Brewster's angle

Bandwidth (computing)

Materials science

Refractive index

Brewster

Telecommunications

Metamaterial

Computer science

Tunable metamaterials

Physical chemistry

Polarization (electrochemistry)

Physics

Metamaterial absorber

Dielectric

Optics

Molar absorptivity

Resonator

Fractional bandwidth

Chemistry

Optoelectronics

Permittivity

Scientific Reports

In this paper, a wide bandwidth angle- and polarization-insensitive symmetric metamaterial (MM) absorber for X and Ku band is proposed. For both normal and oblique incidence in TEM mode, the proposed unit cell shows high absorption at different polarizing angles due to structural symmetry. A four-fold resonator was introduced in the unit cell to enhance the bandwidth. The performance of the proposed absorber is determined by both full-wave simulations and measurements. The simulated and measured absorptions are almost similar at normal incidence with 94.63%, 95.58%, 97% and 75.58% at 11.31 GHz, 14.11 GHz, 14.23 GHz, and 17.79 GHz respectively. At 45° for these frequencies, the absorptions are 95.47%, 97.2%, 97.12% and 75.29% respectively. For 90°, the absorptions are similar to those for 45° except 98.15% for 14.21 GHz. At all these angles and resonance frequencies, either permittivity or permeability was found negative, as a result, the refractive index was negative revealing metamaterial characteristics of the unit cell. Along with high absorptivity and wide incidence angle insensitivity up to 90°, a total of 1.42 GHz of absorption bandwidth was achieved, which is better than recent similar works with FR4 substrate.

Wide Bandwidth Angle- and Polarization-Insensitive Symmetric Metamaterial Absorber for X and Ku Band Applications