Resonant Beam Steering and Carpet Cloaking Using an Acoustic Transformational Metascreen

We invoke the Huygens principle to derive dispersion characteristics of acoustic transformational metasurfaces that can deflect parallel wavefronts in a desired direction. We also propose a dual-Lorentz resonator whose aperture fields can be tuned by geometrical changes to implement a particular phase with unity reflection coefficient. The proposed metascreen is designed by our arranging slightly detuned Lorentz cavities that generate the necessary interference to compensate for the incident wavefronts. Since a complete 0-2π range of the reflection phase is achieved, the metascreen can steer a beam across the full horizon. Moreover, since the proposed dual resonator has subwavelength dimensions, the metascreen is capable of high-resolution imaging, which is an essential trait in cloaking and deceptive acoustics. Successful demonstration of acoustic beam steering and carpet cloaking is done for a wavelength of 790 mm with the help of full-wave simulations.