Independent dual-beam control based on programmable coding metasurface

Abstract

Programmable metasurfaces incorporating with tunable materials or components are emerging as an attractive option to realize reconfigurable manipulations of electromagnetic (EM) behaviors in real-time. Many efforts have been devoted to the realization of active EM manipulations of the metasurface and significant progress has been achieved, showing their unprecedented ability to arbitrarily manipulate wavefronts in dynamic functions. However, most of the existing multi-beam metasurfaces are based on passive building blocks, only possessing one or a few functions, which cannot provide tunable and independent multi-beam control, thus limiting their further uses in wireless communications. Hence, a 1-bit coding metasurface with high-efficiency, programmable, and independent multi-beam control is proposed in this paper, providing dynamic EM responses with real-time reconfigurability, and controlled by external digital circuits through direct current (DC) bias networks. Specifically, the meta-atom loaded with PIN diodes is employed to achieve independently tunable phase characteristics, thus complex EM functions can be manipulated by redistributing the spatial phases of the metasurface. Symmetric/asymmetric independent dual- and multi-beam manipulations are analyzed theoretically and simulated by EM software. Then as an experimental verification, a metasurface consisting of 14 × 14 meta-atoms is fabricated and tested in a standard microwave anechoic chamber, and the measured results accord well with the simulations. The proposed metasurface has promising ability to generate the arbitrary and independent multi-beams, which may largely enhance the information capacity of the metasurfaces, offering untapped potentials in wireless communication systems.