刘晓阳　焦新光

摘 要： 根据电磁材料的相关理论，设计出一种由新型谐振器和金属线组成的电磁双负超材料，即介电常数和磁导率同时为负的电磁材料。新型谐振器通过较小谐振腔并联的方式，在较大的单元尺寸下提高了谐振频率，既使该电磁超材料在K波段实现了双负特性，又保证了材料的辐射面积，克服了高频段超材料由于尺寸太小而难以应用的困难。设计出一种K波段的微带天线，将新型谐振器加载在天线上，并用HFSS软件对未加载谐振器和加载谐振器的天线进行仿真对比。仿真结果表明，相比普通天线，加载新型谐振器的微带天线性能得到明显提升，驻波比2 dB以下的带宽增加了58.3%，增益变大，并且由于谐振器对天线副瓣的抑制，提高了天线的方向性。

关键词： 负磁导率； 负介电常数； K波段； 谐振腔； 微带天线

中图分类号： TN822?34 文献标识码： A 文章编号： 1004?373X（2017）05?0093?04

Abstract： According to the correlation theories of the electromagnetic material， an electromagnetic metamaterial with negative permeability and negative permittivity was designed， which is composed of a novel resonator and metal wire. The novel resonator has raised its resonance frequency in a relatively large cell size by means of the way of the small resonant cavity paralle?ling， which can realize the negative permeability and negative permittivity characteristics of the electromagnetic metamaterial at K?band， ensure the radiating area of the material， and overcome the difficulty that it is hard to apply to the high?frequency metamaterial because of its small size. A K?band microstrip antenna was designed， on which the new resonator is loaded. The antennas with the loaded resonator and without the loaded resonator are conducted for simulation comparisons with HFSS. The simulation results show that， in comparison with the common antennas， the performance of the microstrip antenna loaded with the novel resonator has improved obviously， the VSWR below 2 db is increased by 58.3%， the gain is increased as well， and the directivity of the antenna is improved because of the inhibition of the side lobes on the resonator.

Keywords： negative permeability； negative permittivity； K?band； resonance cavity； microstrip antenna

0 引 言

目前，电磁超材料以其奇异的电磁特性受到人们的广泛关注，其中包括负介电材料、负磁导率材料和双负材料。电磁双负材料是指介电常数和磁导率同时为负的人工合成超材料，其理论最早在文献[1]中于20世纪60年代被证实。文献[2]提出周期性排列的导电金属线和金属谐振环（SRR）分别在一定频率下可以实现负介电常数和负磁导率。以此为基礎，文献[3]设计出了一种金属杆和金属谐振环周期性排列的复合材料，最终使其同时呈现出双负特性，从此引发了人们对电磁超材料研究的热潮。……