| 摘要 |
The invention relates to a reference target, and a method of obtaining such a target, having a small monostatic radar cross section (RCS) at a frequency of interest and in a determined direction. The reference target, which may be a sphere (100), has rotational invariance of 2π/N, wherein N is an integer such that N≥3, relatively to a rotational symmetry axis (Oz). The target has over at least part of its surface a one-dimensional grating of grooves (110) for which the periodicity is substantially less than the wavelength. The depth of the grooves is selected in order to cancel out the backscatter coefficient of an incident wave along the axis (Oz). The grooves may be parallel to one another and form a predetermined angle, such as a right angle, with the rotational symmetry axis (fig. 1), or they may be arranged in a radial direction (fig. 3). The target may have symmetry of revolution around the rotational symmetry axis. The target may be made in a PEC (perfect electrical conductor), typically a metal material, and the grooves may be filled with a dielectric material. |
