Analog signal processing through space‐time digital metasurfaces

Abstract In the quest to realize analog signal processing using subwavelength metasurfaces, in this paper, we present the first demonstration of programmable time‐modulated metasurface processors based on the key properties of spatial Fourier transformation. Exploiting space‐time coding strategy enables local, independent, and real‐time engineering of not only amplitude but also phase profile of the contributing reflective digital meta‐atoms at both central and harmonic frequencies. Several illustrative examples are demonstrated to show that the proposed multifunctional calculus metasurface is capable of implementing a large class of useful mathematical operators, including 1st‐ and 2nd‐order spatial differentiation, 1st‐order spatial integration, and integro‐differential equation solving accompanied by frequency conversions. Unlike the recent proposals based on the Green’s function (GF) method, the designed time‐modulated signal…