An implantable medical device has a conductive housing, electronic circuitry for the operation of the implantable medical device, and radio frequency circuitry for transmitting and/or receiving radio frequency signals, the electronic circuitry and the radio frequency circuitry being interconnected and arranged within in the housing. The housing has at least one slot therein, and a slot feed operatively interconnected between the radio frequency circuitry and the slot. The electrically conductive housing provided with the at least one slot is operable as an antenna for the radio frequency signals. The electric circuitry, the radio frequency circuitry, and the interconnection can be enclosed by the housing so that they are shielded from external radiation in any direction.