Acoustic metamaterials: noise control, Willis coupling and anomalous reflection | Anton Melnikov скачать в хорошем качестве

Acoustic metamaterials: noise control, Willis coupling and anomalous reflection | Anton Melnikov

Anton Melnikov, Fraunhofer Institute for Photonic Microsystems IPMS. Microwave Seminar at The Department of Physics & Engineering, ITMO | 05/18/2020 Title: "Acoustic metamaterials: noise control, Willis coupling and anomalous reflection" --- Abstract: Acoustic metamaterials are structures with exotic acoustic properties, with promising applications in noise mitigation, acoustic beam steering, focusing, and impedance matching. In recent years, many different designs have been proposed and investigated, whereas, not all of them are usable in practice due to expensive manufacturing, impedance mismatch, or thermos viscous losses. However, a simple c-shape meta-atom can overcome most of the issues and allows designing efficient acoustic metamaterials. In the first part of the talk, an acoustic metamaterial capsule for noise control based on a c-shape metaatom is presented including numerical and experimental results. The second part deals with Willis coupling of acoustic scatterers, an acoustic analogy of bianisotropy. Here it is illustrated how Willis coupling can be tailored between zero and its maximum bound using c-shape meta-atoms. Furthermore, this part includes experimental results demonstrating Willis coupling magnitude of 90% of the limit given by the conservation of energy. Finally, the current progress on designing acoustic metagratings with high efficiency anomalous reflection using c-shape meta-atoms is reported. 00:00:00 Speaker presentation 00:01:06 Start of the talk 00:02:33 Introduction to acoustics 00:09:25 Introduction to acoustic waves 00:12:19 Acoustic metamaterials 00:15:16 Question from Alexey Slobozhanyuk about the unit cell manufacturing process. 00:15:50 Concepts for noise mitigation 00:20:39 C-shaped unit cell acoustic metagrating and metacapsule 00:27:21 Application of metamaterial capsule for noise control 00:30:31 Willis coupling of acoustic scatterers 00:33:08 Possible applications of Willis coupling 00:37:16 Theoretical boundary of Willis coupling 00:39:26 Question from Alexey Shcherbakov on non-bianisotropic scattering 00:41:06 Material designs for maximizing Willis coupling 00:45:01 Question from Ivan Toftul on losses 00:47:33 Willis coupling in C-shaped resonators 00:55:56 Question from Alexey Slobozhanyuk about measurement error 00:59:47 Anomalous acoustic reflection with metagratings 01:06:47 Summary 01:09:24 Question from Mikhail Zubkov on anomalous reflection 01:10:06 Questions from Alexey Slobozhanyuk on noise absorbers and prototype manufacturing quality 01:15:31 Questions from Mikhail Zubkov on the realtion of the mata-atom size to its properties and Willis coupling bandwidth The Department of Physics and Engineering of ITMO University (Saint Petersburg, Russia) hosts online weekly seminars to discuss recent scientific achievements of researchers from all over the world with a wide audience. The topics include experimental (Optical seminar) and theoretical (Theoretical seminar) aspects of nanophotonics, solid-state physics, material science, as well as design and applications of radiofrequency structures and devices (Microwave seminar). Upcoming and past events can be found at https://physics.itmo.ru/en/events #MicrowaveSeminar #ITMO #новыйфизтех   / metalab     / physics_ifmo     / meta.lab