缺陷对左手材料负折射的调控行为

采用电路板刻蚀技术制备左手材料样品，由劈尖法分别研究了无缺陷和引入缺陷时左手材料的负折射特性.实验结果表明，引入两种点缺陷材料与无缺陷材料的功率峰值之比分别为1.035和1.256，且负折射率的绝对值分别增大了9.6%和19.6%；引入空位缺陷材料与无缺陷材料的功率峰值之比最大为1.973，最小为0.364，负折射率的绝对值最大增大了68.3%，最小增大了9.6%.缺陷的存在改变了左手材料周期性结构，形成新的电磁谐振条件，使其负折射率和功率峰值发生了变化，实现了对左手材料负折射率的调控. 关键词： 左手材料 负折射 缺陷

Regulating ability of defects on the negative refraction of left-handed metamaterials

We have investigated the defect effect on negative refraction of the left-handed metamaterials (LHMs). The printed circuit boards with LHMs are fabricated using a shadow mask/etching technique. The negative refraction of wedge-shaped LHMs samples with and without defects is investigated respectively. The experimental result shows that when two kinds of point defects are introduced into the sample, the ratio of the maximum power of samples with point defects to that without defects are 1.035 and 1.256, and the absolute value of the negative refraction index increases by 9.6% and 19.6%, respectively. When three kinds of vacant defects are introduced into the sample, the ratios of the maximum power of samples with vacant defects to that without defects have the highest value of 1.973 and the lowest value of 0.364, and the absolute values of the negative refraction index have increased by 68.33% and 9.6% accordingly. We think that the defect breaks the periodic structure of the sample, resulting in a new condition of the electromagnetism resonance which leads to the changes of the negative refraction index and the maximum power. So we can regulate the negative refraction index of LHMs by adjusting the defects.