Real-Time Controllable and Multifunctional Metasurfaces Utilizing Indium Tin Oxide Materials: A Phased Array Perspective

In this paper, two electrically tunable dual-band reflectarray antennas are designed by the integration of a thin layer of indium tin oxide (ITO) into plasmonic multi-sized and multilayer unit cells. The presented geometries include two gold nanoribbons located next to each other with different widths and backed by a stack of alumina-ITO-metallic ground plane and two pairs of vertically stacked gold nanoribbon-alumina-ITO on a metallic ground plane. The double-resonance nature of the double metal-insulator-metal unit-cells is exploited to achieve two distinct operating frequencies in which the control over phase of the reflected beam is obtained via the tunable gate biasing of ITO. An in-depth phased array analysis is developed with emphasis on the accomplishment of a reconfigurable antenna with robust beam scanning and focusing characteristics. The proposed structures can be considered as dual-band bifunctional reflectarray antenna that can operate at two distinct frequencies in the near-infrared regime with two different functionalities as bending and focusing.