Andrew Corporation

Robert D Perelman

Sitaram Rampalli

Vijay K Chopra

Frank R Willis

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.

Fluid detection system and method having a coaxial cable with solid,

An improved foamable dielectric composition comprising a melt extrudable perfluorocarbon resin containing therein (i) a polytetrafluoroethylene (PTFE) nucleating agent and (ii) a volatile blowing agent, preferably a lower fluorocarbon blowing agent having only one or two carbon atoms; a process for forming such a composition; and, products produced therewith. More specifically, a foamed melt extudable fluorinated ethylene-propylene (FEP) polymer containing therein a PTFE nucleating agent and blown to a foamed structure by means of a volatile fluid--e.g., a lower fluorocarbon such as fluoromethane or, preferably, fluoroethane, a process for forming such a foamed composition; and, products produced therewith such as jacketed electrical conductors and/or coaxial cables wherein at least one conductor is bonded to such a foamed melt extrudable resin. The foamed dielectric melt extrudable resin is characterized by its thermal stability, fire resistance, small closed cell structure, low density, and low insulating loss characteristics. In a preferred embodiment, the melt extrudable foamed resin comprises a perfluorocarbon polymer having a closed cellular structure with cells ranging from 10 to 40 mils., a density at least as low as 1.0 g./cc., and an insulation loss of less than 1.8 db/100 ft. at 1000 MHz.

Corrugated coaxial cable

An improved foamable dielectric composition comprising a melt extrudable perfluorocarbon resin containing therein (i) a polytetrafluoroethylene (PTFE) nucleating agent and (ii) a volatile blowing agent, preferably a lower fluorocarbon blowing agent having only one or two carbon atoms; a process for forming such a composition; and, products produced therewith. More specifically, a foamed melt extrudable fluorinated ethylene-propylene (FEP) polymer containing therein a PTFE nucleating agent and blown to a foamed structure by means of a volatile fluid--e.g., a lower fluorocarbon such as fluoromethane or, preferably, fluoroethane, a process for forming such a foamed compostion; and, products produced therewith such as jacketed electrical conductors and/or coaxial cables wherein at least one conductor is bonded to such a foamed melt extrudable resin. The foamed dielectric melt extrudable resin is characterized by its thermal stability, fire resistance, small closed cell structure, low density, and low insulating loss characteristics. In a preferred embodiment, the melt extrudable foamed resin comprises a perfluorocarbon polymer having a closed cellular structure with cells ranging from 10 to 40 mils., a density at least as low as 1.0 g./cc., and an insulation loss of less than 1.8 db/100 ft. at 1000 MHz.

Growing community of inventors

Hazel Crest, IL, United States of America

Robert D Perelman