| 摘要 |
<p>The antenna (12) has an axis of rotation (2,2') through the antenna plane. A drive device (3,4,5), preferably a geared motor, is coupled to the antenna support and rotates the antenna around the axis of rotation. The antenna is contained in a closed housing (20) and has a surface (25) which is transparent to RF radiation and has two areas (27,29) adjacent respectively to two areas (31,34) of the flat antenna when positioned respective to first and second angular directions. The flat antenna is preferably of quadrilateral shape and the axis of rotation is positioned through the diagonals of the quadrilateral. The drive device has a mechanism which ensures the antenna can be positioned in a number of predetermined orientations, with the mechanism switchable between two stable positions.</p> |
