Method of detecting movements around automatic doors

摘要

The invention relates to a planar antenna which comprises the following elements: a plurality of antenna elements positioned relative to each other in a predetermined orientation; each of the plurality of antenna elements being selectively electrically connectable to one or more of the other antenna elements; a plurality of switches which electrically connect the plurality of antenna elements so that closing one of the switches causes at least two antenna elements to be electrically connected, an antenna array which is defined by the plurality of switches in combination with the plurality of antenna elements; the antenna elements are positioned on a planar substrate in such a way that at least two different lobes of the antenna can be provided by activating different antenna elements by means of the switches located on the antenna substrate itself. The planar antenna can be used advantageously in Door opener sensors. <IMAGE>