Electromagnetic smart screen with extended absorption band at microwave frequency

▶ An electromagnetic smart screen was designed based on the periodic patch structure and lossy dielectric substrate. ▶ ESS can be a function of a few design parameters, namely, the dielectric permittivity, magnetic permeability and thickness of substrate. ▶ The relative dynamic bandwidth can be as large as 40%. Electromagnetic smart screen (ESS) containing conductive patch array loaded with pin diodes was investigated experimentally and numerically. Reflectivity of smart screen was measured with free space method and calculated through finite element simulation. The reflectivity of ESS with thickness about 2.3 mm can be as low as −40 dB and the absorption peak can be tuned from 3 GHz to 4 GHz. The relative absorption bandwidth (less than −7.5 dB) can be as large as 40% which is much wider than non-tunable metamaterials.