An implantable cardiac monitoring device and method of manufacture are provided. The device comprises a device housing having electronic components therein. A feedthrough assembly is joined to the device housing. The device comprises an antenna. A header body is mounted to the device housing and encloses the antenna and feedthrough assembly. The antenna includes a pin mounting section and a plate shaped radiating section. The pin mounting and radiating sections are interconnected by a ribbon section having a predetermined length to at least partially tune the antenna to a communication frequency. The radiating section is positioned proximate to, and shaped to extend along, an outer surface of the header body.