Antenna systems for implantable medical device telemetry

• US 20040106967A1
• Filed: 12/03/2002
• Published: 06/03/2004
• Est. Priority Date: 12/03/2002
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Rawat, Prashant, Von Arx, Jeffrey A., Mass, William R.
• Granted Patent: US 7,072,718 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

Abstract

An implantable medical device system includes an implanted device communicating with an external device via telemetry. The implanted device and the external device each have a telemetry module connected to an antenna system to support a radio-frequency (RF) telemetry link. The antenna system of the external device has a manually or automatically controllable directionality. The controllable directionality is achieved, for example, by using two or more directional antennas, one non-directional antenna and one or more directional antennas, or an electronically steerable phased-array directional antenna.

Claims

1. A system for communicating with an implantable medical device, the system comprising:

an external device adapted to be communicatively coupled to the implantable medical device via radio-frequency (RF) telemetry, the external device comprising;

a transceiver;

an antenna system comprising at least two antennas each having a predetermined directionality characteristic;

an antenna interface circuit coupled between the transceiver and the antenna system; and

a directionality controller coupled to the antenna interface circuit, the directionality controller adapted to control a directionality of the antenna system.

2. The system of claim 1, wherein the implantable medical device comprises at least one of a pacemaker, a cardioverter/defibrillator, a cardiac resynchronization therapy device, and a drug delivery device.

3. The system of claim 2, wherein the external device comprises a programmer adapted to program the implantable medical device.

4. The system of claim 2, wherein the external device comprises a monitor adapted to monitor at least one physiologic signal acquired by the implantable medical device.

5. The system of claim 1, further comprising a signal analyzer coupled to the transceiver and the directionality controller, the signal analyzer adapted to analyze a quality of each of one or more RF signals received by one or more of the at least two antennas, and wherein the directionality controller is adapted to control the directionality of the antenna system based on the quality of the each of the one or more RF signals.

6. The system of claim 5, wherein the signal analyzer comprises a signal strength detector adapted to measure an amplitude of the each of the one or more RF signals.

7. The system of claim 5, wherein the signal analyzer comprises a data integrity detector adapted to determine whether data contained in the each of the one or more RF signals meet predetermined quality criteria.

8. The system of claim 5, wherein the implantable medical device comprises an RF test signal generator to generate the one of more RF signals, upon receiving a command from the external device to cause the implantable medical device to operate in a telemetry testing mode.

9. The system of claim 5, wherein:

the antenna interface circuit comprises a switching circuit adapted to provide electrical connection between the transceiver and one of the at least two antennas; and

the directionality controller comprises an antenna selector adapted to control the electrical connection between the transceiver and the at least two antennas based on the quality of the each of the one or more RF signals received by each of the at least two antennas.

10. The system of claim 9, wherein the at least two antennas are each configured to be an antenna having a predetermined half-power beamwidth of less than about 180 degrees.

11. The system of claim 10, wherein the at least two antennas are each one of a planar patch antenna, a slot antenna, a parabolic reflector antenna, a Uda-Yagi antenna, and a helical antenna.

12. The system of claim 10, wherein the at least two antennas are printed on a printed circuit board housed in the external device.

13. The system of claim 12, wherein each of the at least two antennas is one of a planar patch antenna and a slot antenna.

14. The system of claim 9, wherein the at least two antennas are configured to be antennas having substantially different directionality characteristics.

15. The system of claim 14, wherein the at least two antennas comprise a first antenna and a second antenna, the first antenna being approximately non-directional on at least one plane, the second antenna being directional on the at least one plane.

16. The system of claim 15, wherein the first antenna is printed on a printed circuit board housed in the external device, and the second antenna is housed in a hand-held device coupled to the external device via a cable.

17. The system of claim 15, wherein the first antenna is one of a single planar dipole antenna, a planar monopole antenna, and a loop antenna, and the second antenna is one of a planar patch antenna and a slot antenna and has a predetermined half-power beamwidth of less than about 180 degrees.

18. The system of claim 15, wherein the at least two antennas further comprises a third antenna, the third antenna configured to be an additional directional antenna.

19. The system of claim 5, wherein

the antenna interface circuit comprises an antenna orientation circuit adapted to allow effective orientation of the antenna system;

and

the directionality controller comprises an electronic antenna steerer adapted to effectively orient the antenna system based on the quality of the each of the one or more RF signals.

20. The system of claim 19, wherein the at least two antennas comprise substantially identical planar dipole antennas.

21. The system of claim 20, wherein the at least two antennas are printed on a circuit board housed in the external device.

22. The system of claim 19, wherein the signal analyzer comprises a peak detection circuit adapted to determine an effective orientation of the antenna system at which a maximum amplitude is measured.

23. The system of claim 19, wherein the antenna interface circuit comprises a multiplier adapted to multiply weighting signals with the at least two antennas, and the electronic steerer comprises a weighting signal generator adapted to generate a plurality of weighting signals each corresponding to one of the at least two antennas to control the effective orientation of the antenna system.

24. The system of claim 19, wherein the antenna interface circuit comprises a plurality of delay lines, and the electronic steerer comprises a delay line selector adapted to control the effective orientation of the antenna system by selecting one of the plurality of delay lines to be coupled between each of the at least two antennas and the transceiver.

