The concept of fractal geometry, introduced by Mandelbrot has been explored in diverse areas of science, including acoustics [1]. First part of this work relates the properties of far-field Fraunhofer region diffraction in wave acoustics for characterizing reflection on a periodic regular indented plane. Diffusion prediction of a self-similar structure, the Sierpinski carpet, is then developed through the computation of its spatial Fourier transform. Scattering intensity computation results show that after propagation of a coherent plane wave through the structure, the resulting acoustical field displays fractal properties itself, showing a self-similar structure of the reflected signal. This computational approach of the Sierpinski carpet's scattering properties will lead us to develop, in a near future, an acoustic angular scattering measurement process, applied to a Sierpinski tetrahedron 3-D scale model.