Impedance Regulation of Graphene-Loaded Branch for Frequency-Reconfigurable Antenna With Enhanced Radiation Efficiency
Junfeng Li, Bian Wu, Jia-Qi Zhou, Chi Fan, Ying Liu
Abstract
In this letter, a composite impedance network is proposed and loaded on the loop antenna to realize the frequency-reconfigurable function and balance the radiation efficiency of the antenna. First, a frequency-reconfigurable antenna is designed, employing a branch loaded with a single piece of graphene nanosheet, and the working principle of the antenna is analyzed. Then, the impedance characteristics of the graphene-loaded branch are analyzed, and a composite impedance network is proposed to increase the impedance of the branch and applied in the frequency-reconfigurable antenna design to balance the radiation efficiency. Finally, the proposed antenna is fabricated and measured, the working frequency of the antenna can be tuned from 2 to 2.4 GHz continuously, and the radiation efficiency of the antenna at low frequencies exhibits a significant improvement compared to the configuration where the branch is loaded with only one piece of graphene nanosheet.