Abstract: An antenna arrangement is provided in which a slot antenna is attached to the surface of an equipment case made of a dielectric material, there being provided also a ground plane spaced a small distance apart from the case and behind the antenna. The equipment may be a personal computer, e.g. a notebook computer, and the antenna, which may take the form of a copper foil, may be attached to the lid of the computer by an adhesive on its rear surface. The ground plane may, in this case, take the form of an existing display backplane. The invention provides for the realization of a compact antenna arrangement due to the effect of the case dielectric on the effective electrical length of the slot antenna.