An electronic device includes a housing having a first side and a second side, a dielectric cover on the second side, and an electrically conductive peripheral structure along edges of the first and second sides. An antenna feed is coupled to a portion of the peripheral structure for using the portion as a radiating antenna element. A conductive member is located on or underneath the dielectric cover. A purpose of the conductive member is to enlarge the surface area where the electric field is distributed on to increase the antenna aperture for radiation.