In this paper, a broadband metamaterial absorber with a fractional bandwidth of 126.88% was presented. The characteristic mode theory was used to guide the design of the absorber. According to the analysis of characteristic mode and characteristic current, the resistance value of resistive films can be determined. The different modal information obtained through parameter changes can also better guide the design of the absorber. To study its operation mechanism, the equivalent impedance and surface current distribution of the proposed absorber have been analyzed. The final simulation and measurement results show that the proposed absorber has a wide absorbing bandwidth which is from 3.21 to 14.35 GHz, and the absorptivity is greater than 90%, covering the S, C, X, and Ku bands. In addition, for TE and TM polarization, it can achieve an absorptivity of more than 85% at 45° oblique incident and has good angular stability. Hence, the absorber has great potential applications in the field of electromagnetic stealth technology and Radar Cross Section reduction.

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Recent years, reconfigurable metasurfaces become research hotspots since they can manipulate electromagnetic (EM) waves dynamically and flexibly. Achieving cost-effective and energy-efficient wireless communications via reconfigurable intelligent surfaces (RISs) are attractive in various application sceneries. In this work, a +45°-polarized dual-band reconfigurable metasurface with beam steering ability is proposed to combat with signal attenuation for wireless communications. Through varying the bias voltages of the integrated varactors in the specially designed meta-atom, 0 and π phase responses have been excited around both 2.4 GHz and 5.8 GHz. Taking advantage of this unique feature, we proposed a 1-bit coding RIS device which provides dual-band application. To validate the proposed concepts, a reconfigurable metasurface composed of 16×16 elements was fabricated and measured. The measurement results agree well with simulation, which promise the proposed prototype a good candidate for future intelligent communications.

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