Metasurfaces have attracted much attention in recent years due to their powerful abilities in manipulating electromagnetic (EM) waves. However, most of the previously reported metasurfaces are incapable of real-time control of full-space EM waves, including transmission, reflection, and absorption at the same time. In this paper, a reconfigurable multifunctional metasurface is proposed that demonstrates real-time control of transmission, absorption, and reflection of EM waves, which can be continuously controlled from total transmission to total reflection, and to perfect absorption. In the case of total reflection, the reflected waves can be further manipulated in a programmable way by changing the digital coding sequences via bias voltages. Meanwhile, the metasurface can independently control vertical and horizontal polarized waves in broadband. The reconfigurable functionalities of the metasurface are validated by experiments, which agree very well with numerical simulations. In addition, a potential application of the reconfigurable multifunctional metasurface in a stealth radome is proposed and demonstrated.

Space‐time modulated metasurfaces enable efficient manipulations of nonlinear harmonics with more degrees of freedom than conventional materials by simply controlling the element geometries and modulation signals. The theoretical analyses reveal that a group of harmonics in reflected waves could be generated by the metasurface under the incidence of monochromatic wave with the rapid change of surface reflectivity, while the fundamental spectrum is greatly suppressed. However, it remains a great challenge to synthesize a high‐quality single‐tone signal for the reflected waves with excellent rejection ratio for higher‐order harmonics, which is highly desired for applications like wireless communications and radar detection. Here, a new scheme to overcome this limit, which experimentally realizes high‐efficiency frequency conversion from the fundamental harmonic to the +1st/−1storder harmonic of reflected waves, and beam shaping based on the space‐time joint coding strategy are proposed. The measured results show that the maximum conversion efficiency is greater than 88%. This design can also find widespread applications in THz frequencies when the active metasurface for periodical phase modulations is further developed.

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Time-domain digital coding metasurfaces have been proposed recently to achieve efficient frequency conversion and harmonic control simultaneously; they show considerable potential for a broad range of electromagnetic applications such as wireless communications. However, achieving flexible and continuous harmonic wavefront control remains an urgent problem. To address this problem, we present Fourier operations on a timedomain digital coding metasurface and propose a principle of nonlinear scattering-pattern shift using a convolution theorem that facilitates the steering of scattering patterns of harmonics to arbitrarily predesigned directions. Introducing a time-delay gradient into a time-domain digital coding metasurface allows us to successfully deviate anomalous single-beam scattering in any direction, and thus, the corresponding formula for the calculation of the scattering angle can be derived. We expect this work to pave the way for controlling energy radiations of harmonics by combining a nonlinear convolution theorem with a time-domain digital coding metasurface, thereby achieving more efficient control of electromagnetic waves.