埋地式无线传感器的磁感应通信天线模型

(山东科技大学 电子信息工程学院,山东 青岛 266590)

磁感应通信; 超材料; 铁氧体; 埋地式无线传感器

Magnetic induction antenna model for buried wireless sensor
DONG Yu-ying,HAO Jian-jun,MOU Yong-fei

(College of Electronic and Information Engineering,Shandong University of Science and Technology,Qingdao 266590,China)

megnetic induction communication; metamaterial; ferrite; buried wireless sensor

DOI: 10.13800/j.cnki.xakjdxxb.2019.0319

备注

磁感应通信方式由于其传播特性不受介质电学特性影响、无多径效应、天线尺寸小等优点,非常适合在地层介质中或水下环境传输信号使用。然而其在近场衰减快的特点,也限制了传输距离。为增加通信距离,在Zhi Sun超材料天线模型的基础上,提出了一种改进的小型超材料天线模型,即在螺旋线圈内部增加铁氧体棒,随后又对球形超材料壳内用弱磁材料进行了填充。用Comsol对此模型进行了仿真,并比较了大半径线圈模型、大半径铁氧体模型、小半径超材料模型以及改进的小半径超材料模型在不同的填充物条件下接收端天线感应的磁场强度。仿真结果表明相同传播距离条件下,改进的小半径超材料天线方案的磁通信系统的接收端天线处的磁场强度最高; 如果只对接收磁天线超材料壳内加填充材料而发送端天线壳内不加填充材料的情况下,改进的小型超材料天线模型的接收天线处耦合磁场强度相比大半径的线圈模型时接收天线的磁耦合强度提高了约20 dB.

Due to its advantages of being immune to propagation medium's electrical characteristics and multi-path effect with small-sized antenna, magnetic induction communications are suitable for signal transmission in underground or underwater. However, fast propagation attenuation in near field limits its transmission distance. Aimed at increasing its communication range, an improved antenna model based on metamaterials, i.e., a model with a coil wound on ferrite rod in spiral is proposed. And further spherical metamaterial shell is filled with weak-magnetic material. The model is simulated using Comsol. The magnetic fields induced by the large radius coil model, the large radius coil with ferrite rod model, the small radius metamaterial model and the improved small radius metamaterial model with different fillings compared respectively. Simulation results show that the magnetic field intensity induced by the improved small radius metamaterial antenna model is the highest among aforementioned 4 models. And when the receiver antenna are filled with the weak-magnetic materials while the sender antenna filled nothing, the magnetic field intensity in receiver end induced by the improved small-sized metamaterial antenna model is enhanced by about 20dB of compared to that of the large radius coil antenna.