Researchers create a tunable membrane
"metamaterial" with near-zero density, effectively recreating the
quantum tunneling effect for sound waves
Controlling sound transmission with density-near-zero
acoustic membrane network
Abstract
(July 14, 2015) We
demonstrate a design of two-dimensional density-near-zero (DNZ) membrane
structure to control sound transmission. The membrane structure is
theoretically modeled as a network of inductors and capacitors, and the
retrieved effective mass density is confirmed to be close to zero at the
resonance frequency. This scheme proposes a convenient way to construct the
unit cell for achieving DNZ at the designed frequency. Further simulations
clearly demonstrate that the membrane-network has the ability to control sound
transmission such as achieving cloaking, high transmission through sharp
corners, and high-efficient wave splitting. Different from the
phononic-crystal-based DNZ materials, the compact DNZ membrane-network is in
deep subwavelength scale and provides a strong candidate for acoustic
functional devices.