Research / 2019 / Article / Fig 2

Research Article

Direct Transmission of Digital Message via Programmable Coding Metasurface

Figure 2

Demonstration of the working mechanisms of the channel estimation and optimization algorithms. (a, b) The radiation patterns in the x-z plane for the coding patterns with hardware codes 01010 and 00100, respectively. (c-g) The distance matrices for the 16 digital states obtained under different receiving angels and noise thresholds: (c) at all receiving angles and noise threshold 0; (d) at receiving angles 0°, 5°, 10°, 15°, and 20° and noise threshold 0.3; (e) at receiving angles 0°, 10°, and 30° and noise threshold 0.3; (f) at receiving angles 0°, 5°, 10°, 15°, 20°, 25°, and 30° and noise threshold 0.3; (g) at receiving angles 0°, 5°, 10°, 15°, and 20° and noise threshold 0.6. (h) The distance matrix for the 4 available digital states after the optimization treatment to the case in (g).