Telemetry antenna for an implantable medical device

• US 7,016,733 B2
• Filed: 04/23/2003
• Issued: 03/21/2006
• Est. Priority Date: 04/23/2003
• Status: Expired due to Fees

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Verhoef, William D., Haubrich, Gregory J., Twetan, Len D., Dublin, Garry L., Wallace, Rodney S., Kronich, Christine G., Kuschnir, Eugene, Przybyszewski, Piotr J
• Primary Examiner(s): MANUEL, GEORGE C
• Application Number:
  US10/421,179
• Publication Number:
  US 20040215280A1
• Time in Patent Office: 1,063 Days
• Field of Search: 607/32, 607/36, 607/60, 128/903, 343/872, 343/873
• US Class Current: 607/36
• CPC Class Codes: A61N 1/37229 Shape or location of the implanted or external antenna
• CPC Class Codes: A61N 1/375 Constructional arrangements, e.g. casings
• CPC Class Codes: A61N 1/37512 Pacemakers

Abstract

Improved telemetry antennas and methods of fabrication for an implantable medical device (IMD) for use in uplink telemetry (UT) and downlink telemetry (DT) transmissions between the IMD and an external medical device (EMD) are disclosed. A first telemetry antenna element is supported to extend in a first direction along a minor side of the IMD housing by a first header segment, and a second antenna element is supported to extend in a second direction along a second minor side of the IMD housing by a second header segment. The first and second antenna elements are supported to extend apart at substantially 90° to one another, i.e., substantially orthogonally, in substantially a common plane to optimize UT transmission and DT reception of UHF telemetry signals by at least one of the first and second antenna elements depending upon the mutual spatial orientation with the antenna elements of an EMD antenna.

Claims

1. An implantable medical device of the type adapted to provide a therapy to the body and/or to monitor a physiologic condition and to communicate with an external medical device by telemetry transmissions comprising:

a hermetically sealed housing enclosing a telemetry transceiver, the enclosure housing having first and second major sides joined by minor sides separating the major sides apart, at least first and second minor sides joined at a minor side junction and extending substantially orthogonally away from the side junction;

a telemetry antenna feedthrough attached to the hermetically sealed housing at a distance along the first minor side from the side junction having a telemetry feedthrough pin coupled at a feedthrough pin inner end to the telemetry transceiver and having a feedthrough pin outer end;

a header formed of dielectric material comprising a first header segment attached to and extending along the first housing side from a point adjacent to the telemetry antenna feedthrough to the side junction and a second header segment enclosing header components attached to and extending along the second minor side from the side junction; and

an elongated telemetry antenna extending from a telemetry antenna free end to a telemetry antenna fixed end that is attached to the telemetry feedthrough pin outer end, the telemetry antenna comprising a first antenna element supported by the first header segment to extend along the first minor side at a first spacing from the first minor side and a second antenna element supported by the second header segment to extend along the second minor side at a second spacing from the second minor side to the telemetry antenna free end.

2. The implantable medical device of claim 1, wherein the first and second telemetry antenna elements are supported by the respective first and second header segments to extend substantially orthogonally away from the side junction in substantially a common plane.

3. The implantable medical device of claim 2, wherein the telemetry antenna is embedded within the dielectric material of the header and the first and second header segments have first and second header segment outer surfaces, respectively, adapted to contact body tissue upon implantation, whereby the dielectric material overlying the first and second antenna elements functions as a radome.

4. The implantable medical device of claim 3, wherein:

the first antenna element has a first length and is supported to extend at a first side spacing from the first minor side and to extend at substantially a first radome thickness from the first header segment outer surface; and

the second antenna element has a second length and is supported to extend at a second side spacing from the second minor side and to extend at substantially a second radome thickness from the second header segment outer surface,

whereby the first and second antenna elements are tuned for optimal RF telemetry reception and transmission through body tissue and air.

5. The implantable medical device of claim 4, wherein the second header segment encloses connector components for coupling with electrical medical leads.

6. The implantable medical device of claim 5, wherein the connector components for coupling with electrical medical leads are disposed in the second side spacing between the second antenna element and the second minor side.

7. The implantable medical device of claim 6, wherein the header comprises:

an undermold of polymeric material extending through the first and second header segments supporting the connector components and the telemetry antenna; and

an overmold molded over the undermold and the telemetry antenna.

8. The implantable medical device of claim 6, wherein:

the second header segment comprises a pre-formed header fitted to the second minor side of the hermetically sealed housing having a pre-formed header outer surface spaced from the second minor side; and

the first and second header segments further comprise an antenna connector module supporting the telemetry antenna and having first and second module segments, the first module segment attached with the first minor side and the second module segment attached with the pre-formed header outer surface.

9. The implantable medical device of claim 2, wherein:

the first antenna element has a first length and is supported to extend at a first side spacing from the first minor side and to extend at substantially a first radome thickness from a first header segment outer surface; and

the second antenna element has a second length and is supported to extend at a second side spacing from the second minor side and to extend at substantially a second radome thickness from a second header segment outer surface,

whereby the first and second antenna elements are tuned for optimal RF telemetry reception and transmission through body tissue and air.

10. The implantable medical device of claim 2, wherein the second header segment encloses connector components for coupling with electrical medical leads.

11. The implantable medical device of claim 10, wherein the connector components for coupling with electrical medical leads are disposed in the second side spacing between the second antenna element and the second minor side.

12. The implantable medical device of claim 11, wherein the header comprises:

an undermold of polymeric material extending through the first and second header segments supporting the connector components and the telemetry antenna; and

an overmold molded over the undermold and the telemetry antenna.

