Scaling of Air-Coupled Metagratings for Beam Steering

In this paper we report on the investigation and comparison of the behavior of high frequency metagratings scaled to lower frequencies. These metagratings allow unconventional manipulation of acoustic waves. We specifically investigate how adjustments influence at low frequencies, where thermoviscous effects have minimal impact. The metagratings are designed based on optimized geometrical properties and the effects of different fabrication methods on their performance are examined by means of sound field measurements. The results show that scaling of metagratings is successful, but the optimization approach applied at high frequencies is not transferable to low frequencies without corrections.