LOW LOSS BAND PASS FILTER FOR RF DISTANCE TELEMETRY PIN ANTENNAS OF ACTIVE IMPLANTABLE MEDICAL DEVICES

• US 20070123949A1
• Filed: 11/07/2006
• Published: 05/31/2007
• Est. Priority Date: 11/11/2005
• Status: Abandoned Application

• Current Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Original Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Inventors: Stevenson, Robert, Dabney, Warren
• Application Number:
  US11/557,210
• Publication Number:
  US 20070123949A1
• Time in Patent Office: Days
• US Class Current: 607/37
• CPC Class Codes: A61N 1/3718 Monitoring of or protection against external electromagnetic fields or currents
• CPC Class Codes: A61N 1/3754 Feedthroughs
• CPC Class Codes: H01G 4/35 Feed-through capacitors or anti-noise capacitors
• CPC Class Codes: H03H 1/0007 of radio frequency interference filters
• CPC Class Codes: H03H 2001/0042 Wound, ring or feed-through type capacitor
• CPC Class Codes: H03H 2001/0071 comprising zig-zag inductor
• CPC Class Codes: H03H 2001/0085 Multilayer, e.g. LTCC, HTCC, green sheets
• CPC Class Codes: H03H 7/175 Series LC in series path H03H7/1783 takes precedence
• CPC Class Codes: H03H 7/1775 Parallel LC in shunt or branch path H03H7/1791 takes precedence

Abstract

A hermetic terminal for an active implantable medical device (AIMD), includes an RF distance telemetry pin antenna, a capacitor conductively coupled between the antenna and a ground for the AIMD, and an inductor electrically disposed in parallel with the capacitor and conductively coupled between the antenna and a ground for the AIMD. The capacitor and the inductor form a band pass filter for attenuating electromagnetic signals through the antenna except at a selected frequency band. Values of capacitance and inductance are selected such that the band pass filter is resonant at the selected frequency band.

Claims

1. A hermetic terminal for an active implantable medical device (AIMD), comprising:

an RF distance telemetry pin antenna; and

a band pass filter for attenuating electromagnetic signals through the antenna except at a selected frequency band, the band pass filter comprising a capacitor in parallel with an inductor, said band pass filter being conductively coupled between the antenna and a ground for the AIMD.

2. The terminal of claim 1, wherein inductor Q is relatively maximized and capacitor Q is relatively minimized to reduce the overall Q of the band pass filter.

3. The terminal of claim 2, wherein the inductor Q is relatively maximized by minimizing resistive loss in the inductor.

4. The terminal of claim 2, wherein the capacitor Q is relatively minimized by raising equivalent series resistance of the capacitor.

5. The terminal of claim 1, wherein inductor Q is relatively minimized and capacitor Q is relatively maximized to reduce the overall Q of the band pass filter.

6. The terminal of claim 1, wherein inductor Q and capacitor Q are both relatively minimized to reduce the overall Q of the band pass filter.

7. The terminal of claim 1, wherein overall Q of the band pass filter is reduced to permit passage of electromagnetic signals through the antenna along a range of selected frequency bands.

8. The terminal of claim 1, wherein the AIMD comprises a cochlear implant, a piezoelectric sound bridge transducer, a neurostimulator, a brain stimulator, a cardiac pacemaker, a ventricular assist device, an artificial heart, a drug pump, a bone growth stimulator, a bone fusion stimulator, a urinary incontinence device, a pain relief spinal cord stimulator, an anti-tremor stimulator, a gastric stimulator, an implantable cardioverter defibrillator, a congestive heart failure device, a neuromodulator, a cardiovascular stent, or an orthopedic implant.

9. The terminal of claim 1, wherein a process for designing the band pass filter comprises the steps of:

configuring the physical relationship of the capacitor and the inductor of the band pass filter, based on the selected frequency band;

iteratively selecting component values for the capacitor and inductor of the band pass filter; and

analyzing the characteristics of the selected components to assess whether the band pass filter meets all design criteria for use in association with the hermetic terminal.

