Design of acoustic artificial surfaces with abnormal reflection with helmholtz resonator arrays forming phase slope

In this study, an artificial surface design with abnormal reflection was made by creating a phase gradient ranging from 0 to 2π with series decoupled Helmholtz resonator arrays. It has been shown that the change in the phase gradient can be adjusted only depending on the neck width of the second resonator. The phase gradients calculated depending on the geometric parameters of the resonators were studied with two-dimensional models using the Finite Element Method with the COMSOL Multiphysics software package. Periodic resonator arrays were used to create an artificial surface that reflects abnormally at angles of 45 and 60 degrees perpendicular to the incoming wave. The fact that the proposed artificial surface thickness has a thinner structure than the wavelength used (about 1/3 of the wavelength) is important in terms of reducing the size of acoustic devices. In addition, with an example sensor application, it was shown that the abnormal reflection angle varies depending on the temperature (0.056 deg/K). The fact that the reflection angle changes depending on the ambient parameters will shed light on various sensor designs to be designed at high frequencies. Keywords: Acoustic Metasurfaces, Helmholtz Resonators, Phase Gradient, Generalized Snell's Law