Achieving Directive Radiation and Broadband Microwave Absorption by an Anisotropic Metasurface

Simultaneously integrating electromagnetic absorption and wavefront-shaping into a single metasurface with flat and low profile is crucial for many practical applications both in science and engineering community. Here, by introducing lossy components to properly design the impedance of metasurface, we propose an anisotropic metasurface capable of broadband absorption and high-efficient wavefront manipulation, which is sensitive to the excitation of different polarizations. As a practical example, we present a flat metasurface reflector to achieve high-directional radiation with reduced backward scatterings. When a standard waveguide antenna is used to illuminate the metasurface, the reflected wavefront is shaped to directive beam across X-band in microwave regime, with the gain reaches about 25 dBi around 10 GHz. Under the illumination of an orthogonally polarized wave, the incident power is dissipated by the chip resistors to achieve broadband and high-efficient microwave absorption. Experiments are carried out to validate the design principle, and good agreements are observed between the measured and simulated results.