Capacitively loaded implantable loop antenna

An implantable medical device, comprising:

• an implantable housing;
• a header coupled to an outer surface of the implantable housing;
• control circuitry within the implantable housing, the control circuitry including a telemetry circuit configured to enable radio frequency communication with an external device separate from the implantable medical device;
• and
• a capacitively loaded loop antenna disposed within the header configured to facilitate radio frequency communication, the capacitively loaded loop antenna comprising a feed, a radiating element, and a return to a conductor of the implantable medical device serving as a ground plane for the capacitively loaded loop antenna, creating an inductance between the feed and the ground plane of the implantable medical device,
• wherein the feed is configured to couple the telemetry circuit to the radiating element,
• wherein the radiating element comprises a conductor having a length along a major axis with a larger cross section than a cross section of a major axis of the feed and a cross section of a major axis of the return, and a height above the ground plane of the implantable medical device, creating a capacitance between the radiating element and the ground plane, configured to at least partially counter the inductance of the capacitively loaded loop antenna, and
• wherein the length of the radiating element is between 5 and 8 mm, the width of the radiating element is between 1 and 2.5 mm, and the thickness of the radiating element is between 0.2 and 0.6 mm.

An implantable medical device, comprising:

• an implantable housing comprising a conductive surface;
• a header coupled to an outer surface of the implantable housing;
• control circuitry within the implantable housing, the control circuitry including a telemetry circuit configured to enable radio frequency communication with an external device separate from the implantable medical device;
• and
• a capacitively loaded loop antenna disposed within the header and coupled to the telemetry circuit, the capacitively loaded loop antenna configured to facilitate radio frequency communication comprising a feed, a radiating element, and a return to the conductive surface of the implantable housing, creating an inductance between the feed and the conductive surface,
• wherein the feed extends from the conductive surface of the implantable housing, coupling the telemetry circuit to the radiating element through a connector block,
• wherein the radiating element comprises a conductor having a major axis with a larger cross section than a cross section of a major axis of the feed and a cross section of a major axis of the return, and a height above a top surface of the implantable housing, creating a capacitance between the radiating element and the conductive surface, wherein the capacitance of the radiating element is configured to counteract the inductance of the capacitively loaded loop antenna, and
• wherein the return extends from the radiating element to the conductive surface of the implantable housing, coupling the radiating element to the conductive surface of the implantable housing, wherein the conductive surface of the implantable housing functions as a ground plane for the capacitively loaded loop antenna,
• wherein the radiating element comprises a planar conductor having a length and width along a top surface of the implantable housing and a thickness normal to the top surface of the implantable housing,
• wherein the major axis of the radiating element is along the length of the planar conductor, and
• wherein the width of the planar conductor is wider than a width of the feed and the return by at least a factor of two.