Abstract-Ultrathin metasurface-based carpet cloak for terahertz wave

Minggui Wei, Quanlong Yang, Xueqian Zhang, Yanfeng Li, Jianqiang Gu, Jiaguang Han, and Weili Zhang

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-14-15635

Ultrathin metasurfaces with local phase compensation deliver new schemes to cloaking devices. Here, a large-scale carpet cloak consisting of an ultrathin metasurface is demonstrated numerically and experimentally in the terahertz regime. The proposed carpet cloak is designed based on discontinuous-phase metallic resonators fabricated on a polyimide substrate, offering a wide range of reflection phase variations and an excellent wavefront manipulation along the edges of the bump. The invisibility is verified when the cloak is placed on a reflecting triangular surface (bump). The multi-step discrete phase design method would greatly simplify the design process and is probable to achieve large-dimension cloaks, for applications in radar and antenna systems as a thin, lightweight, and easy-to-fabricate solution for radio and terahertz frequencies.

© 2017 Optical Society of America

Abstract-Terahertz carpet cloak based on a ring resonator metasurface

B. Orazbayev, N. Mohammadi Estakhri, M. Beruete, and A. Alù

Phys. Rev. B 91, 195444 – Published 29 May 2015

https://journals.aps.org/prb/abstract/10.1103/PhysRevB.91.195444

In this work we present the concept and design of an ultrathin (λ/22) terahertz (THz) unidirectional carpet cloak based on the local phase compensation approach enabled by gradient metasurfaces. A triangular surface bump with center height of 4.1 mm (1.1λ) and tilt angle of 20° is covered with a metasurface composed of an array of suitably designed closed ring resonators with a transverse gradient of surface impedance. The ring resonators provide a wide range of control for the reflection phase with small absorption losses, enabling efficient phase manipulation along the edge of the bump. Our numerical results demonstrate a good performance of the designed cloak in both near field and far field, and the cloaked object mimics a flat ground plane within a broad range of incidence angles, over 35° angular spectrum centered at 45°. The presented cloak design can be applied in radar and antenna systems as a thin, lightweight, and easy to fabricate solution for radio and THz frequencies.

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