Abstract
In this paper, a wide incidence angle-insensitive metamaterial absorber is proposed using eight-circular-sector (ECS). Under normal incidence, the proposed absorber shows high absorptivity at different polarizations due to its symmetric geometry. Under oblique incidence, zero-reflection conditions for transverse electric (TE) and transverse magnetic (TM) polarization are different. Nevertheless, the proposed absorber shows high absorptivity under oblique incidence of both TE and TM polarization due to ECS. The performance of the proposed absorber was demonstrated with full-wave simulation and measurements. The simulated absorptivity at the specular angles exceed 90% and the frequency variation is less than 0.7% at approximately 9.26 GHz up to a 70° incidence angle in both TM and TE polarization. We built the proposed absorber on a printed-circuit board with 20 × 20 unit cells, and we demonstrated its performance experimentally in free space. The measured absorptivity at 9.26 GHz for the specular angles is close to 98% for all polarization angles under normal incidence. As the incidence angle is varied from 0° to 70°, the measured absorptivity at 9.26 GHz for the specular angles remain above 92% in both TE and TM polarization.
Highlights
The absorptivity of an MM absorber depends on the incident polarization and angle
We successfully demonstrated that the absorptivity for the specular angle of the proposed metamaterial absorber is insensitive to the incident angle of both transverse electric (TE) and transverse magnetic (TM) polarization
Because of the novel ECS design, the proposed absorber is insensitive to incidence angles of both TE and TM polarization
Summary
An EM wave incident onto an MM surface is reflected and transmitted. High absorptivity can be achieved by minimizing both the reflection coefficient Γ(ω) and the transmission coefficient T(ω), because the absorptivity A(ω) is calculated as[19]. When the length one side of the unit cell (P) is increased from 6 mm to 12 mm, the resonant frequency is not changed, and peak impedance is decreased. (d) Measured reflectivity, transmissivity, and absorptivity of the proposed MM absorber under normal incidence after calibration Free-space measurement setup for (a) normal incidence and (b) oblique incidence. (c) Measured S-Parameters of the absorber and a copper plate under normal incidence before calibration. (d) Measured reflectivity, transmissivity, and absorptivity of the proposed MM absorber under normal incidence after calibration
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
