摘要

Electromagnetic (EM) waves are the most versatile and widely adopted physical layer technology for underground wireless communication networks (UWCNs). However, they are not suitable for underground communication especially when coils are buried in soil. Magneto-inductive (MI) communication is a promising technique for UWCNs; it is not affected by large propagation delays, multipath propagation, and fading. Furthermore, MI communication has lower transmitting power and smaller antenna size than EM. A near-field low-power communication device with an electrically small antenna for low-frequency UWCNs is proposed in this study. The device can be easily buried underground. The proposed device is analyzed in terms of basic communication metrics, i.e., magnetic field intensity, bandwidth, path losses, and received power. Comparison of these four metrics shows that the experimental data closely match those of the theoretical model, and the maximum communication distance of 28.5 m, can be achieved. Moreover, according to the experimental results of our device, we further propose the modified received power model. Results show that the device exhibits good performance and can be used as a stand-alone module in directional underground wireless communication.