Broadband and Wide-angle Microwave Metamaterial Absorber with Effective EM Wave Absorption in the S-, C-, X- and Ku-band

A broadband microwave metamaterial absorber with wide-angle property is introduced in this paper. The bandwidth of effective absorption (over 90% absorptivity) of the proposed absorber is from 2.2 GHz to 18.4 GHz, covering almost the whole S-, C-, X-, and Ku-band, with relative absorption bandwidth of 157%. The total thickness of the proposed absorber is 15 mm, which corresponds to 0.11λ at the lowest operating frequency. To provide wide-angle and broadband frequency matching, a wide-angle impedance matching layer is used in the unit cell design. The proposed absorber can realize more than 80% absorptivity for TE polarization and more than 90% absorptivity for TM polarization from S-band to Ku-band when the incident angle is less than 50°. Equivalent circuit method is used to analyze the proposed absorber and the circuit model analysis results agree quite well with the numerical full-wave simulation.