Ultra‐Broadband Metamaterial Absorber Based on Multilayer Resistive Film Frequency Selective Surface

Abstract In this paper, an ultra‐broadband metamaterial absorber is proposed based on multilayer resistive film frequency selective surface (RFSS). Each dielectric‐resistive layer consists of polymethacryimide (PET) and resistive film, achieving effective absorption through multilayer loss. Both strip‐shaped and square‐shaped resistance film layers exhibit significant symmetry. Simulated results reveal that the −10 dB operating bandwidth of metamaterial absorber (MMA) is from 1.07 to 11.84 GHz with a fractional bandwidth of 166% and a thickness of only 0.105 λ_L. It covers the L‐, S‐, C‐, and X‐bands with strong low‐frequency absorption to broaden the bandwidth. The equivalent circuit model is established based on Costa's model, serving as the theoretical analysis. Accurate models for each resistive film surface configuration are derived, modeling the resistive film surface as a series RLC circuit. Additionally, the designed metamaterial absorber is fabricated and measured in microwave anechoic chamber, and the measurement results are generally consistent with the simulated ones, further validating the effectiveness of the design.