An antenna structure including an antenna 10 with an outer main surface 11, where said antenna 10 is integrated in a surface of a surrounding material 20. Further comprising a transition zone 30 arranged along the perimeter of the main surface 11 and overlapping the main surface, where the transition zone 30 comprises a layer of a resistive material with a resistivity that varies with the distance from an outer perimeter of the transition zone 30 to enable a smooth transition of the scattering properties between the antenna 10 and the surrounding material 20.