaxial connector. The coaxial cable comprises: an inner conductor having a termination end; a first dielectric layer that overlies the inner conductor; and an outer conductor that overlies the first dielectric layer having a termination end. The right angle coaxial connector comprises: an inner contact comprising a post configured to mate with the inner conductor body of a mating coaxial cable jack, the inner contact further including a receptacle that receives the termination end of the inner conductor such that the post is generally perpendicular to the inner conductor; and an outer conductor body configured to mate with the outer conductor body of the mating coaxial cable jack, the outer conductor body being connected with the termination end of the outer conductor. A second dielectric layer is interposed between the inner contact of the connector and the inner conductor of the coaxial cable, the second dielectric layer creating a capacitive element between the inner contact and the inner conductor. 
     As a second aspect, embodiments of the invention are directed to a right angle coaxial connector comprising: an inner contact comprising a post configured to mate with the inner conductor body of a mating coaxial cable jack, the inner contact further including a receptacle that is configured to receive the termination end of an inner conductor of a coaxial cable such that the post is generally perpendicular to the inner conductor; and an outer conductor body configured to mate with the outer conductor body of the mating coaxial cable jack, the outer conductor body being connected with the termination end of the outer conductor. A dielectric layer is applied to the receptacle of the inner contact. 
     As a third aspect, embodiments of the invention are directed to a coaxial cable-connector assembly comprising a coaxial cable and a right angle coaxial connector. The coaxial cable comprises: an inner conductor having a termination end; a first dielectric layer that overlies the inner conductor; and an outer conductor that overlies the first dielectric layer having a termination end. The right angle coaxial connector comprises: an inner contact comprising a post configured to mate with the inner conductor body of a mating coaxial cable jack, the inner contact further including a receptacle that receives the termination end of the inner conductor such that the post is generally perpendicular to the inner conductor; and an outer conductor body configured to mate with the outer conductor body of the mating coaxial cable jack, the outer conductor body being connected with the termination end of the outer conductor. A second dielectric layer is interposed between the inner contact of the connector and the inner conductor of the coaxial cable, the second dielectric layer creating a capacitive element between the inner contact and the inner conductor. The outer conductor body is a monolithic component with a sleeve configured to receive the coaxial cable. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a front section view of a right-angle cable-connector assembly according to embodiments of the present invention. 
         FIG. 2  is an enlarged view of a portion of the assembly of  FIG. 1 . 
         FIG. 3  is a front section view of a right-angle cable-connector assembly according to additional embodiments of the present invention. 
         FIG. 4  is an enlarged view of a portion of the assembly of  FIG. 3 . 
         FIG. 5  is a front section view of a right-angle cable-connector assembly according to further embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
     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 in the above description 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. 
     Referring now to the drawings, a right angle connector-cable assembly, designated broadly at  5 , is shown in  FIGS. 1 and 2 . The assembly  5  comprises a coaxial cable  10  and a right angle plug  30 , each of which is described in detail below. 
     Referring to  FIG. 1 , the coaxial cable  10  includes an inner conductor  12 , a dielectric layer  14  that circumferentially overlies the central conductor  12 , an outer conductor  16  that circumferentially overlies the dielectric layer  14 , and a polymeric cable jacket  20  that circumferentially overlies the outer conductor  16 . These components will be well-known to those of skill in this art and need not be described in detail herein.  FIG. 1  illustrates that the outer conductor  16  may be of a corrugated profile; alternatively, the outer conductor  16  may have a smooth, braided or foil profile. All of these outer conductor configurations are known to those of skill in this art and need not be described in detail herein. A solder shield  13  is located at the end of the dielectric layer  14  and outer conductor  16 . 
     Referring again to  FIG. 1 , the plug  30  includes an inner contact  32  and an outer conductor body  34 . As can be seen in  FIG. 1 , the inner contact  32  is generally cylindrical and comprises a post  41  that is configured to mate with the inner conductor body of a mating jack. A ridge  49  extends radially outwardly from the post  41  near the flared tip  47 . A finger  42  with a recessed area  45  extends from one end of the post  41 ; a contact block  43  or other receptacle with a pocket  44  extends from the end of the finger  42 . The contact block  43  includes a mitered surface  46 . 
     As shown in  FIG. 2 , the pocket  44  of the contact block  43  is lined with a dielectric layer  17 . The dielectric layer  17  may comprise a coating, a sleeve, or take another thin laminar configuration. The dielectric layer  17  may be formed of various materials with a high dielectric constant, such as polyester, PTFE and other polymeric materials, glass, metal oxides and ceramics. 
     Referring still to  FIG. 1 , the outer conductor body  34  includes a cable contact sleeve  52 . A housing section  54  rests atop the cable contact sleeve  52 , forming a shoulder  51 . The housing section  54  includes side walls  55 , a rear wall  56 , and a ceiling  57 . A connector contact section  59  extends away from the housing section  54  opposite the rear wall  56 . A dielectric spacer  62  fills an inner portion of the connector contact section  59  and maintains physical and electrical separation of the inner conductor body  32  and the outer conductor body  34 . An annular mating ring  64  extends away from the spacer  62  and is configured to mate with a mating jack. A circular flange  66  extends radially outwardly from the connector contact section  59  and provides a bearing surface  82  for interaction with a coupling nut  80  and/or a retaining clip  78 . 
