In the presented work, a unit cell of a self-complementary metamaterial was designed, which is alternating patches and holes in a conductive graphene-like layer 7 μm thick on a silicon carbide substrate 250 μm thick. The results of a numerical study of the developed structure are presented. The calculations considered the conductivity of the graphene-like film, as well as the dielectric parameters of the silicon carbide substrate. The developed metamaterial is designed to convert circular polarization into linear; the central operating frequency of the resulting structure is 10 GHz. The dimensions of the unit cell are 2.8 mm × 5.6 mm. The elements obtained can be used in microwave technology and antenna structures. For the manufacture of structures, it is planned to use the method of plasma-chemical etching of silicon carbide in a fluorine-containing gas environment, which destroys the silicon component and leaves a graphene-like conductive layer on the surface. The thickness of the graphene-like layer depends on the power of the inductively coupled plasma source and the processing time; in this work, a thickness of 7 µm was taken, obtained at 800 W and 8.5 minutes of etching SiC in an SF6/Ar atmosphere.