Discontinuous cable shield system and method

Abstract

Implementations of a discontinuous cable shield system and method include a shield having a multitude of separated shield segments dispersed along a length of a cable. The separated shield segments can serve as an incomplete, patch-worked, discontinuous, ‘granulated’ or otherwise perforated shield for differential transmission lines such as with twisted wire pairs.

1. A cable having a length along a longitudinal dimension, the cable comprising:
 a plurality of differential transmission lines extending along the longitudinal dimension;  
 a first plurality of shield segments, each shield segment extending along the longitudinal dimension along a portion of the cable length, each of the shield segments of the first plurality of shield segments extending circumferentially about the plurality of the differential transmission lines;  
 a second plurality of shield segments, each shield segment extending along the longitudinal dimension along a portion of the cable length, each of the shield segments of the second plurality of shield segments extending circumferentially about the plurality of the differential transmission lines, each of the shield segments of the first and second pluralities of shield segments being in electrical isolation from all other shield segments of the first and second pluralities of shield segments, each of the shield segments of the first and second pluralities of shield segments being separated from a shield segment adjacent thereto by a segmentation gap, each segmentation gap extending circumferentially about the plurality of the differential transmission lines, the shield segments of the first plurality of shield segments varying in form from the shield segments of the second plurality of shield segments.  
 
     
     
       2. The cable of  claim 1  wherein the shield segments of the first plurality of shield segments vary in form from the shield segments of the second plurality of shield segments by extending different amounts along the longitudinal dimension. 
     
     
       3. The cable of  claim 1  wherein the shield segments of the first plurality of shield segments vary in form from the shield segments of the second plurality of shield segments by having different shapes. 
     
     
       4. The cable of  claim 1  wherein at least some of the shield segments of the first plurality of shield segments vary in form from one another and at least some of the shield segments of the second plurality of shield segments vary in form from one another. 
     
     
       5. The cable of  claim 1  wherein the shield segments of the first and second pluralities of shield segments are made from an electrically conductive material. 
     
     
       6. The cable of  claim 1  wherein each of the differential transmission lines is a twisted wire pair. 
     
     
       7. The cable of claim  2    6  wherein each of the twisted wire pairs are covered by a different group of the shield segments of the first and second pluralities of the shield segments. 
     
     
       8. The cable of  claim 1  wherein the shield segments of the first and second pluralities of shield segments are shaped so that each of the shield segments of the first plurality of shield segments extend circumferentially about the plurality of the differential transmission lines at a different angle than each of the shield segments of the second plurality of shield segments extend circumferentially about the plurality of the differential transmission lines. 
     
     
       9. The cable of  claim 1  wherein each of the shield segments of the first plurality of shield segments have a first shape and each of the shield segments of the second plurality of shield segments have a second shape other than the first shape. 
     
     
       10. The cable of  claim 9  wherein the first shape and the second shape are different jagged patterns. 
     
     
       11. The cable of  claim 9  wherein the first shape and the second shape are different wave patterns. 
     
     
       12. The cable of  claim 9  wherein the first shape and the second shape are different irregular patterns. 
     
     
       13. The cable of  claim 9  wherein the first shape and the second shape have different angular patterns. 
     
     
       14. The cable of  claim 1  wherein the shield segments of the first plurality of shield segments are differently oriented from the shield segments of the second plurality of shield segments. 
     
     
       15. The cable of  claim 1  further comprising an electrically lossy material extending about each of the segmentation gaps. 
     
     
       16. The cable of  claim 1  wherein the segmentation gaps include a first plurality and a second plurality, each of the first plurality being of a different form than each of the second plurality. 
     
     
       17. The cable of  claim 1  further comprising an inner cable sheath and insulation extending about the plurality of the differential transmission lines wherein the shield segments of the first and second pluralities of shield segments extend about the inner cable sheath and the insulation. 
     
     
       18. The cable of  claim 1  further comprising an outer cable sheath extending about the plurality of differential transmission lines and the shield segments of the first and second pluralities of shield segments. 
     
     
       19. The cable of  claim 1  further comprising an outer cable sheath extending about the plurality of differential transmission lines wherein the outer cable sheath extends about the segmentation gaps. 
     
     
       20. The cable of  claim 1  further comprising a third plurality of shield segments and a fourth plurality of shield segments wherein the shield segments of the third plurality of shield segments vary in form from the shield segments of the fourth plurality of shield segments, each of the shield segments of the third plurality of shield segments extending along the longitudinal dimension along a portion of the cable length and extending circumferentially about at least a portion of the shield segments of the first plurality of shield segments and extending about the plurality of the differential transmission lines, each of the shield segments of the third plurality of shield segments being in electrical isolation from the shield segments of the first, second and fourth pluralities of shield segments and from others of the shield segments of the third plurality of shield segments, and each of the shield segments of the fourth plurality of shield segments extending along the longitudinal dimension along a portion of the cable length and extending circumferentially about at least a portion of the shield segments of the second plurality and extending about the plurality of the differential transmission lines, each of the shield segments of the fourth plurality of shield segments being in electrical isolation from the shield segments of the first, second and third pluralities of shield segments and from the others of the shield segments of the fourth plurality of shield segments. 
     
