A highly transparent polarization-insensitive metamaterial absorber with wideband microwave absorption is presented. The broadband absorption (6.0~16.7 GHz, absorptance > 85%) is achieved using three patterned resistive metasurfaces. The visible light transmittance of the absorber is as high as 85.7%. The thickness of the absorber is 4.42 mm, which is only 0.088 times of the upper-cutoff wavelength. A prototype sample is fabricated and measured to demonstrate its excellent performance. The experimental results agree well with the simulation results. In view of its wide band absorption, high transmittance, low profile, polarization insensitivity and wide incidence angle stability, the presented absorber has a wide range of potential applications.

A transparent metamaterial absorber with broadband microwave absorption and polarization insensitiveness is presented in this paper. Consisting of a two-layer closed square ring, one-layer patch-shaped indium tin oxide films, and a three-layer soda-lime glass substrate, the proposed absorber has advantages of broadband absorption with absorptivity higher than 85% ranging from 4.6 to 18 GHz, transparency, good polarization insensitiveness, wide-incident-angle stability, and high shielding efficiency. A prototype sample is fabricated and measured to demonstrate its excellent performance. The experimental results agree well with the numerical simulations.

In this paper, a thin, broadband and low frequency with high absorption (more than 90% absorption) radar absorber (RA) consisting of magnetic-type material substrate and double period frequency selective surface (FSS) is demonstrated. The geometric parameters were investigated for its contribution towards absorption by the finite-difference time domain (FDTD) method. The effects of incidence angles of electromagnetic radiation were also discussed. The simulation indicates that the use of the double period FSS makes a remarkable increase of operational bandwidth and moves the resonant frequency to the lower frequency comparison with single magnetic radar absorption materials (SMRA). Due to the excellent symmetric nature of the proposed structure, the reflectivity is insensitive to incident angle from 0° to 30°. The reflectance of RA lower than -10 dB (over 90% absorption) is obtained in the whole frequency range of L-band which is 1.5 times wider than the bandwidth of the same thickness SMRA when the structure thickness is only 2.62 mm. The simulation method is verified by comparison with the experiment in the literature. Thus, the presented RA breaks the limitation of the thickness (λ/4) for the traditional low-frequency band absorbing material and has wide application prospect in electromagnetic shielding and low-frequency stealth.