A rigorously stated synthesis problem of inhomogeneous stationary and quasistationary impedance planes, which reflect a homogeneous flat wave in the given direction at the required polarization with a frequency shift, is solved. The impedance distribution law is obtained in the explicit form. Restrictions on class of realizable scattering patterns for passive impedance are formulated; formulas for the reflection coefficient of the flat wave reflected by the inhomogeneous impedance plane are developed. Bistatic and monostatic scattering patterns are considered.