Vijay K Chopra

US Patent:

6649841, Nov 18, 2003

Filed:

Nov 21, 2001

Appl. No.:

09/990105

Inventors:

Vijay K. Chopra - Palos Park IL
Hugh R. Nudd - Mokena IL
James A. Krabec - Oak Lawn IL

Assignee:

Andrew Corporation - Orland Park IL

International Classification:

H01B 718

US Classification:

174102R, 174102 D

Abstract:

A corrugated coaxial cable including a core with at least one inner conductor and a highly expanded polymeric foam dielectric surrounding the inner conductor. This coaxial cable has a corrugated outer conductor closely encapsulating the foam dielectric. The corrugated coax cable is dimensioned to provide the cable with a velocity of propagation of greater than 90% of the speed of light.

US Patent:

6717493, Apr 6, 2004

Filed:

Mar 18, 2002

Appl. No.:

10/100541

Inventors:

Vijay K. Chopra - Palos Park IL
Hugh Robert Nudd - Mokena IL

Assignee:

Andrew Corporation - Orland Park IL

International Classification:

H01P 306

US Classification:

333237, 333243

Abstract:

An RF coaxial cable with clad conductors includes an inner tubular conductor having a first base layer formed of a relatively higher conductivity material, and a first bulk layer formed of a relatively lower conductivity material. The first base layer of higher conductivity material extends over an area greater than an area of the first bulk layer to form first margin regions composed of only the higher conductivity material. The first margin regions of the first base layer of the higher conductivity material are joined together to form the inner tubular conductor with only the first margin regions of the higher conductivity material being joined. Also included is a dielectric material surrounding the inner conductor, an outer tubular conductor formed in the same manner as the inner conductor. The first base layer of higher conductivity material of the inner tubular conductor faces outwardly toward the dielectric material and the higher conductivity material corresponding to the outer tubular conductor faces inwardly toward the dielectric material.

US Patent:

20040220287, Nov 4, 2004

Filed:

Sep 22, 2003

Appl. No.:

10/472341

Inventors:

Michel Champagne - St-Thomas d'Aquin, CA
Richard Gendron - Boucherville QC, CA
Caroline Vachon - Laval QC, CA
Vijay Chopra - Palos Park IL, US
Hugh Nudd - Frankforet IL, US
Sitaram Rampalli - Orland Park IL, US

International Classification:

C08J009/00

US Classification:

521/050000

Abstract:

The invention relates to a low loss foam composition and cable, such as a coaxial cable. The foam composition is formed by heating an olefinic polymer, such as a high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, or a combination thereof, into a molten state composition, optionally with a nucleating agent. The molten mixture is extruded under pressure through a die with a blowing agent comprising an atmospheric gas, such as carbon dioxide, nitrogen or air, and a co-blowing agent selected from hydrofluorocarbons, hydrochlorofluorocarbons, or perfluoro compounds, such as HFC-134a. The cable is formed by extruding the foam composition onto a signal carrying conductor and sheathing the foam-coated signal carrying conductor in an appropriate conducting shield.

US Patent:

20080242754, Oct 2, 2008

Filed:

Jun 10, 2008

Appl. No.:

12/136582

Inventors:

Michael F. Champagne - St-Thomas d'Aquin, CA
Richard Gendron - Boucherville, CA
Caroline Vachon - Laval, CA
Vijay K. Chopra - Palos Park IL, US
Hugh R. Nudd - Mokena IL, US
Sitaram Rampalli - Orland Park IL, US

Assignee:

National Research Council of Canada - Ottawa

International Classification:

C08J 9/228
C08J 9/00
B29C 45/03

US Classification:

521 94, 2643281

Abstract:

The invention relates to a low loss foam composition and cable, such as a coaxial cable. The foam composition is formed by heating an olefinic polymer, such as a high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, or a combination thereof, into a molten state composition, optionally with a nucleating agent. The molten mixture is extruded under pressure through a die with a blowing agent comprising an atmospheric gas, such as carbon dioxide, nitrogen or air, and a co-blowing agent selected from hydrofluorocarbons, hydrochlorofluorocarbons, or perfluoro compounds, such as HFC-134a. The cable is formed by extruding the foam composition onto a signal carrying conductor and sheathing the foam-coated signal carrying conductor in an appropriate conducting shield.

US Patent:

49109987, Mar 27, 1990

Filed:

May 1, 1987

Appl. No.:

7/045887

Inventors:

Frank R. Willis - South Holland IL
Sitaram Rampalli - Tinley Park IL
Vijay K. Chopra - Palos Park IL
Robert D. Perelman - Homewood IL

Assignee:

Andrew Corporation - Orland Park IL

International Classification:

G01M 316
H01B 732

US Classification:

73 405R

Abstract:

A fluid detection system includes a cable which is capable of being dried easily after coming into contact with the fluid being detected and displays a measurable change in characteristic impedance immediately upon contact with the fluid. The cable comprises an inner conductor and a cylindrical outer conductor disposed in a substantially parallel and coaxial relationship with each other with a dielectric detection layer coaxially disposed between the inner and outer conductors. The outer conductor is of an open braided construction which permits easy passage therethrough of the fluid to be detected. The detection layer comprises a pair of solid dielectric elements stranded around the inner conductor in a double helical configuration and defining an air gap between the two conductors which is adapted to retain the fluid so as to measurably change the characteristic impedance of the cable. A coating of dielectric material is provided around the solid inner conductor, the thickness of which can be controlled to adjust the change in characteristic impedance resulting from the presence of fluid within the dielectric layer. The improved cable construction allows the dielectric layer to be dried quickly even after the cable has been immersed in the fluid so that successive fluid detection measurements may be made without delay.