10. The process of claim 9, including repeating the iteratively selecting and analyzing steps if the band pass filter does not meet all design criteria for use in association with the hermetic terminal.

11. The process of claim 9, including the steps of:

building a prototype of the AIMD comprising a band pass filter having selected components that have been assessed to be acceptable; and

testing the prototype to determine whether the band pass filter meets all criteria for use in association with the hermetic terminal.

12. The process of claim 11, including repeating the configuring, iteratively selecting and analyzing steps if the prototype fails the testing step.

13. The terminal of claim 1, wherein the capacitor comprises a feedthrough capacitor.

14. The terminal of claim 13, wherein the feedthrough capacitor forms an electromagnetic interference (EMI) filter for a leadwire extending through the hermetic terminal.

15. The terminal of claim 14, wherein the inductor is applied to the feedthrough capacitor.

16. The terminal of claim 14, wherein the inductor forms a spiral on the feedthrough capacitor, and is conductively coupled between the antenna and the ground.

17. The terminal of claim 13, including a substrate onto which the inductor is applied, the substrate being attached to the feedthrough capacitor.

18. The terminal of claim 17, wherein the inductor comprises multiple inductors printed on respective opposite sides of one or more of said substrates.

19. The terminal of claim 13, wherein the inductor is embedded within the feedthrough capacitor.

20. The terminal of claim 19, wherein the inductor is disposed between adjacent layers of the feedthrough capacitor.

21. The terminal of claim 19, wherein the capacitor-inductor structure of the band pass filter is formed utilizing a thick film deposition process.

22. The terminal of claim 14, wherein the inductor comprises a chip inductor conductively coupled between the antenna and the ground.

23. The terminal of claim 22, wherein the chip inductor includes a meander inductor.

24. The terminal of claim 22, wherein the chip inductor includes a spiral inductor.

25. The terminal of claim 22, wherein the chip inductor includes an inductor spiral formed about an insulator.

26. The terminal of claim 1, wherein the capacitor comprises a monolithic chip capacitor.

27. The terminal of claim 26, wherein the inductor comprises a chip inductor conductively coupled between the antenna and the ground.

28. The terminal of claim 27, wherein the capacitor and the inductor are stacked adjacent to one another, each being conductively coupled between the antenna and the ground.

29. The terminal of claim 27, wherein the capacitor and the inductor are disposed on a surface of the hermetic terminal, each being conductively coupled to both the antenna and the ground.

30. The terminal of claim 26, wherein the inductor is applied to a surface of the monolithic chip capacitor.

31. The terminal of claim 26, including a substrate onto which the inductor is applied, the substrate being attached to the monolithic chip capacitor.

32. The terminal of claim 31, wherein the inductor comprises multiple inductors printed on opposite sides of one or more of said substrates.

33. The terminal of claim 26, wherein the inductor is embedded within the monolithic chip capacitor.

34. The terminal of claim 33, wherein the inductor is disposed between adjacent layers of the monolithic chip capacitor.

35. The terminal of claim 33, wherein the capacitor-inductor structure of the band pass filter is formed utilizing a thick film deposition process.

36. The terminal of claim 30, wherein the inductor comprises a meander shape.

37. The terminal of claim 33, including an insulative layer disposed between the inductor and an adjacent capacitor plate.

38. A hermetic terminal for an active implantable medical device (AIMD), comprising:

an RF distance telemetry pin antenna;

a capacitor conductively coupled between the antenna and a ground for the AIMD; and

an inductor electrically disposed in parallel with the capacitor, and conductively coupled between the antenna and a ground for the AIMD;

wherein the capacitor and the inductor form a band pass filter for attenuating electromagnetic signals through the antenna except at a selected frequency band, and wherein values of capacitance and inductance are selected such that the band pass filter is resonant at the selected frequency band.

