Receive coil arrangements for leadless rechargeable epicardial pacemaker

A wireless power transfer system, the system comprising:

• two or more electrodes configured to be placed proximal to target tissue of a patient;
• an implantable medical device comprising:
• circuitry configured to:
• measure bioelectrical signals of the patient via the two or more electrodes;
• and
• receive wireless power;
• an electrical energy storage device configured to provide electrical energy to the circuitry, wherein the circuitry is configured to charge the energy storage device using the wireless power;
• and
• a secondary antenna configured to configured to receive the wireless power and conduct the wireless power to the circuitry, the secondary antenna comprising:
• a first coil that defines a first aperture, the first aperture oriented in a first direction;
• a second coil that defines a second aperture, the second aperture oriented in a second direction substantially orthogonal to the first aperture;
• and
• a third coil that defines a third aperture, wherein the third aperture:
• is oriented in a third direction substantially orthogonal to the first direction and the second direction;
• and
• has at least twice the area as either of the first aperture and the second aperture.

A method of manufacturing a wireless power receiving device comprising:

• forming a first coil around a ferrite core, wherein the first coil defines a first aperture, the first aperture oriented in a first direction;
• forming a second coil around the ferrite core, wherein the second coil defines a second aperture, the second aperture oriented in a second direction substantially orthogonal to the first aperture;
• arranging the ferrite core proximal to circuitry and electrically connecting the first coil and the second coil to the circuitry;
• arranging an electrical energy storage device proximal to the circuitry and electrically connecting the electrical energy storage device to the circuitry, wherein the circuitry is configured to receive wireless power via the first coil and the second coil, wherein the circuitry is configured to charge the energy storage device using the wireless power received during a charging session, wherein the electrical energy storage device is configured to provide electrical energy to the circuitry;
• and
• forming a third coil that defines a third aperture, wherein the third aperture:
• is oriented in a third direction substantially orthogonal to the first direction and the second direction;
• and
• has at least twice the area as either of the first aperture and the second aperture.