Fu Xiaojian, Zeng Xinxi, Cui Tie Jun, Lan Chuwen, Guo Yunsheng, Zhang Hao Chi, Zhang Qian
State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing 210096, China.
Synergetic Innovation Center of Wireless Communication Technology, Southeast University, Nanjing 210096, China.
Sci Rep. 2016 Aug 9;6:31274. doi: 10.1038/srep31274.
We investigate the resonant modes of split-ring resonator (SRR) metamaterials that contain high-permittivity BST block numerically and experimentally. We observe interesting mode-jumping phenomena from the BST-included SRR absorber structure as the excitation wave is incident perpendicularly to the SRR plane. Specifically, when the electric field is parallel to the SRR gap, the BST block in the gap will induce a mode jumping from the LC resonance to plasmonic resonance (horizontal electric-dipole mode), because the displacement current excited by the Mie resonance in the dielectric block acts as a current channel in the gap. When the electric field is perpendicular to the gap side, the plasmonic resonance mode (vertical electric-dipole mode) in SRR changes to two joint modes contributed simultaneously by the back layer, SRR and BST block, as a result of connected back layer and SRR layer by the displacement current in the BST dielectric block. Based on the mode jumping effect as well as temperature and electric-field dependent dielectric constant, the BST-included SRR metamaterials may have great potentials for the applications in electromagnetic switches and widely tunable metamaterial devices.
我们通过数值模拟和实验研究了包含高介电常数BST块的分裂环谐振器（SRR）超材料的谐振模式。当激发波垂直入射到SRR平面时，我们从包含BST的SRR吸收器结构中观察到了有趣的模式跳跃现象。具体而言，当电场平行于SRR间隙时，间隙中的BST块会导致模式从LC谐振跃迁至等离子体谐振（水平电偶极模式），这是因为介质块中的米氏谐振激发的位移电流在间隙中充当了电流通道。当电场垂直于间隙侧时，由于BST介质块中的位移电流将后层和SRR层连接起来，SRR中的等离子体谐振模式（垂直电偶极模式）会转变为由后层、SRR和BST块同时贡献的两种联合模式。基于模式跳跃效应以及温度和电场依赖的介电常数，包含BST的SRR超材料在电磁开关和广泛可调谐超材料器件的应用中可能具有巨大潜力。
