零折射率超材料对喇叭天线波前相位的改善

为改善喇叭天线波前相位,获得更高的增益,提出一种3层金属网格零折射率超材料结构,将其加载到喇叭天线口径上。理论分析和提取的等效折射率表明,在7.1 GHz附近,该结构的电磁波的频率接近等离子体频率,从而使得其等效折射率接近于零,并通过劈尖仿真验证了这一零折射零的特性。当其作为喇叭天线的覆层时,喇叭天线的波前相位由球面波被调制为均匀平面波,方向图波束角变窄、旁瓣降低,并且增益提高2.6 dB。这种零折射率超材料结构调制喇叭天线波前相位的作用,为改善喇叭天线的波前相位从而实现更高增益提供一种思路,有一定的应用前景。

Improvement of the Horn Antenna's Wave-front Phase Using Zero-index Metamaterial

This paper, in order to improve the front wave of the horn antenna and to get the higher gain, presents a three-layered metallic grid meta-material structure. Both the theory analysis and the retrieved effective refraction show that the zero index refraction occurs at about 7.1 GHz. A prism experiment is carried out to verify the properties of this zero refraction. When this structure is used as the superstratum of a horn antenna, the front wave phase of the antenna is changed from spherical wave to plane wave, the angle of the beam-width becomes narrower and the gain of the antenna is increased by 2.6 dB. The effect of zero-index metamaterial can improve the front wave of the antenna, which provides a method for realizing the higher gain of horn antennas. This metamaterial will have some applications in practice.