Abstract: The invention relates to a cover structure for a portable radio device, which structure also serves the forming of an antenna for the radio device. The cover of the radio device comprises a conductive planar component (330) and a dielectric planar component (340) fastened together. A certain part of the dielectric component extends under the conductive component. On the lower surface of that component, i.e. on the inner surface of the cover of the radio device and isolated from the conductive component of the cover, there is a conductive element (320), which is dimensioned to function as the feed element of the conductive component of the cover. Then the conductive component of the cover for its part functions as the radiator of the antenna of the radio device. Thus the cover structure of the radio device is utilized with only minor changes to implement such an antenna structure in which the electromagnetically fed radiating element is part of the cover of the radio device.