IMPLANTABLE MULTI-LENGTH RF ANTENNA

• US 20090228076A1
• Filed: 03/03/2009
• Published: 09/10/2009
• Est. Priority Date: 03/04/2008
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Ameri, Masoud
• Granted Patent: US 8,170,680 B2
• Time in Patent Office: Days
• US Class Current: 607/60
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• 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 1/36 Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewithH01Q1/08, H01Q1/14 take precedence
• CPC Class Codes: H01Q 1/40 Radiating elements coated with or embedded in protective material
• CPC Class Codes: H01Q 5/321 within a radiating element or between connected radiating elements

Abstract

This document discusses, among other things, a system and method for wirelessly transferring information electromagnetically at a specified first operating frequency range in a first medium and at a specified second operating frequency range in a second medium using an implantable multi-length antenna. In certain examples, the implantable multi-length antenna can be configured to appear electrically as a first electrical length in the first medium and as a different second electrical length in the second medium. In certain examples, the first operating frequency range can be specified using the first electrical length and the second operating frequency range can be specified using the second electrical length.

Claims

1. A system comprising:

an implantable telemetry circuit;

an implantable multi-length antenna electrically connected to the implantable telemetry circuit and configured to wirelessly transfer information electromagnetically at a specified first operating frequency range in a first medium and at a specified second operating frequency range in a different second medium;

wherein the implantable multi-length antenna is configured to appear electrically as a first electrical length in the first medium and as a different second electrical length in the second medium; and

wherein the first operating frequency range is specified using the first electrical length and the second operating frequency range is specified using the second electrical length.

2. The system of claim 1, wherein the first operating frequency range is substantially equal to the second operating frequency range.

3. The system of claim 1, wherein the first operating frequency range includes at least one of:

a medical implant communication service (MICS) range from approximately 402 MHz to 405 MHz;

a short range device (SRD) range from approximately 862 MHz to 870 MHz;

a first industrial scientific and medical (ISM) range from approximately 902 MHz to 928 MHz;

or

a second ISM range from approximately 2400 MHz to 2500 MHz.

4. The system of claim 1, wherein the first medium includes a dielectric material having a relative dielectric constant of approximately 1 and the second medium includes a dielectric material having a relative dielectric constant greater than or equal to 5.0.

5. The system of claim 4, wherein the first medium is air and the second medium is a biological medium, wherein the biological medium includes at least one of bodily fluid, skin tissue, fat tissue, muscle tissue, organ tissue, or bone.

6. The system of claim 1, wherein the first electrical length in the first medium is different than the second electrical length in the second medium due at least in part to a difference in a relative dielectric constant of the first medium and a relative dielectric constant of the second medium.

7. The system of claim 1, wherein the first electrical length in the first medium is different than the second electrical length in the second medium due at least in part to a capacitive coupling of at least a portion of the multi-length antenna in at least one of the first medium or the second medium.

8. The system of claim 1, wherein the implantable multi-length antenna includes:

a first segment positioned approximately parallel to a first axis;

a first switchback, electrically connected to the first segment, the first switchback comprising;

(1) a first switchback segment electrically connected to the first segment using a first transition segment, the first switchback segment approximately parallel to a second axis;

(2) a second switchback segment electrically connected to the first switchback segment using a second transition segment, the second switchback segment approximately parallel to the second axis; and

(3) a third transition segment;

a second segment electrically connected to the first switchback, the second segment approximately parallel to the first axis.

9. The system of claim 8, wherein, in the second medium, the first switchback segment capacitively couples to the second switchback segment;

and

wherein the second electrical length in the second medium is less than the first electrical length in the first medium due at least in part to the capacitive coupling of the first switchback segment and the second switchback segment in the second medium.

10. The system of claim 8, wherein at least one of the first switchback segment or the second switchback segment comprise an arc shaped segment having a constant radius from a specified position.

11. The system of claim 8, wherein the second axis is substantially perpendicular to the first axis;

and

wherein the implantable multi-length antenna includes a second switchback electrically connected to the second segment, wherein the first switchback is positioned in a plane defined by the first axis and the second axis, wherein the second switchback is positioned in a plane defined by the first axis and a third axis, and wherein the third axis is substantially perpendicular to the first axis and different than the second axis.

12. The system of claim 8, wherein the implantable multi-length antenna includes:

a second switchback electrically connected to the second segment, the second switchback located a first distance from the first switchback;

a third segment electrically connected to the second switchback, the third segment approximately parallel to the first axis; and

a third switchback electrically connected to the third segment, the third switchback located a different second distance from the second switchback.

13. The system of claim 12, wherein the implantable multi-length antenna is configured to wirelessly transfer information electromagnetically at a specified third operating frequency range in the first medium and at a specified fourth operating frequency range in the second medium;

wherein the third operating frequency range is different than the first operating frequency range and the fourth operating frequency range is different than the second operating frequency range;

wherein the first operating frequency range and the second operating frequency range are specified using the first distance between the first switchback; and

wherein the third operating frequency range and the fourth operating frequency range are specified using the second distance between the second switchback and the third switchback.

14. A method comprising:

wirelessly transferring information electromagnetically at a specified first operating frequency range in a first medium and a specified second operating frequency range in a different second medium using an implantable multi-length antenna;

wherein the implantable multi-length antenna is configured to appear electrically as a first electrical length in the first medium and as a different second electrical length in the second medium; and

wherein the first operating frequency range is specified using the first electrical length and the second operating frequency range is specified using the second electrical length.

15. The method of claim 14, wherein the first operating frequency range is substantially equal to the second operating frequency range.

16. The method of claim 14, wherein the first operating frequency range includes at least one of:

a medical implant communication service (MICS) range from approximately 402 MHz to 405 MHz;

a short range device (SRD) range from approximately 862 MHz to 870 MHz;

a first industrial scientific and medical (ISM) range from approximately 902 MHz to 928 MHz;

or

a second ISM range from approximately 2400 MHz to 2500 MHz.

17. The method of claim 14, wherein the first medium includes a dielectric material having a relative dielectric constant of approximately 1 and wherein the second medium includes a dielectric material having a relative dielectric constant greater than or equal to 5.0.

18. The method of claim 17, wherein the first medium is air and the second medium is a biological medium, wherein the biological medium includes at least one of bodily fluid, skin tissue, fat tissue, muscle tissue, organ tissue, or bone.

19. The method of claim 14, wherein the first electrical length in the first medium is different than the second electrical length in the second medium due at least in part to a difference in a relative dielectric constant of the first medium and a relative dielectric constant of the second medium.

20. The method of claim 14, wherein the first electrical length in the first medium is different than the second electrical length in the second medium due at least in part to a capacitive coupling of at least a portion of the multi-length antenna in at least one of the first medium or the second medium.