There is disclosed an antenna system for mobile handsets and other devices. The antenna system comprises a dielectric substrate having first and second opposed surfaces, a conductive track on the substrate, and a separate, directly driven antenna to drive the parasitic loop antenna formed by the conductive track. Two grounding points are provided adjacent to each other on the first surface of the substrate, with the arms of the conductive track extending in generally opposite directions from the grounding points. The conductive tracks then extend towards an edge of the dielectric substrate, before passing to the second surface of the dielectric substrate and then passing across the second surface of the dielectric substrate following a path generally following the path taken on the first surface of the dielectric substrate. The conductive tracks then connect to respective sides of a conductive arrangement formed on the second surface of the dielectric substrate that extends into a central part of a loop formed by the conductive track on the second surface of the dielectric substrate.