Minnesota Mining and Manufacturing Company

3m Innovative Properties Company

Mitsui Chemicals, Inc.

Denis D Springer

Harry A Loder

Atsushi Morita

Masaji Yoshimura

Robert S Dodsworth

Randall L Alberg

John L Roche

Kouichi Sano

Hiroyasu Kido

John W Benedict

Tomoaki Sato

Daniel Patrick Sheehy

Mark W Breault

James H Voth

The amount of air dielectric in air core coaxial and twinaxial cables is increased by spacer structures installed between the center conductor and the outer shield which have provision for air voids or pockets running lengthwise. The extra air space provides lower effective dielectric constant for the cable. In one embodiment, a single-element extruded spacer is formed with air cavities or voids that run continuously throughout the length of the spacer. Several spacer 'profiles' or cross-sections are disclosed that place less solid dielectric mass in proximity to the center conductor. The result is a greater volume of air dielectric, and hence a lowered cable dielectric constant. In a further embodiment the spacer is a circular cross-sectioned element consisting of a central dielectric strength member surrounded with foamed material. Strength strands such as Kevlar&#xae; may be added to the spacer.

High propagation speed coaxial and twinaxial cable

A converter for terminating a coaxial connector to a coaxial cable when the cable shield layer outer diameter is larger than an interior dimension of the connector shell. The converter includes a conductive shell having a first end and a second end. The first end of the converter shell has an inner diameter larger than the outer diameter of the cable conductive shield layer, and the second end of the converter shell has an outer diameter smaller than the interior dimension of the connector shell. A dielectric insulation insert is positioned with the converter shell. The converter may be designed to match the impedance of either the coaxial cable or the connector, or the converter may smoothly transition from the impedance of the cable to the impedance of the connector.

Coaxial cable converter

A resin composition containing components (A), (B), (C) and (D) wherein component (A) is a resin composition containing a thermoplastic polyimide resin, component (B) is carbon fiber, component (C) is mica, component (D) is an internal mold-releasing agent, and relative to 100 parts by weight of component (A), component (B) is from 1 to 80 parts by weight, component (C) 1 to 100 parts by weight, and component (D) is 0.1 to 50 parts by weight.

Resin composition and heat-resistant, returnable IC tray obtained by

A ribbon cable with improved skew control has a plurality of substantially parallel longitudinal conductors lying in a single plane, with insulation encasing the plurality of conductors. The insulation defines first and second outer surfaces which are substantially parallel to the plane of the plurality of conductors. A first sheet of extensible metallic foil is positioned adjacent the first outer surface of the insulation, and a second sheet of extensible metallic foil is positioned adjacent the second outer surface of the insulation. A third sheet of metallic foil is wrapped around substantially all cross-sectional sides of the plurality of conductors, insulation, and first and second sheets of metallic foil to provide a continuous electromagnetic shield around the conductors. A flexible jacket may be provided on the cable to protect the assembly.

Reduced skew shielded ribbon cable

A high speed signal transmission cable including spaced, parallel conductors and an insulation layer comprising blown micro fiber web surrounding the conductors, preferably further including a layer of another dielectric material surrounding the microfiber material.

Blown microfiber insulated cable

A high impedance cable includes a first layer of insulation surrounding a series of conductors to form a conventional ribbon cable and a second layer of insulation which conforms to the first layer of insulation and is retained in contact with the first layer of insulation in a manner which substantially excludes air from between the two layers of insulation but permits the second layer of insulation to be stripped from the ribbon cable for convention mass termination of the ribbon cable.

High impedance, strippable electrical cable

Ribbon cables have lower capacitance, higher impedance, and faster propagation velocities with microporous fibril thermoplastic dielectric insulation, because they have great amounts of air adjacent to the conductors and the improved electrical performance is due in part to the improved crush resistance. Crystallizable thermoplastic polymers having good fibril structure and crush resistance include polyolefins such as polypropylene and polymethylpentene. A layer of metal adhered to the dielectric insulation provides improved transmission line properties.

Ribbon cable construction

A ribbon cable or discrete wires, having a layer of thermally stable, crush resistant, fibril microporous heat sealable thermoplastic crystallizable polymer dielectric surrounding said conductor. The thermoplastic dielectric having a void volume in excess of 70%, a propagation velocity of the insulated conductor greater than 85% the propagation velocity in air and the crush resistance being the recovery rate of the material after being under a 500 gram weight for 10 minutes greater than 92% of the initial thickness.

Growing community of inventors

Austin, TX, United States of America

Denis D Springer