Capacitor for an active implantable medical device (AIMD) for handling high RF power induced in an implanted lead from an external RF field
First Claim
Patent Images
1. An RF capacitor, comprising:
- a) a dielectric body comprising a dielectric sidewall extending along a longitudinal axis from a dielectric body first end to a dielectric body second end;
b) a terminal member supported in the dielectric body and comprising a length extending to first and second terminal ends spaced from the respective first and second dielectric body ends;
c) a plurality of active electrode plates supported in the dielectric body, each active electrode plate having an active electrode length extending from a first active edge to a second active edge electrically connected to the terminal member,d) a plurality of ground electrode plates supported in the dielectric body, each ground electrode plate having a ground electrode length extending from a first ground edge to a second ground edge electrically connectable to an energy dissipating surface comprising a conductive ferrule or an active implantable medical device (AIMD) housing,e) wherein the ground and active electrode plates are in an interleaved, spaced relationship with only a portion of the active and ground electrode lengths extending from the first active and ground edges to the respective second active and ground edges being vertically above or below the other of the active and ground electrode plates in an orientation extending along the longitudinal axis of the dielectric body; and
f) at least three extra ground electrode plates in the dielectric body, each extra ground electrode plate extending from an extra ground electrode plate first edge electrically connectable to the energy dissipating surface to an extra ground electrode plate second edge spaced from the terminal member and being in a spaced relationship with the plurality of interleaved active and ground electrode plates along the longitudinal axis without any active electrode plates being interleaved between the three extra ground electrode plates.
5 Assignments
0 Petitions
Accused Products
Abstract
An RF filter for an active medical device (AMD), for handling RF power induced in an associated lead from an external RF field at a selected MRI frequency or range frequencies includes a capacitor having a capacitance of between 100 and 10,000 picofarads, and a temperature stable dielectric having a dielectric constant of 200 or less and a temperature coefficient of capacitance (TCC) within the range of plus 400 to minus 7112 parts per million per degree centigrade. The capacitor'"'"'s dielectric loss tangent in ohms is less than five percent of the capacitor'"'"'s equivalent series resistance (ESR) at the selected MRI RF frequency or range of frequencies.
45 Citations
31 Claims
-
1. An RF capacitor, comprising:
-
a) a dielectric body comprising a dielectric sidewall extending along a longitudinal axis from a dielectric body first end to a dielectric body second end; b) a terminal member supported in the dielectric body and comprising a length extending to first and second terminal ends spaced from the respective first and second dielectric body ends; c) a plurality of active electrode plates supported in the dielectric body, each active electrode plate having an active electrode length extending from a first active edge to a second active edge electrically connected to the terminal member, d) a plurality of ground electrode plates supported in the dielectric body, each ground electrode plate having a ground electrode length extending from a first ground edge to a second ground edge electrically connectable to an energy dissipating surface comprising a conductive ferrule or an active implantable medical device (AIMD) housing, e) wherein the ground and active electrode plates are in an interleaved, spaced relationship with only a portion of the active and ground electrode lengths extending from the first active and ground edges to the respective second active and ground edges being vertically above or below the other of the active and ground electrode plates in an orientation extending along the longitudinal axis of the dielectric body; and f) at least three extra ground electrode plates in the dielectric body, each extra ground electrode plate extending from an extra ground electrode plate first edge electrically connectable to the energy dissipating surface to an extra ground electrode plate second edge spaced from the terminal member and being in a spaced relationship with the plurality of interleaved active and ground electrode plates along the longitudinal axis without any active electrode plates being interleaved between the three extra ground electrode plates. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
-
-
30. A capacitor, comprising:
-
a) a dielectric body comprising a dielectric sidewall extending along a longitudinal axis from a dielectric body first end to a dielectric body second end; b) a terminal member supported in the dielectric body and comprising a length extending to first and second terminal ends spaced from the respective first and second dielectric body ends; c) a plurality of active electrode plates supported in the dielectric body, each active electrode plate having an active electrode length extending from a first active edge to a second active edge electrically connected to the terminal member, d) a plurality of ground electrode plates supported in the dielectric body, each ground electrode plate having a ground electrode length extending from a first ground edge to a second ground edge electrically connectable to an energy dissipating surface comprising a conductive ferrule or an active implantable medical, device (AIMD) housing, e) wherein there are at least ten ground and ten active electrode plates in an interleaved, spaced relationship with only a portion of the active and ground electrode lengths extending from the first active and ground edges to the respective second active and ground edges being vertically above or below the other of the active and ground electrode plates in an orientation extending along the longitudinal axis of the dielectric body; and f) at least three extra ground electrode plates in the dielectric body, each extra ground electrode plate extending from an extra ground electrode plate first edge electrically connectable to the energy dissipating surface to an extra ground electrode plate second edge spaced from the terminal member and being in a spaced relationship with the plurality of interleaved active and ground electrode plates along the longitudinal axis without any active electrode plates being interleaved between the three extra ground electrode plates; g) wherein the capacitor has a capacitance of from 10 to 20,000 picofarads, and h) wherein the dielectric has a dielectric constant of 200 or less, and a temperature coefficient of capacitance (TCC) within the range of plus 400 to minus 7112 parts per million per degree centigrade (ppm/°
C.);i) wherein the capacitor'"'"'s dielectric loss tangent in ohms is less than five percent of the capacitor'"'"'s equivalent series resistance (ESR) at the desired center frequency or desired range of frequencies; and j) wherein the equivalent series resistance is less than 100 milliohms.
-
-
31. A capacitor, comprising:
-
a) a dielectric body comprising a dielectric sidewall extending along a longitudinal axis from a dielectric body first end to a dielectric body second end; b) a terminal member supported in the dielectric body and comprising a length extending to first and second terminal ends spaced from the respective first and second dielectric body ends; c) a plurality of active electrode plates supported in the dielectric body, each active electrode plate having an active electrode length extending from a first active edge to a second active edge electrically connected to the terminal member, d) a plurality of ground electrode plates supported in the dielectric body, each ground electrode plate having a ground electrode length extending from a first ground edge to a second ground edge electrically connectable to an energy dissipating surface comprising a conductive ferrule or an active implantable medical device (AIMD) housing, e) wherein the ground and active electrode plates are in an interleaved, spaced relationship with only a portion of the active and ground electrode lengths extending from the first active and ground edges to the respective second active and ground edges being vertically above or below the other of the active and ground electrode plates in an orientation extending along the longitudinal axis of the dielectric body; and f) at least three extra ground electrode plates in the dielectric body, each extra ground electrode plate extending from an extra ground electrode plate first edge electrically connectable to the energy dissipating surface to an extra ground electrode plate second edge spaced from the terminal member and being in a spaced relationship with the plurality of interleaved active and ground electrode plates along the longitudinal axis without any active electrode plates being interleaved between the three extra ground electrode plates; g) wherein the capacitor has a capacitance of from 10 to 20,000 picofarads, and h) wherein the dielectric has a dielectric constant of 200 or less and a temperature coefficient of capacitance (TCC) within the range of plus 400 to minus 7112 parts per million per degree centigrade (ppm/°
C.);i) wherein an equivalent series resistance (ESR) of the capacitor at a designated MRI center frequency or designated range of frequencies is less than 0.1 ohms; j) wherein the capacitor'"'"'s dielectric loss tangent in ohms is less than five percent of the ESR at the designated MRI center frequency or designated range of frequencies.
-
Specification