加载电磁带隙EBG反射板的低电磁辐射比吸收率SAR天线

Low specific absorption rate antenna with reflection board of electromagnetic band gap

如何减小移动通信中移动终端电磁信号对人体脑部的影响成为公众关注的焦点之一,电磁带隙(EBG)结构在其禁带内具有阻抗高、反射波与入射波位相相同的特点,可以抑制印刷线路板的表面波改善天线辐射性能,减少进入脑部的电磁信号。在1.8 GHz频段,对加载EBG结构的反射板的天线系统进行了仿真,结果表明,与未加载EBG的天线系统相比,加载EBG结构的偶极天线系统不仅可以保证天线的辐射增益,同时人体脑部电磁波的比吸收率大大降低,加载EBG反射板可以有效抑制人体脑部的电磁场强度;由于天线与反射板的互相耦合,天线的尺度与未加载EBG结构的天线相比尺度变小,同位相反射偶极天线与EBG距离很近,实现了低轮廓天线。

h becomes more and more attention of the public that the research on the reduction of the specific absorption rate （SAR） of electromagnetic radiation on the human brain with the development of the mobile communications. The electromagnetic band gag（EBG） structure has high-impedance in some frequency band and its reflection wave is in-phase with that of the incident wave, so it could suppress the surface waves formed on the printed board and improve antenna＇ s radiation preventing the transmission of electromagnetic wave in the direction of the human head. The simulation is carried out on the antenna with EBG at 1.8 GHz. The results show that comparing with the antenna without EBG structure, the SAR of electromagnetic wave is greatly reduced. Meanwhile, the antenna satisfies the technique indication such as S-parameters, radiation etc. The simulation also show that the antenna＇ s dimension is smaller. Based on the in-phase reflection a low-profile antenna with low SAR is achieved in this paper.