Janus Metasurface for Super Radome with Asymmetric Diffusion and Absorption

Metasurface radome is crucial to protect the radiating antenna and control electromagnetic waves flexibly. However, current design methods for metasurface radome merely focus on the single propagation direction, with limited degrees of freedom. Here, a super radome is proposed with a directional scattering response based on Janus metasurface that can realize the phase modulation of y-polarized waves and the amplitude modulation of x-polarized waves with a judiciously designed structure. Both numerical and experimental results illustrate two cross-polarized transmission windows with intensity exceeding 0.9 centered at 10 and 12.2 GHz and two out-of-band invisibility with considerable backward radar cross-section reduction over −10 dB within 9.3–15.4 and 7.5–23.8 GHz when the radome is illuminated by y- and x-polarized waves along negative and positive z directions, respectively. Moreover, the radar cross-section reduction is maintained for off-normal incidence even up to 45°. This method sets up a directional degree of freedom for advanced radome design and demonstrates its enormous potential in developing next-generation stealth antennas.