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Sealed External Printed Circuit Board Coax Cable

IP.com Disclosure Number: IPCOM000121171D
Original Publication Date: 1991-Jul-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 1 page(s) / 46K

Publishing Venue

IBM

Related People

Antonucci, RF: AUTHOR [+4]

Abstract

Disclosed is a technique to ensure the electrical performance of miniature coaxial cables terminated directly to the external wiring plane of a Printed Circuit Board.

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This is the abbreviated version, containing approximately 95% of the total text.

Sealed External Printed Circuit Board Coax Cable

      Disclosed is a technique to ensure the electrical performance
of miniature coaxial cables terminated directly to the external
wiring plane of a Printed Circuit Board.

      The miniature coax cable consists of a Center Conductor (A), a
Drain Wire (B), a Dielectric (C), a Shield (D) and an Outer Jacket
(E).  A Sealant (F) is applied to produce an envelopment of the
exposed Shield (D) and Dielectric (C) between the Outer Jacket (E)
and the exposed Center Conductor (A) and Drain Wire (B).  See Figure
1.

      The electrical parameters of Time Delay, Impedance, and
Insulation Resistance are degraded by the penetration of humidity and
process fluids into the open cell structure of the Dielectric (C)
during board assembly and subsequent field use.  The Sealant (F)
impedes this penetration of gas and liquid contaminants that:  1)
displaces the critical air content of the Dielectric (C), and 2)
potentially creates conductive paths between Center Conductor (A) and
Drain Wire (B).

      Other important functional benefits are produced by the Sealant
(F):  1) exposed Shield (D) is electrically insulated from adjacent
signal and power sites at initial termination and during transient
shrinkage of Outer Jacket (E) and Dielectric (C); 2)  the need for
precise tolerances during the stripping operation are reduced; and 3)
it is space efficient;  no connector housings are required to
captivate sealant, thereby...