Null-free antenna array for use in communication with implantable medical devices

• US 6,463,329 B1
• Filed: 08/01/2000
• Issued: 10/08/2002
• Est. Priority Date: 08/01/2000
• Status: Expired due to Fees

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Goedeke, Steven D.
• Primary Examiner(s): Getzow, Scott M.
• Application Number:
  US09/629,999
• Time in Patent Office: 798 Days
• Field of Search: 607/60, 607/30, 607/31, 607/32, 128/899
• US Class Current: 607/60
• CPC Class Codes: A61N 1/37229 Shape or location of the implanted or external antenna

Abstract

An improved telemetry head that employs two coils is disclosed. A first, larger diameter outer coil is generally employed to initiate telemetric communication between the programmer or monitor and the implanted device. In the event that successful communication is not accomplished using the outer coil, the programmer or monitor attempts communication using the inner coil. Any resultant reduced signal strength that may be associated with use of the smaller diameter inner coil is acceptable based on the assumption that the antenna of the implanted device is located in the null associated with the outer antenna coil and thus is located in close proximity to the inner coil. To prevent loss of signal strength, addition turns may be employed to implement the inner coil. In one embodiment, at least one of the first and second coils is of a dual-coil configuration having two coils in series opposition to improve the signal-to-noise ratio.

Claims

1. An apparatus for communicating with a device implanted within a patient'"'"'s body, comprising:

a telemetry head comprising a major surface adapted to be placed adjacent the patient'"'"'s body and comprising first and second coil antennas located generally parallel to the major surface;

a transceiver;

a switching circuit for selectably coupling the transceiver to either of the first or second antennas; and

means for determining integrity of communications between the transceiver and an implanted device and wherein the switching circuitry selectably couples the transceiver to the first or second antenna as a function of the integrity of the communications.

2. The apparatus according to claim 1, wherein at least one of the first and second coil antennas includes first and second coils coupled in series opposition to one another to provide improved signal-to-noise ratio.

3. The apparatus according to claim 2, wherein both of the first and second coil antennas includes first and second coils coupled in series opposition to one another, wherein the first coil of the first coil antenna is co-planar with respect to the first coil of the second coil antenna, and wherein the second coil of the first coil antenna is co-planar with respect to the second coil of the second coil antenna.

4. The apparatus according to claim 1, wherein the telemetry head further comprises a permanent magnet to activate a reed switch within the device implanted within the patient'"'"'s body.

5. The apparatus according to claim 1, and further including a control circuit coupled to the switching circuit to control the selectable coupling by the switching circuit of the transceiver to the first or second antennas.

6. The apparatus according to claim 5, further including

a storage device to store programmed data signals; and

a microprocessor coupled to the control circuit and the storage device, the microprocessor operating under the control of the programmed data signals to control the operations of the control circuit.

7. The apparatus according to claim 1, wherein the first and second coil antennas are concentric with respect to each other.

8. The apparatus according to claim 1, wherein the first and second coil antennas are co-planar with respect to each other.

9. The apparatus according to claim 1, wherein the first coil antenna has a different geometry with respect to the second coil antenna.

10. A method of communicating with a device implanted within a patient'"'"'s body, comprising:

placing adjacent the patient'"'"'s body a major surface of a telemetry head comprising first and second coil antennas located generally parallel to the major surface;

employing a transceiver to communicate with the implanted device;

employing a switching circuit to selectably couple the transceiver to either of the first and second antennas; and

determining integrity of communications between the transceiver and an implanted device and employing the switching circuitry to selectably couple the transceiver to the first or second antenna as a function of the integrity of the communications.

11. The method according to claim 10, further comprising providing, for at least one of the first and second coil antennas, first and second coils coupled in series opposition to one another to provide improved signal-to-noise ratio.

12. The method according to claim 10, further comprising employing a permanent magnet to activate a reed switch within the device implanted within the patient'"'"'s body.

13. The method according to claim 10, further comprising controlling the selectable coupling by the switching circuit of the transceiver to the first or second antennas utilizing a control circuit.

14. The method according to claim 13, further comprising:

storing programmed data signals in a storage device; and

controlling the operations of the control circuit via a microprocessor executing under the control of the programmed data signals.

15. The method according to claim 10, wherein the first and second coil antennas are in different planes with respect to one another.

16. The method according to claim 10, wherein the first and second coil antennas are not concentric with respect to each other.