The present invention concerns a slot antenna for an electronic device, e.g. a set top box. A printed circuit board (210) comprising a dielectric material (310, 320, 330, 340, 350) and electrodes (240, 360) extends into a rectangular slot (120) in the metal enclosure (110) of the device such that the electrodes are coupled with locations on opposite edges of the long dimension of the rectangular slot. The coupling may be capacitively in order to affect the level of coupling or to optimize the driving point return loss. The presence of the dielectric in the slot allows the use of a shorter slot for a given wavelength.