Reflective Beam Steering of Metasurface Using Circular Inter-Digitated Self-Phased Pixels/Cells

Metasurfaces (MTSs) are well-known for manipulating electromagnetic (EM) waves by controlling the local phase of subwavelength elements. In this work, we present a reconfigurable MTS (R-MTS) design for reflective beam steering. By introducing the circular inter-digitated self-phased structure as the controlled tunable element in the array, the proposed MTS can dynamically change individual phases of its elements to generate beam steering. Rather than using active circuit components in the design, we use constituent material in the dielectric layer supporting the MTSs' unit elements to achieve tunable phase shifting in an extremely electrically thin (λ0/23.4) profile. As the constituent material permittivity changes, the resonance frequency of the element also changes, which results in a local phase change. The circular inter-digitated self-phased (CID-SP) structure consists of dual-circular-ring, incorporating a meandered slot or interdigitated lines in between, all are integrated over a dielectric layer (used as a constituent material) with metal backing. Key features of our R-MTS design are polarization independence, a miniaturized meta-atom footprint, and an electrically controllable phase response using a tunable material, rather than embedded circuit elements, such as diode. The simulated scattering pattern is shown to able to deflect the beam ±26 degrees with respect to z-axis for any arbitrary polarization. This work paves the way towards the realization of adaptable MTS, which can be digitally reprogrammed to fit different radar and or communication applications.