     
       21. The cable of  claim 1  wherein the shield segments of the first and second pluralities of shield segments are formed from at least one of the following: adhesive backed foil, foil thermally coupled with plastic sheath, metalized spray, and ink. 
     
     
       22. A method comprising:
 providing a plurality of differential transmission lines;  
 providing a plurality of shield segments;  
 positioning each of the plurality of shield segments within proximity of the differential transmission lines to substantially reduce potential of field interference;  
 positioning each of the plurality of shield segments to be in electrical isolation from one another; and  
 selecting at least some of the plurality of shield segments to vary from each other in form to vary how the selected shield segments interact with electromagnetic energy across a spectrum of frequencies to diminish the number of the selected shield segments that would otherwise have a resonant interaction with electromagnetic energy of a particular frequency of the spectrum of frequencies.  
 
     
     
       23. The method of  claim 22  wherein the selecting at least some of the plurality of shield segments to vary from each other includes selecting according to at least one of the following: size of the at least some of the plurality of shield segments and shape of the at least some of the plurality of shield segments. 
     
     
       24. The method of  claim 23  wherein the selecting at least some of the plurality of shield segments to vary from each other includes selecting according to a dimension limit for the shield segments related to at least one of the following: twist rate pitch and differential pair spacing of the differential transmission lines. 
     
     
       25. The method of  claim 23  wherein positioning each of the plurality of shield segments within proximity of the differential transmission lines to substantially reduce potential of field interference of at least one of the following types: field interference imparted upon the differentially transmission lines from an external source and field interference emitting from the differential transmission lines. 
     
     
       26. An electrical signal transmission cable comprising:
   at least one differential transmission line pair of twisted insulated conductive wires extending longitudinally along a length of cable for carrying electrical signals there - along; and        a plurality of electrically isolated conductive shield segments extending longitudinally along and at least partially circumferentially around respectively corresponding portions of at least one differential transmission line pair sufficient to effect, while in use carrying electrical communication signals there - along:    ( a )  substantial electrostatic coupling to each wire of at least one differential transmission line pair thereby tending to average together positive and negative electrostatic near - field emissions from the at least one differential transmission line pair, and      ( b )  substantial magnetic coupling via eddy currents to each wire of at least one differential transmission line pair thereby tending to average together oppositely directed magnetic field emissions from the at least one differential transmission line pair.       
     
     
       27. An electrical signal transmission cable as in  claim 26  wherein at least some of said plurality of electrically isolated conductive shield segments extend entirely about the circumference of a respectively associated at least one differential transmission line pair. 
     
     
       28. An electrical signal transmission cable as in  claim 27  wherein said at least some of said plurality of electrically isolated conductive shield segments provide a continuous electrically conductive path about the circumference of the respectively associated at least one differential transmission line pair. 
     
     
       29. An electrical signal transmission cable as in  claim 26  wherein:
   while in use carrying electrical communication signals there - along, each wire of said at least one differential transmission line pair exhibits a substantially equal and opposite electrical potential vis - à - vis the other wire of that pair along said length; and    
   a plurality of said differential transmission line pairs are encompassed by said plurality of electrically isolated conductive shield segments sufficiently to effect substantially equal electrostatic coupling to each wire of each of said plurality of differential transmission line pairs along respectively corresponding portions of said cable length.   
 
     
     
       30. An electrical signal transmission cable as in  claim 26  wherein each said shield segment extends longitudinally for a distance that is at least a substantial portion of one differential transmission line twist rate pitch period. 
     
     
       31. An electrical signal transmission cable as in  claim 26  wherein said plurality of electrically isolated conductive shield segments are of at least two different sizes. 
     
     
       32. An electrical signal transmission cable as in  claim 31  wherein said different sizes comprise at least one of: ( a )  different longitudinal lengths,  ( b )  different shapes, and  ( c )  different thicknesses.   
     
     
       33. An electrical signal transmission cable as in  claim 26  wherein minimum and maximum dimensions of each shield segment establish corresponding resonant frequencies higher than a highest intended frequency of electrical signals to be transmitted along said cable while in use carrying electrical communication signals there- along.   
     
     
       34. An electrical signal transmission cable as in  claim 26  wherein at least some of said shield segments are spirally wrapped about the at least one differential transmission line. 
     
     
       35. An electrical signal transmission cable as in  claim 26  wherein said shield segments are electrically isolated from each other by gaps between longitudinally adjacent shield segments. 
     
     
       36. An electrical signal transmission cable as in  claim 26  further comprising an electrically lossy dissipative material disposed between at least some longitudinally adjacent shield segments. 
     
