One-dimensional periodic surfaces are present in many constructions. When a wave encounters a surface of this kind with oblique incidence, a scattering phenomenon is produced. This can not be modelled accurately by standard specular reflection coefficient models. In order to improve the planning tools, mainly for indoor environments, specific models have been developed and tested by comparison with actual measurements. Three different plastic materials have been used in the measurement campaign, and their surfaces were carved in various shapes: flat, cosine, triangular, and rectangular waves. The measurement frequency was 5.8 GHz, which falls into a band assigned to wireless local area networks. The scattering pattern in the incidence plane has been modelled applying the classical formulation of Beckmann by segments. This option provides improved results, compared to the direct application of the model.