Broadband Metamaterial for Nonresonant Matching of Acoustic Waves
Abstract
Unity transmittance at an interface between bulk media is quite common for polarized electromagnetic waves incident at the Brewster angle, but it is rarely observed for sound waves at any angle of incidence. In the following, we theoretically and experimentally demonstrate an acoustic metamaterial possessing a Brewster-like angle that is completely transparent to sound waves over an ultra-broadband frequency range with .100% bandwidth. The metamaterial, consisting of a hard metal with subwavelength apertures provides a surface impedance matching mechanism that can be arbitrarily tailored to specific media. The nonresonant nature of the impedance matching effectively decouples the front and back surfaces of the metamaterial allowing one to independently tailor the acoustic impedance at each interface. On the contrary, traditional methods for acoustic impedance matching, for example in medical imaging, rely on resonant tunneling through a thin antireflection layer, which is inherently narrowband and angle specific.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 28, 2012
- Accession Number
- ADA568707
Entities
People
- A. Alu
- A. D. Mathias
- G. D'aguanno
- K. Q. Le
- M. J. Bloemer
- N. Aközbek
- N. Mattiucci
- R. Trimm