Full Manipulation of the Power Intensity Pattern in a Large Space‐Time Digital Metasurface: From Arbitrary Multibeam Generation to Harmonic Beam Steering Scheme

Abstract

Beyond the scope of space-coding metasurfaces, space-time digital metasurfaces can substantially expand the application scope of digital metamaterials. In this paper, by adopting a superposition operation of terms with unequal coefficients, Huygens' principle, and a proper time-varying biasing mechanism, some useful closed-form formulas in the class of large digital metasurfaces are presented for predicting the absolute directivity of scatted beams. Moreover, in the harmonic beam steering scheme, by applying several suitable assumptions, two separate expressions are derived for calculating the exact total radiated power at harmonic frequencies and total radiated power for scattered beams located at the end-fire direction. Despite the simplifying assumptions applied, it is proved that the provided formulas can still be a good and fast estimate for developing a large digital metasurface with a predetermined power intensity pattern. The effect of quantization level and metasurface dimensions as well as the limitation on the maximum scan angle in harmonic beam steering are addressed. Several demonstrative examples numerically demonstrated through MATLAB software and the good agreement between simulations and theoretical predictions are observed. The author believes that the proposed straightforward approach discloses a new opportunity for various applications such as multiple-target radar systems and communication.

A Time-Modulated Transparent Nonlinear Active Metasurface for Spatial Frequency Mixing

“…As a type of surface EM component, a metasurface [9][10][11] with artificially designed structures exhibits novel properties for spatial EM wave manipulation, such as multibeam generation [12], beam steering [13], vortex beam generation [14] and so on. Furthermore, the EM response of the metasurface can be electrically adjusted by loading active devices on every unit cell [15][16][17][18], i.e., the smallest atom of a metasurface.…”

Deep neural network-based automatic metasurface design with a wide frequency range

“…Metamaterials, defined as artificial media composed of engineered subwavelength periodic or nonperiodic geometric arrays, have witnessed significant attention due to their exotic properties capable of modifying the permittivity and permeability of materials 1 – 3 . Today, just two decades after the first implementation of metamaterials by Smith et al 4 who unearthed Veselago’s original paper 5 , metamaterials and their 2D counterpart, metasurfaces, have been widely used in practical applications such as, but not limited to, polarization conversion 6 , 7 , reconfigurable wave manipulation 8 , 9 , vortex generation 10 , 11 , and perfect absorption 12 , 13 .…”

A wide-angle and TE/TM polarization-insensitive terahertz metamaterial near-perfect absorber based on a multi-layer plasmonic structure

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