基于石墨烯的频率可重构微带阵列天线设计

Design of Frequency Reconfigurable Microstrip Array Antenna Based on Graphene

提出一款基于石墨烯开关的频率可重构平面微带阵列天线,该阵列天线单元为添加L型双枝节的矩形金属贴片,枝节和矩形贴片之间加载石墨烯。使用电压调控石墨烯表面阻抗,从而改变电流路径及有效长度,实现工作频率的可重构。首先,对天线单元进行了模拟仿真,结果表明该天线单元可实现1 GHz的频率可调范围,反射系数在4.2,5.2 GHz 2个工作频点处均低于-15 dB。其次,分析了天线单元的L型双枝节和金属贴片的关键参数对天线单元频移范围的影响,并设计了对应的并联微带馈电网络,将该天线单元组成4×4的微带阵列天线。然后对阵列天线进行仿真分析,结果表明,微带阵列天线最大辐射增益拓展至11.53 dBi。最后,根据设计天线进行了实物加工,并在微波暗室内进行了测试,测试结果表明:阵列天线实现了4.05 GHz和5.56 GHz的双频点可重构,最大辐射增益约为9.6 dBi,验证了天线的频率可重构性,证明了该天线在不同的工作频点均具有良好的辐射特性。

In this paper,a frequency reconfigurable microstrip array antenna based on graphene is proposed.The array antenna unit is a rectangular patch loaded with two L-shaped branches,and graphene is loaded between the branches and the rectangular patch.The surface impedance of graphene is regulated by bias voltage to activate or deactivate graphene.This changes the current path and effective length,and therefore realizing the reconfiguration of the resonant frequency.Firstly,the antenna unit is simulated.The simulation results show that the frequency tunable range of the antenna unit is 1 GHz,and the reflection coefficient is lower than-15 dB at the operating frequency 5.2 GHz and 4.2 GHz.Then,the influence of the parameters of the L-shaped branches and patch on the frequency reconfiguration is simulated by analyzing the surface current.The corresponding parallel microstrip feeding network is designed,and the microstrip antenna array is composed of 4×4 units.The maximum radiation gain is extended to 11.53 dBi.Finally,an prototype of the array antenna is fabricated according to the design and measured in a microwave darkroom.The measured results show that the array antenna realizes dual-frequency reconfiguration at 4.05 and 5.56 GHz,and the maximum radiation gain is 9.6 dBi.The frequency reconfiguration of the antenna is verified,and the antenna has good radiation pattern at different operating frequencies.