物理学报2016，Vol.65Issue(15)：15401-1-15401-7,7.DOI:10.7498/aps.65.154101
单层高效透射型相位梯度超表面的设计及实验验证∗
Zhuang Ya-Qiang Wang Guang-Ming† Zhang Chen-Xin Zhang Xiao-Kuan Zong Bin-Feng Ma Wei-Dong Wang Ya-Wei
摘要
Abstract
Polarization characteristic is an important feature of electromagnetic (EM) wave. Manipulating polarization state and controlling propagation direction of EM wave by phase-gradient metasurface (PGM) have become a research hotspot in recent years. However, using transmissive PGM for polarization manipulation often suffers a low efficiency. To alle-viate this problem, multilayered structure was utilized. However, it often suffered bulky volume and design complexity. Therefore, engineering a thin high-efficiency transmissive PGM with polarization manipulation is a pressing and challeng-ing issue. In this paper, a single-layer high-efficiency transmissive PGM with cross-polarization conversion and anomalous refraction is designed. To illustrate the working mechanism, the PGM is comprehensively investigated through theo-retical analysis, EM simulations and experimental measurements. The unit cell evolving from an electric-field-coupled resonator is carefully designed to exhibit a Pancharatnam-Berry phase gradient. Each rotated element irradiated sepa-rately by the normally-incident left-handed circularly polarized (LHCP) and right-handed circularly polarized (RHCP) waves is simulated in CST microwave studio. The results show that the cross-polarization transmission magnitude keeps over 0.9 and does not change as the rotation angle varies. Moreover, the phase shift is twice the rotation angles and the direction of refracted beam is opposite under the above two different polarizations. In addition, the cross-polarization conversion ratio is above 0.9 from 14 GHz to 15.8 GHz. On the premise of high transmission magnitude, the phase of the cross-polarized transmission can be freely manipulated via varying axis orientation. By spatially arranging six unit cells in rotation angle steps of 30◦, a PGM with a phase difference of 60◦ between adjacent unit cells is designed. As is well known, linearly-polarized (LP) EM waves can be decomposed into LHCP and RHCP waves with equal amplitudes. Therefore, an LP wave through the PGM will be separated into two counterpropagating CP waves. The high-efficiency anomalous refraction of the PGM is verified from simulated near-field electric field distributions and far field normal-ized power patterns. The simulated refracted angle is 33.5◦, which is in accordance with the theoretical designed value (33.75◦). Moreover, the transmissive power intensity spectrum under the normally-incident LP waves is simulated and measured. The simulated and measured results are in good agreement with each other, showing that the transmitted wave is perfectly split into two counterpropagating waves from 14.9 GHz to 15.3 GHz. Compared with the available transmissive PGMs, our proposed PGM features high efficiency and thin structure with only single layer, making the proposed PGM a promising alternative to manipulating propagation and polarization of EM waves.关键词
相位梯度超表面/奇异透射/高效Key words
phase-gradient metasurface/anomalous refraction/high efficiency引用本文复制引用
庄亚强,王光明,张晨新,张小宽,宗彬锋,马卫东,王亚伟..单层高效透射型相位梯度超表面的设计及实验验证∗[J].物理学报,2016,65(15):15401-1-15401-7,7.基金项目
国家自然科学基金(批准号:61372034)资助的课题 （批准号:61372034）
