Predicting scattering properties of a periodic-type diffuser with a rectangular profile

The periodic-type diffuser is a kind of important acoustical structures in architectures. It is usually beneficial to improve diffusion and prevent echoes. However, sometimes it also leads to side effects of coloration because of its periodically arranged structure. Here, a grating effect-based method was developed to predict scattering properties of a periodic-type diffuser with a rectangular profile most widely used in room acoustics. Firstly, the derivation of the grating effect-based method was introduced in detail. This method was capable of calculating the scattering energy of reflection waves using the geometrical parameters of the diffuser without time-consuming numerical simulations. Then, the calculation and comparison of scattering coefficients in examples showed that the proposed method has a good accuracy to predict scattering properties. Lastly, the scattering properties of the periodic-type diffuser with a rectangular profile were analyzed using the grating effect-based method. The results demonstrated that the periodic-type diffuser with a rectangular profile has properties of missing order scattering and symmetric scattering; based on these special properties, the periodic-type diffuser with a rectangular profile can not only be more reasonably used in room acoustics, but also play an important role in other engineering fields, such as, spatial filtering, spectrum control, and noise control.