Compact Acoustic Retroreflector Based on A Mirrored Luneburg Lens

Abstract

We propose and demonstrate a compact acoustic retroreflector that reroutes probing signals back towards the source with minimal scattering. Gradient refractive index (GRIN) acoustic metamaterials, based on Archimedean spiral structures, are designed to fulfill the required refractive index profile. The experiments show that the compact acoustic retroreflector, whose radius is only approximately one wavelength, works in an incident angular range up to 120 degrees over a relatively broad bandwidth of about 27% of the central frequency. Such compact acoustic retroreflectors can be potentially applied in pulse-echo based acoustic detection and communication, such as unmanned aerial vehicle (UAV) sonar systems, robotic ranging detectors, ultrasonic imaging systems.

10 pages, 5 figures, Journal paper

References in corpus (4)

• Wavefront Modulation and Subwavelength Diffractive Acoustics with an Acoustic Metasurface
• Plasmonic Luneburg and Eaton Lenses
• An omnidirectional retroreflector based on the transmutation of dielectric singularities
• Sonic Gradient Index Lens for Aqueous Applications

Cited by in corpus (7)

• Ultrasound Beam Steering with Flattened Acoustic Metamaterial Luneburg Lens
• Switchable bifunctional metasurfaces: nearly perfect retroreflection and absorption at THz regime
• Broadband Acoustic Collimation and Focusing using Reduced Aberration Acoustic Luneburg Lens
• Acoustic imaging by three-dimensional acoustic Luneburg meta-lens with lattice columns
• Topological transition in spiral elastic valley metamaterials
• Bi-functional Structural Luneburg Lens for Broadband Structural Wave Cloaking and Waveguide
• Realization of Flattened Structural Luneburg Lens Based on Quasi-Conformal Transformation