Slot antenna for an implantable device

1. An implantable medical device having a case configured to house components of the implantable medical device, the implantable medical device comprising:

an inductive coil coupled to a rechargeable battery, the inductive coil operative to inductively couple to an external coil and to transfer energy from the external coil to the rechargeable battery to recharge the rechargeable battery;

a cutout formed in the case of the implantable medical device and filled with a dielectric material, wherein the cutout is operative to reduce eddy currents in the case during recharge of the rechargeable battery; and

a slot antenna disposed within the case, the slot antenna operative to communicate with an external device through the cutout in the case;

wherein the slot antenna comprises: a first dielectric layer; a slot formed in a first metal layer above the first dielectric layer; and a feed line formed in a second metal layer below the first dielectric layer.

2. The implantable medical device of claim 1 , further comprising:

a dielectric layer positioned between the slot antenna and the case.

3. The implantable medical device of claim 2 , wherein the dielectric layer is formed on the slot antenna.

4. The implantable medical device of claim 1 , wherein the slot antenna further comprising:

a metal via formed in the first dielectric layer, the metal via configured to couple the feed line to the first metal layer.

5. The implantable medical device of claim 4 , further comprising:

a second dielectric layer formed over the first metal layer and the slot.

6. The implantable medical device of claim 4 , further comprising:

a third dielectric layer formed below the second metal layer.

7. The implantable medical device of claim 1 , wherein the dielectric material is ceramic.

8. The implantable medical device of claim 1 , wherein the slot antenna is operative to communicate with the external device during recharge of the rechargeable battery.

9. An implantable medical device having a case configured to house components of the implantable medical device, the implantable medical device comprising:

a slot antenna disposed within the case, the slot antenna operative to communicate with an external device through a cutout in the case, the slot antenna further comprising:

a slot formed in a first metal layer above a first dielectric layer;

a feed line formed in a second metal layer below the first dielectric layer; and

a second dielectric layer formed over the first metal layer and the slot.

10. The implantable medical device of claim 9 , wherein the slot antenna further comprising:

a metal via formed in the first dielectric layer, the metal via configured to couple the feed line to the first metal layer.

11. The implantable medical device of claim 9 , wherein the case includes a plurality of cutouts and the slot antenna includes a plurality of slots formed in the first metal layer, wherein the plurality of slots are approximately aligned to the plurality of cutouts in the case.

12. The implantable medical device of claim 11 , wherein the plurality of cutouts and the corresponding plurality of slots are configured in a radial pattern, wherein the feed line formed in the second layer is curved to form a circular or a semi-circular shape, wherein the feed line is configured to pass under two or more of the plurality of slots.

13. The implantable medical device of claim 9 , further comprising:

a transmitter coupled to the feed line; and

a receiver coupled to the feed line;

wherein the feed line is operative to provide radio frequency current from the transmitter to the slot and to provide radio frequency signals received at the slot to the receiver.

14. The implantable medical device of claim 9 , wherein the first dielectric layer is a printed circuit board.