School of Electrical and Electronics Engineering, Chung-Ang University, Heukseok-Dong, Dongjak-Gu, 156-756, Republic of Korea.
Sci Rep. 2017 Jun 9;7(1):3204. doi: 10.1038/s41598-017-03591-2.
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.
本文提出了一种使用八边形环（ECS）的宽入射角不敏感超材料吸收体。在正入射下，由于其对称的几何形状，该吸收体在不同的偏振下表现出高吸收率。在斜入射下，横向电场（TE）和横向磁场（TM）偏振的零反射条件不同。然而，由于 ECS 的存在，该吸收体在 TE 和 TM 偏振的斜入射下表现出高吸收率。该吸收体的性能通过全波仿真和测量进行了验证。在 TM 和 TE 偏振下，在镜面角的模拟吸收率超过 90%，在约 9.26GHz 时频率变化小于 0.7%，入射角可达 70°。我们在具有 20×20 个单元的印刷电路板上构建了所提出的吸收体，并在自由空间中进行了实验演示。在正常入射下，对于所有偏振角，在 9.26GHz 时镜面角的测量吸收率接近 98%。当入射角从 0°变化到 70°时，在 TE 和 TM 偏振下，在 9.26GHz 时镜面角的测量吸收率在 92%以上。
