Wang Shuang, Wang Song, Li Quan, Zhao Xiaoli, Zhu Jianyu
School of Electronic Engineering, Tianjin University of Technology and Education, Tianjin 300222, China.
National-Local Joint Engineering Laboratory of Intelligent Manufacturing Oriented Automobile Die & Mould, Tianjin University of Technology and Education, Tianjin 300222, China.
Materials (Basel). 2018 Oct 19;11(10):2036. doi: 10.3390/ma11102036.
We proposed and fabricated a flexible, planar, U-shape-modified structure metamaterial (MM) that was composed of two metallic pattern layers separated by a polyimide layer, where each metallic pattern layer consists of two U-shaped split ring resonators (USRRs). The coupling effect between the two USRRs in the same metallic layer was vital to the formation of dual toroidal dipole (TD) resonances. The measured and simulated results showed that both low quality factor (Q) (1.82) and high Q (10.31) TD resonances were acquired synchronously at two different frequencies in the MMs by adjusting the distance between the two coplanar USRRs. With the interaction of the USRRs, the energy levels of the USRRs were split into inductance-capacitance (LC)-induced TD resonance at low frequency and dipole-induced TD resonance at high frequency. Thus, the electric multipole interaction played an important role in determining the energy level of the TD resonance. The better strength of the high frequency TD resonance can be confined to an electromagnetic field inside a smaller circular region, and thus, a higher Q was obtained. In order to investigate the TD mechanism more in depth, the power of the electric dipole, magnetic dipole, electric circular dipole, and TD were quantitatively calculated. Dual TD MMs on a freestanding substrate will have potential applications in functional terahertz devices for practical applications.
我们提出并制造了一种柔性、平面、U形改性结构超材料（MM），它由两层金属图案层组成，中间隔着一层聚酰亚胺层，其中每个金属图案层由两个U形开口环谐振器（USRR）组成。同一金属层中两个USRR之间的耦合效应对于双环形偶极（TD）共振的形成至关重要。测量和模拟结果表明，通过调整两个共面USRR之间的距离，在超材料中的两个不同频率处同步获得了低品质因数（Q）（约1.82）和高品质因数（约10.31）的TD共振。在USRR的相互作用下，USRR的能级在低频处分裂为电感 - 电容（LC）诱导的TD共振，在高频处分裂为偶极诱导的TD共振。因此，电多极相互作用在确定TD共振的能级方面起着重要作用。高频TD共振的更好强度可以限制在较小圆形区域内的电磁场中，从而获得更高的Q值。为了更深入地研究TD机制，对电偶极、磁偶极、电圆偶极和TD的功率进行了定量计算。独立基板上的双TD超材料在实际应用的功能性太赫兹器件中将具有潜在应用。
