High-strength microwave antenna assemblies

• US 9,041,616 B2
• Filed: 02/04/2014
• Issued: 05/26/2015
• Est. Priority Date: 11/02/2001
• Status: Expired due to Fees

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: Prakash, Mani N., Rossetto, Francesca, Lee, Anthony C., Kim, Steven, Su, Ted, Glassman, Jonathan L.
• Primary Examiner(s): PHAN, THO GIA
• Application Number:
  US14/172,177
• Publication Number:
  US 20140155881A1
• Time in Patent Office: 476 Days
• Field of Search: 343/790, 343/791, 343/792, 606/33, 606/41, 607/101
• US Class Current: 343/790
• CPC Class Codes: A61B 18/18 by applying electromagnetic radiation, e.g. microwaves radiation therapy A61N5/00
• CPC Class Codes: A61B 18/1815 using microwaves
• CPC Class Codes: A61B 2018/00077 high, i.e. electrically conducting
• CPC Class Codes: A61B 2018/00083 low, i.e. electrically insulating
• CPC Class Codes: A61B 2018/00136 with polymer
• CPC Class Codes: A61B 2018/00142 lubricating
• CPC Class Codes: A61B 2018/00178 Electrical connectors
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/1823 Generators therefor
• CPC Class Codes: A61B 2018/1838 Dipole antennas
• CPC Class Codes: A61B 2018/1853 Monopole antennas
• CPC Class Codes: A61B 2018/1869 with an instrument interstitially inserted into the body, e.g. needles
• CPC Class Codes: A61B 2018/1892 Details of electrical isolations of the antenna
• CPC Class Codes: Y10T 29/49005 Acoustic transducer
• CPC Class Codes: Y10T 29/49007 Indicating transducer
• CPC Class Codes: Y10T 29/49016 Antenna or wave energy "plumbing" making
• CPC Class Codes: Y10T 29/49018 with other electrical component

Abstract

Various high-strength microwave antenna assemblies are described herein. The microwave antenna has a radiating portion connected by a feedline to a power generating source, e.g., a generator. The antenna is a dipole antenna with the distal end of the radiating portion being tapered and terminating at a tip to allow for direct insertion into tissue. Antenna rigidity comes from placing distal and proximal radiating portions in a pre-stressed state, assembling them via threaded or overlapping joints, or fixedly attaching an inner conductor to the distal portion. The inner conductor is affixed to the distal portion by, e.g., welding, brazing, soldering, or by adhesives. A junction member made from a hard dielectric material, e.g., ceramic, can be placed between the two portions and can have uniform or non-uniform shapes to accommodate varying antenna designs. Electrical chokes may also be used to contain returning currents to the distal end of the antenna.

Claims

1. A microwave antenna assembly comprising:

a proximal radiating portion having an inner conductor and an outer conductor separated by a dielectric layer;

a distal radiating portion disposed distally of the proximal radiating portion, the inner conductor extending at least partially through the distal radiating portion; and

an electrical choke disposed proximally of the distal radiating portion and including a conductive layer in electrical contact with the outer conductor, at least a portion of the conductive layer separated from the outer conductor by an inner dielectric layer.

2. The microwave antenna assembly according to claim 1, further comprising a junction member disposed between the proximal and distal radiating portions, wherein the inner conductor extends through an opening of the junction member.

3. The microwave antenna assembly according to claim 2, wherein the distal and proximal radiating portions apply a compressive force on at least a portion of the junction member.

4. The microwave antenna assembly according to claim 2, wherein the junction member has a radial thickness that is non-uniform about a longitudinal axis defined by the junction member.

5. The microwave antenna assembly according to claim 1, further comprising a second inner dielectric layer disposed over the inner dielectric layer.

6. The microwave antenna assembly according to claim 1, wherein the electrical choke is covered by a coating configured to conform the electrical choke to the outer conductor.

7. The microwave antenna assembly according to claim 1, wherein the electrical choke is attached to the outer conductor by a method selected from the group consisting of welding, brazing, soldering, crimping, and conductive adhesives.

8. The microwave antenna assembly according to claim 1, further comprising a sealant coating disposed at least partially over at least one of the distal radiating portion or the proximal radiating portion.

9. The microwave antenna assembly according to claim 8, wherein a gap is defined between the electrical choke and the sealant coating.

10. The microwave antenna assembly according to claim 8, wherein the electrical choke and sealant coating at least partially overlap.

11. The microwave antenna assembly according to claim 8, wherein the sealant coating comprises a thermoplastic polymer.

12. A microwave ablation system, comprising:

an electrosurgical energy source;

a microwave antenna assembly operatively connected to the electrosurgical energy source, the microwave antenna assembly including;

a proximal radiating portion having an inner conductor and an outer conductor separated by a dielectric layer;

a distal radiating portion disposed distally of the proximal radiating portion, the inner conductor extending at least partially through the distal radiating portion; and

an electrical choke disposed proximally of the distal radiating portion and including a conductive layer in electrical contact with the outer conductor, at least a portion of the conductive layer separated from the outer conductor by an inner dielectric layer.

13. The microwave ablation system according to claim 12, wherein the antenna assembly further comprises a junction member disposed between the proximal and distal radiating portions, wherein the inner conductor extends through an opening of the junction member.

14. The microwave ablation system according to claim 13, wherein the distal and proximal radiating portions apply a compressive force on at least a portion of the junction member.

15. The microwave ablation system according to claim 12, wherein the antenna assembly further includes a second inner dielectric layer disposed over the inner dielectric layer.

16. The microwave ablation system according to claim 12, wherein the electrical choke is disposed at least partially over the proximal radiating portion.

17. The microwave ablation system according to claim 12, wherein the electrosurgical energy source is a microwave generator.