Characterization of scattering coefficients of periodical surfaces by numerical analysis

In order to quantify scattering coefficients of wall surfaces, the reverberation room method for measuring the random-incidence values has been standardized by ISO 17497-1. On the other hand, the incidence-angle-dependent values can be obtained in a free field by the directivity correlation method, which is suitable for numerical simulation with the boundary element method. In this paper, characteristics of scattering coefficients of 1D periodical surface are numerically investigated, focusing on the effects of shape, height and period of surface profile. Additionally, 1:4 scale model measurements are performed for typical profiles in order to verify the numerical results. Finally, the optimal height-toperiod ratios, maximizing random-incidence scattering coefficient, are found for sinusoidal, triangular and rectangular profiles, respectively.