Patent ID: 6527768
Filing Date: 2003-03-04
Classification: A61B

Abstract:
A horn antenna assembly for use with a microwave ablation instrument including a coaxial transmission line having a line inner conductor and a line outer conductor separated by a line dielectric material having a first dielectric constant, said horn antenna assembly comprising:an antenna outer conductor electrically coupled to said line outer conductor and having a peripherally extending interior wall defining a recess, and flaring outwardly from a proximal end to a distal end of the horn antenna assembly; an antenna inner conductor electrically coupled to said line inner conductor and terminating in said recess of said antenna outer conductor, said antenna inner conductor and said antenna outer conductor cooperating to emit an electromagnetic field sufficiently strong to cause tissue ablation, and in a direction generally away from the distal end of said horn antenna assembly; and an antenna dielectric material having a second dielectric constant and disposed in said recess of said antenna outer conductor, said antenna dielectric material having a proximal face in conductive contact with said line dielectric material and a distal face spaced-apart from said proximal face by a predetermined distance enabling resonance of the emitted electromagnetic field at said distal face proportionately based upon the first dielectric constant and second dielectric constant.