Ablation devices with dual operating frequencies, systems including same, and methods of adjusting ablation volume using same

1. An ablation device, comprising:

a feedline including an inner conductor having a distal end, an outer conductor coaxially disposed around the inner conductor, and a dielectric material disposed between the inner conductor and the outer conductor;

an elongated electrically-conductive member longitudinally disposed at the distal end of the inner conductor and having a proximal end;

a dielectric junction having a distal-most end coupled to the proximal end of the elongated electrically-conductive member and a proximal end coupled to a distal end of the outer conductor, the inner conductor extending through the dielectric junction and terminating at the distal-most end of the dielectric junction;

a dielectric layer coaxially disposed around at least a portion of the outer conductor and extending distally beyond the distal end of the inner conductor; and

a first balun disposed around at least a portion of the outer conductor and including an electrically-conductive layer, the dielectric layer coaxially disposed around the electrically-conductive layer of the first balun.

2. The ablation device according to claim 1 , wherein the first balun is disposed proximally to the elongated electrically-conductive member.

3. The ablation device according to claim 1 , further comprising a second balun disposed around at least a portion of the outer conductor and longitudinally spaced from the first balun.

4. The ablation device according to claim 1 , wherein the elongated electrically-conductive member includes a diameter different than a diameter of the inner conductor.

5. The ablation device according to claim 1 , wherein the elongated electrically-conductive member includes a diameter greater than a diameter of the inner conductor.

6. The ablation device according to claim 1 , wherein a portion of the inner conductor and the dielectric material of the feedline extend distally beyond the outer conductor at a distal end of the feedline.

7. The ablation device according to claim 1 , further comprising an outer jacket disposed around at least a portion of the feedline and defining a coolant chamber adapted to circulate coolant fluid therethrough, the coolant chamber defined between the dielectric layer and the outer jacket.

8. A tissue ablation system, comprising:

an energy source; and

an ablation device operably associated with the energy source, the ablation device including:

a feedline including an inner conductor having a distal end, an outer conductor coaxially disposed around the inner conductor, and a dielectric material disposed between the inner conductor and the outer conductor;

a dielectric junction having a proximal end coupled to a distal end of the outer conductor, the inner conductor extending through the dielectric junction and terminating at a distal-most end of the dielectric junction;

a dielectric layer coaxially disposed around at least a portion of the outer conductor and extending distally beyond the distal end of the inner conductor; and

a balun disposed around at least a portion of the outer conductor and including an electrically-conductive layer, the dielectric layer coaxially disposed around the electrically-conductive layer of the balun.

9. The system according to claim 8 , wherein the ablation device further comprises an elongated electrically-conductive member longitudinally disposed at the distal end of the inner conductor.

10. The system according to claim 9 , wherein the elongated electrically-conductive member is disposed distal to the balun.

11. The system according to claim 8 , wherein the ablation device further includes an outer jacket disposed around at least a portion of the feedline and defining a lumen therein.

12. The system according to claim 11 , further comprising a coolant supply system in fluid communication with the lumen defined by the outer jacket.

13. The system according to claim 8 , wherein the energy source is a microwave energy source.

14. The system according to claim 8 , wherein the energy source is a radio frequency energy source.

15. The ablation device of claim 8 , wherein the dielectric layer is configured to direct current into the balun.

16. An ablation device, comprising:

a feedline including an inner conductor having a distal end, an outer conductor coaxially disposed around the inner conductor, and a dielectric material disposed between the inner conductor and the outer conductor;

an elongated electrically-conductive member longitudinally disposed at the distal end of the inner conductor and having a proximal end;

a dielectric junction having a distal-most end coupled to the proximal end of the elongated electrically-conductive member and a proximal end coupled to a distal end of the outer conductor, the inner conductor extending through the dielectric junction and terminating at the distal-most end of the dielectric junction;

a dielectric layer coaxially disposed around at least a portion of the outer conductor and extending distally beyond the distal end of the inner conductor;

a balun disposed around at least a portion of the outer conductor and including an electrically-conductive layer, the dielectric layer coaxially disposed around the electrically-conductive layer of the balun; and

an outer jacket disposed around at least a portion of the feedline, the outer jacket defining a coolant chamber adapted to circulate coolant fluid therethrough, the coolant chamber defined between the dielectric layer and the outer jacket.