     
       37. An electrical signal transmission cable as in  claim 26  wherein variations are provided along said cable length in at least one of: ( a )  shield segment lengths,  ( b )  shield segment shapes,  ( c )  shield segment thicknesses,  ( d )  gap dimensions between shield segments,  ( e )  gap shapes between shield segments, and  ( f )  gap orientations between shield segments.   
     
     
       38. An electrical signal transmission cable as in  claim 26  wherein:
   said plurality of shield segments are divided into at least electrically isolated first and second groups of electrically isolated shield segments; and    
   said second group being spaced radially outwardly from said first group and longitudinally interleaved with said first group to provide shield segments of the second group overlapping gaps between shield segments of the first group.   
 
     
     
       39. An electrical signal transmission cable as in  claim 26  wherein at least some of said shield segments are wrapped circumferentially around said at least one differential transmission line with longitudinally extending overlapped edges. 
     
     
       40. An electrical signal transmission cable as in  claim 39  wherein said overlapped edges are in electrical contact to provide circumferentially continuous electrical conductivity within a respectively corresponding shield segment. 
     
     
       41. An electrical signal transmission cable as in  claim 26  wherein at least some of said shield segments are wrapped circumferentially around said at least one differential transmission line with longitudinally abutting edges. 
     
     
       42. An electrical signal transmission cable as in  claim 41  wherein said longitudinally abutting edges are in electrical contact to provide circumferentially continuous electrical conductivity within a respectively corresponding shield segment. 
     
     
       43. An electrical signal transmission cable as in  claim 26  wherein said plurality of shield segments establish an irregular pattern of segments to assist in reduction of interference including alien crosstalk. 
     
     
       44. An electrical signal transmission cable as in  claim 26  wherein said plurality of shield segments provide a combination of small sizes and irregular shapes of shield segments to offset tendencies for resonant frequencies and/or to reduce cross- talk.   
     
     
       45. An electrical signal transmission cable as in  claim 26  further comprising an insulating material interposed between adjacent edges of separate ones of said plurality of conductive shield segments. 
     
     
       46. An electrical signal transmission cable as in  claim 26  wherein at least some of said plurality of shield segments contain radially oriented corrugations to aid in bending the transmission cable. 
     
     
       47. An electrical signal transmission cable as in  claim 46  wherein said radially oriented corrugations are diagonally oriented with respect to the longitudinal length of said cable. 
     
     
       48. An electrical signal transmission cable comprising:
   at least one twisted wire pair differential transmission line extending longitudinally along a length of cable; and        a plurality of electrically isolated conductive shield segments extending longitudinally along respectively corresponding portions of said cable length in proximity to both wires of said at least one twisted wire pair for at least a substantial portion of one twist period sufficient to effect, while in use carrying electrical communication signals there - along:    ( a )  substantial electrostatic coupling to each wire of said at least one twisted wire pair thereby tending to average together positive and negative electrostatic near - field emissions from the at least one twisted wire pair, and      ( b )  substantial magnetic coupling via eddy currents to each wire of said at least one twisted wire pair thereby tending to average together oppositely directed magnetic field emissions from the at least one twisted wire pair.       
     
     
       49. An electrical signal transmission cable as in  claim 48  wherein said shield segments also extend circumferentially completely around said at least one twisted wire pair. 
     
     
       50. An electrical signal transmission cable as in  claim 48  wherein variations are provided along said cable length in at least one of: ( a )  shield segment lengths,  ( b )  shield segment shapes,  ( c )  shield segment thicknesses,  ( d )  gap dimensions between shield segments,  ( e )  gap shapes between shield segments, and  ( f )  gap orientations between shield segments.   
     
     
       51. An electrical signal transmission cable comprising:
   at least one differential transmission line having a pair of insulated wire conductors extending along a longitudinal direction of cable length; and        a plurality of electrically isolated conductive shield segments extending longitudinally along respectively corresponding portions of said cable length in proximity to both wires of at least one said differential transmission line sufficient to effect, while in use carrying electrical communication signals there - along:    ( a )  substantial electrostatic coupling to each wire thereby tending to average together positive and negative electrostatic near - field emissions from the at least one differential transmission line, and      ( b )  substantial magnetic coupling via eddy currents to each wire thereby tending to average together oppositely directed magnetic field emissions from the at least one differential transmission line.       
     
     
       52. An electrical signal transmission cable as in  claim 51  wherein said shield segments also extend circumferentially around said at least one differential transmission line. 
     
     
       53. An electrical signal transmission cable as in  claim 51  wherein variations are provided along said cable length in at least one of: ( a )  shield segment lengths,  ( b )  shield segment shapes,  ( c )  shield segment thicknesses,  ( d )  gap dimensions between shield segments,  ( e )  gap shapes between shield segments, and  ( f )  gap orientations between shield segments.