@Article{icces.2023.09236,
AUTHOR = {Zhuoma Wang, Ruoyan Li, Wenjing Ye, Yijun Liu},
TITLE = {A 1-D Non-Local Metasurface-Based Broadband Acoustic Diffuser},
JOURNAL = {The International Conference on Computational \& Experimental Engineering and Sciences},
VOLUME = {27},
YEAR = {2023},
NUMBER = {4},
PAGES = {1--2},
URL = {http://www.techscience.com/icces/v27n4/55199},
ISSN = {1933-2815},
ABSTRACT = {An acoustic diffuser refers to a device that spreads sound energy uniformly in all directions. Such a device 
plays a very important role in architectural acoustics, i.e., concert halls and auditoriums. Many designs such 
as the wellknown Schroeder diffusers [1] have been proposed and developed throughout the past several 
decades. However, most of these conventional designs achieve uniform sound diffusion by using different 
air trenches to create a phase shift profile following a specific sequence such as maximum length sequence 
or quadratic residue sequence derived from the number theory [1,2]. As such, these diffusers have 
considerable thicknesses, which makes them difficult to be applied in certain practical settings. Recently, 
metasurface-based diffusers have been proposed. These local resonator-based diffusers can significantly 
reduce the thickness, resulting in ultrathin diffusers that potentially have high commercial values [3,4]. 
However, resonators naturally have narrow bands. Hence, designing high-performance broadband 
resonator-based diffusers is challenging. In this talk, we will present a general design methodology based 
on genetic algorithm (GA) and topology optimization (TO) for the design of broadband metasurface-based 
acoustic diffusers. The diffusion performance is set explicitly as the design objective and a nonlocal design 
is carried out with the consideration of the interaction between different parts of the diffuser. Hence, optimal 
designs are no longer limited to designs based on specific phase shift profiles and high-performance can be 
achieved. Several designs targeting at different frequency ranges will be presented. Numerical results show 
that the proposed designs have comparable or even better performance compared to Schroeder diffusers
over a broad frequency range and wide incident angles, but with much reduced thicknesses.},
DOI = {10.32604/icces.2023.09236}
}