Topology optimization design of dual-channel metasurface structure with controllable amplitude of retroreflection and mirror reflection

Abstract

For oblique incident electromagnetic waves, the generation of double reflection channels including retroreflection channel is of great significance in improving target recognition performance and navigation performance. In double channel reflection, controlling the ratio of retroreflection to specular reflection is the key to realizing reflection power distribution. In order to realize the control of the proportion of the reflected power in each channel, a topology optimization method for designing the reflective metasurface microstructure with dual channel is proposed in this paper. The implementation mechanism is investigated, physical model of metasurface with dual reflection channel including retroreflection channel is established, and the topology optimization model of metasurface microstructure with specific power ratio of the retroreflection to specular reflection is established. As a numerical example, a dual channel metasurface reflector with a 1∶1 ratio of retroreflection power to specular reflection power is designed for a 10 GHz plane wave in the TE mode with a pitch angle of –30°. The designed metasurface exhibits strong directionality in the retroreflective direction, and the reflection amplitudes in both directions are similar. The retroreflective metasurface with the maximum retroreflection ratio is designed. The retroreflection ratio of the designed metasurface is 0.093. There is no specular reflection or other singular reflection, and the strong reflection on the metasurface is concentrated at –30°. The ratio of the main beam power to the total reflection power is 0.900. The simulated and experimental results verify the feasibility of the proposed method.