13. The implantable medical device of claim 2, wherein:

the second header segment comprises a pre-formed header fitted to the second minor side of the hermetically sealed housing having a pre-formed header outer surface spaced from the second minor side; and

the first and second header segments further comprise an antenna connector module supporting the telemetry antenna and having first and second module segments, the first module segment attached with the first minor side and the second module segment attached with the pre-formed header outer surface.

14. The implantable medical device of claim 1, wherein:

the second header segment comprises a pre-formed header fitted to the second minor side of the hermetically sealed housing having a pre-formed header outer surface spaced from the second minor side; and

the first and second header segments further comprise an antenna connector module supporting the telemetry antenna and having first and second module segments, the first module segment attached with the first minor side and the second module segment attached with the pre-formed header outer surface.

15. The implantable medical device of claim 1, wherein:

the first antenna element has a first length and is supported to extend at a first side spacing from the first minor side and to extend at substantially a first radome thickness from a first header segment outer surface; and

the second antenna element has a second length and is supported to extend at a second side spacing from the second minor side and to extend at substantially a second radome thickness from a second header segment outer surface,

whereby the first and second antenna elements are tuned for optimal RF telemetry reception and transmission through body tissue and air.

16. The implantable medical device of claim 1, wherein the second header segment encloses connector components for coupling with electrical medical leads.

17. The implantable medical device of claim 16, wherein the connector components for coupling with electrical medical leads are disposed between the second antenna element and the second minor side.

18. The implantable medical device of claim 17, wherein the header comprises:

an undermold of polymeric material extending through the first and second header segments supporting the connector components and the telemetry antenna; and

an overmold molded over the undermold and the telemetry antenna.

19. The implantable medical device of claim 1, wherein the telemetry antenna feedthrough is attached to a feedthrough opening extending through the first major side adjacent to the first minor side, and the telemetry antenna fixed end extends to the telemetry feedthrough pin outer end.

20. The implantable medical device of claim 1, wherein:

the first major side is formed with a telemetry recess and feedthrough opening adjacent to the first minor side;

the telemetry antenna feedthrough is attached to the feedthrough opening extending through the first major side adjacent to the first minor side;

the telemetry antenna fixed end comprises an antenna pad extending into the telemetry recess;

the telemetry feedthrough pin outer end is attached to the antenna pad within the telemetry recess; and

the telemetry recess, antenna pad, and the telemetry feedthrough pin outer end are covered with a bio-compatible electrically insulating material.

22. The implantable medical device of claim 20, wherein:

the first antenna element has a first length and is supported by the supporting means to extend at the first side spacing from the first minor side; and

the second antenna element has a second length and is supported by the supporting means to extend at the second side spacing from the second minor side.

23. The implantable medical device of claim 22, wherein the supporting means is formed of a dielectric material that encloses the first and second antenna elements and forms a radome overlying the first and second antenna elements, whereby the first and second antenna elements are tuned for optimal RF telemetry reception and transmission through body tissue and air.

21. An implantable medical device of the type adapted to provide a therapy to the body and/or to monitor a physiologic condition and to communicate with an external medical device by telemetry transmissions comprising:

a hermetically sealed housing enclosing a telemetry transceiver, the enclosure housing having first and second major sides joined by minor sides separating the major sides apart, at least first and second minor sides joined at a side junction and extending substantially orthogonally away from the side junction;

a telemetry antenna feedthrough attached to the hermetically sealed housing at a distance along the first minor side from the side junction having a telemetry feedthrough pin attached at a feedthrough pin inner end to the telemetry transceiver and a feedthrough pin outer end;

an elongated telemetry antenna extending from a telemetry antenna fixed end to a telemetry antenna free end and having first and second antenna elements;

attaching means for attaching the telemetry antenna fixed end to the feedthrough pin outer end; and

supporting means for supporting the first antenna element along the first minor side at a first side spacing from the first minor side and the second antenna element extending along the second minor side at a second side spacing from the second minor side, the first and second antenna elements extending substantially orthogonally away from the side junction in substantially a common plane.

24. The implantable medical device of claim 21, wherein the telemetry antenna feedthrough is attached to a feedthrough opening extending through the first major side adjacent to the first minor side, and the telemetry antenna fixed end extends to the telemetry feedthrough pin outer end and is attached thereto.

25. The implantable medical device of claim 21, wherein:

the first major side is formed with a telemetry recess and feedthrough opening adjacent to the first minor side;

the telemetry antenna feedthrough is attached to the feedthrough opening extending through the first major side adjacent to the first minor side;

the telemetry antenna fixed end comprises an antenna pad extending into the telemetry recess;

the telemetry feedthrough pin outer end is attached to the antenna pad within the telemetry recess; and

the telemetry recess, antenna pad, and the telemetry feedthrough pin outer end are covered with a bio-compatible electrically insulating material.

26. A method of fabricating an implantable medical device of the type adapted to provide a therapy to the body and/or to monitor a physiologic condition and to communicate with an external medical device by telemetry transmissions comprising:

forming a hermetically sealed housing enclosing a telemetry transceiver, the enclosure housing having first and second major sides joined by minor sides separating the major sides apart, at least first and second minor sides joined at a side junction and extending substantially orthogonally away from the side junction;

attaching a telemetry antenna feedthrough to the hermetically sealed housing at a distance along the first minor side from the side junction, the telemetry antenna feedthrough having a telemetry feedthrough pin attached at a feedthrough pin inner end to the telemetry transceiver and a feedthrough pin outer end;

forming an elongated telemetry antenna extending from a telemetry antenna fixed end to a telemetry antenna free end and having first and second antenna elements;

supporting the first antenna element along the first minor side at a first spacing from the first minor side and the second antenna element extending along the second minor side at a second spacing from the second minor side, the first and second antenna elements extending substantially orthogonally away from the side junction in substantially a common plane.