39. The terminal of claim 38, wherein the capacitor comprises a feedthrough capacitor.

40. The terminal of claim 39, wherein the feedthrough capacitor forms an electromagnetic interference (EMI) filter for a leadwire extending through the hermetic terminal, and wherein the inductor is applied to the feedthrough capacitor.

41. The terminal of claim 39, wherein the inductor is applied to the feedthrough capacitor.

42. The terminal of claim 39, wherein the inductor forms a spiral on the feedthrough capacitor, and is conductively coupled between the antenna and the ground.

43. The terminal of claim 39, including a substrate onto which the inductor is applied, the substrate being attached to the feedthrough capacitor.

44. The terminal of claim 43, wherein the inductor comprises multiple inductors printed on respective opposite sides of one or more of said substrates.

45. The terminal of claim 39, wherein the inductor is embedded within the feedthrough capacitor.

46. The terminal of claim 45, wherein the inductor is disposed between adjacent layers of the feedthrough capacitor.

47. The terminal of claim 45, wherein the capacitor-inductor structure of the band pass filter is formed utilizing a thick film deposition process.

48. The terminal of claim 39, wherein the inductor comprises a chip inductor conductively coupled between the antenna and the ground.

49. The terminal of claim 38, wherein the capacitor comprises a monolithic chip capacitor.

50. The terminal of claim 49, wherein the inductor comprises a chip inductor conductively coupled between the antenna and the ground.

51. The terminal of claim 50, wherein the capacitor and the inductor are stacked adjacent to one another, each being conductively coupled between the antenna and the ground.

52. The terminal of claim 50, wherein the capacitor and the inductor are disposed on a surface of the hermetic terminal, each being conductively coupled to both the antenna and the ground.

53. The terminal of claim 49, wherein the inductor is applied to a surface of the monolithic chip capacitor.

54. The terminal of claim 49, including a substrate onto which the inductor is applied, the substrate being attached to the monolithic chip capacitor.

55. The terminal of claim 54, wherein the inductor comprises multiple inductors printed on opposite sides of one or more of said substrates.

56. The terminal of claim 49, wherein the inductor is embedded within the monolithic chip capacitor.

57. The terminal of claim 56, wherein the inductor is disposed between adjacent layers of the monolithic chip capacitor.

58. The terminal of claim 56, wherein the capacitor-inductor structure of the band pass filter is formed utilizing a thick film deposition process.

59. The terminal of claim 53, wherein the inductor comprises a meander shape.

60. The terminal of claim 56, including an insulative layer disposed between the inductor and an adjacent capacitor plate.

61. A hermetic terminal for an active implantable medical device (AIMD), comprising:

an RF distance telemetry pin antenna;

a feedthrough capacitor conductively coupled between the antenna and a ground for the AIMD; and

an inductor electrically disposed in parallel with the capacitor, and conductively coupled between the antenna and a ground for the AIMD;

wherein the capacitor and the inductor form a band pass filter for attenuating electromagnetic signals through the antenna except at a selected frequency band; and

wherein overall Q of the band pass filter is reduced to prevent passage of electromagnetic signals through the antenna along a range of selected frequency bands.

62. The terminal of claim 61, wherein the AIMD comprises a cochlear implant, a piezoelectric sound bridge transducer, a neurostimulator, a brain stimulator, a cardiac pacemaker, a ventricular assist device, an artificial heart, a drug pump, a bone growth stimulator, a bone fusion stimulator, a urinary incontinence device, a pain relief spinal cord stimulator, an anti-tremor stimulator, a gastric stimulator, an implantable cardioverter defibrillator, a congestive heart failure device, a neuromodulator, a cardiovascular stent, or an orthopedic implant.

63. The terminal of claim 61, wherein the feedthrough capacitor forms an electromagnetic interference (EMI) filter for a leadwire extending through the hermetic terminal, and wherein the inductor is applied to the feedthrough capacitor.

