Design of a broadband multifunctional switchable absorber/reflector based on active frequency selective surfaces

Abstract

Metamaterial absorbers are candidates for stealth systems due to their excellent wave modulation capabilities. With the rapid development of radar detection technology, the switching ability of metamaterial absorbers is becoming more demanding. A broadband multifunctional switchable absorber/reflector based on active frequency selective surfaces (AFSS) is presented in this paper. The proposed structure comprises an absorbing layer, a switching layer, and a ground with air spacers sandwiched between each layer. The PIN diodes can realize significant broadband conditioning performance between absorption and reflection functions by switching four operating states: ‘00’, ‘01’, ‘10’, and ‘11’. The bias network of this structure features horizontal and vertical configurations that independently coordinate the two polarization directions. It is worth noting that the bias network of the designed structure is very simple to minimize the impact on the structure. Distributions of surface current, an equivalent circuit model, and structural parameters are analyzed for a better professional insight into the working mechanism of the absorber/reflector. Finally, a prototype is fabricated and measured to verify the simulation.