Numerical Study of an Ultra-Broadband and Polarization Independence Metamaterial Cross-Shaped Fractal Absorber

• Published in: Plasmonics (Norwell, Mass.) Vol. 15; no. 5; pp. 1517 - 1524
• Main Authors: Liu, Juefu, Chen, Jiao, Liu, Huan, Liu, Yuanyuan, Zhu, Lu
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.10.2020; Springer Nature B.V
• Subjects: Absorbers; Absorbers (materials); Absorption; Absorptivity; Bandwidths; Biochemistry; Biological and Medical Physics; Biophysics; Biotechnology; Broadband; Chemistry; Chemistry and Materials Science; Corrosion resistance; Energy harvesting; Finite difference time domain method; Fractals; High temperature; Incidence angle; Iron; Metamaterials; Nanotechnology; Polarization; Self-similarity; Solar energy; Time domain analysis; Metamaterial absorber; Ultra-broadband; Fractal; Polarization independence
• ISSN: 1557-1955; 1557-1963
• DOI: 10.1007/s11468-020-01156-0

A three-dimensional cross-shaped fractal metamaterial absorber with ultra-wide wavelength band, polarization-independence and wide-angle, is numerically investigated by the finite-difference time-domain method. In this absorber, the solar energy is trapped by the cross-shaped fractal of the upper layer, and the Si-ring filled with iron in the middle layer and the wavelength band can be broadened by the self-similarity of fractal structure. The absorber exhibits absorptivity higher than 91% for the wavelengths from 400 to 2000 nm and an absorption bandwidth of about 133%. Furthermore, the proposed absorber realizes polarization independence, and the maximum incident angle is 76°. However, as the iron material applied in the nano-metamaterial absorber (NMA) can be easily oxidized and rusted, it is replaced by nickel with characteristics such as corrosion resistance and high-temperature resistance; thus, an improved NMA is obtained. The improved absorber not only eliminates the corrosion-prone defects of the above proposed structure but also maintains polarization independence and high absorption and widens the angle of incidence up to 79° and thereby can be applied in many areas, such as solar energy harvesting.