       FIG. 1  illustrates the assembled plug  30  and cable  10 . The cable contact sleeve  52  of the outer conductor body  34  fits over the outer conductor  16  of the cable  10 , with the termination end of the outer conductor  16  abutting the shoulder  51  of the cable contact sleeve  52  to establish an electrical connection. In illustrated embodiment, a solder joint  70  mechanically and electrically attaches the outer conductor  16  to the cable contact sleeve  52 . The inner conductor  12  extends into the cavity of the housing section  54 . The pocket  44  of the contact block  43  of the inner conductor body  32  receives the end of the inner conductor  12 . The post  41  of the inner conductor body  32  extends through the dielectric spacer  62  and into the space encircled by the mating ring  64 . The “right angle” nature of the plug  30  is thus established by the generally perpendicular orientation of the longitudinal axis of the post  41  of the inner conductor body  32  as compared to the longitudinal axis of the inner conductor  12  and the housing section  54 . A strain relief sheath  85  covers the lower portion of the cable contact sleeve  52  and adjacent portions of the outer conductor  16  and jacket  20 . 
     Due to the presence of the dielectric layer  17  lining the pocket  44  of the inner contact  32 , a capacitive element is created between the inner conductor  12  and the inner contact  32 . The capacitive element so created can avoid the generation of PIM that can occur in interconnections between coaxial cables and/or connectors, particularly with soldered connections. Other materials, configurations and techniques for creating capacitive coupling between cable conductors and connectors are discussed in U.S. Patent Publication No. 2014/0370747 to Vaccaro, the disclosure of which is hereby incorporated herein in its entirety. 
     Also, because the end of the inner conductor  12  can be fitted into the pocket  44  without soldering, there is no need for the connector body  34  to include a port for soldering, thus enabling the connector body  34  to be formed as a single monolithic component (which can also reduce PIM and eliminate the possibility of a cap on the port becoming dislodged or leaking. The inclusion of the mitered surface  46  can provide better electrical performance (some one-piece connector body designs do not permit the inclusion of a mitered surface due to soldering constraints). 
     It should also be noted that, although the pocket  44  in the contact block  43  is shown as continuous, it may be discontinuous; for example, the contact block  43  may include one or more slots to encourage radial expansion. Receptacles of other configurations may also be suitable for use with the plug  30 . In addition, in some embodiments the end of the inner conductor  12  may be covered with the dielectric layer  17  (rather than the pocket  44  being lined with the dielectric layer  17 ); such a dielectric layer may be a coating, sleeve or the like. 
     Those of skill in this art will appreciate that, although the plug  30  is illustrated herein, a jack or other connector may be suitable for use with the concepts discussed above. Also, although a galvanic connection is anticipated between the plug  30  and a mating jack, the concepts may be employed with connectors designed for capacitive coupling (see, e.g., U.S. patent application Ser. No. 14/303,745, filed Jun. 13, 2014, the disclosure of which is hereby incorporated herein in its entirety). 
       FIGS. 3 and 4  illustrate an alternative embodiment of a cable-connector assembly, designated broadly at  105 . The assembly  105  is similar to the assembly  5  described above, with the exception that an inner conductor post  133  is mounted to the end of the inner conductor  112  of the cable  110  and, thus, serves as an extension of the inner conductor  112 . The inner conductor post  133  has a recess  135  that receives the end of the inner conductor  112 , typically with a soldered joint. At its opposite end, the inner conductor post  133  is inserted into a hole  144  in the inner contact  132 . Either of the inner surface of the hole  144  or the outer surface of the inner conductor post  133  includes a dielectric layer  117  that creates a capacitive element between the inner contact  132  and the inner conductor post  133  (see  FIG. 4 ). 
     This arrangement may have economic and/or practical advantages. Soldering of the secondary inner contact  133  to the end of the inner conductor  112  may be performed prior to insertion into the connector body  134 , therefore being more easily controlled. The secondary inner contact  133  may be configured for easier handling than the inner conductor  112 . Also, the secondary inner contact  133  may have a surface finish (e.g., for applying the dielectric layer  117 ) that is preferable to or cannot be achieved by the cable inner conductor  112 . 
       FIG. 5  illustrates an additional embodiment of an assembly  205 . In the assembly  205 , the connector body  234  is not soldered to the outer conductor  216  of the cable  210 ; instead, a dielectric layer  218  is interposed between the outer conductor  216  and the sleeve  252  to form a capacitive element therebetween. As such, both of the interfaces between the conductors  212 ,  216  of the cable  210  and, respectively, the inner contact  232  and the connector body  234  are capacitive, which can reduce PIM. In addition, because no soldering operations are performed, the solder shield shown in assemblies  5 ,  105  can be omitted. 
     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.