INVERTED E ANTENNA WITH PARALLEL PLATE CAPACITOR FORMED ALONG AN ARM OF THE ANTENNA FOR USE WITH AN IMPLANTABLE MEDICAL DEVICE

• US 20140002318A1
• Filed: 04/02/2013
• Published: 01/02/2014
• Est. Priority Date: 06/29/2012
• Status: Active Grant

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Inventors: Meulmester, Micah, Imani, Reza, Lim, Wisit, Li, Perry
• Granted Patent: US 9,634,381 B2
• Time in Patent Office: Days
• US Class Current: 343/720
• CPC Class Codes: A61N 1/36521 the parameter being derived from measurement of an electrical impedance
• CPC Class Codes: A61N 1/36542 controlled by body motion, e.g. acceleration
• CPC Class Codes: A61N 1/37229 Shape or location of the implanted or external antenna
• CPC Class Codes: A61N 1/37264 Changing the program; Upgrading firmware
• CPC Class Codes: A61N 1/375 Constructional arrangements, e.g. casings
• CPC Class Codes: A61N 1/37512 Pacemakers
• CPC Class Codes: A61N 1/3754 Feedthroughs
• CPC Class Codes: A61N 1/3962 in combination with another heart therapy
• CPC Class Codes: A61N 1/39622 Pacing therapy
• CPC Class Codes: B29C 65/48 using adhesives , i.e. using supplementary joining material; solvent bonding
• CPC Class Codes: B29L 2031/753 Medical equipment; Accessories therefor bloodbags, medical bags B29L2031/7148; artificial eyes B29L2011/0008
• CPC Class Codes: H01Q 1/22 by structural association with other equipment or articles
• 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 9/0421 with a shorting wall or a shorting pin at one end of the element H01Q9/0414 takes precedence
• CPC Class Codes: H01Q 9/42 with folded element, the folded parts being spaced apart a small fraction of the operating wavelength

Abstract

The device includes radio frequency (RF) communication components installed within a case of the device and an antenna with an inverted E shape mounted within a header of the device. The antenna has three branches extending from a main arm: a capacitive branch connecting one end of the main arm to the case; an RF signal feed branch connecting a middle portion of the main arm to the internal RF components of the device via a feedthrough; and an inductive branch connecting the opposing (far) end of the main arm to the case to provide a shunt to ground.

Claims

1. An implantable medical device for implant within a patient, the device comprising:

radio frequency (RF) communication components installed within a case of the device; and

an antenna coupled to the RF communication components and having an inverted E shape wherein a first branch of the antenna includes a capacitor formed of a set of conducting plates with a non-conductive medium interposed between the plates.

2. The device of claim 1 wherein the antenna includes a second branch providing an RF signal feed and a third branch providing a shunt to ground.

3. The device of claim 1 wherein the capacitor of the first branch is formed between a distal end of the first branch and a center arm of the antenna, the distal end of the first branch being coupled to the case of the device.

4. The device of claim 1 wherein the set of plates of the capacitor includes a pair of parallel plates.

5. The device of claim 1 wherein a capacitance provided by the set of plates is set based on respective sizes of the plates, distances between the plates and electrical characteristics of the non-conductive medium interposed between the plates.

6. The device of claim 1 wherein the non-conductive medium includes a dielectric.

7. The device of claim 1 wherein the plates are formed of titanium.

8. The device of claim 1 wherein the first branch is mounted to a case of the device that provides a ground plane for the antenna.

9. The device of claim 2 wherein the second branch of the antenna is coupled to the RF communication components within the case via a feedthrough.

10. The device of claim 2 wherein an impedance of the antenna is set based on a location of the second branch relative to the first and third branches of the antenna.

11. The device of claim 2 wherein the third branch is mounted directly to the case of the device and provides an inductance.

12. The device of claim 11 wherein an inductance of the third branch is set based on a length of the third branch.

13. The device of claim 12 wherein a resonant frequency of the antenna is adjustable based on one or more of:

relative lengths of the first, second and third branches;

a capacitance of the first branch;

a location of the second branch relative to the third branch and a cross-sectional area of conducting elements forming the components of the antenna.

14. The device of claim 2 wherein a capacitance of the first branch is set relative to an inductance of the antenna to provide substantially no reactance.

15. The device of claim 1 wherein an input impedance of the antenna is substantially equal to a complex conjugate of an impedance of the RF frequency components.

16. The device of claim 1 wherein the implantable medical device is a cardiac rhythm management device.

17. The device of claim 1 wherein the RF components include one or more of Medical Implant Communication Service (MICS) components and Medical Device Radiocommunications Service (MedRadio) components.

18. The device of claim 1 wherein the inverted E-shaped antenna is fitted within a header of the device, the header mounted to an exterior surface of the case.

19. An antenna for use with an implantable medical device, the antenna comprising:

a main conducting arm;

a first conducting branch extending from a first end of the main arm and including a capacitor formed of a set of conducting plates with a non-conductive medium interposed between the plates;

a second conducting branch extending from a middle portion of the main arm for providing a radio frequency (RF) signal feed; and

a third conducting branch extending from a second end of the main arm for providing a shunt to ground.

20. A method for use with an implantable medical device for implant within a patient, the method comprising:

installing a radio frequency (RF) antenna having an inverted E shape in a header of the device, the inverted E shape antenna including three branches, wherein a first branch of the antenna is capacitive, a second branch provides an RF signal feed and a third branch provides a shunt to ground; and

wherein the first branch includes a capacitor formed of a set of conducting plates with a non-conductive medium interposed between the plates;

generating RF signals using RF communication components installed within a case of the device; and

transmitting the RF signals using the antenna with the inverted E shape.