Patent ID: 6409724
Filing Date: 2002-06-25
Classification: A61B

Abstract:
An electrosurgical instrument comprising:an elongate inner tubular member having a proximal end and a distal end, at least a portion of the inner member being electrically conductive in order that there is d.c. electrical continuity between said ends; and an elongate tubular electrically conductive sheath surrounding the inner member but spaced from the conductive material of the inner member to form an electrically insulative layer, whereby the inner member and the sheath constitute a coaxial transmission line, the sheath being electrically coupled to the inner member at a location spaced proximally from the distal end; a feeder coupled to the inner member distally of the connection between the sheath and the inner member; and an r.f. isolating structure between said couplings of the inner member to the feeder and to the sheath, the isolating structure presenting a series impedance between said couplings at an operating frequency of the instrument.