Co-Fired Multi-Layer Antenna for Implantable Medical Devices and Method for Forming the Same

• US 20100114246A1
• Filed: 12/31/2008
• Published: 05/06/2010
• Est. Priority Date: 10/31/2008
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Haubrich, Gregory John, Yamamoto, Joyce K., Hill, Gerard J.
• Granted Patent: US 8,983,618 B2
• Time in Patent Office: Days
• US Class Current: 607/60
• CPC Class Codes: A61N 1/37223 Circuits for electromagnetic coupling
• CPC Class Codes: A61N 1/37229 Shape or location of the implanted or external antenna
• CPC Class Codes: H01Q 1/273 Adaptation for carrying or wearing by persons or animals
• CPC Class Codes: H01Q 11/08 Helical antennas
• CPC Class Codes: H01Q 9/40 Element having extended radiating surface
• CPC Class Codes: Y10T 29/49016 Antenna or wave energy "plumbing" making

Abstract

An antenna for an implantable medical device (IMD) is provided including a monolithic structure derived from a plurality of discrete dielectric layers having an antenna embedded within the plurality of dielectric layers. The antenna includes antenna portions formed within different layers of the monolithic structure with at least one conductive via formed to extend through the dielectric layers in order to provide a conductive pathway between the portions of the antenna formed on different layers, such that an antenna is formed that extends between different vertical layers. The dielectric layers may comprise layers of ceramic material that can be co-fired together with the antenna to form a hermetically sealed monolithic antenna structure. The antenna embedded within the monolithic structure can be arranged to have a substantially spiral, helical, fractal, meandering or planer serpentine spiral shape.

Claims

1. An antenna for an implantable medical device (“

IMD”

), comprising;

a structure derived from a plurality of discrete dielectric layers; and

a three dimensional (“

3D”

) antenna embedded within the structure that is in contact with multiple layers of the plurality of discrete dielectric layers.

2. The antenna of claim 1, wherein the 3D antenna includes:

a first portion of the antenna positioned under a selected one of the plurality of dielectric layers;

a second portion of the antenna positioned over the selected one of the plurality of dielectric layers;

at least one conductive via extending through the selected one of the plurality of dielectric layers that connects the first portion of the antenna to the second portion of the antenna.

3. The antenna of claim 2, wherein the first and second portions of the antenna and the at least one conductive via are arranged such that the 3D antenna possesses a substantially spiral or helical shape within the structure derived from the plurality of discrete dielectric layers.

4. The antenna of claim 2, wherein the first and second portions of the antenna and the at least one conductive via are arranged such that the 3D antenna possesses at least one of a fractal, meandering or planer serpentine spiral shape within the structure derived from the plurality of discrete dielectric layers.

5. The antenna of claim 1, wherein at least one of the dielectric layers comprises a ceramic material.

6. The antenna of claim 5, wherein the dielectric layers, the first and second portions of the antenna, and the at least one conductive via are co-fired together.

7. The antenna of claim 1, wherein at least one of the dielectric layers comprises a low temperature co-fire ceramic (LTCC) material.

8. The antenna of claim 7, wherein the LTCC material has a melting point between about 850 C.°

and 1150 C.°

.

9. The antenna of claim 1, wherein at least one of the dielectric layers comprises a high temperature co-fire ceramic (HTCC) material.

10. The antenna of claim 9, wherein the HTCC material has a melting point between about 1100 C.°

and 1700 C.°

.

11. The antenna of claim 2, wherein the at least one via includes an impedance that is selected to achieve a desired impedance for the antenna.

12. The antenna of claim 2, wherein a via is represented by a plurality of separate sub-vias having respective cross-sectional areas, wherein the via includes a cross-sectional area represented by the collection of respective cross-sectional areas of the separate sub-vias.

13. The antenna of claim 1, further comprising a cavity formed in the structure derived from a plurality of discrete dielectric layers with respect to the 3D antenna to enable radio frequency (RF) impedance matching.

14. The antenna of claim 2, wherein the first and second portions of the antenna and the at least one conductive via are formed from a biocompatible conductive material.

15. The antenna of claim 1, wherein the antenna is positioned within a header block for the IMD.

16. The antenna of claim 1, wherein the structure is attached to a housing for the IMD using at least one of a brazing, glassing, diffusion bonding or other bonding technique that provides a hermetic seal between the structure and the housing.

17. The antenna of claim 1, wherein the structure is attached to a housing for the IMD using at least one of a brazing, glassing, diffusion bonding or other bonding technique that provides a hermetic seal between the structure and the housing.

18. An antenna for an implantable medical device (“

IMD”

), comprising;

a monolithic structure derived from a plurality of discrete dielectric layers having an antenna, interconnects and impedance matching elements embedded within the monolithic structure.

19. The antenna of claim 18, wherein the antenna includes:

a first portion of the antenna positioned under a selected one of the plurality of dielectric layers;

a second portion of the antenna positioned over the selected one of the plurality of dielectric layers; and

at least one conductive via extending through the selected one of the plurality of dielectric layers that connects the first portion of the antenna to the second portion of the antenna.

20. The antenna of claim 19, wherein the at least one conductive via serves as the impedance matching elements embedded within the monolithic structure.

21. The antenna of claim 18, further comprising at least one cavity formed in the monolithic structure to provide embedded radio frequency (RF) impedance matching functionality for the antenna.

22. The antenna of claim 18, wherein at least one of the dielectric layers comprises a ceramic material, further wherein the dielectric layers, the antenna and the impedance matching elements are co-fired together into the monolithic structure.

23. The antenna of claim 18, further comprising surface mounted impedance matching elements mounted on a surface of the monolithic structure for providing additional impedance matching functionality.

24. A method for fabricating an antenna for an implantable medical device (“

IMD”

), comprising;

forming a structure including a plurality of discrete dielectric layers;

forming at least one aperture extending through at least a selected one of the plurality of dielectric layers;

depositing a conductive material in the least one aperture to form at least one via in the selected one of the plurality of dielectric layers;

positioning a conductive material adjacent to opposite surfaces of the selected one of the plurality of dielectric layers and in contact with the at least one via, and

co-firing the dielectric layers and conductive material together into a monolithic structure, wherein the conductive material resulting in the co-fired monolithic structure comprises an antenna arranged in a three dimensional (“

3D”

) shape that is in contact with multiple layers of the plurality of discrete dielectric layers.

25. The method of claim 24, wherein the 3D shape for the antenna within the monolithic structure comprises at least one of a substantially spiral, helical, fractal, meandering or planer serpentine spiral shape.

26. The method of claim 24, further comprising:

selecting a cross-sectional area of the at least one aperture and the corresponding at least one via formed in the selected one of the plurality of dielectric layers to provide a desired antenna inductance.

27. The method of claim 24, further comprising attaching the monolithic structure to a housing for the IMD using at least one of a brazing, glassing, diffusion bonding or other bonding technique that provides a hermetic seal between the monolithic structure and the housing.