25. The system of claim 24, wherein each delay line of the plurality of delay lines comprises a conductive path having a predetermined length.

26. A method for communicating with an implantable medical device via radio-frequency (RF) telemetry, the method comprising:

receiving one or more RF signals from the implantable medical device using one or more antennas of an antenna system, the one or more antennas each having a predetermined directionality characteristic;

analyzing a quality of each of the one or more RF signals; and

controlling a directionality of the antenna system based on an outcome of the analyzing.

27. The method of claim 26, further comprising sending a command to the implantable medical device to cause it to produce and send the one or more RF signals.

28. The method of claim 26, further comprising transmitting commands via the antenna system to control the operation of the implantable medical device.

29. The method of claim 28, wherein transmitting commands via the antenna system to control the operation of the implantable medical device comprises transmitting commands via the antenna system to control delivery of at least one of a pacing therapy, a cardiovertion therapy, a defibrillation therapy, a cardiac resynchronization therapy, and a drug therapy.

30. The method of claim 28, further comprising receiving at least one of data indicative of an operational status of the implantable medical device and physiological data acquired by the implantable medical device via the antenna system.

31. The method of claim 26, wherein:

receiving the one or more RF signals comprises receiving a first RF signal using an antenna and receiving at least one further RF signal using at least one further antenna;

analyzing the quality comprises analyzing a quality of each of the first and further RF signals; and

controlling a directionality of the antenna system comprises selecting one of the first and further antennas.

32. The method of claim 31, wherein:

receiving the first RF signal comprises using a first directional antenna to receive the first RF signal; and

receiving the further RF signal comprises using a further directional antenna to receive the further RF signal.

33. The method of claim 31, wherein:

receiving the first RF signal comprises using an approximately non-directional antenna to receive the first RF signal; and

receiving the further RF signal comprises using a directional antenna to receive the further RF signal.

34. The method of claim 31, wherein:

analyzing the quality comprises;

determining a signal strength of the first RF signal;

determining a signal strength of the further RF signal; and

comparing the signal strengths of the first and further RF signals; and

selecting one of the antennas comprises selecting the antenna associated with the highest signal strength.

35. The method of claim 31, wherein:

each of the first RF signal and the further RF signal contain binary data;

analyzing the quality comprises;

determining data integrity of the first RF signal;

determining data integrity of the further RF signal;

determining whether the data integrity of the first RF signal satisfies a predetermined data integrity standard; and

determining whether the data integrity of the further RF signal satisfies the predetermined data integrity standard; and

selecting one of the antennas comprises selecting one of the antennas associated with an satisfactory data integrity.

36. The method of claim 26, further comprising steering electronically an effective orientation of the antenna system, wherein the antenna system comprises a plurality of antennas forming a phased-array antenna, and wherein:

receiving the one or more RF signals comprises receiving a first RF signal using the phased-array antenna oriented at each of a plurality of effective orientations;

analyzing the quality comprises analyzing a quality of the first RF signal associated with the each of the plurality of effective orientations; and

controlling the directionality of the antenna system comprises selecting one of the plurality of effective orientations based on an outcome of the analyzing the quality.

37. The method of claim 36, wherein analyzing the quality comprises measuring a signal strength of the first RF signal at each of the plurality of effective orientations, and selecting one of the plurality of effective orientations comprises selecting one of the plurality of effective orientations associated with the highest signal strength.

38. The method of claim 36, wherein analyzing the quality comprises measuring a signal strength and data integrity of the first RF signal at each of the plurality of effective orientations, and selecting one of the plurality of effective orientations comprises selecting, among the one or more of plurality of effective orientations where the data integrity of the first RF signal is satisfactory, one of the plurality of effective orientations associated with the highest signal strength.

39. The method of claim 36, further comprising repeating the steering, receiving, analyzing, and controlling on a periodic basis.

40. The method of claim 36, wherein steering electronically comprises applying weighting factors to the plurality of antennas and adjusting the values of the weighting factors to steer the effective orientation of the phased-array antenna.

41. The system of claim 36, wherein steering electronically comprises controlling transmission delays associated with the plurality of antennas and adjusting the transmission delays to steer the effective orientation of the phased-array antenna.

42. The method of claim 41, wherein adjusting the transmission delays comprises selecting delay lines coupled to the plurality of antennas.

43. The method of claim 26, wherein:

receiving the one or more RF signals comprises receiving a first RF signal using an antenna having a directionality characteristic;

analyzing the quality comprises analyzing a quality of the first RF signal and determining whether the quality satisfies a predetermined signal quality standard; and

receiving the one or more RF signals further comprises receiving at least one further RF signal from the implantable medical device using at least one further antenna having a further directional characteristic if the quality of the first RF signal does not satisfy the predetermined signal quality standard.

44. The method of claim 43, wherein the further antenna having the further directional characteristic is more directional on at least one plane than the antenna having the directionality characteristic.

45. The method of claim 43, further comprising:

analyzing a quality of the further RF signal;

determining whether the quality of the further RF signal satisfies the predetermined signal quality standard.

46. The method of claim 45, wherein:

the first and further RF signals each contain binary data;

analyzing the quality of the first RF signal comprises determining data integrity of the first RF signal; and

analyzing the quality of the further RF signal comprises determining data integrity of the further RF signal.