Raychem Limited

Michael Booth

Richard J Penneck

A piezoelectric coaxial cable comprises a central stretchable electrical conductor (1), preferably formed from a low melting point metal alloy, a piezoelectric intermediate layer (2), preferably formed from a vinylidene fluoride polymer which has been stretched and radially polarized to render it piezoelectric, and an outer electrical conductor (3). The intermediate layer has a ratio R of its internal radius to its external radius which is preferably not more than 0.5 and more preferably not more than 0.4. This construction enables coaxial cables to be formed without voiding or breaking of the internal conductor during stretching.

Method of making coaxial cable

A piezoelectric coaxial cable comprises a central stretchable electrical conductor (1), preferably formed from a low melting point metal alloy, a piezoelectric intermediate layer (2), preferably formed from a vinylidene fluoride polymer which has been stretched and radially polarized to render it piezoelectric, and an outer electrical conductor (3). The intermediate layer has a ratio R of its internal radius to its external radius which is preferably not more than 0.5 and especially not more than 0.4. This construction enables coaxial cables to be formed without voiding or breaking of the internal conductor during stretching.

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Swindon, United Kingdom

Michael Booth