Basic properties of interaction between electromagnetic waves and self-complementary metasurfaces in recent papers are studied. Some general properties for the transmission and reflection coefficients are derived using linear and circular polarized incident waves. We show a self-complementary metasurface example made of rectangular holes and rectangular patches and the scattering parameters obtained by simulation. This geometry may be used for conversion from circular to linear polarization with any polarization angle, broadband power dividing or birefringence.