High-accuracy beam generation and scanning using reconfigurable coding metasurface

Metasurface technology has attracted widespread attention, owing to its remarkable capability to control electromagnetic properties. In this paper, we design a reconfigurable reflective metasurface array operating at 5 GHz for beam generation and scanning based on coding metasurface. Field programmable gate array (FPGA) is equipped for switching the states of PIN (positive-intrinsic-negative) diodes loaded on the metasurface in real-time, resulting in a 180° phase difference. To obtain multi-beam radiation and high-accuracy beam steering, the coding sequence to produce the target radiation pattern is calculated by an algorithm program. We design the fitness function of a genetic algorithm (GA) to optimize the sequence corresponding to the target directions. The simulation result shows that with the accuracy of 1°, the proposed metasurface is capable of generating multi-beam and scanning two-dimensional beams within the 50° range. Further, we fabricate and measure a prototype sample of 15 × 15 elements, which is verified feasible by comparing the measured result and the simulation. This work demonstrates the great potential of applying this reflective metasurface to wireless communication or radar.