宽频带小单元异向介质设计与负折射特性验证(英文)

Investigation of negative refraction property for a compact LHM with broad bandwidth

本文设计了一种宽频带小单元的异向介质,经过优化,其带宽达到2．6 GHz,而其结构单元可以达到的最小长度只有0．1个工作波长。首先对该异向介质的传输特性进行了深入研究,结果表明,在9．2～11．8 GHz频段上该异向介质存在一个通带,而就是在这个频率上,该异向介质的负磁导率部分和负介电常数部分均为阻带,该结果与已报道的异向介质传输特性相一致,因此在一定程度上确定了本研究设计结果的正确性。同时,为了得到更为肯定的答案,研究中进一步针对该异向介质的负折射特性展开研究,结果表明,同样是在9．2～11．8 GHz,可以清晰地观察到由该异向介质斜折射到空气中的电磁波束与入射波束位于法线同侧。本研究提出的小单元异向介质使设计性能更为优良的微波器件,譬如小型化谐振腔,滤波器,以及高增益天线等,成为可能,而这些微波器件将在各种微波仪器中被广泛地应用。

In this paper, a compact left-handed metamaterial （LHM） with miniaturized unit cell and broad bandwidth is proposed. By optimization design, its bandwidth is up to 2.6 GHz, and the smallest electrical length of the LHM unit cell is only 0.1 of the working wavelength at the lowest operating frequency where the LHM is available. The transmission parameters （S21） are given for the scattering of the normally incident plane wave from the LHM with both the ENG （epsilonnegative） part and MNG （Mu-negative） part, LHM with only the ENG part and LHM with only the MNG part. Results show that there is a pass-band only for the LHM with both ENG and MNG within 9.2 GHz - 11.8 GHz. In addition, the negative refraction characteristic of the wedge-shaped LHM are investigated using full-wave simulation, it is shown that the designed LHM exhibits negative refraction in a broadband of 9.2 GHz - 11.8 GHz range, and the existence of the LHM is proven. The designed compact LHM provides a good opportunity to design and fabricate devices or components, which are used in MW measurements frequently, with better performance such as miniaturized cavity resonator, miniaturized filter, and antenna with better directionality and so on.