Electrosurgical devices with balun structure for air exposure of antenna radiating section and method of directing energy to tissue using same

An energy applicator for directing energy to tissue, comprising:na feedline having an inner conductor, an outer conductor coaxially disposed around the inner conductor, and a dielectric material disposed therebetween;an antenna assembly having a radiating section operably coupled to the feedline;a first balun structure configured to substantially confine energy to the radiating section when the energy applicator is energized and disposed in tissue, wherein the first balun structure includes a first balun and a second balun disposed so as to at least partially overlap the first balun;the first balun including:na first balun insulator disposed around a distal portion of the outer conductor;a first balun conductor disposed around at least a portion of the first balun insulator;the second balun including:na second balun insulator disposed so as to at least partially overlap a proximal portion of the first balun conductor;a second balun conductor electrically coupled to the outer conductor; anda second balun structure configured to substantially prevent energy emitted from the radiating section from propagating proximal to the second balun structure along the feedline when the energy applicator is energized but not disposed in tissue.

An energy applicator for directing energy to tissue, comprising:na feedline having an inner conductor, an outer conductor coaxially disposed around the inner conductor, and a dielectric material disposed therebetween;an antenna assembly having a radiating section operably coupled to the feedline;a first balun structure configured to substantially confine energy to the radiating section when the energy applicator is energized and disposed in tissue, the first balun structure including:na first balun insulator disposed around a distal portion of the outer conductor;a first balun conductor disposed around at least a portion of the first balun insulator; anda second balun structure configured to substantially prevent energy emitted from the radiating section from propagating proximal to the second balun structure along the feedline when the energy applicator is energized but not disposed in tissue, wherein the second balun structure includes a second balun insulator disposed so as to at least partially overlap the first balun conductor and a second balun conductor electrically coupled to the outer conductor.

An energy applicator for directing energy to tissue, comprising:na feedline having an inner conductor, an outer conductor coaxially disposed around the inner conductor, and a dielectric material disposed therebetween;an antenna assembly having a radiating section operably coupled to the feedline;a first balun structure configured to substantially confine energy to the radiating section when the energy applicator is energized and disposed in tissue, wherein the first balun structure includes a first balun portion and a second balun portion disposed so as to at least partially overlap the first balun portion;the first balun portion including:na first balun insulator disposed around a first portion of the outer conductor;a first balun conductor disposed around at least a portion of the first balun insulator;the second balun portion including:na second balun insulator including a first portion and a second portion, the first portion coaxially disposed around a second portion of the outer conductor proximal to the first portion of the outer conductor, the second portion of the second balun insulator disposed so as to at least partially overlap a proximal portion of the first balun conductor;a second balun conductor electrically coupled to the outer conductor; anda second balun structure configured to substantially prevent energy emitted from the radiating section from propagating proximal to the second balun structure along the feedline when the energy applicator is energized but not disposed in tissue.