Dual-band and dual-polarization coding metasurface for independent controls of phases and amplitudes with cross-polarized transmissions in two bands

Abstract

An ideal metasurface design encompasses the control of all the degrees of freedom of electromagnetic (EM) waves. Here, we present a digital coding metasurface optimized for dual-band operations (in K and Ka band) for orthogonal polarizations. The proposed design allows for independent and the simultaneous control of the phases and amplitudes of cross-polarized transmitted waves in both (±z) direction. We employ the design to demonstrate distinct functionalities, which include single and multiple vortex beams carrying orbital angular momentum (OAM) of orders ‘l=+1’ and ‘l=−1’, and beam shaping with the feature of intensity modulations in distinct operating bands. We tested a prototype of the proposed design in the standard EM measurement environment, and the measured results agree well with the corresponding simulations. We remark that the digital coding metasurfaces presented here should improve the capacity of multiple-input multiple-output (MIMO) optical communication systems for power allocations in multi-band operations.