Investigation on microwave virtual beam-forming method of optical window

The separation technology of optical and electromagnetic signal of optical window, known as transparent electromagnetic shielding technology, is important in fields such as communication, defense and aerospace. Particularly, in the fields of aerospace and defense, the instruments for optical detection are widely equipped by aircraft and weapon, which require that the optical windows must shield harmful electromagnetic wave,have highly optical transmission and has excellent imaging performance. To realize radar cross section optimization or stealth function without changing the base of optical windows, it is urgent to develop new optical/electromagnetic functional materials. We proposed a patternring method for electromagnetic metamaterial based on metal mesh (EMMM) and designed optically transparent resonant units with tunable scattering characteristics in microwave band. The optical window with spherical cap surface was designed by using generalized Snell's law to mimic microwave scattering characteristics of double-metal inclined plate. Numerical results validate the achievement of virtual beam shaping for the optical window with spherical cap surface at 19 GHz. And the vertically incident electromagnetic waves are modulated to the directions (54.4°, 0.0°) and (54.4°, 180.0°), which match that of the target metal inclined plate with (50.0°, 0.0°) and (50.0°, 180.0°). The patterned EMMM strategy can flexibly regulate the microwave scattering characteristics of the optical/electromagnetic window, and the research results have important application prospects in the fields of radar cross section reduction, electromagnetic protection, intelligent communication and wearable devices.