Abstract: A reflective target plate for mounting on a floating roof of a tank for ensuring satisfactory reflection of radar signals emitted from a radar level gauge towards the floating roof. The plate comprises a plurality of elongated grooves, each formed by two flat, radar reflective surfaces facing each other, normals of the surfaces being perpendicular to each other. A first set of elongated grooves has grooves extending with their longitudinal axis in a first direction, and a second set of elongated grooves has grooves extending with their longitudinal axis in a second direction, the first and second directions being perpendicular to each other. The target plate will sufficiently reflect circularly polarized radar and linearly polarized radar will be equally reflected regardless of the rotation of the plate. This will facilitate installation, as the orientation of the plate becomes less critical.