64. The terminal of claim 61, wherein the inductor forms a spiral on the feedthrough capacitor, and is conductively coupled between the antenna and the ground.

65. The terminal of claim 61, including a substrate onto which the inductor is applied, the substrate being attached to the feedthrough capacitor.

66. The terminal of claim 65, wherein the inductor comprises multiple inductors printed on respective opposite sides of one or more of said substrates.

67. The terminal of claim 61, wherein the inductor is embedded within the feedthrough capacitor.

68. The terminal of claim 67, wherein the inductor is disposed between adjacent layers of the feedthrough capacitor.

69. The terminal of claim 67, wherein the capacitor-inductor structure of the band pass filter is formed utilizing a thick film deposition process.

70. The terminal of claim 61, wherein the inductor comprises a chip inductor conductively coupled between the antenna and the ground.

71. The terminal of claim 61, wherein a process for designing the band pass filter comprises the steps of:

configuring the physical relationship of the capacitor and the inductor of the band pass filter, based on the selected frequency band;

iteratively selecting component values for the capacitor and inductor of the band pass filter; and

analyzing the characteristics of the selected components to assess whether the band pass filter meets all design criteria for use in association with the hermetic terminal.

72. The process of claim 71, including repeating the iteratively selecting and analyzing steps if the band pass filter does not meet all design criteria for use in association with the hermetic terminal.

73. The process of claim 71, including the steps of:

building a prototype of the AIMD comprising a band pass filter having selected components that have been assessed to be acceptable; and

testing the prototype to determine whether the band pass filter meets all criteria for use in association with the hermetic terminal.

74. The process of claim 73, including repeating the configuring, iteratively selecting and analyzing steps if the prototype fails the testing step.

75. A hermetic terminal for an active implantable medical device (AIMD), comprising:

an RF distance telemetry pin antenna;

a monolithic chip capacitor conductively coupled between the antenna and a ground for the AIMD; and

an inductor electrically disposed in parallel with the capacitor, and conductively coupled between the antenna and a ground for the AIMD;

wherein the capacitor and the inductor form a band pass filter for attenuating electromagnetic signals through the antenna except at a selected frequency band.

76. The terminal of claim 75, wherein the inductor comprises a chip inductor conductively coupled between the antenna and the ground.

77. The terminal of claim 76, wherein the capacitor and the inductor are stacked adjacent to one another, each being conductively coupled between the antenna and the ground.

78. The terminal of claim 76, wherein the capacitor and the inductor are disposed on a surface of the hermetic terminal, each being conductively coupled to both the antenna and the ground.

79. The terminal of claim 75, wherein the inductor is applied to a surface of the monolithic chip capacitor.

80. The terminal of claim 75, including a substrate onto which the inductor is applied, the substrate being attached to the monolithic chip capacitor.

81. The terminal of claim 80, wherein the inductor comprises multiple inductors printed on opposite sides of one or more of said substrates.

82. The terminal of claim 75, wherein the inductor is embedded within the monolithic chip capacitor.

83. The terminal of claim 82, wherein the inductor is disposed between adjacent layers of the monolithic chip capacitor.

84. The terminal of claim 82, wherein the capacitor-inductor structure of the band pass filter is formed utilizing a thick film deposition process.

85. The terminal of claim 79, wherein the inductor comprises a meander shape.

86. The terminal of claim 82, including an insulative layer disposed between the inductor and an adjacent capacitor plate.

87. The terminal of claim 75, wherein the AIMD comprises a cochlear implant, a piezoelectric sound bridge transducer, a neurostimulator, a brain stimulator, a cardiac pacemaker, a ventricular assist device, an artificial heart, a drug pump, a bone growth stimulator, a bone fusion stimulator, a urinary incontinence device, a pain relief spinal cord stimulator, an anti-tremor stimulator, a gastric stimulator, an implantable cardioverter defibrillator, a congestive heart failure device, a neuromodulator, a cardiovascular stent, or an orthopedic implant.