An antenna device for use in a portable radio communication device comprises a ground plane (110), a microstrip line (114) connected to a feed point (116) for feeding and/or receiving radio frequency signals. A package (120) having an electrically conductive housing (122) is provided in the radio communication device, wherein the housing is provided above the ground plane and the microstrip line, wherein the housing is galvanically insulated from the microstrip line, and wherein the housing is capacitively coupled to the microstrip line. The antenna device thus has a large radiating area and thus providing better performance of the device. Also, an already existing part in the radio communication device, e.g., a battery package, can be used also as radiating element, saving space and costs.