Patent attributes
A method for designing a surface pattern for an impedance surface which results in a position-dependent target impedance of said impedance surface, and the impedance surface having the position-dependent target impedance radiates a desired first-type electromagnetic field radiation in reaction to being irradiated by a second-type electromagnetic field radiation. The method includes obtaining a first modal representation on the basis of the first-type electromagnetic field radiation in terms of a set of base modes that are chosen in accordance with a model function of the position-dependent target impedance, and obtaining a second modal representation on the basis of the second-type electromagnetic field radiation and the model function in terms of the set of base modes. The method further includes obtaining a first position-dependent quantity indicative of the position-dependent target impedance on the basis of the first modal representation and the second modal representation by determining values for a plurality of parameters of the model function for maximizing an overlap between the first modal representation and the second modal representation, and obtaining, as the surface pattern, a second position-dependent quantity indicative of geometric characteristics of the impedance surface on the basis of the first position-dependent quantity and a relationship between geometric characteristics of the impedance surface and corresponding impedance values.