Design and analysis of a compact ultrathin polarization‐ and incident angle‐independent triple band metamaterial absorber

This article reports a compact ultrathin metamaterial absorber with three resonances in S‐band, X‐band, and Ku‐band. The geometry of the proposed absorber consists of a square ring, a splitted square ring, and a plus shaped resonating structure. The plus shaped structure is enclosed within a split ring resonator and it is further enclosed by an outer square ring. The proposed absorber is fabricated on a low cost FR4 substrate of thickness 1 mm that is, 0.011 λlowest (where, λ is the lowest resonating frequency). The size of unit cell is 10 × 10 mm2. It exhibits 99.6%, 99.1%, and 99.1% absorption at 3.4, 9.6, and 13 GHz, respectively. Moreover, the physical insight of the design is explained by surface current distribution and equivalent circuit analysis. Stability of the proposed design is validated with different incident (for transverse electric (TE) and transverse magnetic (TM) modes) angles and different polarization angles. Finally, a prototype of the absorber is fabricated and validated experimentally.