Leaky-wave antennas for medical applications

Abstract

A device for directing energy to a target volume of tissue includes an inner conductor having a length and an outer conductor coaxially surrounding the inner conductor along the length. The outer conductor has a proximal portion and a distal portion. The distal portion of the outer conductor is provided with a number of apertures N defined therein for radiating energy, where N is an integer greater than 1, each aperture having a size and extending at an angle relative to a longitudinal axis of the outer conductor. At least one of the size and the angle of each aperture is varied in relation to the other apertures N−1 such that the energy radiated along the distal portion is substantially uniform.

1 - 16 . (canceled) 
     
     
         17 . A microwave ablation probe for directing energy to tissue, comprising:
 an inner conductor;   an outer conductor coaxially disposed about at least a portion of the inner conductor, the inner conductor and the outer conductor defining a first longitudinal axis, the outer conductor including a plurality of apertures defined therein, each of the plurality of apertures defining a second longitudinal axis that is disposed at an angle relative to the first longitudinal axis, each of the angles being different from each other;   a dielectric material disposed between the inner conductor and the outer conductor; and   a sleeve member coaxially disposed about at least a portion of the outer conductor and movable relative to the outer conductor, the sleeve member configured to selectively expose a distal portion of the outer conductor to adjust delivery of energy to tissue.   
     
     
         18 . The microwave ablation probe according to  claim 17 , wherein the outer conductor includes a plurality of inclusion elements disposed substantially adjacent to an edge of a corresponding aperture of the plurality of apertures. 
     
     
         19 . The microwave ablation probe according to  claim 18 , wherein each of the plurality of inclusion elements extends beyond the edge of the corresponding aperture and inwardly toward the inner conductor at an angle relative to a plane substantially coextensive with the corresponding aperture. 
     
     
         20 . The microwave ablation probe according to  claim 18 , wherein each of the plurality of inclusion elements have the same dimensions as the corresponding aperture. 
     
     
         21 . The microwave ablation probe according to  claim 17 , wherein each of the apertures has a different size. 
     
     
         22 . The microwave ablation probe according to  claim 17 , wherein the sleeve member is at least one of rotationally or longitudinally moveable relative to the outer conductor. 
     
     
         23 . The microwave ablation probe according to  claim 17 , wherein the sleeve member includes a plurality of sleeve apertures. 
     
     
         24 . The microwave ablation probe according to  claim 23 , wherein the sleeve member is movable between a first position in which the plurality of sleeve apertures are substantially aligned with the plurality of apertures and a second position in which at least a portion of the plurality of apertures are enclosed by the sleeve member. 
     
     
         25 . The microwave ablation probe according to  claim 19 , wherein each of the inclusion elements has a size and a shape, and at least one of the size, the shape, or the angle of each inclusion element controls a wavelength of the energy radiated along the inner and outer conductors. 
     
     
         26 . The microwave ablation probe according to  claim 25 , wherein at least one of the size, the shape, and the angle of each inclusion element is based on a distance of the corresponding aperture relative to a distal tip of the microwave ablation probe. 
     
     
         27 . The microwave ablation probe according to  claim 19 , wherein the dielectric material has a first dielectric constant and each of the inclusion elements includes a second dielectric material having a second dielectric constant different than the first dielectric constant. 
     
     
         28 . A system for directing energy to tissue, comprising:
 a source of microwave energy configured to generate a microwave waveform; and   an antenna assembly coupled to the source of microwave energy, the antenna assembly including:
 an inner conductor; 
 an outer conductor coaxially disposed about at least a portion of the inner conductor, the inner conductor and the outer conductor defining a first longitudinal axis, the outer conductor including a plurality of apertures defined therein, each of the plurality of apertures defining a second longitudinal axis that is disposed at an angle relative to the first longitudinal axis, each of the angles being different from each other; 
 a dielectric material disposed between the inner conductor and the outer conductor; and 
 a sleeve member coaxially disposed about at least a portion of the outer conductor and movable relative to the outer conductor, the sleeve member configured to selectively expose a distal portion of the outer conductor to adjust delivery of energy to tissue. 
   
     
     
         29 . The system according to  claim 28 , wherein the outer conductor includes a plurality of inclusion elements disposed substantially adjacent to an edge of a corresponding aperture of the plurality of apertures. 
     
     
         30 . The system according to  claim 29 , wherein each of the plurality of inclusion elements extends beyond the edge of the corresponding aperture and inwardly toward the inner conductor at an angle relative to a plane substantially coextensive with the corresponding aperture. 
     
     
         31 . The system according to  claim 28 , wherein each of the apertures has a size and extends at an angle relative to a longitudinal axis of the outer conductor and at least one of the size and the angle of each aperture is varied in relation to the other apertures. 
     
     
         32 . The system according to  claim 28 , wherein the sleeve member is at least one of rotationally or longitudinally moveable relative to the outer conductor. 
     
     
         33 . The system according to  claim 28 , wherein the sleeve member includes a plurality of sleeve apertures. 
     
     
         34 . The system according to  claim 33 , wherein the sleeve member is movable between a first position in which the plurality of sleeve apertures are substantially aligned with the plurality of apertures and a second position in which at least a portion of the plurality of apertures are enclosed by the sleeve member. 
     
     
         35 . The system according to  claim 30 , wherein each of the inclusion elements has a size and a shape, and at least one of the size, the shape, and the angle of each inclusion element controls a wavelength of the microwave waveform. 
     
     
         36 . The system according to  claim 35 , wherein at least one of the size, the shape, and the angle of each inclusion element is based on a distance of the corresponding aperture relative to a distal tip of the antenna assembly. 
     
     
         37 . The system according to  claim 29 , wherein the dielectric material has a first dielectric constant and wherein each of the inclusion elements includes a second dielectric material having a second dielectric constant different than the first dielectric constant.