Adaptive acoustic metasurfaces for the active sound field control Project ID: GA16-11965S Provider: Czech Science Foundation Period: Jan 01, 2016 - Jul 22, 2020 Recipient -- coordinator: -- Prof. Ing. Pavel Mokrý, Ph.D. Co-recepient(s) / PI(s): Institute of Plasma Physics, Czech Academy of Sciences, Prague -- Ing. Pavel Psota Ph.D. Co-investigators from IPP J. Kovačičinová, D. Vápenka, R. Doleček, K. Steiger, M. Šulc Aims of the project: The proposed project is focused on (i) research of fundamental properties of adaptive acoustic metasurfaces designed for the active control of sound field and (ii) on the basic research of methods for measurement of local values of specific acoustic impedance on the outside of the metasurface using digital holographic interferometry. The adaptive acoustic metasurfaces will be constructed as thin curved piezoelectric membranes. Local value of the specific acoustic impedance on the outside of the metasurface will be controlled using a negative impedance converter, gyrator or other type of digital synthetic impedance. Methods to control the sound field and to control the propagation of the acoustic energy through the metasurface will be analyzed. The stability of acoustic properties of metasurfaces in varying conditions will be ennsured by means of adaptive control algorithms.