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

Abstract

AbstractBeyond 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.