Subject matter such as a method or apparatus can include an implantable antenna assembly, comprising a dielectric shell including first and second substantially parallel outer face portions, and a third outer face portion extending between the first and second portions, a spiral conductor extending along the first, second, and third portions on a surface of the dielectric shell. The dielectric shell and spiral conductor can be configured to be mechanically attached to a dielectric compartment, such as configured to be coupled to a housing of an implantable medical device. In an example, the implantable antenna assembly is configured to be electrically coupled to an implantable telemetry circuit configured to wirelessly transfer information electromagnetically using the implantable telemetry antenna, such as included as a portion of an implantable medical device.