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为克服晶体管或者电子开关在太赫兹频段上的不足,将石墨烯应用于太赫兹可重构天线中。根据石墨烯表面电导率模型,分析了其面电导率随频率、化学势和温度的变化关系,以及表面阻抗与化学势的关系,证明了石墨烯应用于可重构天线的优势。设计了一款外加偏置电压的石墨烯方向图可重构天线,天线结构包括金属偶极子(有源振子)以及作为反射器/引向器的金属和石墨烯振子。利用改变化学势(外加偏置电压)的方式调节无源振子中石墨烯贴片的阻抗状态,改变电流分布,使得无源振子在反射器与引向器之间转换。通过HFSS软件的仿真优化,天线实现了在0°,±32°,±37°,±40°方向的辐射,工作频率在(1.07±0.06)THz范围内,相对带宽大于7.84%,辐射效率最高达89.96%。7个辐射方向中,最大辐射增益达8.312dB。该天线具有体积小、重量轻、调控方式简便且稳定的优点,在太赫兹波束可重构天线领域有一定的应用价值。
To overcome the shortage of transistors or electronic switches in the terahertz band, graphene is used in terahertz reconfigurable antennas. According to the surface conductivity model of graphene, the relationship between the surface conductivity and frequency, chemical potential and temperature, as well as the relationship between surface resistance and chemical potential, and the advantages of graphene for reconfigurable antennas are analyzed. A graphene pattern reconfigurable antenna with bias voltage is designed. The antenna structure includes metal dipole (active dipole) and metal and graphene oscillator as reflector / director. By changing the chemical potential (plus a bias voltage), the impedance of the graphene patch in the passive oscillator is adjusted and the current distribution is changed so that the passive oscillator is switched between the reflector and the director. Through the simulation and optimization of HFSS software, the antenna achieves radiation at 0 °, ± 32 °, ± 37 ° and ± 40 ° with an operating frequency of (1.07 ± 0.06) THz and a relative bandwidth of more than 7.84% with the highest radiation efficiency Up to 89.96%. Of the 7 radiation directions, the maximum radiation gain reached 8.312 dB. The antenna has the advantages of small size, light weight, simple and stable regulation and control method and has certain application value in the field of terahertz beam reconfigurable antennas.