Antenna for Implantable Medical Devices Formed on Extension of RF Circuit Substrate and Method for Forming the Same

• US 20100114245A1
• Filed: 12/19/2008
• 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: Yamamoto, Joyce K., Denzene, Quentin Scott, Barror, Michael William
• Granted Patent: US 9,399,143 B2
• Time in Patent Office: Days
• US Class Current: 607/60
• CPC Class Codes: A61N 1/37229 Shape or location of the implanted or external antenna
• CPC Class Codes: H01Q 1/2283 mounted in or on the surface of a semiconductor substrate as a chip-type antenna or integrated with other components into an IC package
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: Y10T 29/49016 Antenna or wave energy "plumbing" making

Abstract

An antenna for an implantable medical device (IMD) is provided that is formed on the same substrate as the telemetry circuitry for the IMD. The telemetry circuitry is formed on a portion of the substrate within the interior of a housing for the IMD, while at least one antenna is formed on an exterior portion of the substrate on the exterior of the housing to allow for far field telemetry. At least one electrical interconnect is formed on the substrate for connecting the antenna to the telemetry circuitry, where the electrical interconnect may comprise a controlled impedance line to minimize loss. A conformally-shaped hermetic cover, such as a ceramic material, may be formed in a desired shape around the exterior portion of the substrate and antenna and cofired together to form a monolithic structure encasing the antenna and exterior portion of the substrate.

Claims

1. An implantable medical device (“

IMD”

), comprising;

a housing;

a substrate including an interior portion extending within the housing and an exterior portion extending outside of the housing;

telemetry circuitry connected to the interior portion of the substrate; and

an antenna formed on the exterior portion of the substrate.

2. The implantable medical device of claim 1, further comprising at least one electrical interconnect formed on the substrate and extending from the exterior portion of the housing to the interior portion for connecting the antenna to the telemetry circuitry.

3. The implantable medical device of claim 2, wherein the at least one electrical interconnect is a controlled impedance line.

4. The implantable medical device of claim 2, wherein the substrate is a circuit board and the electrical interconnect is printed wiring formed on the circuit board.

5. The implantable medical device of claim 1, further comprising a hermetic covering positioned around the exterior portion of the substrate covering the antenna.

6. The implantable medical device of claim 5, wherein the hermetic covering comprises a ceramic material.

7. The implantable medical device of claim 6, wherein the hermetic covering comprises a cofired ceramic material conformally shaped based on a desired implantation location for the IMD.

8. The implantable medical device of claim 6, wherein the hermetic covering comprises a cofired ceramic material shaped to provide additional support for the exterior portion of the substrate.

9. The implantable medical device of claim 1, wherein the exterior portion of the substrate extends outside of the housing a sufficient distance to allow the antenna to be positioned a sufficient distance from the housing to avoid signal interference from the housing.

10. The implantable medical device of claim 1, wherein the antenna is positioned at an end portion of the exterior portion of the substrate so that the antenna can transmit and receive signals in multiple directions from the substrate.

11. The implantable medical device of claim 1, further comprising at least one additional antenna formed on the exterior portion of the substrate.

12. The implantable medical device of claim 11, further comprising a switching device operatively connected to each of the antennas formed on the exterior portion of the substrate for allowing desired ones of the antennas to be selected for use in the antenna.

13. An antenna structure for an implantable medical device (“

IMD”

), comprising;

a cofired ceramic material connecting to a housing for the IMD, wherein the cofired ceramic material is conformally shaped based on a desired implantation location for the IMD; and

an antenna embedded within the cofired ceramic material.

14. The antenna structure of claim 13, wherein the cofired ceramic material includes hermetically sealed portions around a portion of its periphery

15. The antenna structure of claim 13, wherein the cofired ceramic material and the antenna are cofired together into a monolithic structure.

16. The antenna structure of claim 13, wherein cofired ceramic material comprises a high temperature co-fire ceramic (HTCC) material having a melting point between about 1100°

C. and 1700°

C.

17. The antenna structure of claim 13, wherein the antenna is formed on an exterior portion of a substrate extending from the housing for the IMD, further wherein the cofired ceramic material encases the exterior portion of the substrate.

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

IMD”

), comprising;

forming an antenna from a biocompatible conductive material;

forming a ceramic material into a desired conformal shape based on a desired implantation location for the IMD; and

cofiring the ceramic material and the antenna together into a monolithic antenna structure.

19. The method of claim 18, wherein the ceramic material comprises a high temperature co-fire ceramic (HTCC) material having a melting point between about 1100°

C. and 1700°

C., the method further comprising cofiring the ceramic material and the antenna together at a temperature between about 1100°

C. and 1700°

C.